Drivers of fluorescent dissolved organic matter in the global epipelagic ocean

T.S. Catalá, X. A. Álvarez-Salgado, J. Otero, F. Iuculano, B. Companys, B. Horstkotte, C. Romera-Castillo, M. Nieto-Cid, M. Latasa, X. A. G. Morán, J. M. Gasol, C. Marrasé, Colin Stedmon, I. Reche

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Fluorescent dissolved organic matter (FDOM) in open surface waters (< 200 m) of the Atlantic, Pacific, and Indian oceans was analysed by excitation-emission matrix (EEM) spectroscopy and parallel factor analysis (PARAFAC). A four-component PARAFAC model was fit to the EEMs, which included two humic- (C1 and C2) and two amino acid-like (C3 and C4) components previously identified in ocean waters. Generalizedadditive models (GAMs) were used to explore the environmental factors that drive the global distribution of these PARAFAC components. The explained variance for the humic-like components was substantially larger (> 70%) than for the amino acid-like components (< 35%). The environmental variables exhibiting the largest effect on the global distribution of C1 and C2 were apparent oxygen utilisation followed by chlorophyll a. Positive non-linear relationships between both predictor variables and the two humic-like PARAFAC components suggest that their distribution are biologically controlled. Compared with the dark ocean (> 200 m), the relationships of C1 and C2 with AOU indicate a higher C1/AOU and C2/AOU ratios of the humic-like substances in the dark ocean than in the surface ocean where a net effect of photobleaching is also detected. C3 (tryptophan-like) and C4 (tyrosine-like) variability was mostly dictated by salinity (S), by means of positive non-linear relationships, suggesting a primary physical control of their distributions at the global surface ocean scale that could be related to the changing evaporation-precipitation regime. Remarkably, bacterial biomass (BB) only contributed to explain a minor part of the variability of C1 and C4
Original languageEnglish
JournalLimnology and Oceanography
Volume61
Issue number3
Pages (from-to)1101-1119
ISSN0024-3590
DOIs
Publication statusPublished - 2016

Fingerprint Dive into the research topics of 'Drivers of fluorescent dissolved organic matter in the global epipelagic ocean'. Together they form a unique fingerprint.

Cite this