Journal articles: 'Upper Lakes Shipping Limited' – Grafiati (2024)

Abstract:

The European zebra mussel (Dreissena polymorpha) is now firmly established in the lower Great Lakes and in isolated locations in the upper Great Lakes. Dispersal is aided by high fecundity, a planktonic larval stage, and ability of the mussel to be transported via shipping and recreational boating. Almost all waterbodies in Ontario which are downstream of established colonies or which can be reached through boating are vulnerable to invasion. However, there are ecological requirements (derived from European literature) which limit successful zebra mussel reproduction. Using data from over 6000 inland lakes in the province, we have prepared maps which show the distribution of pH, calcium, and major access routes and which indicate our estimated potential for success or failure of zebra mussel colonization. The utility of the maps is dependent on the validity of the ecological requirements for successful development of zebra mussel larvae, which were developed in Europe. There is a need to test the chemical requirements of the zebra mussel in North American waters.

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Abstract. The Himalayan region are home to the world’s youngest and largest mountains, and origins of major rivers systems of South Asia. The present work highlight the importance of remote sensing (RS) data based precipitation and terrain products such as digital elevation models, glacier lakes, drainage morphology along with limited ground data for improving the accuracy of hydrological and hydrodynamic (HD) models in various Himalayan river basins such as Upper Ganga, Beas, Sutlej, Teesta, Koshi etc. The satellite based rainfall have mostly shown under prediction in the study area and few places have are also showing over estimation of rainfall. Hydrological modeling results were most accurate for Beas basin, followed by Upper Ganga basin and were least matching for Sutlej basin. Limited ground truth using GNSS measurements showed that digital elevation model (DEM) for carto version 3.1 is most accurate, followed by ALOS-PALSAR 12.5 DEM as compared to other open source DEMs. Major erosion and deposition was found in Rivers Bhagirathi, Alakhnanda, Gori Ganga and Yamuna in Uttarakhand state and Beas and Sutlej Rivers in Himachal Pradesh using pre and post flood DEM datasets. The terrain data and river cross section data showed that river cross sections and water carrying capacity before and after 2013 floods have changed drastically in many river stretches of upper Ganga and parts of Sutlej river basins. The spatio-temporal variation and evolution of glacier lakes was for lakes along with GLOF modeling few lakes of Upper Chenab, Upper Ganga, Upper Teesta and Koshi river basin was done using time series of RS data from Landsat, Sentinel-1 and Google earth images.

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The multi-objective optimal operation and the joint scheduling of giant-scale reservoir systems are of great significance for water resource management; the interactions and mechanisms between the objectives are the key points. Taking the reservoir system composed of 30 reservoirs in the upper reaches of the Yangtze River as the research object, this paper constructs a multi-objective optimal operation model integrating four objectives of power generation, ecology, water supply, and shipping under the constraints of flood control to analyze the inside interaction mechanisms among the objectives. The results are as follows. (1) Compared with single power generation optimization, multi-objective optimization improves the benefits of the system. The total power generation is reduced by only 4.09% at most, but the water supply, ecology, and shipping targets are increased by 98.52%, 35.09%, and 100% at most under different inflow conditions, respectively. (2) The competition between power generation and the other targets is the most obvious; the relationship between water supply and ecology depends on the magnitude of flow required by the control section for both targets, and the restriction effect of the shipping target is limited. (3) Joint operation has greatly increased the overall benefits. Compared with the separate operation of each basin, the benefits of power generation, water supply, ecology, and shipping increased by 5.50%, 45.99%, 98.49%, and 100.00% respectively in the equilibrium scheme. This study provides a widely used method to analyze the multi-objective relationship mechanism, and can be used to guide the actual scheduling rules.

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Using two independent procedures, we estimate relative contributions of in-lake alkalinity generation to total basin alkalinity budgets for drainage lakes in selected regions of the Eastern United States. The first method is based on the assumption of approximately equal areal rates of alkalinity production by watersheds and lakes, and uses watershed area to lake area ratio as a direct estimator of relative akalinity contributions. The second approach is based on existing models for in-lake alkalinity generation estimated from sulfate retention. Projections from the two methods are comparable, and show that for most drainage lakes in Northeastern United States, Southern Blue Ridge Province, and Upper Midwest, in-lake alkalinity generation is a minor contributor to net basin alkalinity production, contributing [Formula: see text] of total net basin alkalinity production in typical watersheds in any of the regions. The close agreement between the two procedures lends support to the use of watershed area to lake area ratio as a convenient estimator of relative alkalinity sources requiring only map-derived parameters. Regional assessment of current or future effects of acidic deposition on surface water chemistry in the Northeastern United States, the Southern Blue Ridge Province or other areas dominated by drainage lakes with high watershed to lake area ratio would not appear to be seriously comprised by use of models limited to consideration of terrestrial processes. In areas such as the Upper Midwest which are characterized by high proportions of seepage lakes or for lakes with long hydrologic residence times, in-lake processes and hydrologic influences must be considered.

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We examined genetic population structure in 3253 sea lampreys (Petromyzon marinus) sampled at 53 sites in northeastern North America and the British isles. Hierarchical F-statistics of allozyme frequencies indicated that genetic divergence from lake to lake and river to river was greater than divergence among sites within fakes or rivers and also greater than that attributable to the separation of landlocked freshwater from coastal anadromous systems. Lampreys from different lakes varied considerably in the amount of spatial differentiation evident. New York freshwater populations of uncertain invasion history were no more genetically differentiated than were recently introduced upper Great Lakes populations. The apparent reproductive isolation of lampreys in Lake Erie from Lake Ontario populations, despite canal connections, suggests that movement is limited between lakes. Future studies should determine the cause so that management techniques to restrict movement can be developed to control populations.

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The ratio of the areas of a terminal lake to its total basin provides a geomorphological measure, which characterises the geobotanical state of water limited climates. A minimalist model of this lake area ratio is introduced combining the water balances of lake and land, the Budyko–Schreiber rainfall–runoff chain over land and, as a closure, the land and lake potential evaporation to be of similar magnitude. The following results are analysed. (i) Model diagnostics quantify a dryness threshold separating water from energy limited climate regimes, which coincides with an upper bound for the area ratio of terminal lakes to remain hydrologically closed. (ii) Model validations for Qinghai Lake and Lake Chad demonstrate model and observed water flux budgets to be in close agreement. (iii) Finally, a paleo-climate sensitivity study for Lake Chad demonstrates that the minimalist model appears to be a viable tool for future and paleo-climate estimates based on lake area ratio changes only and a single reference water flux. Furthermore, a stochastic interpretation of the rainfall–runoff chain allows estimates of water flux variability.

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In 2013, Dinkin reported an unexpectedly sharp dialect boundary in northern New York between the communities of Ogdensburg and Canton in St. Lawrence County: Ogdensburg exhibited the Northern Cities Vowel Shift (NCS) and very little evidence of the low back merger, while Canton showed low back merger nearing completion and no NCS. This article investigates the nature of this dialect boundary via new sociolinguistic interview data from eight neighboring communities: four along the St. Lawrence River and four 25 miles south of it. An east-west division is observed in merger incidence: the four communities to the west, including Ogdensburg, show relatively robust lot-thought distinction, though apparent-time trends toward merger exist; east of Ogdensburg, the merger is much more advanced. A similar sharp boundary may hold for the NCS raising of trap (though the data are spottier due to the NCS’s obsolescence). The geographical sharpness of this boundary suggests that it is not due merely to socioeconomic differences between communities. It may be due to historical patterns of transportation: in the nineteenth century, Ogdensburg was the easternmost navigable point of the upper St. Lawrence River, meaning communities east of Ogdensburg were not directly accessible to the Great Lakes shipping network.

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ABSTRACT Palynofacies analysis was carried out on 92 core samples from the fluvio-deltaic Middle to Upper Triassic Mungaroo Formation, Northern Carnarvon Basin, Western Australia. The analyses demonstrate that each depositional environment (“depofacies”) sampled has a characteristic palynofacies assemblage reflecting the varied origins, transport, sorting, and preservation histories of organic particles in sediments. The sampling covered a wide range of depofacies identified in fluvial channel, floodplain, crevasse splay, distributary channel, and tidal zone paleoenvironments and included laminated to massive mudstones and siltstones, cross-bedded sandstones, immature pedogenically altered paleosols, and coals. Although each depofacies has a characteristic palynofacies association, there is a high degree of variability within and overlap between preparations. Black-opaque particles were the dominant component in active fluvial, crevasse, and distributary channels. In contrast, palynomorphs, brown wood particles, and cuticle were more common in abandoned channels, floodplain lakes, and other lower-energy environments. The composition of palynomorphs also varies greatly between depofacies due to factors including the bioproductivity of the surrounding vegetation source area, water-table levels, preservation potential, and the fluid dynamic properties of organic particles. The depofacies were grouped into five “process regimes” (active channels, abandoned channels, lakes and periodically flooded areas, paleosols and swamps, tidal mudflats) based on their dominant depositional process. Depofacies in the same process regime tended to have similar palynofacies associations. Active channels yielded similar assemblages irrespective of whether they were fluvial, crevasse, or distributary channels because their dominant characteristic is high flow energy, which encourages the bypass of finer-grained particles, enhances the mechanical degradation of plant debris, and may inhibit local vegetation growth. Organic particles found in lower-energy environments (e.g., floodplain lakes) are on average larger, more elongate, and better preserved than particles found in high-energy environments (e.g., active channels). Although this study was restricted to samples from the upper Samaropollenites speciosus and lower Minutosaccus crenulatus biostratigraphic zones in a geographically limited area, its results are not influenced by the specific taxonomic composition of the vegetation but by the physiographic structure of surrounding plant communities; this suggests that palynofacies analysis could be used to distinguish depositional environments in deltaic settings from other stratigraphic intervals.

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Abstract. Microbial methanogenesis in sediment plays a crucial role in CH4 emission from freshwater lake ecosystems. However, knowledge of the layer-depth-related changes of methanogen community structure and activities in freshwater lake sediment is still limited. The present study was conducted to characterize the methanogenesis potential in different sediment-layer depths and the vertical distribution of microbial communities in two freshwater lakes of different trophic status on the Yunnan Plateau (China). Incubation experiments and inhibitor studies were carried out to determine the methanogenesis potential and pathways. 16S rRNA and mcrA genes were used to investigate the abundance and structure of methanogen and archaeal communities, respectively. Hydrogenotrophic methanogenesis was mainly responsible for methane production in sediments of both freshwater lakes. The layer-depth-related changes of methanogenesis potential and the abundance and community structure of methanogens were observed in both Dianchi Lake and Erhai Lake. Archaeal 16S rRNA and mcrA genes displayed a similar abundance change pattern in both lakes, and the relative abundance of methanogens decreased with increasing sediment-layer depth. Archaeal communities differed considerably in Dianchi Lake and Erhai Lake, but methanogen communities showed a slight difference between these two lakes. However, methanogen communities illustrated a remarkable layer-depth-related change. Order Methanomicrobiales was the dominant methanogen group in all sediments, while Methanobacteriales showed a high proportion only in upper layer sediments. The trophic status of the lake might have a notable influence on the depth-related change pattern of methanogenesis activity, while the methanogen community structure was mainly influenced by sediment depth.

Abstract:

North America’s Great Lakes contain 21% of the planet’s fresh water, and their protection is a matter of national security to both the USA & Canada. One of the greatest threats to the health of this unparalleled natural resource is invasion by non-indigenous species, several of which already have had catastrophic impacts on property values, the fisheries, shipping, and tourism industries, and continue to threaten the survival of native species and wetland ecosystems. The Great Lakes Invasives Network is a consortium (20 institutions) of herbaria and zoology museums from among the Great Lakes states of Minnesota, Wisconsin, Illinois, Indiana, Michigan, Ohio, and New York created to better document the occurrence of selected non-indigenous species and their congeners in space and time by imaging and providing online access to the information on the specimens of the critical organisms. The list of non-indigenous species (1 alga, 42 vascular plants, 22 fish, and 13 mollusks) to be digitized was generated by conducting a query of all fish, plants, algae, and mollusks present in the database of GLANSIS – the Great Lakes Aquatic Nonindigenous Species Information System – maintained by the National Oceanic and Atmospheric Administration (NOAA). The network consists of collections at 20 institutions, including 4 of the 10 largest herbaria in North America, each of which curates 1-7 million specimens (NY, F, MICH, and WIS). Eight of the nation’s largest zoology museums are also represented, several of which (e.g., Ohio State and U of Minnesota) are internationally recognized for their fish and mollusk collections. Each genus includes at least one species that is considered a Great Lakes non-indigenous taxon – several have many, whereas others have congeners on “watchlists”, meaning that they have not arrived in the Great Lakes Basin yet, but have the potential to do so, especially in light of human activity and climate change. Because the introduction and spread of these species, their close relatives, and hybrids into the region is known to have occurred almost entirely from areas in North America outside of the Basin, our effort will include non-indigenous specimens collected from throughout North America. Digitized specimens of Great Lakes non-indigenous species and their congeners will allow for more accurate identification of invasive species and hybrids from their non-invasive relatives by a wider audience of end users. The metadata derived from digitized specimens of Great Lakes non-indigenous species and their congeners will help biologists to track, monitor, and predict the spread of invasive species through space and time, especially in the face of a more rapidly changing climate in the upper Midwest. All together consortium members will digitize >2 million individual specimens from >860,000 sheets/lots of non-indigenous species and their congeneric taxa. Data and metadata are uploaded to the Great Lakes Invasives Network, a Symbiota portal (GreatLakesInvasvies.org), and ingested by the National Resource for Advancing Digitization of Biodiversity Collections (ADBC) (iDigBio.org) national resource. Several initiatives are already in place to alert citizens to the dangers of spreading aquatic invasive species among our nation's waterways, but this project is developing complementary scientific and educational tools for scientists, students, wildlife officers, teachers, and the public who have had little access to images or data derived directly from preserved specimens of invasive species collected over the past three centuries.

Abstract:

We evaluated patterns of denitrification and factors effecting denitrification in the upper Mississippi River. Measurements were taken over 2 years, during which river discharge ranged from record flooding to base flow conditions. Over the period of study, average denitrification enzyme activity was highest in backwater lakes and lowest in the main channel. Throughout the study reach, highest denitrification enzyme activity occurred during fall and lowest occurred in winter. Rates during spring floods (2001) were only slightly higher than during the preceding winter. Mean unamended denitrification rates ranged from 0.02 (fall 2001 in backwaters) to 0.40 µg N·cm–2·h–1 (spring 2001 in backwaters). Laboratory experiments showed that denitrification rates increased significantly with addition of NO3– regardless of sediment C content, while rates increased little with addition of labile C (glucose). Denitrification in this reach of the upper Mississippi River appears to be NO3– limited throughout the growing season and the delivery of NO3– is strongly controlled by river discharge and hydrologic connectivity across the floodplain. We estimate that denitrification removes 6939 t N·year–1 or 6.9% of the total annual NO3– input to the reach. Hydrologic connectivity and resultant NO3– delivery to high-C sediments is a critical determinant of reach-scale processing of N in this floodplain system.

Abstract:

Abstract. Floodplain lakes (FPLs) constitute a very important element of river valleys, both in terms of ecology and hydrology. Dynamic physicochemical, morphometric and biological changes of lake waters are determined by the variability of the functional periods of lakes: limnophases, potamophases and inundations. This paper presents factors that shape long-term dynamics of the frequencies and durations of potamophases and limnophases in 20 selected FPLs. The study area included the left fraction of the Bug River valley located at the European Union's eastern border stretched along countries like Poland, Ukraine, and Belarus. The analysis covered the water years 1952 to 2013. Assigning the value of Limnological Effective Rise (LER) was essential for determining the functional periods for each of the study lakes. The dynamics of the phenomenon was analysed using volatility indicators, while factors determining functional periods were distinguished using Principal Component Analysis (PCA). Results showed that short (0–8 days) and medium-length limnophases were observed most frequently during the study period. In the case of potamophases they most often lasted from 8 to 30 days, continuously. Double-mass curves showed four periods of increasing significance of one of the functional phases: 1952–1962 (limnophases), 1963–1982 (potamophases), 1983–1997 (limnophases) and 1998–2013 (potamophases). A variability that was observed in each floodplain lake under study resulted from two main factors: water input and lake basin morphometry. The major role in FPLs' input was played by potamic supply (inflow of water from the parent river), which was a derivative of Bug River water stages and discharge. Atmospheric precipitation played a smaller role. However, the role of local precipitation was marginal in relation to precipitation in the upper part of the Bug River catchment. Spatial variability of the frequencies and durations of potamophases and limnophases was also associated with the topography of the floodplain lake catchments. Hydrological connection to the river favoured (confluent lakes) or limited (contrafluent and contrafluent–confluent lakes) the frequencies of potamophases in the study period of 62 years.

Abstract:

Abstract. We present a new method of modelling the growth of supraglacial lakes at the western margin of the Greenland ice sheet, based on routing runoff estimated by a regional climate model across a digital elevation model (DEM) of the ice sheet surface. Using data acquired during the 2003 melt season, we demonstrate that the model is 19 times more likely to correctly predict the presence (or absence) of lakes than it is to make incorrect predictions, within an elevation range of 1100 to 1700 metres above sea level (m a.s.l.), when compared with MODIS satellite imagery. Of the 66% of observed lake locations which the model correctly reproduces, the simulated lake onset day is found to be correlated with that observed with a Pearson correlation coefficient of 0.76. Our model accurately simulates maximum cumulative lake area with only a 1.5% overestimate. However, because our model does not simulate processes leading to lake stagnation or decay, such as refreezing or drainage, at present we do not simulate absolute daily lake area. We find that the maximum potential lake-covered ice sheet area is limited by topography to 6.4%. We estimate that this corresponds to a volume of 1.49 km3, 12% of the runoff produced in 2003. This can be taken as an upper bound given uncertainty in the DEM. This study has proved a good first step towards capturing the variability of supraglacial lake evolution with a numerical model. These initial results are promising and suggest that the model is a useful tool for use in analysing the behaviour of supraglacial lakes on the Greenland ice sheet in the present day and potentially beyond.

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One of the largest wetlands along the Gulf Coast of North America (ca. 150 000 ha) occurs around the shorelines of Lake Pontchartrain and Lake Maurepas in southeastern Louisiana, just north and west of New Orleans. We provide an introduction to the environmental history of the marshes and swamps in the upper Lake Pontchartrain basin, a review of the existing vegetation patterns and their possible causes, and a discussion of restoration targets and priorities. The Mississippi River produced the St. Bernard Delta 3000–4000 years ago, trapping fresh water to produce both Lake Maurepas and Lake Pontchartrain (Frazier 1967). The natural vegetation of much of the region remains fresh or brackish marshes, mixed with swamps dominated by bald cypress ( Taxodium distichum ) and tupelo ( Nyssa aquatica ). Yearly flooding by the Mississippi River was once a major factor controlling vegetation patterns, but these processes have been greatly impaired by the construction of artificial levees for flood control. Humans also removed most of the cypress swamps in a pulse of logging between 1876 and 1956. Continued subsidence of the land, slowly rising sea levels, salinity pulses from hurricanes, and canals from the Gulf of Mexico, add further stress to these wetlands. Over the past century there has been a steady loss of wetland area, and a gradual conversion of fresh water to salt water vegetation types. Biotic processes are also important. An exotic species of mammal, nutria ( Myocastor coypus ), consumes both aboveground and belowground parts of wetland plants. Reforestation is strictly limited by the combination of salt pulses, competition, and nutria. Alligators are the top predator in this system, but their potential for reducing the impacts of nutria has received minimal attention from biologists. There are many potential future states for this ecosystem. In the extreme case of rising sea level and warmer climate, the area may become a salt and brackish embayment fringed with mangroves. The state closest to historical conditions would be large areas of bald cypress swamp. Two important priorities are to increase flow of freshwater into the system from multiple pulsed fresh water diversions, and to decrease saltwater intrusions by closing canals such as the Mississippi River Gulf Outlet.

Abstract:

AbstractSediment cores from three lakes in the Upper Kolyma region, northeast Russia, provide the first well-dated continuous record of late Quaternary vegetation change from far southwestern Beringia. The oldest pollen zone, tentatively assigned to the Karginsk (mid-Wisconsinan) Interstade, indicates an Artemisia shrub tundra with Pinus pumila, Betula, and Alnus at mid- to low elevations. With the onset of the Sartan (late Wisconsinan) Stade, Pinus disappeared, probably indicating severely cold, dry winters and cool summers. As conditions deteriorated further, an Artemisia -Gramineae tundra developed. Selaginella rupestris and minor herb taxa indicate the presence of poor soils and disturbed ground. This herb tundra was replaced by a short-lived (< 1000 yr) Betula-Alnus shrub tundra followed by the rapid establishment of a Larix dahurica forest with a Betula exilis-ericales-lichen understory. Populus suaveolens and Chosenia may have formed limited hardwood gallery forests at this time. Modern vegetation associations probably developed during the early Holocene with the arrival of Pinus pumila ca. 9000 yr B.P. This shrub became important in the forest understory and, with B. exilis, formed a belt of shrub tundra beyond altitudinal treeline. Comparison of the Upper Kolyma and Alaskan pollen records indicates that important differences in vegetation types and timing of vegetation change occurred across Beringia during the late Quaternary.

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Abstract. The quality of spatial analyses of biodiversity is improved by (i) utilizing study areas with well defined physiogeographical boundaries, (ii) limiting the impact of widespread species, and (iii) using taxa with heterogeneous distributions. These conditions are typically met by ecosystems such as oceanic islands or ancient lakes and their biota. While research on ancient lakes has contributed significantly to our understanding of evolutionary processes, statistically sound studies of spatial variation of extant biodiversity have been hampered by the frequently vast size of ancient lakes, their limited accessibility, and the lack of scientific infrastructure. The European ancient Lake Ohrid provides a rare opportunity for such a reliable spatial study. The comprehensive horizontal and vertical sampling of a species-rich taxon, the Gastropoda, presented here, revealed interesting patterns of biodiversity, which, in part, have not been shown before for other ancient lakes. In a total of 284 samples from 224 different locations throughout the Ohrid Basin, 68 gastropod species, with 50 of them (= 73.5%) being endemic, could be reported. The spatial distribution of these species shows the following characteristics: (i) within Lake Ohrid, the most frequent species are endemic taxa with a wide depth range, (ii) widespread species (i.e. those occurring throughout the Balkans or beyond) are rare and mainly occur in the upper layer of the lake, (iii) while the total number of species decreases with water depth, the proportion of endemics increases, and (iv) the deeper layers of Lake Ohrid appear to have a higher spatial hom*ogeneity of biodiversity. Moreover, gastropod communities of Lake Ohrid and its feeder springs are both distinct from each other and from the surrounding waters. The analysis also shows that community similarity of Lake Ohrid is mainly driven by niche processes (e.g. environmental factors), but also by neutral processes (e.g. dispersal limitation and evolutionary histories of species). For niche-based mechanisms it is shown that large scale effects such as type of water body or water depth are mainly responsible for the similarity of gastropod communities, whereas small scale effects like environmental gradients affect gastropod compositions only marginally. In fact, neutral processes appear to be more important than the small scale environmental factors, thus emphasizing the importance of dispersal capacities and evolutionary histories of species.

Abstract:

Abstract. Spatial heterogeneity of biodiversity arises from evolutionary processes, constraints of environmental factors and the interaction of communities. The quality of such spatial analyses of biodiversity is improved by (i) utilizing study areas with well defined physiogeographical boundaries, (ii) limiting the impact of widespread species, and (iii) using taxa with heterogeneous distributions. These conditions are typically met by ecosystems such as oceanic islands or ancient lakes and their biota. While research on ancient lakes has contributed significantly to our understanding of evolutionary processes, statistically sound studies of spatial variation of extant biodiversity have been hampered by the frequently vast size of ancient lakes, their limited accessibility, and the lack of infrastructure around them. The small European ancient Lake Ohrid provides a rare opportunity for such a reliable spatial study. The comprehensive horizontal and vertical sampling of a species-rich taxon, the Gastropoda, presented here, revealed interesting patterns of biodiversity, which, in part, have not been shown before for other ancient lakes. In a total of 224 locations throughout the Ohrid Basin, representatives of 68 gastropod species with 50 of them being endemic (=73.5%) could be reported. The spatial distribution of these species shows the following characteristics: (i) within Lake Ohrid, the most frequent species are endemic taxa with a wide depth range, (ii) widespread species (i.e. those occurring throughout the Balkans or beyond) are rare and mainly occur in the upper layer of the lake, (iii) while the total number of species decreases with water depth, the share of endemics increases, (iv) the deeper layers of Lake Ohrid appear to have a higher spatial hom*ogeneity of biodiversity and related environmental factors, (v) biotic interaction due to possible spillover effects may contribute to the establishment of hotspots, and (vi) eco-insularity within the Ohrid Basin occurs at two levels, at the level of the lake proper and at the level of the feeder-springs. It is also shown that large scale effects such as type of water body or water depth are mainly responsible for the distribution of biodiversity. In addition, small scale effects like environmental gradients or biotic interaction affect gastropod composition within a particular depth zone.

Abstract:

Photographic surveys have been used since the early 1940’s to document coastlines, fuel supplies and river courses. The US Navy, post world war II, flew over the Arctic coast to document possible locations for oil extraction. These very same photos are now being utilized to compare changes in tundra vegetation at the same locations today. John Muirs’ photos of Glacier Bay are a startling testament to the melted glaciers no longer visible from the same vantage point in present times. Taking photographs to monitor change may not tell the entire story behind a change in landscape. However, photos taken over a number of years from the same vantage points, can help monitor landscape changes due to habitat fragmentation, global warming, forest fire, cattle grazing and other land management issues. Photo monitoring is inexpensive, simple and can portray change to many different groups. Of course, photos taken to reveal change must start with documenting current or normal conditions. This is sometimes called baseline monitoring. The park ranger in Glacier National Park did not realize when he took his picture of the Grinnell glacier in 1911 that his photo would become an alarming baseline photo for evidence of global warming. The purpose of this project was to document the Snake River headwater basin and its riparian zones as a document in time for future reference. The original documentation included 48 images of two main headwater areas; the Shoshone and Lewis Lake areas and the Fox Park-Two Ocean Bear Management Areas near the Yellowstone Park border. Since the Shoshone-Lewis lakes are easily assessable and photo space here is limited, I have chosen to only use photos from the more remote areas.

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Abstract. Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator–prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is “pegged”; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant “pegged” value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay “pegged” at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing “false” turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-attenuation measurements or suspended-sediment samples) are necessary to correct these low false turbidity measurements and accurately measure turbidity.

Abstract:

Recent three-dimensional mapping investigations in southern Simcoe County, Ontario, allow refinement of the existing regional stratigraphic framework. Analysis of 25 continuously cored boreholes has revealed a complex but consistent sediment succession that provides a record of the last two glacial cycles (Marine Isotope Stages 1–6). Five stratigraphic units (SU1–SU5) comprise the pre-Late Wisconsin record. The stratigraphy is floored by a presumed Illinoian glacial complex consisting of a lower, coarse-grained till (SU1), locally overlain by stratified glaciolacustrine and glaciofluvial sediments (SU2), but more commonly capped by a stone-poor, fine-grained till (SU3) of the Georgian Bay lobe. A widespread subaerial unconformity developed on the upper surface of SU3 contains organic-bearing, nonglacial deposits (SU4) ranging between 54 800 ± 3000 years BP (considered beyond the limits of radiocarbon dating) and 37 450 ± 590 14C years BP. SU4 is abruptly overlain by a thick succession of rhythmically laminated lacustrine muds graded upwards into glaciolacustrine silts and clays interrupted by regionally continuous sand bodies (SU5). The succession is capped (and locally truncated) by Late Wisconsin Newmarket Till. The sedimentary record of southern Simcoe County is correlated with other well-studied reference sections in southern Ontario and contains information that informs reconstructions of former ice extents in the lower Great Lakes region following the Illinoian glaciation. Several sediment units host aquifers, but limited thickness and spatial extent, as well as issues with naturally occurring dissolved gases and solids, restrict their use for groundwater supply.

Abstract:

In some cases, the oil shale deposited in shallow lakes may be genetically associated with the coal-bearing successions. Although paleovegetation is an important controlling factor for the formation of oil shale- and coal-bearing successions, few studies have focused on their joint characterization. In this study, a total of twenty-one oil shale and coal samples were collected from the upper member of the Lower Cretaceous Muling Formation (K1ml2) in the Laoheishan Basin, and investigated for their bulk geochemical, maceral, palynological, and terpenoid biomarker characteristics, in order to reconstruct the paleovegetation and reveal its influence on the formation of oil shale and coal. The K1ml2 is subdivided into lower, middle, and upper units. The studied oil shale samples from the lower and upper units display a high ash yield (Ad), low total organic carbon (TOC) and sulfur (S) contents, and limited hydrocarbon generation potential. The studied coal samples from the middle unit are characterized by low Ad, and high TOC and low S values, and show significant hydrocarbon generation potential. The paleovegetation during the formation of the lower unit was dominated by mire vegetation, such as shrubs (e.g., Lygodiaceae, Schizaeaceae), tree ferns (e.g., Dicksoniaceae/Cyatheaceae), and coniferous trees (e.g., Podocarpaceae). In the middle unit interval, the paleovegetation was represented by highland vegetation (Pinaceae and Araucariaceae) and peat-forming coniferous plants (e.g., Podocarpaceae, Cupressaceae/Taxodiaceae). Various vegetation, such as herbs (e.g., Osmundaceae), shrubs (e.g., Schizaeaceae), and coniferous trees (e.g., Podocarpaceae) was prosperous during the upper unit interval. Coniferous trees could provide abundant hydrogen-rich materials (e.g., resins) to the mire/lake, which may elevate the hydrogen content in peat/lake sediments, and finally result in higher hydrocarbon generation potential in the coal than in the oil shale. Therefore, the influence of paleovegetation on the formation of oil shale and coal should be fully considered when studying oil shale- and coal-bearing successions. The results also provide guidance for further exploration studies on oil shale and coal in northeast China.

Abstract:

The reservoir of Platanovrysi in the Nestos valley has a long and narrow shape, limited in area and volume, deep close to the dam wall (90 m) and very shallow at its uphill end (5m). It receives considerable volume of water from the upper large reservoir of Thesaurus all through the year, as well as limited volumes of water in seasonal flows from its drainage basin. Platanovrysi reservoir has distinct morphological and operational characteristics that make it different from natural lakes regarding temperature and dissolved oxygen distribution in the water column. The epilimnion is limited at the area of the deeper part of the lake only. It forms an entrapped warm wedge, with the maximum depth close to the dam and a horizontal extension up to the beginning of the shallow part of the lake. This is due to both the inflows of large volumes of cold water from Thesaurus as well as the lack of a surface outflow from the dam of Platanovrysi. The water temperatures of the surface water of the upper part of the lake as well as the temperatures of the hypolimnion are similar. The temperature is very low during the spring and the summer (6-7°C), becomes higher during autumn (14-15°C) and drops again during winter (9-10°C). This shifting of seasonal temperatures is purely due to the inflows of cold water from the hypolimnion of the reservoir of Thesaurus in spring and summer periods and from the base of epilimnion during autumn. The water is rich in oxygen during the spring and the summer while it becomes poor in oxygen during the autumn and the beginning of winter. The operation of Platanovrysi Power Station allows the cold water from the hypolimnion of the lake to flow into the river Nestos channel and brings cold water during the warm period of the year downstream. This type of change of the water temperature may affect the natural processes of the river fauna and flora as well as the human processes in the plains of Nestos (irrigation). It is therefore necessary to construct and operate the last (lower) reservoir of Temenos in Nestos, to regulate the flow and warm the water of the river Nestos channel.

Abstract:

Spatial distributions of crayfish were evaluated in relation to glacial geography and possible modes of dispersal from refugia. Species dispersal patterns were a priori hypothesized and tested using principle components analysis (PCA). PCA factor loading plots were evaluated for hypothesized crayfish dispersal patterns. Cambarus laevis was limited to the unglaciated region, while Orconectes immunis, Orconectes virilis, and Procambarus gracilis may have dispersed from western glacial refugia in the upper Missouri drainage. Fallicambarus fodiens and Procambarus acutus dispersed from south of the glacial advance within the Mississippi embayment. Previous dispersal hypotheses for Orconectes propinquus recognized that northern refugia may have been from the Driftless Area in Wisconsin and Illinois and may have invaded more than one refuge since this species was common in unglaciated areas of southwestern Indiana. Orconectes indianensis center of abundance is in the unglaciated region. Disjunct populations likely dispersed into temporary glacial lakes that, when receded, left populations in previously glaciated areas. Cambarus polychromatus possibly dispersed from southern refugia, while Cambarus sp. A cf. diogenes dispersed from southern refugia not sympatric with C. polychromatus. The glacial refugia included western and southern areas of the glacial maximum; however, northern dispersal routes may be important with global climate change.

Abstract:

Abstract A new functional form of the neutral drag coefficient for moderate to high wind speeds in the marine atmospheric boundary layer for a range of field measurements as reported in the literature is proposed. This new form is found to describe a wide variety of measurements recorded in the open ocean, coast, fetch-limited seas, and lakes, with almost one and the same set of parameters. This is the result of a reanalysis of the definition of the drag coefficient in the marine boundary layer, which finds that a constant is missing from the traditional definition of the drag coefficient. The constant arises because the neutral friction velocity over water surfaces is not directly proportional to the 10-m wind speed, a consequence of the transition to rough flow at low wind speeds. Within the rough flow regime, the neutral friction velocity is linearly dependent on the 10-m wind speed; consequently, within this rough regime, the new definition of the drag coefficient is not a function of the wind speed. The magnitude of the new definition of the neutral drag coefficient represents an upper limit to the magnitude of the traditional definition.

Abstract:

This paper describes a means by which the capsize risk associated with various fishing vessel operating conditions can be evaluated. Rather than relying on the static restoring moment curve as the primary criteria for vessel safety, modern nonlinear systems analysis is applied to the problem of extreme nonlinear rolling in random beam sea. While the method is quite general and not limited to small vessels, it is illustrated with a specific application involving Native American trap net fishing on the upper Great Lakes. General trap net operations, as practiced by Native American fishermen and women in the Grand Traverse Bay region, are presented in detail. The most significant characteristic of trap net operations is the heel induced during net deployment and net lifting. The increased risk to the vessel, in terms of the increased probability of capsize is quantified for various heel angles and various sea states. A significant advantage of the capsize analysis method presented here is its ability to investigate quickly the effects of many parameters (e.g., trap net line tension, wave height, and/or wave period) on a nonlinear dynamic system without having to resort to extensive simulation studies.

Abstract:

Abstract Glacigenic perialpine lakes can constitute continuous post-last glacial maximum (LGM) geological archives which allow reconstruction of both lake-specific sedimentological processes and the paleoenvironmental setting of lakes. Lake Mondsee is one among several perialpine lakes in the Salzkammergut, Upper Austria, and has been previously studied in terms of paleoclimate, paleolimnology and (paleo)ecology. However, the full extent and environment of Late Glacial to Holocene sediment deposition had remained unknown, and it was not clear whether previously studied core sections were fully representative of 3D sediment accumulation patterns. In this study, the sedimentary infill of Lake Mondsee was examined via high-resolution seismic reflection survey over a 57-km extent (3.5 kHz pinger source) and a sediment core extracted from the deepest part of the lake, with a continuous length of 13.76 m. In the northern basin, seismic penetration is strongly limited in most areas because of abundant shallow gas (causing acoustic blanking). In the deeper areas, the acoustic signal reaches depths of up to 80 ms TWT (two-way travel time), representing a postglacial sedimentary sequence of at least 60-m thickness. Holocene deposits constitute only the uppermost 11.5 m of the sedimentary succession. Postglacial seismic stratigraphy of Lake Mondsee closely resembles those of well-studied French and Swiss perialpine lakes, with our data showing that most of Lake Mondsee’s sedimentary basin infill was deposited within a short time period (between 19,000 BP and 14,500 BP) after the Traun Glacier retreated from the Mondsee area, indicating an average sedimentation rate of about 1.4 cm/yr. Compared to other perialpine lakes, the seismic data from Lake Mondsee reveal little indication of mass movement activities during the Holocene. One exception, however, is rockfalls that originate from a steep cliff, the Kienbergwand, situated on the southern shore of Lake Mondsee, where, in the adjacent part of the lake, seismic profiles show mass transport deposits (MTDs), which extend approximately 450 m from the shore and are mappable over an area of about 45,300 m2. Sediment cores targeting the MTDs show two separate rockfall events. The older event consists of clast-supported angular dolomitic gravels and sands, showing high amounts of fine fraction. The younger event exhibits dolomitic clasts of up to 1.5 cm in diameter, which is mixed within a lacustrine muddy matrix. Radiocarbon dating and correlations with varve-dated sediment cores hint at respective ages of AD 1484 ± 7 for Event 1 and AD 1639 ± 5 for Event 2. As our data show no evidence of larger-scale mass movements affecting Lake Mondsee and its surroundings, we infer that the current-day morphology of the Kienbergwand is the result of infrequent medium-scale rockfalls.

Abstract:

Lotbinière Sand and Deschaillons Varves are indicators of the drainage pattern of the St. Lawrence watershed, which presumably occurred during the Late Sangamonian (5c and 5c–5b transition?). The pollen content of the Lotbinière Sand suggests there was a Picea mariana – Betula – Pinus boreal forest in the valley. In the lowermost zone of the Deschaillons Varves, the pollen is very abundant: the boreal forest was progressively flooded by Lake Deschaillons. Above this zone, the vegetation seems to evolve toward a Picea and Betula open forest. The pollen of the upper contorted varves was presumably reworked from older material or transported from remote sources. The following paleoenvironmental sequence is reconstructed in the St. Lawrence Valley: (i) lowering of the relative drainage level, as indicated by the erosional disconformity in lower rythmites; this phase, of unknown duration, is ascribed to an eustatic lowering related to a global climatic cooling; (ii) an aggradation phase, as indicated by the Lotbinière Sand, before and at the beginning of a glacial damming in the middle estuary; (iii) progressive flooding of the valley and its boreal forest as ice caps are present on adjacent Laurentian and Appalachian highlands; (iv) expansion of Lake Deschaillons, limited by the Glens Falls sill, New York. The relative elevation of the lake was at least 56 m. Great Lakes and upper St. Lawrence River drainage system was probably deflected to the Hudson River. According to the number of varves, the regional ice caps preceded the general invasion by Laurentide Ice Sheet of approximatively 3800 years.

Abstract:

Over the last five years a research program has been carried out to assess the performance of the spectral wave model SWAN in the Wadden Sea so that it may be used for the transformation of offshore wave conditions to wave boundary conditions near the sea defenses (dikes and dunes). The assessment was done on the basis of extensive wave measurements conducted in Ameland inlet and the Dutch Eastern Wadden Sea, as well as relevant data from lakes and estuaries. After a first round of assessment, we found that SWAN performed reasonably well for storm conditions but three aspects required further attention. Firstly, focusing on the main channel, SWAN formulations needed to be modified in order to eliminate overprediction of the significant wave height in opposing currents. Secondly, the primary spectral peak of North Sea waves penetrating into the inlet was underpredicted. Best results were obtained when the refraction of low-frequency waves was limited and the bottom friction coefficient was set at a lower value than the current default for wind seas. Thirdly, over the tidal flats the computed ratio of integral wave height over water depth showed an apparent upper limit using the conventional Battjes and Janssen (1978) depth-limited wave breaking formulation, because the wave growth over finite depth is hampered by the present formulation of depth-induced wave breaking. The problem has been solved using a new breaker formulation. All these improvements have lead to a wave transformation model with which reliable wave conditions in the Wadden Sea and related complex areas can be determined.

Abstract:

Abstract. CO2 outgassing from rivers is a critical component for evaluating riverine carbon cycle, but it is poorly quantified largely due to limited measurements and modeling of gas transfer velocity in subtropical streams and rivers. We measured CO2 flux rates and calculated k and partial pressure (pCO2) in 60 river networks of the Three Gorges Reservoir (TGR) region, a typical area in the upper Yangtze River with monsoonal climate and mountainous terrain. The determined k600 (gas transfer velocity normalized to a Schmidt number of 600 (k600) at a temperature of 20 ∘C) value (48.4±53.2 cm h−1) showed large variability due to spatial variations in physical processes related to surface water turbulence. Our flux-derived k values using chambers were comparable with k values using the model derived from flow velocities based on a subset of data. Unlike in open waters, e.g., lakes, k600 is more pertinent to flow velocity and water depth in the studied river systems. Our results show that TGR river networks emitted approx. 0.69 to 0.71 Tg CO2 (1 Tg =1012 g) during the monsoon period using varying approaches such as chambers, derived k600 values and models. This study suggests that incorporating scale-appropriate k measurements into extensive pCO2 investigations is required to refine basin-wide carbon budgets in subtropical streams and small rivers. We concluded that the simple parameterization of k600 as a function of morphological characteristics is site specific for regions and watersheds and hence highly variable in rivers of the upper Yangtze. k600 models should be developed for stream studies to evaluate the contribution of these regions to atmospheric CO2.

Abstract:

Since the early 1990s, a substantial number of deformed frogs have been observed in North America, particularly in the upper Midwest and Canada. Attempts to understand the etiology of the deformed frog problem have met with limited success to date with nearly as many proposed explanations as research groups working on the problem. Models for the mechanism underlying the development of deformed frogs include parasite/predation, ultraviolet radiation, and chemical exposure. Each model has its strengths and weaknesses. Despite contentious debate among researchers, there is an overall consensus that the increasing prevalence of deformed frogs is the result of a water-borne contaminant that has recently appeared, or reached a critical concentration. Our detailed analysis of malformed frogs collected in Minnesota ponds and lakes suggested that limb patterning was being modified by the disruption of a retinoid-sensitive developmental signaling pathway. Accordingly, we focused in the identification and characterization of bioactive retinoids from lake water and showed that retinoid treatment of frog embryos at sensitive times of development could recapitulate the full spectrum of limb abnormalities observed in field specimens in the laboratory. These data have led to the conclusion that inappropriate modulation of retinoid signaling by environmental contaminants is the mechanism underlying the increased incidence of frog malformations.

Abstract:

Knowledge of maximum river runoff trends is of great practical importance, especially for design and operation of hydraulic structures. This article presents the results of the research of the Southern Buh River's maximum runoff. The water of the river is widely used for hydropower engineering, industrial and municipal water supply, agriculture, irrigation, shipping, tourism etc. The research of the maximum runoff was based on the Indicators of Hydrologic Alteration (IHA) method which is widely used in the whole world. This method enables calculation of quantitative statistical characteristics of rivers', lakes', reservoirs' runoff and determination of the degree of their hydrological regime changes. The IHA is used for water bodies having natural or regulated runoff. However, the IHA method was not widely used in Ukraine before. The purpose of this publication is using the Indicators of Hydrologic Alterations method in order to study the characteristics of maximum runoff and their changes along the Southern Buh River. The research was carried out based on the data of observations at 5 gauge stations located along the Southern Buh River. The research uses the mean daily discharges that has been recorded since the beginning of observations up to 2018 and 2019 inclusive. The river's runoff at each of gauge stations was divided into five components: "Extremely low runoff", "Low runoff", "High runoff pulses", "Small floods", "Large floods". This made it possible to separate three classes of high (maximum) runoff, for which the IHA statistics were calculated, from the total runoff. It was discovered that the long-term high runoff changes differed in each of its three components, although they had general trends. The most significant changes were found for large floods, with no significant changes found for high runoff pulses. General trends of high runoff showed that over time the values of maximum discharges tend to decrease, with the increasing duration of high runoff periods. The values of the main statistical indicators of high runoff gradually increase from the river's source to its mouth, which fully corresponds to the physical and geographical conditions of its formation. Nevertheless, some features of high runoff were still found. Thus small floods and high runoff pulses have the largest duration in the upper reach of the river. On average, the Southern Buh River experiences large floods once in every 10 years, small floods - once in every 2 years, high runoff pulses - 4-8 times a year in its upper reach and 9-14 times a year in its middle reach.

Abstract:

Eastern hemlock (Tsuga canadensis (L.) Carrière) is a shade-tolerant, slow-growing tree once common in forests across the Great Lakes region. It was heavily exploited in the late 19th and early 20th centuries and now experiences limited regeneration across much of its range. This failure to regenerate has been ascribed to poor seedbed conditions, insufficient canopy openings, warmer climate, and browsing by white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) or snowshoe hare (Lepus americanus Erxleben, 1777). To test whether deer or hare limit hemlock regeneration, we studied >2000 hemlock seedlings inside and adjacent to experimental deer exclosures at 59 sites randomly distributed across hemlock and hemlock-component stands in northern Wisconsin and the western Upper Peninsula of Michigan in the United States. We monitored local deer and hare abundance, seedling growth, and seedling survival for 20 years. Two First Nations reservations showed lower deer density and greater survival and growth of unprotected seedlings than three national forests of the United States. Cohorts of hemlock seedlings protected from deer survived at a rate four times higher than those exposed to deer (59.3% vs. 15.0%) and shared a combined height 5.2 times greater. Hare densities significantly affected seedling survival only within exclosures. This extensive, long-term study identifies deer as the primary factor constraining hemlock regeneration in the region.

Abstract:

Abstract Despite considerable progress in mesoscale numerical weather prediction (NWP), the ability to predict summer severe rainfall (SSR) in terms of amount, location, and timing remains very limited because of its association with convective or mesoscale phenomena. In this study, two representative missed SSR events that occurred in the highly populated Great Lakes regions are analyzed within the context of moisture availability, convective instability, and lifting mechanism in order to help identify the possible causes of these events and improve SSR forecasts/nowcasts. Results reveal the following limitations of the Canadian regional NWP model in predicting SSR events: 1) the model-predicted rainfall is phase shifted to an undesired location that is likely caused by the model initial condition errors, and 2) the model is unable to resolve the echo-training process because of the weakness of the parameterized convection and/or coarse resolutions. These limitations are related to the ensuing model-predicted features: 1) vertical motion in the areas of SSR occurrence is unfavorable for triggering parameterized convection and grid-scale condensation; 2) convective available potential energy is lacking for initial model spinup and later for elevating latent heating to higher levels through parameterized convection, giving rise to less precipitation; and 3) the conversion of water vapor into cloud water at the upper and middle levels is underpredicted. Recommendations for future improvements are discussed.

Abstract:

Rhamdia quelen (Jundiá) is a catfish species of great interest to fish producers and researchers due to several favorable characteristics for inclusion in the Brazilian list of commercially raised fish. It has a wide geographical distribution, with occurrences reported from Central Argentina to South Mexico. Studies on the biological aspects of this species have been limited to captive adult fishes that were researched for farming purposes. Research related to ichthyoplankton has provided valuable information on spawning periods and sites and other aspects of breeding for numerous species of fish. This information is crucial for implementing management and protection strategies for these species. The studied floodplain is located in a lotic remnant between the Reservoirs of Itaipu and Engenheiro Sérgio Motta. This area is located inside a protected area (Ilha Grande National Park) in the last portion of dam-free land along the Paraná River in the Brazilian territory; however, it is still threatened by the negative effects of the dams. We conducted monthly nocturnal collections during four periods from October to March, 2003 to 2007, in 22 locations along the main channel, secondary lakes and main tributaries of the Paraná River. After collection, the individuals were classified according to the degree of development and the notochord flexion and caudal fin support elements. Data were analyzed using principal component analysis (PCA), ANOVA and Pearson correlation to relate abiotic and larval density data. The increase of capture abundances in the four studied stages suggests that R. quelen is finding conditions that are favorable to its reproduction. The increase in captures can generate questions regarding R. quelen reproductive activity, for instance, whether the species is adapting or is influenced by environmental changes created by the Paraná River dams.

Abstract:

The lake Imandra is a major Arctic water basin where harmful algal blooms (HABs) are observed regularly starting from the turn of the 20th and 21st centuries. HABs occur in the lake at significantly lower temperatures and phosphorus (P) and nitrogen (N) levels than in lakes located at lower latitudes. With regard to the above, the interrelationships between and the patterns of the spatial distributions of P, N and chlorophyll-a (Chl-a) in the upper layers of the lake have been considered. The complex outline of and strong gravity currents in the lake combined with potent focal anthropogenic sources of P and N determine the gradients of biogenic elements levels in the lake. Their examination suggest that HABs development is limited mutually by the levels of N and P and by their stoichiometric proportions. At the levels of total P and N (Ptot and Ntot) below 17 µg/L and 150 µg/L respectively, HABs probability is low. At Ptot>17 µg/L, HABs are limited by N rather than P. At Ntot>180 µg/L, HABs probability becomes increased. In the major part of the lake, N is mostly organic and NO3– levels are low, NH4+ being predominant among the inorganic forms of N. This makes conditions for the development of green algae and for the predominance of cyanobacteria. At [NO3-]:[NH4+] within 0.1 to 1.0, the probability of cyanoHABs is high. HABs development is promoted by [NO3-] > 2.5 µg/L upon [РО43-] > 3.1 µg/l, the N:P ratio being above 9.7. The ascertaining of the critical levels of N- and P-containing compounds will be useful in HABs forecasting and in understanding of HABs development in Arctic water basins.

Abstract:

Debris flows caused by glacial lake outburst floods (GLOFs) are common hazards in mountain environments. The risk posed by glacial lake outburst hazards is particularly evaluated where the lower reaches of catchments are populated. A potentially dangerous lake has been identified adjacent to the Uchitel Glacier in Northern Tien Shan. This lake formed between 1988 and 1994 on the site of a retreated glacier in the upper part of the Aksay Valley. In this study we consider the possibility of an outburst of this pro-glacial lake in the future. The study involved bathymetry mapping of the lake, detailed profile sections of the valley, flow rate measurements on the Aksay river, and monitoring of the lake development using satellite images. Modelling of secondary debris flow inundation heights and hazard footprints has been undertaken. The outburst of this lake could cause powerful debris flows posing a threat to permanent residents living downstream, in the Ala-Archa Valley. Monitoring of the lake over the past ten years suggests certain changes in the runoff to the subsurface, and an increase in lake depth is observed. Glacial lakes with subsurface drainage are considered to be the most hazardous type as the knowledge of drainage channels functioning is still very limited and, thus, the timing of an outburst is hard to predict. Development of monitoring approaches to support forecasting of these hazards is of paramount importance to safety in mountain territories globally.

Abstract:

Herbivorous tetrapods make their first appearance in Upper Carboniferous fossil assemblages but only become abundant and diverse in Upper Permian ones. During the Late Carboniferous-Early Permian interval, herbivory appeared independently at least five times: in diadectids, bolosaurids, captorhinids, edaphosaurids and caseids. These animals ranged from small forms with aptitudes for collection and processing of low-fiber plant tissues (as well as terrestrial invertebrates) to giants particularly apt for utilization of high-fiber tissues. Our report focuses on the latter group since the development of high-fiber herbivory has had a critical impact on evolution of terrestrial plants and animals as well as on the organization of terrestrial ecosystems.The low abundance and diversity of early, high-fiber herbivores reflect on one hand, sampling biases toward habitats suboptimal for herbivory, and on the other, the limited ecological capabilities of the animals themselves. Most of the Permo-Carboniferous assemblages derive from wet-land swamp and forest ecosystems where plant tissues would have been relatively rare and/or inaccessible and predation relatively intense. The likely herbivores appear apt for life in wet-land ecosystems; there they probably utilized localized patchs of productive shrub and herb along rivers and around lakes as refuges from disturbance (desiccation, temperature extremes and predation) as well as sources of food. Their low metabolic levels and growth rates minimized nutritional requirements but along with large size provided adequately for adult maintenance and for reproduction. High adult survivorship and production of a large number of eggs through a long adult lifespan would have offset high egg and juvenile mortality.Only a few Late Carboniferous and Early Permian assemblages sample drier woodland and shrub habitats where conditions would have been more favorable for high-fiber herbivory, but by Late Permian such assemblages occur in much greater numbers and diversity. The high-fiber herbivores in these dry-land ecosystems had ecological aptitudes comparable to wet-land forms but were relatively more abundant and diverse, reflecting both a greater abundance and extent of shrubby vegetation and a lower incidence of predation.

Abstract:

The eastern margin of the Kechika Graben in the vicinity of Muncho and Moose lakes, northeastern British Columbia, contains Middle Cambrian rift-related strata herein named the Mount Roosevelt Formation. The formation conformably overlies a quartzite package equivalent to the uppermost clastic unit of the informal late Early Cambrian Gataga group ( Bonnia – Olenellus zone) and is conformably overlain by a thick, unnamed carbonate sequence of Middle Cambrian age ( Plagiura – Poliella zone). The Mount Roosevelt Formation is subdivided into three members. The lowermost member is characterized by oöid-bearing siltstone and sandstone, interbedded with dolostone, limestone, and hematitic conglomerate. Conformably above this, the middle member is a thick sequence of polymict cobbly pebble conglomerate. The upper member includes karstified dolostone, calcareous-cemented conglomerate and sandstone, and limestone. Collectively the Mount Roosevelt Formation reflects alluvial fan delta progradation into a transgressive marine environment. Deposition occurred in an active fault-controlled basin, located on the eastern margin of the Kechika Graben adjacent to the Muskwa High. Basin initiation in the late Early Cambrian coincided with the reactivation of pre-existing regional faults. High rates of subsidence during the initial phase of extension were accommodated on these faults, which provided a locus for fan delta deposition. Continuing high rates of subsidence limited basinward fan delta development. Deposition of the formation ended with base-level transgression in the early Middle Cambrian that drowned the fan deltas and the adjacent Muskwa High and allowed development of the Kechika Trough above the older graben system.

Abstract:

U.S. Weather Research Program (USWRP) prospectus development teams (PDTs) are small groups of scientists that are convened by the USWRP lead scientist on a one-time basis to discuss critical issues and to provide advice related to future directions of the program. PDTs are a principal source of information for the Science Advisory Committee, which is a standing committee charged with the duty of making recommendations to the Program Office based upon overall program objectives. PDT-1 focused on theoretical issues, and PDT-2 on observational issues; PDT-3 is the first of several to focus on more specialized topics. PDT-3 was convened to identify forecasting problems related to U.S. coastal weather and oceanic conditions, and to suggest likely solution strategies. There were several overriding themes that emerged from the discussion. First, the lack of data in and over critical regions of the ocean, particularly in the atmospheric boundary layer, and the upper-ocean mixed layer were identified as major impediments to coastal weather prediction. Strategies for data collection and dissemination, as well as new instrument implementation, were discussed. Second, fundamental knowledge of air–sea fluxes and boundary layer structure in situations where there is significant mesoscale variability in the atmosphere and ocean is needed. Companion field studies and numerical prediction experiments were discussed. Third, research prognostic models suggest that future operational forecast models pertaining to coastal weather will be high resolution and site specific, and will properly treat effects of local coastal geography, orography, and ocean state. The view was expressed that the exploration of coupled air-sea models of the coastal zone would be a particularly fruitful area of research. PDT-3 felt that forecasts of land-impacting tropical cyclones, Great Lakes-affected weather, and coastal cyclogenesis, in particular, would benefit from such coordinated modeling and field efforts. Fourth, forecasting for Arctic coastal zones is limited by our understanding of how sea ice forms. The importance of understanding air-sea fluxes and boundary layers in the presence of ice formation was discussed. Finally, coastal flash flood forecasting via hydrologic models is limited by the present accuracy of measured and predicted precipitation and storm surge events. Strategies for better ways to improve the latter were discussed.

Abstract:

The western pond turtle (WPT) was formerly considered a single species (Actinemys or Emys marmorata) that ranged from southern British Columbia, Canada to Baja California, México. More recently it was divided into a northern and a southern species. WPTs are found primarily in streams that drain into the Pacific Ocean, although scattered populations exist in endorheic drainages of the Great Basin and Mojave deserts. Populations in the Mojave Desert were long thought to be restricted to the Mojave River, but recently another population was documented in Piute Ponds, a terminal wetland complex associated with Amargosa Creek on Edwards Air Force Base. WPT fossils in the Mojave Desert are known from the Miocene to the Pleistocene. Recently, Pleistocene fossils have been found as far into the desert as Salt Springs, just south of Death Valley. The oldest fossil records suggest that WPTs were present in wetlands and drainages of the geological feature known as the Mojave block prior to the uplift of the Sierra Nevada Range about 8 Ma and prior to the ~ 3 Ma uplift of the Transverse Ranges. Archaeological records document use of turtles by Native Americans for food and cultural purposes 1,000 or more years ago at the Cronese Lakes on the lower Mojave River and Oro Grande on the upper river. The first modern publication documenting their presence in the Mojave River was 1861. Museum specimens were collected as early as 1937. These fossil and early literature records support the indigenous status of WPTs to the Mojave River. However, mtDNA-based genetic evidence shows that Mojave River turtles share an identical haplotype with turtles on the California coast. Limited nuclear data show some minor differences. Overdraft of water from the Mojave River for municipal and agricultural uses, urban development, and saltcedar expansion are threats to the continued survival of WPTs in the Mojave River.

Abstract:

In this article, I show how an Ultisol, representative of a globally-important group of soils with clay-rich subsoils, low base saturation, and low fertility, in the central Waikato region in northern North Island, can be evaluated using soil stratigraphy and tephrochronology to answer challenging questions about its genesis, age and classification. The Kainui soil, a Typic Kandiudult (Soil Taxonomy) and Buried-granular Yellow Ultic Soil (New Zealand Soil Classification), occurs on low rolling hills of Mid-Quaternary age mainly in the Hamilton lowlands in, and north and northeast of, Hamilton city. It is a composite, multi-layered tephra-derived soil consisting of two distinct parts, upper and lower. The upper part is a coverbed typically c. 0.4–0.7 m in thickness (c. 0.6 m on average) comprising numerous late Quaternary rhyolitic and andesitic tephras that have been accumulating incrementally since c. 50 ka (the age of Rotoehu Ash at the coverbed’s base) whilst simultaneously being pedogenically altered (i.e., forming soil horizons) via developmental upbuilding pedogenesis during Marine Oxygen Isotope Stages (MOIS) 3-1. Any original depositional (fall) bedding has been almost entirely masked by pedogenic alteration. Sediments in lakes aged c. 20 ka adjacent to the low hills have preserved around 40 separate, thin, macroscopic tephra-fall beds mainly rhyolitic in composition, and equivalent subaerial deposits together form the upper c. 30 cm of the coverbed. Okareka (c. 21.8 ka), Okaia (c. 28.6 ka), Tāhuna (c. 39.3 ka) and (especially) Rotoehu tephras make up the bulk of the lower c. 30 cm of the coverbed. Tephra admixing has occurred throughout the coverbed because of soil upbuilding processes. Moderately well drained, this upper profile is dominated by halloysite (not allophane) in the clay fraction because of limited desilication. In contrast, Otorohanga soils, on rolling hills to the south of Hamilton, are formed in equivalent but thicker (>c. 0.8 m) late Quaternary tephras ≤c. 50 ka that are somewhat more andesitic although predominantly rhyolitic overall. These deeper soils are well drained with strong desilication and thus are allophanic, generating Typic Hapludands. Ubiquitous redox features, together with short-lived contemporary reduction observed in the lower coverbed of a Kainui soil profile, indicate that the Kainui soil in general is likely to be saturated by perching for several days, or near saturation for several months, each year. The perching occurs because the coverbed overlies a slowly-permeable, buried, clay-rich paleosol on upper Hamilton Ash beds, >c. 50 ka in age, which makes up the lower part of the two-storeyed Kainui soil. The coverbed-paleosol boundary is a lithologic discontinuity (unconformity). Irregular in shape, it represents a tree-overturn paleosurface that may be c. 74 ka in age (MOIS 5/4 boundary). The buried paleosol is markedly altered and halloysitic with relict clay skins (forming paleo-argillic and/or paleo-kandic horizons) and redoximorphic features. It is inferred to have formed via developmental upbuilding pedogenesis during the Last Interglacial (MOIS 5e). The entire Hamilton Ash sequence, c. 3 m in thickness and overlain unconformably by Rotoehu Ash and underlain by c. 330-ka Rangitawa Tephra at the base, represents a thick composite (accretionary) set of clayey, welded paleosols developed by upbuilding pedogenesis from MOIS 10 to 5.

Abstract:

The current understanding of Lake Warren as a proglacial lake stage in the Lake Erie basin during the last deglaciation is based on limited stratigraphic information from strandlines and a wide range of radiocarbon ages. The purpose of this study is to use ground-penetrating radar (GPR) and optically stimulated luminescence (OSL) dating to reconstruct the stratigraphy, depositional environment, and age of the Oak Openings Ridge (OOR), a former strandline of Lake Warren in northwestern Ohio. Both sedimentary exposures and >4 km of GPR data were used to demonstrate that the OOR is a barrier spit that migrated from the northeast to the southwest, and is currently blanketed by an aeolian sheet. Sediments observed in exposures show a shallowing-up sequence attributed to the retreat of proglacial lakes from the area. Corresponding GPR data reveal three distinct GPR facies. The lowermost radar facies 1 (RF1) is a sandy barrier spit platform of a lower beach face prograding across finer-grained lacustrine mud or till. Eroded into RF1 is an upper beach face of RF2, the top of which is visible in cutbank and borrow pit exposures. Overlying the RF2 beach face is uppermost unit RF3, consisting of low-relief, aeolian parabolic dunes and sand sheets. Four OSL ages from a climbing ripple sequence in RF2 average 14.2 ± 0.5 ka, consistent with an earlier published OSL age of 14.1 ± 1.0 ka (Campbell et al. in 2011) from the same unit. From earlier work, the overlying aeolian dunes (RF3) record westerly winds after formation of the OOR, and OSL dating records episodic activity from the Younger Dryas chronozone to ∼8000 years ago. The results suggest that the OOR formed in two phases. First, a barrier spit prograded into Lake Warren from the northeast. Second, parabolic sand dunes and a sand sheet formed episodically for ∼5000 years thereafter. The sediment source for the sand body is from southeast Michigan, but it is of uncertain origin.

Abstract:

An outburst flood from Ape Lake in October 1984 severely affected channel and floodplain morphology of Noeick River. This event, estimated to have exceeded 103 m3∙s−1, was as much as 2.4 times greater than the probable maximum meteorological flood. Storage of water in ponds, lakes, and floodplain margins resulted in attenuation of the flood peak as it progressed downstream. As a result, flood effects were most evident in the alluvial reaches of upper Noeick River, below Ape Lake between km 10 and km 23. Here, the channel zone widened from a preflood average of 75 m to almost 200 m, the area of eroded valley bottom increased by about 2.5 times, and a cumulative length of 2.5 km of valley-side colluvial fans was eroded. Transported sediment stored in the floodplain and along valley margins resulted in aggradation of up to 0.75 m, except in restricted reaches where limited sediment supply and increased stream power caused degradation of up to 3 m. A second, and fractionally larger, outburst flood in August 1986 caused mobilization of sediment and some channel infilling but, overall, further morphological changes were minimal. The first flood in this sequence can be characterized as "catastrophic" because it destroyed the normal (climatic) regime of the river. The event effected an abrupt change in the regime of the river, resetting it to be in equilibrium with channel-forming events of order 103 m3∙s−1, such as the second outburst event. There have been no further outburst floods, resulting in a return to disequilibrium conditions. Ultimate recovery, measured in morphological terms as adjustment to accommodate normal meteorological floods or, in sediment transport terms as a balance between boundary shear stress and available sediment sue, will take on the order of decades to a century. Establishment of riparian vegetation will be an important determinant of the extent and timing of channel and floodplain recovery.

Abstract:

Abstract. Chronic high surface ozone (O3) levels and the increasing sulfur oxides (SOx = SO2+SO4) ambient concentrations over South Coast (SC) and other areas of California (CA) are affected by both local emissions and long-range transport. In this paper, multi-scale tracer, full-chemistry and adjoint simulations using the STEM atmospheric chemistry model are conducted to assess the contribution of local emission sourcesto SC O3 and to evaluate the impacts of transported sulfur and local emissions on the SC sulfur budgetduring the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O3 levels. California biogenic and fire emissions contribute 3–4 ppb to near-surface O3 over SC, with larger contributions to other regions in CA. During a long-range transport event from Asia starting from 22 June, high SOx levels (up to ~0.7 ppb of SO2 and ~1.3 ppb of SO4) is observed above ~6 km, but they did not affect CA surface air quality. The elevated SOx observed at 1–4 km is estimated to enhance surface SOx over SC by ~0.25 ppb (upper limit) on ~24 June. The near-surface SOx levels over SC during the flight week are attributed mostly to local emissions. Two anthropogenic SOx emission inventories (EIs) from the California Air Resources Board (CARB) and the US Environmental Protection Agency (EPA) are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared withobservations. The CARB EI shows improvements over the National Emission Inventory (NEI) by EPA, but generally underestimates surface SC SOx by about a factor of two. Adjoint sensitivity analysis indicated that SO2 levels at 00:00 UTC (17:00 local time) at six SC surface sites were influenced by previous day maritime emissions over the ocean, the terrestrial emissions over nearby urban areas, and by transported SO2 from the north through both terrestrial and maritime areas. Overall maritime emissions contribute 10–70% of SO2 and 20–60% fine SO4 on-shore and over the most terrestrial areas, with contributions decreasing with in-land distance from the coast. Maritime emissions also modify the photochemical environment, shifting O3 production over coastal SC to more VOC-limited conditions. These suggest an important role for shipping emission controls in reducing fine particle and O3 concentrations in SC.

Abstract:

AbstractBasins in orogenic hinterlands are directly coupled to crustal thickening and extension through landscape processes and preserve records of deformation that are unavailable in footwall rocks. Following prolonged late Mesozoic–early Cenozoic crustal thickening and plateau construction, the hinterland of the Sevier orogen of western North America underwent late Cenozoic extension and formation of metamorphic core complexes. While the North American Cordillera is one of Earth’s best-studied orogens, estimates for the spatial and temporal patterns of initial extensional faulting differ greatly and thus limit understanding of potential drivers for deformation. We employed (U-Th)/(He-Pb) double dating of detrital zircon and (U-Th)/He thermochronology of detrital apatite from precisely dated Paleogene terrestrial strata to quantify the timing and magnitude of exhumation and explore the linkages between tectonic unroofing and basin evolution in northeastern Nevada. We determined sediment provenance and lag time evolution (i.e., the time between cooling and deposition, which is a measure of upper-crustal exhumation) during an 8 m.y. time span of deposition within the Eocene Elko Basin. Fluvial strata deposited between 49 and 45 Ma yielded Precambrian (U-Th)/He zircon cooling ages (ZHe) with 105–740 m.y. lag times dominated by unreset detrital ages, suggesting limited exhumation and Proterozoic through early Eocene sediment burial (&lt;4–6 km) across the region. Minimum nonvolcanic detrital ZHe lag times decreased to &lt;100 m.y. in 45–43 Ma strata and to &lt;10 m.y. in 43–41 Ma strata, illustrating progressive and rapid hinterland unroofing in Eocene time. Detrital apatite (U-Th)/He ages present in ca. 44 and 39 Ma strata record Eocene cooling ages with 1–20 m.y. lag times. These data reflect acceleration of basem*nt exhumation rates by &gt;1 km/m.y., indicative of rapid, large-magnitude extensional faulting and metamorphic core complex formation. Contemporaneous with this acceleration of hinterland exhumation, syntectonic freshwater lakes developed in the hanging wall of the Ruby Mountains–East Humboldt Range metamorphic core complex at ca. 43 Ma. Volcanism driven by Farallon slab removal migrated southward across northeastern Nevada, resulting in voluminous rhyolitic eruptions at 41.5 and 40.1 Ma, and marking the abrupt end of fluvial and lacustrine deposition across much of the Elko Basin. Thermal and rheologic weakening of the lithosphere and/or partial slab removal likely initiated extensional deformation, rapidly unroofing deeper crustal levels. We attribute the observed acceleration in exhumation, expansion of sedimentary basins, and migrating volcanism across the middle Eocene to record the thermal and isostatic effects of Farallon slab rollback and subsequent removal of the lowermost mantle lithosphere.

Abstract:

AbstractFrom G. F. Becker's and L. V. Pirsson's early enunciations linking the dynamics of magma chambers to the rock records of sills and plutons to this day, two features stand at the centre of nearly every magmatic process: solidification fronts and phenocrysts. The structure and behaviour of the envisioned solidification front, however, has been mostly that akin to non-silicate, non-multiply-saturated systems, which has led to confusion in appreciating its role in magmatic evolution. The common habit of intruding magmas to carry significant amounts of phenocrysts, which can lead to efficient fractionation, layering, and interstitial melt flow within extensive mush piles, when coupled with solidification fronts, allows a broad understanding of the processes leading to the rock records of sills and lava lakes. These same processes are fundamental to understanding all magmas.The spatial manifestation of the liquidus and solidus is the Solidification Front (SF); all magmas, stationary or in transit, are encased by SFs. In the ideal case of an initially crystal-free, cooling magma, crystallinity increases from nucleation on the leading liquidus edge to a holocrystalline rock at the trailing solidus. The package of SF isotherms advances inward, thickening with time and, depending on location — roof, floor, or walls — and the initial crystallinity of the magma, is instrumental in controlling magmatic evolution. Bimodal volcanism as well as much of the structure of the oceanic crust may arise from the behaviour of SFs.In mafic magmas, somewhere near a crystallinity (N) of 55% (vol), depending on the phase assemblage, the SF changes from a viscous fluid (suspension (0<N<25) and mush (25<N<55%)) to an elastic crystalline network (rigid crust (55<N<100%)) of some strength containing interstitial residual melt. With thickening of the roofward SF of some mafic magmas, the weight of the leading, viscous portion repeatedly tears the crust near N ∼ 55–60%, efficiently segregating the local residual melt into zones of interdigitating silicic lenses. This is SF instability (SFI), a process of possible importance in continental crust initiation and evolution, in producing silicic segregations in oceanic crust, and in recording the inability of the viscous part of the upper SF ever to detach wholly in typical (<∼ 1 km) sheet-like magmas. These granophyric and pegmatitic segregations, individually reaching 1–2 m in thickness and 30–50 m in length, form thick (∼ 50–75 m) zones that can be misconstrued as sandwich horizons where the last liquids might have accumulated. In effectively splitting the magma chemically and spatially, SFI is, in essence, a form of chaos (i.e. silicic chaos).Differentiation of initially crystal-free, stationary magmas is limited to processes occurring within SFs, which operate in competition with the rate of inward advancement of solidification. Local processes operating on characteristic time scales longer than the time for the SF to advance a distance equal to its own thickness are suppressed. Enormous increases in viscosity outward within the viscous, leading portion of the SF efficiently partition the distribution of melt accessible to eruption. Eruptible melts lie essentially inward of the SF and are thus severely restricted in silica enrichment. The silica-enriched SFI melts are thus generally inaccessible to collection and eviction unless the host SF is reprocessed or “burned back” through, respectively, later regional magmatism or massive, late-stage re-injection. And because of large viscosity contrasts between SFI melts and host basalts, once freed, SFI melts are literally impossible to hom*ogenize back into the system and may collect and compact against the roof to form large silicic masses. Unusually voluminous, bulbous masses of silicic granophyre present along, and sometimes warping, the roofs of large diabase sills may reflect collections of remobilized blobs of SFI melts. These bulbous masses may be later added to the continental crust through solid state creep.In sheets made of phenocryst-rich, singly saturated magma, most phenocrysts are able through settling or floating to avoid capture by the advancing SFs. Significant differentiation is possible through extensive settling of initial phenocrysts and upward leakage of interstitial residual melt from the associated cumulate pile, which over-thickens the lower SF, greatly tipping the competitive edge against suppression of melt leakage by advancing solidification. Dense interstitial melts may similarly drain from roofward cumulates of light phenocrysts. The variation in crystal size and modal abundance in these cumulate piles are intimate records of prior crystallization, transport, and filling.Magmas in transit erode SFs and thoroughly charge the magma with crystals, facilitating fractionation and differentiation, especially if the body occasionally comes to rest. The key to protracted differentiation through fractional crystallization is not crystallization in stationary, closed chambers, but the repeated transport and chambering of magma or the periodic resupply to chambers of phenocryst-rich magma. This is punctuated differentiation, which may be the general case. Close corollaries are that thick, closed sheets of initially crystal-free, multiply-saturated magma undergo precious little overall differentiation, and that deciphering the sequence and crystallinity, including in transit phenocryst entrainment, growth, and sorting, of the filling events is central to unravelling intrusive history.Variations in temperature, whether on phase diagrams or in actual magmas, are intrinsically linked to commensurate variations in space and time in magmatic systems. The spectrum of all physical and chemical processes associated with magma is accordingly strongly partitioned in space and time.The idea of a magma chamber as a vat of low crystallinity melt crystallizing everywhere within and differentiating through crystal settling is unrealistic. A magma chamber formed of any number of crystal-laden inputs, encased by inward-propagating, dynamic solidification fronts, and where significant differentiation is tied to the dynamics of late-stage, interstitial melt within extensive mush piles is more in accord with the rock record.

Abstract:

Purpose. The physico-chemical processes in river mouth area, which include the Don and Kuban rivers, limited the transport capacity of the main ports of the Sea of Azov as a result of the silting by suspended matter by the river runoff. The fall of the depths in the the ports and marine channels is one of the key problems of the functioning of the ports. Dredging works and dumping linked with shipping as well as shipping linked with the world economy. It is impossible to abandon shipping, as well it is impossible to abandon the dredging and damping. For this reason, the purpose of the work is to assess the optimal dredging works for the exploitation of the ports of Ukraine in the Sea of Azov. Methods. The comparative analysis of modern hydrometeorological conditions, including the dominant influence of wind activity, the velocity and the direction of currents according to actual data, the transparency of sea water, the runoff the river Kalmius had been done. The available images of DigitalGlobe’s remote sensing satellites and dredging results, which were periodically performed to support the depths on the sea marine channel to the port water area, were examined. Modern and retrospective data of bathymetric surveys using GIS processing technologies for comparing the results, as well as standard methods of statistical data processing were also used. Results. During the investigated period, the images of the Earth's remote sensing satellites from DigitalGlobe were studied. An anthropogenic impact to the silting in the study area was revealed (the turning point between 0 km of the marine channel of the port and the shallow water area of the port of Azovstal). For compare the depths in the investigated area which is under the the river Kalmius influence positions of the surveyed post had been established. As result of analysis of direct measurement data and graphic material the permanent silting of the marine channel was not established as well as the direct statistical relationship between the silting and the river run incoming with suspended matter with Kalmius river. The main process of sedimentation determines by the Don river. The upper limit of maximum sedimentation is 5–7 ‰, coincides with the investigated area, where theoretically one should expect the process of accumulation of bottom sediments. Conclusion. The result of comparing Kalmius river runoff with depths in the marine channel of the port of Azovstal, in the area of area of river mouth, revealed there is not representative statistical relationship. It is necessary monitoring data for a long period of data for representative comparing the runoff Kalmius river and siling processes. In modern period the runoff of the Don river is significantly deformed under the influence of anthropogenic factors and the representative statistical estimation have to be done using only the direct measurements, which are fairly limited. Nevertheless, the reduction of Don river runoff and, thus, the direct impact on the recording capacity of the studied water area determines the need for and technological accessibility of dredging at a significantly lower the cost of wokrs at the present stage.

Abstract:

Abstract Context The North American Waterfowl Management Plan and the Upper Mississippi River/Great Lakes Joint Venture waterfowl habitat conservation strategy provide continental and regional guidance, respectively, for waterfowl habitat conservation planning. They were not designed to guide watershed- scale waterfowl habitat delivery. Objective Our goal was to develop a waterfowl habitat decision support framework for the state of Wisconsin using biological and social criteria to guide state and local-scale practitioners with an explicit link to larger scale objectives. Methods We engaged a core group of wetland and waterfowl experts to decide upon decision support layers relevant to biological and social objectives, evaluate variables, establish weights, and review model outputs for reasonableness and accuracy. We used spatial analyst tools, kernel density estimators, and weighted sums to create spatially explicit models to identify landscapes and watersheds important for waterfowl. We identified habitat resources that exist currently (Conservation Capital) and considered potential resources (Conservation Opportunities) which could enhance wetland restoration efforts. Results We developed a transparent framework to identify and prioritize landscapes for conserving waterfowl habitat at the Hydrologic Unit Code 12 watershed scale in Wisconsin, by maintaining continental and regional priorities, and including local landscape characteristics, biological criteria, and researcher, manager, and biologist expertise. Conclusions Local detail is critical for implementing waterfowl habitat delivery and making efficient use of limited funds for conservation but can be more abstract in larger regional or continental conservation planning. Our models are science-based, transparent, defensible, and can be modified as social, political, biological, and environmental forces change.

Abstract:

Abstract. Suharno, Kadir A, Sembiring E, Masiki AD, Mubarak T, Lessil N, Ratnawati LD, Idris D, Imbenai JG. 2021. Population estimation of freshwater crocodiles (Crocodylus novaeguineae) and tree vegetation diversity at wildlife reserve of Mamberamo Foja, Papua, Indonesia. Biodiversitas 22: 2928-2936. The structure and composition of vegetation in the conservation area have a major influence on the existence of other flora and fauna, including freshwater crocodiles (C. novaeguineae). Wildlife Reserve of Mamberamo Foja (WRMF) is a conservation area in Papua that aims to protect the habitat and existence of freshwater crocodiles. The purpose of this study was to estimate the number of freshwater crocodile populations and tree species diversity in the WRMF, Papua. The method used was a field survey. The crocodile survey was carried out using the spotlight night count method. Tree species diversity was assessed using the line-transect plot method in 6 different locations representing the Upper, Central, and Lower Mamberamo. The results of the investigation showed that the freshwater crocodile population in the WRMF was around 0.3-19.7 individuals per kilometer. The population of this freshwater crocodile was very high, with an average of 4.5 individuals per 1-kilometer distance. The highest population numbers were found in the upstream Mamberamo River area 6.22 ind./km, followed by the central Mamberamo (2.21 ind./km) and downstream Mamberamo area (2.05 ind./km). Crocodiles were found in the Mamberamo River and other river systems, such as swamps and lakes. The tree vegetation in this area is still relatively good, and there are 112 species, dominated by the Moraceae, Burseraceae, Myrtaceae, Rubiaceae, Lauraceae, Dipterocarpaceae, and Euphorbiaceae families. The results of this study are important as a basis for determining the conservation policy for freshwater crocodiles that have limited distribution.