Dissolved Organic Matter Composition and Bioavailability Reflect Ecosystem Productivity in the Western Arctic Ocean
Yuan Shen: http://orcid.org/0000-0001-6618-4226
Ronald Benner: https://orcid.org/0000-0002-1238-2777
Dissolved organic carbon (DOC) and total dissolved amino acids (TDAA) were measured in high (Chukchi Sea) and low (Beaufort Sea) productivity regions of the western Arctic Ocean to investigate the composition and bioavailability of dissolved organic matter (DOM). Concentrations and DOC-normalized yields of TDAA in Chukchi surface waters were relatively high, indicating an accumulation of bioavailable DOM. High concentrations and yields of TDAA were also observed in the upper halocline of slope and basin waters, indicating off-shelf transport of bioavailable DOM from the Chukchi Sea. In contrast, concentrations and yields of TDAA in Beaufort surface waters were relatively low, indicting DOM was of limited bioavailability. Concentrations and yields of TDAA in the upper halocline of slope and basin waters were also low, suggesting the Beaufort is not a major source of bioavailable DOM to slope and basin waters. In shelf waters of both systems, elevated concentrations and yields of TDAA were often observed in waters with higher chlorophyll concentrations and productivity. Surface concentrations of DOC were similar (p > 0.05) in the two systems despite the contrasting productivity, but concentrations and yields of TDAA were significantly higher (p < 0.0001) in the Chukchi than in the Beaufort. Unlike bulk DOC, TDAA concentrations and yields reflect ecosystem productivity in the western Arctic. The occurrence of elevated bioavailable DOM concentrations in the Chukchi Sea implies an uncoupling between the biological production and utilization of DOM and has important implications for sustaining heterotrophic microbial growth and diversity in oligotrophic waters of the central Arctic basins.
Published in Frontiers Marine Science, Volume 9, Issue 12, 2012, pages 4993-5005.
© 2016 Shen, Fichot, and Benner. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Shen, Y., Fichot, C., & Benner, R. (2012). Dissolved Organic Matter Composition and Bioavailability Reflect Ecosystem Productivity in the Western Arctic Ocean. Frontiers Marine Science, 9(12), 4993–5005.
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