2017-2018 USAP Field Season
Cobalamin and Iron Co-Limitation Of Phytoplankton Species (CICLOPS) in Terra Nova Bay
Dr. Giacomo DiTullio
College of Charleston
Supporting Stations: RV/IB Nathaniel B. Palmer
Two primary groups of algae typically dominate the Ross Sea phytoplankton community composition: diatoms and the colonial Phaeocystis antarctica. Diatoms typically have dominated the stratified waters in Terra Nova Bay, but as recently as 2010, Phaeocystis blooms started to appear. This shift in community composition is not fully understood. The major objective of this research is to determine whether iron and vitamin B12 dynamics are primarily responsible for causing this shift in phytoplankton community composition in Terra Nova Bay. These blooms typically occur later in the summer relative to central Ross Sea blooms, presumably because of ice conditions and wind forcing. Researchers will locate and track the blooms using a Lagrangian process. They will use a free-floating drifter array to investigate in-situ microbial dynamics within two developing Phaeocystis and diatom blooms.
Field Season Overview
A team of 18 scientists, led by three co-PIs, will deploy on a two-leg cruise to carry out multiple in situ daily measurements and require 35 science days to complete this work. They will use satellite imagery to track two blooms, one diatom and one Phaeocystis, and will ideally spend 14-16 days at each bloom. Once the team locates and identifies a bloom and the ship has arrived on site, the scientists will deploy a Lagrangian drifter and sediment trap followed by three to four CTD casts every six hours daily while tracking the bloom and drifters. The sediment trap and drifter deployments and recoveries will occur in three-day cycles. The primary interest is in the upper 200 meters of the water column. In addition the team plans to conduct CTD casts to the bottom in the Terra Nova Bay vicinity up to 1000 meters.
The science team will also deploy the USAP trace metal CTD rosette and four to five grantee-provided McLane pumps as part of this Lagrangian study. They will collect seawater with these in situ submersible pumps for on-deck incubations with USAP deck incubators, and hand-deployed net tows to collect whole Phaeocystis colonies. Shipboard 55Fe, 14C and 57Co radioisotope work will take place in the USAP-provided radioisotope van and as part of deck incubation experiments.
Deploying Team Members