131898 - Ambient nitrate switches the ammonium consumption pathway.pdf (1.2 MB)
Ambient nitrate switches the ammonium consumption pathway in the euphotic ocean
journal contribution
posted on 2023-05-20, 02:43 authored by Wan, XS, Sheng, HX, Dai, M, Zhang, Y, Shi, D, Trull, T, Zhu, Y, Lomas, MW, Kao, SJPhytoplankton assimilation and microbial oxidation of ammonium are two critical conversion pathways in the marine nitrogen cycle. The underlying regulatory mechanisms of these two competing processes remain unclear. Here we show that ambient nitrate acts as a key variable to bifurcate ammonium flow through assimilation or oxidation, and the depth of the nitracline represents a robust spatial boundary between ammonium assimilators and oxidizers in the stratified ocean. Profiles of ammonium utilization show that phytoplankton assemblages in nitrate-depleted regimes have higher ammonium affinity than nitrifiers. In nitrate replete conditions, by contrast, phytoplankton reduce their ammonium reliance and thus enhance the success of nitrifiers. This finding helps to explain existing discrepancies in the understanding of light inhibition of surface nitrification in the global ocean, and provides further insights into the spatial linkages between oceanic nitrification and new production.
History
Publication title
Nature CommunicationsVolume
9Article number
915Number
915Pagination
1-9ISSN
2041-1723Department/School
Institute for Marine and Antarctic StudiesPublisher
Nature Publishing GroupPlace of publication
United KingdomRights statement
Copyright 2018 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/Repository Status
- Open