Crustacean zooplankton release copious amounts of dissolved organic matter as taurine in the ocean

Author(s)

Elisabeth L. Clifford, Dennis A. Hansell, Marta M. Varela, Mar Nieto-Cid, Gerhard J. Herndl, Eva Sintes

Abstract

Taurine (Tau), an amino acid-like compound, is present in almost all marine metazoans including crustacean zooplankton. It plays an important physiological role in these organisms and is released into the ambient water throughout their life cycle. However, limited information is available on the release rates by marine organisms, the concentrations and turnover of Tau in the ocean. We determined dissolved free Tau concentrations throughout the water column and its release by abundant crustacean mesozooplankton at two open ocean sites (Gulf of Alaska and North Atlantic). At both locations, the concentrations of dissolved free Tau were in the low nM range (up to 15.7 nM) in epipelagic waters, declining sharply in the mesopelagic to about 0.2 nM and remaining fairly stable throughout the bathypelagic waters. Pacific amphipod–copepod assemblages exhibited lower dissolved free Tau release rates per unit biomass (0.8 ± 0.4 μmol g

⁻¹ C-biomass h

⁻¹) than Atlantic copepods (ranging between 1.3 ± 0.4 μmol g

⁻¹ C-biomass h

⁻¹ and 9.5 ± 2.1 μmol g

⁻¹ C-biomass h

⁻¹), in agreement with the well-documented inverse relationship between biomass-normalized excretion rates and body size. Our results indicate that crustacean zooplankton might contribute significantly to the dissolved organic matter flux in marine ecosystems via dissolved free Tau release. Based on the release rates and assuming steady state dissolved free Tau concentrations, turnover times of dissolved free Tau range from 0.05 d to 2.3 d in the upper water column and are therefore similar to those of dissolved free amino acids. This rapid turnover indicates that dissolved free Tau is efficiently consumed in oceanic waters, most likely by heterotrophic bacteria.

Organisation(s)

Functional and Evolutionary Ecology

External organisation(s)

Miami University, IEO - Centro Oceanográfico A Coruña, Spanish National Research Council (CSIC), Royal Netherlands Institute for Sea Research, Utrecht University

Journal

Limnology and Oceanography

Volume

Pages

2745-2758

No. of pages

ISSN

0024-3590

DOI

https://doi.org/10.1002/lno.10603

Publication date

11-2017

Peer reviewed

Yes

Austrian Fields of Science 2012

106021 Marine biology

Keywords

ASJC Scopus subject areas

Aquatic Science, Oceanography

Sustainable Development Goals

SDG 14 - Life Below Water

Portal url

https://ucrisportal.univie.ac.at/en/publications/crustacean-zooplankton-release-copious-amounts-of-dissolved-organic-matter-as-taurine-in-the-ocean(2065216d-1cce-406d-96dd-d7d3ceeae4ac).html