Intra- and inter-spatial variability of meiofauna in hadal trenches is linked to microbial activity and food availability

Type Article
Date 2022-03
Language English
Author(s) Shimabukuro Mauricio1, 2, Zeppilli Daniela1, Leduc D.3, Wenzhöfer F.2, 4, Berg P.5, Rowden A. A.3, 6, Glud R. N.2, 7, 8
Affiliation(s) 1 : Laboratoire Environnement Profond, REM/EEP, Institut Français de Recherche Pour L’Exploitation de La Mer, ZI de La Pointe du Diable, CS 10070, 29280, Plouzané, France
2 : Department of Biology, HADAL & Nordcee, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
3 : National Institute of Water and Atmospheric Research, Wellington, New Zealand
4 : Helmholtz Centre for Polar and Marine Research, Alfred-Wegener Institute, Bremerhaven, Germany
5 : Department of Environmental Sciences, University of Virginia, 291 McCormick road, Charlottesville, VA, 22904-4123, USA
6 : Victoria University of Wellington, Wellington, New Zealand
7 : Danish Institute for Advanced Study, University of Southern Denmark, Odense, Denmark
8 : Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
Source Scientific Reports (2045-2322) (Springer Science and Business Media LLC), 2022-03 , Vol. 12 , N. 1 , P. 4338 (11p.)
DOI 10.1038/s41598-022-08088-1
WOS© Times Cited 2
Abstract

Hadal trenches are depocenters for organic material, and host intensified benthic microbial activity. The enhanced deposition is presumed to be reflected in elevated meiofaunal standing-stock, but available studies are ambiguous. Here, we investigate the distribution of meiofauna along the Atacama Trench axis and adjacent abyssal and bathyal settings in order to relate the meiofauna densities to proxies for food availability. Meiofauna densities peaked at the sediment surface and attenuated steeply with increasing sediment depth. The distribution mirrored the vertical profile of the microbial-driven oxygen consumption rate demonstrating a close linkage between microbial activity and meiofauna density. Meiofaunal standing-stock along the trench axis varied by a factor of two, but were markedly higher than values from the abyssal site at the oceanic plate. Overall, meiofaunal densities poorly correlated with common proxies for food availability such as total organic carbon and phytopigments, but strongly correlated with the microbial benthic O2 consumption rate. We argue that microbial biomass likely represents an important meiofaunal food source for hadal meiofauna. Observations from three trench systems underlying surface water of highly different productivity confirmed elevated meiofaunal densities at the trench axis as compared to abyssal sites on oceanic plates. Food availability appear to drive elevated abundance and variations in meiofauna densities in hadal sediments.

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