Consistent Fine Scale Changes in Dissolved Organic Matter Composition with Depth at the Bermuda Atlantic Time Series Station (BATS)

Michael Gonsior1, Leanne Powers1, Norbert Hertkorn2, Philippe Schmitt-Kopplin2 and Madeline Lahm1, (1)University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, MD, United States, (2)Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry, Neuherberg, Germany
The fine scale differences in DOM composition in oligotrophic ocean waters remain poorly described even when ultrahigh resolution mass spectrometry is applied. Here we show the fine scale differences in DOM analyzed by 12 Tesla FT-ICR MS and between samples collected every 200 m throughout the entire water column down to 4,520 m at the long-term Bermuda Atlantic Time Series Station (BATS). Three complete profiles were collected and extracted. Besides the more traditional solid-phase extraction using the Agilent PPL resin, we also used a weak anion exchange resin sequentially together with PPL to extract a complementary pool of organic compounds. FT-ICR MS data revealed consistent trends within the water column and emphasized the importance of linking biological sources in the photic zone with presumed microbial processing at greater depth.