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shallow lake

Sarah P Slotznick, Nicholas L Swanson-Hysell, Erik A Sperling
Terrestrial environments have been suggested as an oxic haven for eukaryotic life and diversification during portions of the Proterozoic Eon when the ocean was dominantly anoxic. However, iron speciation and Fe/Al data from the ca. 1.1-billion-year-old Nonesuch Formation, deposited in a large lake and bearing a diverse assemblage of early eukaryotes, are interpreted to indicate persistently anoxic conditions. To shed light on these distinct hypotheses, we analyzed two drill cores spanning the transgression into the lake and its subsequent shallowing...
December 3, 2018: Proceedings of the National Academy of Sciences of the United States of America
Jakub Žák, Martin Reichard, Lumír Gvoždík
The coexistence of ectothermic species is enabled among other factors by the differentiation of their thermal niches. While this phenomenon is well described from deep temperate lakes, it is unclear whether the same pattern applies to temporary pools. In this study, we examined fundamental thermal niches in three coexisting annual killifish species Nothobranchius furzeri, N. orthonotus and N. pienaari from temporary pools in southern Mozambique. We hypothesized that the disparate thermal requirements of the three congeneric species are a candidate niche component that facilitates their local coexistence...
December 2018: Journal of Thermal Biology
Hamed A El-Serehy, Hala S Abdallah, Fahad A Al-Misned, Saleh A Al-Farraj, Khaled A Al-Rasheid
Lake Timsah is considered as the biggest water body at Ismailia City with a surface area of 14 km2 . It is a saline shallow water basin lies approximately mid-way between the south city of Suez and the north city of Port Said at 30o 35'46.55"N and 32o 19'30.54″E. Because it receives water with high and low salinities, salinity stratification is producing in the Lake Timsah, with values of 14-40‰ for the surface water and over 40‰ for the bottom water. The temperature of the lake water decreased to below 19 °C in the winter and rose to above 29 °C in the summer; the concentration of dissolved oxygen ranged between 6...
November 2018: Saudi Journal of Biological Sciences
Huacheng Xu, Li Ji, Ming Kong, Mengwen Xu, Xizhi Lv
Colloidal particles are omnipresent in lake sediments and substantially influence the retention, transportation, and fate of contaminants in lake ecosystems. In this study, the abundance, chemical composition and adsorption behavior of sedimentary colloids (including total and inorganic colloids) from different ecological regions, were for the first time investigated via ultrasonic extraction, spectral analysis and batch absorption experiments. Results showed that the extraction efficiencies of sedimentary colloids showed an ultrasonic energy-dependent enhancement, and the algae-dominated area contained comparable colloidal abundance with the macrophyte-dominated area (i...
November 23, 2018: Chemosphere
Junyu Zou, Yuesuo Yang, Siqi Jia, Cuiping Gao, Zefeng Song
The biogeochemical cycling and response mechanisms of carbon within the Wudalianchi UNESCO Global Geopark were characterized by the isotopic compositions of dissolved inorganic carbon (δ13 CDIC ) and dissolved organic carbon in ground and surface (lake) waters and their relating carbon isotopic composition of soil (δ13 CSOC ) and sediment organic carbon (δ13 Corg ). In addition to mantle-derived CO2 , the oxidation of organic matter was prevalent in shallow groundwater during the summer. Their associated degassing of CO2 produced higher pCO2 values than in autumn or winter and elevated δ13 CDIC values...
November 29, 2018: Environmental Science and Pollution Research International
Haojie Su, Yao Wu, Wulai Xia, Lei Yang, Jianfeng Chen, Wenxuan Han, Jingyun Fang, Ping Xie
Catastrophic regime shifts in shallow lakes are hard to predict due to a lack of clear understanding of the associate mechanisms. Theory of alternative stable states suggests that eutrophication has profound negative effects on the structure, function and stability of freshwater ecosystems. However, it is still unclear how eutrophication destabilizes ecosystems stoichiometrically before a tipping point is reached. The stoichiometric homeostasis (H), which links fine-scale process to broad-scale patterns, is a key parameter in ecological stoichiometry...
November 12, 2018: Water Research
Ke Zhang, Xiangdong Yang, Giri Kattel, Qi Lin, Ji Shen
Global lake systems have undergone rapid degradation over the past century. Scientists and managers are struggling to manage the highly degraded lake systems to cope with escalating anthropogenic pressures. Improved knowledge of how lakes and social systems co-evolved up to the present is vital for understanding, modeling, and anticipating the current and future ecological status of lakes. Here, by integrating paleoenvironmental, instrumental and historical documentary resources at multi-decadal scales, we demonstrate how a typical shallow lake system evolved over the last century in the Yangtze River Basin, an urbanized region containing thousands of shallow lakes...
November 21, 2018: Scientific Reports
Maarten Van Steenberge, Joost André Maria Raeymaekers, Pascal István Hablützel, Maarten Pieterjan Maria Vanhove, Stephan Koblmüller, Jos Snoeks
Background: Species delineation is particularly challenging in taxa with substantial intra-specific variation. In systematic studies of fishes, meristics and linear measurements that describe shape are often used to delineate species. Yet, little is known about the taxonomic value of these two types of morphological characteristics. Here, we used Tropheus (Teleostei, Cichlidae) from the southern subbasin of Lake Tanganyika to test which of these types of characters best matched genetic lineages that could represent species in this group of stenotypic rock-dwelling cichlids...
2018: Frontiers in Zoology
Stijn Van Onsem, Ludwig Triest
The aquatic vegetation in nutrient-rich shallow lakes and ponds is structured by the interplay of multiple biotic and abiotic drivers. We tested the contribution of the macrophyte propagule bank and the delayed as well as direct impact of waterbirds on submerged aquatic vegetation in a peri-urban pond system. To clarify the functional hierarchy of predictor variables, effects of herbivorous waterfowl and propagule bank potential were ranked relative to environmental, phytoplankton, and zooplankton indicators...
2018: Frontiers in Plant Science
Priit Zingel, Helen Agasild, Katrit Karus, Linda Buholce, Tiina Nõges
We estimated the consumption of planktonic ciliates by fish larvae in the Väinameri Sea (a shallow semi-enclosed bay of the Baltic Sea) and Lake Võrtsjärv (a shallow and eutrophic lake). Our primary hypothesis was that planktonic ciliates constitute a substantial component of the diet of fish larvae in both environments. We also assumed that the contribution of ciliates to larval nutrition is bigger in lacustrine than in marine environment because ciliates are usually more abundant in lakes. The nutrition of field collected larval fish was determined by gut content analysis using epifluorescence microscopy...
November 2, 2018: European Journal of Protistology
David T Flannery, Abigail C Allwood, Robert Hodyss, Roger Everett Summons, Michael Tuite, Malcolm R Walter, Kenneth H Williford
Ooids are accretionary grains commonly reported from turbulent, shallow-water environments. They have long been associated with microbially dominated ecosystems and often occur in close proximity to, or embedded within, stromatolites, yet have historically been thought to form solely through physicochemical processes. Numerous studies have revealed both constructive and destructive roles for microbes colonizing the surfaces of modern calcitic and aragonitic ooids, but there has been little evidence for the operation of these processes during the Archean and Proterozoic, when both ooids and microbially dominated ecosystems were more widespread...
November 18, 2018: Geobiology
Patricia Elizabeth García, Claudia Queimaliños, María C Diéguez
In aquatic environments the reactive oxygen species hydrogen peroxide (H2 O2 ) is produced through photochemical reactions involving chromophoric dissolved organic matter (CDOM). Andean Patagonian freshwaters experience challenging underwater UV levels, which promote high levels of photochemical weathering. In this investigation, we study natural H2 O2 levels and experimentally address the photochemical formation of H2 O2 in stream and lake water with a range of dissolved organic matter (DOM) concentrations and quality...
October 29, 2018: Chemosphere
Francisco Rivera Vasconcelos, Sebastian Diehl, Patricia Rodríguez, Per Hedström, Jan Karlsson, Pär Byström
Productivity and trophic structure of aquatic ecosystems result from a complex interplay of bottom-up and top-down forces that operate across benthic and pelagic food web compartments. Projected global changes urge the question how this interplay will be affected by browning (increasing input of terrestrial dissolved organic matter), nutrient enrichment and warming. We explored this with a process-based model of a shallow lake food web consisting of benthic and pelagic components (abiotic resources, primary producers, grazers, carnivores), and compared model expectations with the results of a browning and warming experiment in nutrient-poor ponds harboring a boreal lake community...
November 15, 2018: Global Change Biology
Zhichun Li, Yanping Zhao, Xiaoguang Xu, Ruiming Han, Mingyue Wang, Guoxiang Wang
The decomposition processes of accumulated cyanobacteria can release large amounts of organic carbon and affect the carbon cycling in shallow eutrophic lakes. However, the migration and transformation mechanisms of dissolved carbon (DC) require further study and discussion. In this study, a 73-day laboratory microcosm experiment using suction samplers (Rhizon and syringe) was conducted to understand the migration and transformation of DC during the cyanobacteria decomposition. The decomposition of cyanobacteria biomass caused anoxic and reduction conditions, and changed the acid-base environment in the water column...
2018: PeerJ
Qing Sheng Zhu, Ling Yang Kong, Li Chen, Xiao Wang, Jiao Yuan Wang, Wen Gang Kang, Rui Li, Hong Liang, Guang Jie Chen
Shallow lakes, sensitive to environmental changes due to low environmental carrying capacity, generally experience decreases in ecosystem function and even regime shifts after over-exploitation. Surface sediments of 18 shallow lakes in Yunnan were collected and analyzed to identify the spatial pattern and the influencing factors of cladoceran communities. The results showed that there was significant heterogeneity in the spatial distribution of cladocera in those lakes. For example, the cladoceran community was generally dominated by benthic taxa in alpine lakes, while there was a clear replacement of benthic cladocerans by planktonic ones with increasing nutrient levels across lakes from Southeast Yunnan...
September 2018: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
Rasha M Abou Samra, R R Ali
Soil salinization is one of the major environmental problems facing agricultural lands in arid and semiarid areas of the world because of its detrimental impacts on agricultural production and on the sustainable development of land resources. Hence, predicting soil salinity is essential to avoiding further soil degradation. The present study is intended to develop a model for predicting soil salinity in soils around Idku Lake by using remote sensing and geographic information system techniques. This lake is a shallow brackish basin located in the western part of the Nile Delta...
November 8, 2018: Environmental Monitoring and Assessment
Daniel C Brown, Cale F Brownstead, Anthony P Lyons, Thomas B Gabrielson
Measurements have been made near normal incidence of the two-dimensional spatial coherence of the acoustic field scattered from the lakebed in Seneca Lake, New York. In the test region, the lakebed consists of a series of sediment layers created by a sequence of distinct depositional processes. The spatial coherence length of the scattered field is shown to be dependent on the structure of the underlying sediment sequences. Significant ping-to-ping variability in the spatial coherence surface was also observed for each sediment sequence...
October 2018: Journal of the Acoustical Society of America
Chengcheng Li, Xubo Gao
Dramatic decreases in groundwater quality have raised widespread concerns about water supplies and ecological crises in China. In this study, hydrochemistry, stable isotopes, graphical and multivariate statistical methods are integrated to identify hydrogeochemical processes controlling groundwater quality in the Yuncheng Basin, China. Our results show that groundwater with 21 variables (pH, temperature-T, TDS, major-trace elements and stable isotopes) is chemically classified into three distinct clusters: fresh water [C1], brackish-saline water [C2], and saline water [C3]...
October 30, 2018: Ground Water
Yunlong Zhang, Xuan Wang, Chunhui Li, Yanpeng Cai, Zhifeng Yang, Yujun Yi
Three meteorological parameters, including one parameter representing water conditions (i.e., precipitation) and two parameters representing energy conditions (i.e., net radiation and air temperature), were used to make an in-depth analysis of the response of Normalized Difference Vegetation Index (NDVI) dynamics to climate change in Lake Baiyangdian, a shallow lake located in Xiong'an New Area (XNA), a future metropolitan in North China. The results showed that the vegetation coverage of the entire area remained at a medium level with average NDVI being 0...
October 29, 2018: Scientific Reports
Yawen Ge, Ke Zhang, Xiangdong Yang
Land use and land cover changes (LUCCs) have largely altered terrestrial ecosystems and landscapes during the Anthropocene. Reconstructing past LUCCs is necessary to better understand terrestrial ecosystem succession and human-environment interactions so that ecosystem services can be used conservatively and developed sustainably. In this paper, we reconstructed the LUCCs over the past century in a typical anthropogenic watershed based on a high-resolution pollen record from Changdang Lake, eastern China. The sediment core was 210 Pb dated and constrained cluster analysis identified different periods of LUCCs associated with the 110-year pollen record...
February 10, 2019: Science of the Total Environment
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