Untangling hidden nutrient dynamics: rapid ammonium cycling and single-cell ammonium assimilation in marine plankton communities.

ABSTRACT: Ammonium is a central nutrient in aquatic systems. Yet, cell-specific ammonium assimilation among diverse functional plankton is poorly documented in field communities. Combining stable-isotope incubations (¹⁵N-ammonium, ¹⁵N₂ and ¹³C-bicarbonate) with secondary-ion mass spectrometry, we quantified bulk ammonium dynamics, N₂-fixation and carbon (C) fixation, as well as single-cell ammonium assimilation and C-fixation within plankton communities in nitrogen (N)-depleted surface waters during summer in the Baltic Sea. Ammonium production resulted from regenerated (≥91%) and new production (N₂-fixation, ≤9%), supporting primary production by 78-97 and 2-16%, respectively. Ammonium was produced and consumed at balanced rates, and

SUBMITTER: Klawonn I 

PROVIDER: S-EPMC6776039 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature