Winter Picoplankton Diversity and Distribution in the US Antarctic Marine Living Resources Study Area - Northern Antarctic Peninsula

Study Extent

The study was conducted in the US AMLR Study Area which covers coastal and off-shore waters in the vicinity of the South Shetland Islands and Elephant Island including the Bransifeld Strait, northern Weddell Sea, Weddell Sea confluence with the Scotia Sea, and Antarctic circumpolar current in Southern Drake Passage. We participated in three oceanographic polar winter cruises between August to early September in 2012, 2013, and 2014.

Sampling

Hydrographic surveys were conducted using CTD rossette outfitted with niskin bottle samplers to retrieve water samples at 15, 50, 75, 100, 200, and 750 m (or above the bottom if bottom depth was shallower than 750 m). Water was filtered immediately once on board the ship in a cold room at 0C. Samples for DNA extraction and subsequent sequencing were passed through in-line 2.7 micron filters to remove larger organisms, and the picoplankton fraction was collected on 0.2 micron Sterivex cartridge filters. A sucrose-Tris-EDTA buffer was added to the filters and they were stored frozen at -80C until extraction at our home institutions.

Quality Control

Nucleic extraction blanks were carried out through amplification steps and sequence analysis quality control measures were followed on data analyzed. Oceanographic instruments were calibrated at SeaBird before the cruise and sample blanks were periodically run for chlorophyll and nutrient analyses.

Method steps

1. These details will be reported in the literature.

Bacterial, archaeal, and eukaryotic diversity in seawater picoplankton (< 3.0 micron fraction) and the diversity of the sea ice microbial community were described based on small subunit ribosomal RNA amplicon sequencing.

1. Bacteria
   rank: domain
2. Archaea
   rank: domain
3. Eukarya
   rank: domain

This is the U.S. Antarctic Marine Living Resources study area. Hydrographic surveys were conducted across three broad sub-areas in this region, around Elephant Island, in the Bransfield Strait, west of the South Shetland Islands.