Virus-driven nitrogen cycling enhances phytoplankton growth

Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems

We present an analysis of the global impact of microplanktonic grazers on marine phytoplankton and its implications for remineralization processes in the microbial community. The data were obtained by an extensive literature search that yielded 788 paired rate estimates of autotrophic growth (m) and microzooplankton grazing (m) from dilution experiments. From studies in which phytoplankton stan...

Nitrogen Metabolism in Phytoplankton

Sagebrush carrying out hydraulic lift enhances surface soil nitrogen cycling and nitrogen uptake into inflorescences.

Plant roots serve as conduits for water flow not only from soil to leaves but also from wetter to drier soil. This hydraulic redistribution through root systems occurs in soils worldwide and can enhance stomatal opening, transpiration, and plant carbon gain. For decades, upward hydraulic lift (HL) of deep water through roots into dry, litter-rich, surface soil also has been hypothesized to enha...

Cycling of colloidal organic carbon and nitrogen during an estuarine phytoplankton bloom

To establish the influence of phytoplankton blooms on the cycling of dissolved and particulate species of organic carbon and nitrogen, we conducted a field study during a series of blooms in a coastal embayment on Shelter Island, NY. Using cross-flow filtration, we collected highand low-molecular-weight (HMW and LMW) dissolved organic matter (DOM), along with particulate organic matter (POM). T...

Inorganic nitrogen metabolism by Antarctic phytoplankton with special reference to ammonium cycling

Nitrogen metabolism of planktonic populations in coastal waters of the southern Scotia Sea was studied in February-March 1981 aboard R/V M e l d l e . In spite of the high concentration of nitrate present in these waters (21 to 29 FM), up to 93 % of phytoplankton nitrogen was assimilated in the form of ammonium, with the overall mean being 78 %. Time course experiments showed that uptake of nit...