High-resolution net and gross biological production during a Celtic Sea spring bloom

Seguro, Isabel, Marca, Alina D., Painting, Suzanne J., Shutler, Jamie D., Suggett, David J and Kaiser, Jan (2019) High-resolution net and gross biological production during a Celtic Sea spring bloom. Progress in Oceanography, 177. ISSN 0079-6611

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Abstract

Shelf seas represent only 10% of the ocean area, but support up to 30% of all oceanic primary production. There are few measurements of shelf-sea biological production at high spatial and temporal resolution in such heterogeneous and physically dynamic systems. Here, we use dissolved oxygen-to-argon (O2/Ar) ratios and oxygen triple isotopes (16O, 17O, 18O) to estimate net and gross biological production in the Celtic Sea during spring 2015. O2/Ar ratios were measured continuously using a shipboard membrane inlet mass spectrometer (MIMS). Additional discrete water samples from CTD hydrocasts were used to measure O2/Ar depth profiles and the δ(17O) and δ(18O) values of dissolved O2. These high-resolution data were combined with wind-speed based gas exchange parameterisations to calculate biologically driven air-sea oxygen fluxes. After correction for disequilibrium terms and diapycnal diffusion, these fluxes yielded estimates of net community (N(O2/Ar)) and gross O2 production (G(17O)). N(O2/Ar) was spatially heterogeneous and showed predominantly autotrophic conditions, with an average of (33±41) mmol m-2 d-1. G(17O) showed high variability between 0 and 424 mmol m-2 d-1. The ratio of N(O2/Ar) to G(17O), ƒ(O2), was (0.18±0.03) corresponding to 0.34±0.06 in carbon equivalents. We also observed rapid temporal changes in N(O2/Ar), e.g. an increase of 80 mmol m-2 d-1 in less than 6 hours during the spring bloom, highlighting the importance of high-resolution biological production measurements. Such measurements will help reconcile the differences between satellite and in situ productivity observations, and improve our understanding of the biological carbon pump.

Item Type: Article
Uncontrolled Keywords: net community production,gross production,ar ratio,oxygen triple isotopes,shelf seas,spring bloom,shelf seas,spring bloom,gross production,ar ratio,oxygen triple isotopes,geology,aquatic science ,/dk/atira/pure/subjectarea/asjc/1900/1907
Faculty \ School: Faculty of Science > School of Environmental Sciences
Faculty of Science > School of Biological Sciences
Related URLs:
Depositing User: Pure Connector
Date Deposited: 08 Dec 2017 11:09
Last Modified: 19 May 2020 00:00
URI: https://ueaeprints.uea.ac.uk/id/eprint/65722
DOI: 10.1016/j.pocean.2017.12.003

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