The main objectives of this study were to uncover the pathways used for methanogenesis in three different boreal peatland ecosystems and to describe the methanogenic populations involved. The mesotrophic fen had the lowest proportion of CH4 produced from H2-CO2. The oligotrophic fen was the most hydrogenotrophic, followed by the ombrotrophic bog. Each site was characterized by a specific group ...

Hyperspectral profiles of downwelling irradiance and upwelling radiance in natural waters (oligotrophic and mesotrophic) are combined with inverse radiative transfer to obtain high resolution spectra of the absorption coefficient (a) and the backscattering coefficient (b(b)) of the water and its constituents. The absorption coefficient at the mesotrophic station clearly shows spectral absorptio...

Although cyanobacterial blooms are typically found in eutrophic lakes, where they are able to exert inhibitory effects on other plankton, they are also reported from oligotrophic and mesotrophic lakes. Here, we explored whether trophic state mediates the effects of Gloeotrichia echinulata blooms in freshwater ecosystems. This taxon is a large, colonial cyanobacterium that may be increasing in l...

In this study, the influence of eutrophication on arsenic speciation in lake waters was investigated. Surface water samples (n=1-10) were collected from 18 lakes in Japan during July 2007 and February 2008. The lakes were classified into mesotrophic (7 lakes) and eutrophic (11 lakes) based on the total phosphate (T-P) and chlorophyll-a (Chl-a) concentrations in water column. Inorganic, methylat...

Global warming, as well as europhication are predicted to promote cyanobacterial blooms, but how tropical phytoplankton communities from different trophic state systems respond to temperature variation is less known. To further explore the effect of temperature changes and nutrient addition on phytoplankton communities and to get insight in possible resistance to these effects, we tested the hy...

This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modelin...

Primary productivity and chlorophyll a concentrations were measured in 8 reservoirs in New York City drinking-water-supply watersheds. The light-and-dark bottle O2-change procedure was used to measure gross primary productivity (GPP) once each summer from 2000 to 2002. GPP normalized for photosynthetically active radiation (PAR) in the Neversink and Schoharie averaged only 0.025 and 0.035 g O2/...

Until the early 1960s, Lake Ladoga was oligotrophic and characterized by good water quality, but within the past 20–30 years, as a result of human impact, the ecological state seems to have deteriorated. Especially since the 1970s, its trophic state has changed to mesotrophic, with elevated nutrient concentrations and decreased transparency. Conditions at some of the worst polluted sites have a...

Nutrient and grazing levels were manipulated in a 10 wk field experiment at 2 sites in a subtropical lagoon in Bermuda to evaluate their relative effects on the abundance and growth of the dominant seagrass and macroalgae. One site was eutrophic, the other mesotrophic to oligotrophc. Nutrients were added to the sediment-water interface using slow-release fertilizer, and the dominant herbivores ...