Periphyton succession was studied over 89 d in longitudinally adjacent reaches (a riffle and run) in Sycamore Creek, a spatially intermittent desert stream. Effects of nitrogen limitation were assessed by comparing algal development on clay saucers containing either nitrate-enriched or unenriched agar. We evaluated effects of grazing on periphyton accrual by amending agar in half the substrata ...

1. Pacific salmon and steelhead once contributed large amounts of marine-derived carbon, nitrogen and phosphorus to freshwater ecosystems in the Pacific Northwest of the United States of America (California, Oregon, Washington and Idaho). Declines in historically abundant anadromous salmonid populations represent a significant loss of returning nutrients across a large spatial scale. Recently, ...

we studied the role of nutrients on various aspects of the periphyton community in artificialstreams. dry mass, ash-free dry mass, chlorophyll a and biovolume of the periphyton community weremeasured under 3 different nutrient regimes, including one from natural streams as a control and twowhich were enriched with n and n+p. results of this experiment indicate that the standing crop of theperip...

Reservoirs are intrinsically linked to the rivers that feed them, creating a river–reservoir continuum in which water and sediment inputs are a function of the surrounding watershed land use. We examined the spatial and temporal variability of sediment denitrification rates by sampling longitudinally along an agriculturally influenced river–reservoir continuum monthly for 13 months. Sediment de...

Stream bioassessment is important for understanding algal-nutrient relationships and the development of scientifically defensible numeric nutrient criteria. However, multiple methods of periphyton data collection are currently used, and little is known about the comparability of resulting datasets. Literature also suggests other factors besides nutrients (i.e. variable grazing, light, and flow)...

Clams of the genus Donax are worldwide the dominating group of the invertebrate community on sandy beaches. They are primary consumers that provide a significant abundance and biomass to the ecosystem. In the Caribbean, Donax striatus has an important role for nature and human, nonetheless studies on the population dynamics of this beach clam are scarce and no information exists on secondary pr...

The influence of the herbivorous snail (Physa sp.) on the algal periphyton community from the Gamasiyab River, Kermanshah province in western Iran was examined by establishing a gradient of Physa sp. density in artificial streams. The impact of Physa grazing was evaluated by measuring dry mass, ash-free dry mass (AFDM) and chlorophyll a in the periphyton community. Snails significantly depresse...

Dendritic tidal creek networks are important habitats for sustaining biodiversity and ecosystem functioning in salt marsh wetlands. To evaluate the importance of creek heterogeneity in supporting benthic secondary production, we assess the spatial distribution and secondary production of a representative polychaete species (Dentinephtys glabra) in creek networks along a stream-order gradient in...

Heterotrophic microbes colonizing detritus obtain nitrogen (N) for growth by assimilating N from their substrate or immobilizing exogenous inorganic N. Microbial use of these two pools has different implications for N cycling and organic matter decomposition in the face of the global increase in biologically available N. We used sugar maple leaves labeled with 15N to differentiate between micro...

Supplemental feeding to mitigate the effects of food shortages may in some cases provide critical help species conservation. However, supplemental have both positive and negative on wildlife environment. A scientifically designed project helps achieve conservation targets reduces adverse effects. Here, we summarize a three-step framework for supplementation that used practice: (1) determining w...