The roles of priority effects and predation in structuring anuran communities have not been considered important in desert environments characterized by highly ephemeral pools and anuran species that breed synchronously. Predation is one mechanism that can set the stage for priority effects to be important, especially in ephemeral pools where resources are limiting and densities are high. We ob...

The Coweeta Hydrologic Laboratory, USFS Southern Research Station, worked with state and local agencies and various organizations to provide guidance and tools to reduce sedimentation and facilitate restoration of the 1900km2 Conasauga River watershed in northern Georgia and southern Tennessee. The Conasauga River has the most diverse aquatic ecosystem of any river in the region and is currentl...

sperm morphology, biochemistry and physiology were compared between siberian sturgeon Acipenser baerii and sterlet A. ruthenus in the present study. We observed wide morphological variations between spermatozoa of the two species. the average length of the spermatozoon head was 7.01 and 5.14 μm in A. baerii and A. ruthenus, respectively. Significant differences were observed in terms of Na+, k+...

T wo decades ago, David Mangelsdorf did not expect his basic research findings to help launch an entire field of biology with farreaching implications for a raft of human diseases, including cancer, metabolic disorders, and parasitic infections. Mangelsdorf, a Howard Hughes Medical Institute investigator and a professor of pharmacology at the University of Texas Southwestern Medical Center at D...

Water and sediment samples were collected from 20 location of the Buriganga river of Bangladesh during Summer and Winter 2009 to determine the spatial distribution, seasonal and temporal variation of different heavy metal contents. Sequential extraction procedure was employed in sediment samples for the geochemical partitioning of the metals. Total trace metal content in water and sediment samp...

Five rapid visual stream assessment methods were applied to 65 restored streams in North Carolina, and the results were correlated with measured macroinvertebrate community metrics to evaluate predictive ability. The USEPA Rapid Bioassessment Protocol (RBP), USDA Stream Visual Assessment Protocol (SVAP), Peterson’s Riparian Channel and Environmental Inventory (RCE), NCSU Eco-Geomorphological As...

Potential use of retention/detention reservoirs stocked with vascular aquatic macrophytes was evaluated, using a microcosm reservoir for reducing the N and P levels of agricultural drainage effluents (waste water). The treatments evaluated were reservoirs stocked with (i) pennywort (Hydrocotyle umbellata L.), (ii) water hyacinth (Eichhornia crassipes [Mart] Solms), (iii) cattails (Typha latifol...

A turbulent diffusion model shows that there are two different mechanisms for the development of phytoplankton blooms. One of these mechanisms works in well-mixed environments and corresponds to the classical critical depth theory. The other mechanism is based on the rate of turbulent mixing. If turbulent mixing is less than a critical turbulence, phytoplankton growth rates exceed the vertical ...

External gradients of matter and energy drive the behavior of dissipative structures. Therefore, it can be believed that external gradients also drive, ultimately, the behavior of self-organizing, complex, dissipative systems, like ecosystems. Nutrient gradients are ordinarily expressed between a lake and its environment and also between the lake biota and its chemical-physical environment. For...

As the world’s population increases, the rising demand for water will be compounded further by the need to sustain economic growth (Vörösmarty et al. 2000). According to one report by the United Nations Environment Program (UNEP), the stress on freshwater resources is expected to significantly magnify and spread to other regions of the world by 2025 (see Fig. 1; UNEP 2002). Historically, one of...