Disentangling Biological Transformations and Photodegradation Processes from Marine Dissolved Organic Matter Composition in the Global Ocean

Bercovici, Sarah K.; Wiemers, Maren; Dittmar, Thorsten; Niggemann, Jutta. 2023 Disentangling Biological Transformations and Photodegradation Processes from Marine Dissolved Organic Matter Composition in the Global Ocean. Environmental Science & Technology, 57 (50). 21145-21155. https://doi.org/10.1021/acs.est.3c05929

Before downloading, please read NORA policies.

Preview

Text © 2023 The Authors. Published by American Chemical Society bercovici-et-al-2023-disentangling-biological-transformations-and-photodegradation-processes-from-marine-dissolved.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (11MB) | Preview

Abstract/Summary

Dissolved organic matter (DOM) holds the largest amount of organic carbon in the ocean, with most of it residing in the deep for millennia. Specific mechanisms and environmental conditions responsible for its longevity are still unknown. Microbial transformations and photochemical degradation of DOM in the surface layers are two processes that shape its molecular composition. We used molecular data (via Fourier transform ion cyclotron resonance mass spectrometry) from two laboratory experiments that focused on (1) microbial processing of fresh DOM and (2) photodegradation of deep-sea DOM to derive independent process-related molecular indices for biological formation and transformation (Ibio) and photodegradation (Iphoto). Both indices were applied to a global ocean data set of DOM composition. The distributions of Iphoto and Ibio were consistent with increased photodegradation and biological reworking of DOM in sunlit surface waters, and traces of these surface processes were evident at depth. Increased Ibio values in the deep Southern Ocean and South Atlantic implied export of microbially reworked DOM. Photodegraded DOM (increased Iphoto) in the deep subtropical gyres of Atlantic and Pacific oceans suggested advective transport in warm-core eddies. The simultaneous application of Iphoto and Ibio disentangled and assessed two processes that left unique molecular signatures in the global ocean.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1021/acs.est.3c05929
ISSN:	0013-936X
Date made live:	10 Jan 2024 12:26 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/536629

Actions (login required)

View Item

Document Downloads

More statistics for this item...