Contrasting Roles of DOP as a Source of Phosphorus and Energy for Marine Diazotrophs

Frontiers in Marine Science

Marine Science

Elvira Pulido-Villena¹  Olivier Grosso¹  France Van Wambeke¹  Sophie Bonnet¹  Mar Benavides²  Alba Filella²  Angela Vogts³  Solange Duhamel⁴  Lasse Riemann⁵  Julia M. Diaz⁶ 

[1] Aix Marseille Univ, Université de Toulon, CNRS, IRD, Marseille, France;Aix Marseille Univ, Université de Toulon, CNRS, IRD, Marseille, France;Turing Center for Living Systems, Aix-Marseille University, Marseille, France;Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Rostock, Germany;Department of Molecular and Cellular Biology, The University of Arizona, Tucson, AZ, United States;Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark;Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States;

关键词: nitrogen fixation;    Trichodesmium;    Crocosphaera;    polyphosphate;    phosphoanhydride;    phosphoester;   

DOI  :  10.3389/fmars.2022.923765

 received in 2022-04-19, accepted in 2022-06-20,  发布年份 2022

来源: Frontiers

【 摘 要 】

The oceanic dissolved organic phosphorus (DOP) pool is mainly composed of P-esters and, to a lesser extent, equally abundant phosphonate and P-anhydride molecules. In phosphate-limited ocean regions, diazotrophs are thought to rely on DOP compounds as an alternative source of phosphorus (P). While both P-esters and phosphonates effectively promote dinitrogen (N2) fixation, the role of P-anhydrides for diazotrophs is unknown. Here we explore the effect of P-anhydrides on N2 fixation at two stations with contrasting biogeochemical conditions: one located in the Tonga trench volcanic arc region (“volcano,” with low phosphate and high iron concentrations), and the other in the South Pacific Gyre (“gyre,” with moderate phosphate and low iron). We incubated surface seawater with AMP (P-ester), ATP (P-ester and P-anhydride), or 3polyP (P-anhydride) and determined cell-specific N2 fixation rates, nifH gene abundance, and transcription in Crocosphaera and Trichodesmium. Trichodesmium did not respond to any DOP compounds added, suggesting that they were not P-limited at the volcano station and were outcompeted by the low iron conditions at the gyre station. Conversely, Crocosphaera were numerous at both stations and their specific N2 fixation rates were stimulated by AMP at the volcano station and slightly by 3polyP at both stations. Heterotrophic bacteria responded to ATP and 3polyP additions similarly at both stations, despite the contrasting phosphate and iron availability. The use of 3polyP by Crocosphaera and heterotrophic bacteria at both low and moderate phosphate concentrations suggests that this compound, in addition to being a source of P, can be used to acquire energy for which both groups compete. P-anhydrides may thus leverage energy restrictions to diazotrophs in the future stratified and nutrient-impoverished ocean.

【 授权许可】

Unknown   
Copyright © 2022 Filella, Riemann, Van Wambeke, Pulido-Villena, Vogts, Bonnet, Grosso, Diaz, Duhamel and Benavides