Factors regulating lake periphyton biomass and nutrient limitation status across a large trophic gradient

Nutrient availability and phytoplankton nutrient limitation across a gradient of atmospheric nitrogen deposition.

Atmospheric nitrogen (N) deposition to lakes and watersheds has been increasing steadily due to various anthropogenic activities. Because such anthropogenic N is widely distributed, even lakes relatively removed from direct human disturbance are potentially impacted. However, the effects of increased atmospheric N deposition on lakes are not well documented. We examined phytoplankton biomass, t...

Nitrogen fixation and phosphatase activity in periphyton growing on nutrient diffusing substrata: evidence for differential nutrient limitation in stream periphyton

We explored N2 fixation and alkaline phosphatase activity (APA) in periphyton from a N-limited stream ecosystem by coupling measurements of these processes with nutrient diffusion substrata (NDS) experiments. We measured periphyton biomass accumulation (as ash-free dry mass [AFDM] and chlorophyll a [CHLA]), N2 fixation, and APA to evaluate the relative importance of N2 fixation as an N source t...

Trophic Status of the Lake

The Effects of Ultraviolet Radiation and Nutrient Additions on Periphyton Biomass and Composition in a Sub-Alpine Lake (Castle Lake, USA)

Rising levels of ultraviolet radiation (UVR) striking the Earth’s surface have led to numerous studies assessing its inhibitory effects on phytoplankton and periphyton in aquatic systems. Mineral nutrients such as nitrogen (N) and phosphorus (P) have been shown to increase aspects of algal metabolism and compensate for UVR inhibition. An in situ substratum enrichment technique and UV shielding ...

Nutrient recycling by Tropheus brichardi across a littoral productivity gradient in Lake Tanganyika Student:

Nutrient recycling occurs when nutrients are released into the environment by animals or microbial consumers. Fishmediated nutrient recycling is an important source of nutrients for primary producers in many aquatic ecosystems, sometimes even exceeding external loading rates (Attayde and Hansson 2001). Consumers release non-assimilated nutrients as liquid waste that is available to primary prod...