Nitrogen uptake by phytoplankton and bacteria during an induced Phaeocystis pouchetii bloom, measured using size fractionation and flow cytometric sorting

Incidence of phytoplankton and environmental conditions on the bacterial ammonium uptake in a subtropical coastal lagoon

“…The positive and significant correlations found between bacterioplankton and phytoplankton NH 4 + uptake rates support this finding, suggesting that this process was coupled between these communities in the North of Laguna de Rocha. Coupling in the ammonium uptake by phytoplankton and bacterioplankton has also been reported in other estuarine environments as the Delaware estuary (Parker, 2005) or coastal waters (Bradley et al, 2010).…”

Dynamics of Dissolved Organic Nitrogen

“…Sanderson et al (2008) found urea uptake rates to account for the majority of total N uptake in both phytoplankton and bacterial size classes during a Phaeocystis bloom within a Raunefjord, Norway mesocosm study. Similarly Bradley and colleagues also found that urea contributed 10-25% of total N uptake by both phytoplankton and bacteria in mesocosm studies in Raunefjord, Norway (Bradley et al, 2010c) as well as in surface waters at LEO-15 in the Mid-Atlantic Bight where urea served as the dominant N form utilized (Bradley et al, 2010b). Uptake of urea in the coastal Chukchi Sea was determined to be very low under ice conditions (Baer et al, submitted), however, rates were much higher in the Data were taken from text, tables, estimated from graphs, or obtained from the authors and are presented as the mean ± standard deviation.…”

“…Uptake rates of AA by the bacterial size class were often greater than that of NH 4 + in a bloom of Phaeocystis within mesocosm studies in Raunefjord, Norway (Sanderson et al, 2008). Bradley et al (2010c) showed that although DFAA uptake was negligible in phytoplankton it accounted for 11% of total N utilized by bacteria. A similar approach was used with 35 S-labeled methionine to estimate DFAA uptake by Prochlorococcus and Synechococcus in the South Atlantic (Zubkov and Tarran, 2005).…”

Differentiating the role of different-sized microorganisms in peptide decomposition during incubations using size-fractioned coastal seawater

“…Recent studies showed that a significant fraction of labile organic matter, such as peptides, is processed by protists in the >3-5 µm seawater (Berg et al, 2002;Bradley et al, 2010;Karner et al, 1994). As single-cell eukaryotes, protists include autotrophic phytoplankton, heterotrophic flagellates, microzooplanktonic ciliates and mixotrophic microbes (Kirchman, 2008).…”