Systematic removal of neutral sugars within dissolved organic matter across ocean basins

Abstract

Received 23 June 2011; revised 2 August 2011; accepted 3 August 2011; published 7 September 2011. [1] Dissolved combined neutral sugars (DCNS) support heterotrophic bacterioplankton metabolism throughout the ocean, which affects ocean carbon cycling and biogeochemistry. Variability in DCNS composition also provides information about the diagenetic state of oceanic dissolved organic matter (DOM). Here, we present results of the DCNS composition in ∼600 discrete samples from ocean basin‐scale sections within the North Atlantic and South Pacific Oceans; and at the Bermuda Atlantic Time‐series Study site in the Sargasso Sea. As DCNS concentrations decline with water mass age the mole percentages of glucose, mannose + xylose, and galactose change in a ratio of +2.10:−1.10:−1.00 enriching the DOM pool in glucose relative to mannose + xylose, and galactose. A new proxy is presented based on the relative change in these major sugars, diagenetic distance, which allows for comparison of the diagenetic state of DOM over broad regions of the global ocean while simultaneously quantifying progress along this pathway. In all, this inter‐ basin comparison suggests that there is a common diagenetic pathway for oceanic DOM. Citation: Goldberg, S. J., C. A. Carlson, M. Brzezinski, N. B. Nelson, and D. A. Siegel (2011), Systematic removal of neutral sugars within dissolved organic matter across ocean basins, Geophys. Res. Lett., 38, L17606,