We investigated the response of the microbial components of the pelagic food web to re-oligotrophication of large, deep Lake Constance where total phosphorus concentrations during mixing decreased from a maximum of 2.81 mmol L 1 in 1979 via 1.87 mmol L 1 in 1987 to 0.26 mmol L 1 in 2007. Measurements of heterotrophic bacteria, autotrophic picoplankton (APP) and heterotrophic nanoflagellates (HN...

Microbial transformations are key processes in marine phosphorus cycling. In this study, we investigated the contribution of phototrophic and heterotrophic groups to phosphate (Pi) uptake fluxes in the euphotic zone of the lowPi Mediterranean Sea and estimated Pi uptake kinetic characteristics. Surface soluble reactive phosphorus (SRP) concentrations were in the range of 6–80 nmol L across the ...

The Mediterranean Sea is one of the most oligotrophic marine areas on earth where nitrogen fixation has formally believed to play an important role in carbon and nitrogen fluxes. Although this view is under debate, the diazotrophs responsible for this activity have still not been investigated in the open sea. In this study, we characterised the surface distribution and species richness of unice...