Size fractionated organic carbon and nitrogen concentration and stable isotopes from water column of the East Pacific Rise in April 2019 on the R/V Atlantis cruise AT42-09

On R/V Atlantic cruise AT42-09 in April 2019, size fractionated suspended particulate organic matter samples from the water column at the East Pacific Rise (9°50'N 104°18.14'W) were obtained by opening the bottom of the Niskin bottle to ensured that particles that had sunk below the spigot were included. Between 100 and 120 L of water was gravity filtered, in sequence, through nylon mesh (142 mm diameter) of decreasing pore size (500, 180, 53, 20 µm and 5 µm mesh). The resuspended particulate matter from each sample and size class was collected by vacuum filtration through a 1.2 µm nominal pore size, pre-combusted GF/C glass fiber filter. Samples were wafted with HCl overnight to remove carbonate and sent to the UC Davis Stable Isotope Facility for C and N analysis concentration and stable isotope analysis.

The purpose of these samples was were used to create particle size to carbon and nitrogen relationships for models, while gaining insights into the origins and fate of particulate organic matter in the ocean. Additionally, these organic matter fractions are directly linked to 16S rRNA amplicon data. 16S rRNA sequence amplicons exactly corresponding to this organic matter data are deposited in SRA (Short Read Archive) under BioProject PRJNA1191024.

Jacob Cram conceived of the idea. Benjamin Tully of Center for Dark Energy Biosphere Investigations, University of Southern California oversaw sample collection. Paulina Huanca Valenzuela and Clara Fuchsman prepped the samples in the laboratory and analyzed the data.