Table of Contents

• Dataset Description
  • Methods & Sampling
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Sampling:
Water samples collected during the cruise aboard the research vessel icebreaker (RV/IB) Nathaniel B. Palmer, as part of the TRacing the fate of Algal Carbon Export in the Ross Sea (TRACERS) program included nutrients (nitrate, nitrite, silica, phosphate, DOC, DIC, dC13, ). Samples for biological measurements were collected using a rosette sampler fitted with 20 12 L Niskin bottles (General Oceanics), a conductivity, temperature, and depth (CTD) sensor (Sea-Bird Electronics), an SBE 43 dissolved oxygen sensor, and a fluorometer (WET Labs). All seawater samples were stored immediately within 1 h of collection using HDPE amber bottles and all biological material was treated with 0.1% sodium azide (NaN3) solution and stored at 4ºC until analysis.

Metagenome samples:
Two liters of seawater were taken directly from Niskin bottles and filtered onto 47 mm diameter 0.22 µm size pore polycarbonate filters (Millipore) and flash frozen in liquid nitrogen for storage until later analysis. DNA was extracted using the DNeasy Plant Mini Kit from QIAGEN. Illumina adapters and primers for sequencing on PCR products were used (TruSeq). 100 bp, PE reads were generated on the Illumina HiSeq 2500 platform.

Metatranscriptome samples:
Two liters of seawater were taken directly from Niskin bottles and filtered onto 47 mm diameter 0.22 µm size pore polycarbonate filters (Millipore) and flash frozen in liquid nitrogen for storage until later analysis. Illumina ScripSeq kit was used for library prep and ribosomal depletion was done with Epidemiology kit.

Sorted cells metagenome samples:
Size and fluorescene sorted cells (2,000) were resuspended in PBS. Genome amplification was conducted with RepliG kit. Library preparation was conducted with TruSeq kit.

Sinking particles are a major element of the biological pump and they are commonly assigned to two fates: mineralization in the water column and accumulation at the seafloor. However, there is another fate of export hidden within the vertical decline of carbon, the transformation of sinking organic matter to fine suspended and/or dissolved organic fractions. This process has been suggested but has rarely been observed or quantified. As a result, it is presumed that the solubilized fraction is largely mineralized over short time scales. However, global ocean surveys of dissolved organic carbon are demonstrating a significant water column accumulation of organic matter under high productivity environments. This proposal will investigate the transformation of organic particles from sinking to solubilized phases of the export flux in the Ross Sea. The Ross Sea experiences high export particle production, low dissolved organic carbon export with overturning circulation, and the area has a predictable succession of production and export events. In addition, the basin is shallow (< 1000 m) so the products the PIs will target are relatively concentrated. To address the proposed hypothesis, the PIs will use both well-established and novel biochemical and optical measures of export production and its fate. The outcomes of this work will help researchers close the carbon budget in the Ross Sea.