نتایج جستجو برای: freshwater ecosystem
تعداد نتایج: 107604 فیلتر نتایج به سال:
Many factors contribute to the nonrandom processes of extinctions and invasions that are changing the structure of ecological communities worldwide. These factors include the attributes of the species, their abiotic environment, and the interactions and feedbacks between them. The relative importance of these factors has been difficult to quantify. We used nested subset theory and a novel permu...
The diatom composition on some Charophyceae taxa was investigated in different freshwater ecosystems in Bosnia and Herzegovina, Croatia and Montenegro during 2007. A total of 91 taxa belonging to 37 genera were identified. The genus Gomphonema with 9 taxa was the most diverse, followed by Navicula (7), Nitzschia, Pinnularia and Gyrosigma (5). The number of taxa at the localities varied from nin...
large tropical storms can have dramatic effects on coastal, estuarine and terrestrial ecosystems. However, it is not as well understood how these types of disturbances might impact freshwater communities further inland. Storm surges can change critical water quality parameters for kilometers upstream, potentially causing subtle shifts in community structure or more drastic fish kills. Hurricane...
/ This paper presents a foundation for improving the risk assessmentprocess for freshwater wetlands. Integrating wetland science, i.e., use of anecosystem-based approach, is the key concept. Each biotic and abiotic wetlandcomponent should be identified and its contribution to ecosystem functionsand societal values determined when deciding whether a stressor poses anunreasonable risk to the sust...
likely, therefore, that allowance for the fixation of organic carbon as both DOC and POC would tend to reduce the ratio of I : PP in oligotrophic versus eutrophic systems. In conclusion, I disagree with Calbet (2001, p. 1828) that ‘‘the relative importance of microand mesozooplankton in the food dynamics of marine ecosystems, as well as the role of mesozooplankton grazing, must be reevaluated.’...
Invertebrates living in streams where predatory fish are present are often able to detect them through waterborne chemical cues and respond with behavioural changes that lower predation risk. We hypothesised that behavioural responses to a predatory fish (brown trout, Salmo trutta) would be stronger in grazing mayflies (Baetis sp. and Epeorus sp.) than in detritivorous caddisflies (Potamophylax...
Lake ecosystems across the globe have responded to climate warming of recent decades and are expected to further change in the future. Anticipating impacts that are detrimental to water quality is critically important given that lakes constitute a major part of the earth’s freshwater resources. A central concern is the climate impact on phytoplankton, including algae and cyanobacteria, since it...
Conversion of land to grow crops, raise animals, obtain timber, and build cities is one of the foundations of human civilization. While land use provides these essential ecosystem goods, it alters a range of other ecosystem functions, such as the provisioning of freshwater, regulation of climate and biogeochemical cycles, and maintenance of soil fertility. It also alters habitat for biological ...
Subarctic Siberian freshwater ecosystems are unique due to severe climatic conditions and strong seasonal changes of water supply, temperature and nutrient availability. In this work we evaluated the relative influence of the illumination level linked with the diurnal cycle, local environmental heterogeneity and water level changes during the receding flood on the distribution and migrations of...
In 2001 the LIMNOPOLAR Project was launched with the aim of addressing the suitability of freshwater ecosystems as useful sentinels of climate change. In this project, an automatic weather station was deployed on Byers Peninsula (Livingston Island, South Shetland Islands) near several freshwater ecosystems under research. Here the multi-year data recorded are presented and compared with meteoro...
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