Seasonal dynamics and net production of dissolved organic carbon in an oligotrophic coastal environment

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 456:7-19 (2012) - DOI: https://doi.org/10.3354/meps09677 Seasonal dynamics and net production of dissolved organic carbon in an oligotrophic coastal environment Gemma Vila-Reixach1,*, Josep M. Gasol2, Clara Cardelús2, Montserrat Vidal1 1Departament d’Ecologia, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Catalunya, Spain 2Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CSIC, 08003 Barcelona, Catalunya, Spain *Email: gemmavila@ub.edu ABSTRACT: To understand dissolved organic carbon (DOC) seasonal dynamics in a coastal oligotrophic site in the north-western Mediterranean Sea, we monitored DOC concentrations monthly over 3 yr, together with the meteorological data and the food-web-related biological processes involved in DOC dynamics. Additional DOC samples were taken in several inshore−offshore transects along the Catalan coast. We found DOC concentrations of ~60 µmol C l−1 in winter, with increasing values through the summer and autumn and reaching 100 to 120 µmol C l−1 in November. There was high inter-annual variability in this summer DOC accumulation, with values of 36, 69 and 13 µmol C l−1 for 2006, 2007 and 2008, respectively. The analysis of the microbial food-web processes involved in the DOC balance did not reveal the causes of this accumulation, since the only occasion on which we observed net DOC production (0.3 ± 1 µmol C l−1 d−1 on average) was in 2007, and the negative DOC balance of 2006 and 2008 did not prevent DOC accumulating. The DOC accumulation episodes coincided with low rates of water renewal (average 0.037 ± 0.021 d−1 from May to October) compared with those of winter to early spring (average 0.11 ± 0.048 d−1 from November to April). Indeed, the amount of DOC accumulated each year was inversely correlated with the average summer rainfall. We hypothesize that decreased DOC turn-over due to photochemical or biological processes—mostly active during the summer—and low water renewal rate combine to determine seasonal DOC accumulation and influence its inter-annual variability. KEY WORDS: Coastal DOC · Seasonality · Primary production · Bacterial metabolism · Physical transport Full text in pdf format PreviousNextCite this article as: Vila-Reixach G, Gasol JM, Cardelús C, Vidal M (2012) Seasonal dynamics and net production of dissolved organic carbon in an oligotrophic coastal environment. Mar Ecol Prog Ser 456:7-19. https://doi.org/10.3354/meps09677 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 456. Online publication date: June 07, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.