Bridging the spatiotemporal gap in diazotroph activity and diversity with high-resolution measurements
- 1Institut de Recherche Pour le Développement (IRD), France
- 2UMR7294 Institut Méditerranéen d'océanographie (MIO), France
- 3Ocean Technology and Engineering Group, National Oceanography Centre, University of Southampton, United Kingdom
The biological fixation of dinitrogen (N2) by marine microbes called ‘diazotrophs’ sustains ~50% of primary production in the ocean, boosting CO2 absorption by photoautotrophs and thus contributing to the mitigation of climate change. At present, the paucity and biased geographical coverage of N2 fixation and diazotroph diversity measurements impedes constraining nitrogen inputs to the ocean. Most studies have been conducted at very distant spatiotemporal scales, including: i) discrete and short duration measurements in small seawater volumes isolated from the environment, and ii) spatial extrapolations and global models of diazotrophy projected over decades to centuries. This knowledge gap lies at the fine scales: dynamic seawater structures <200 km wide and <2 months lifetime. However, the spatiotemporal resolution of conventional oceanographic cruises, with stations separated by tens to hundreds of kilometers, is too poor to resolve fine scale processes. Bridging this gap requires implementing high spatiotemporal resolution measurements. Here we present and discuss the advantages and disadvantages of contemporary methods and equipment able to provide high-resolution measurements at sea. We also provide insights into high-resolution sampling approaches to be developed in the near future. Increasing the spatiotemporal resolution of diazotroph activity and diversity will provide more realistic quantifications of nitrogen fluxes in the dynamic ocean.
Keywords: diazotrophs, Fine scale dynamics, physical-biological coupling, Cyanobacteria, N2 fixation
Received: 02 Jun 2020;
Accepted: 03 Sep 2020.
Copyright: © 2020 Benavides and Robidart. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Mar Benavides, Institut de Recherche Pour le Développement (IRD), Marseille, France, email@example.com