Sea-ice and biodiversity gradient
Underwater seaweed forests dominate the coastal margins of the region around Palmer Station, Antarctica. Palmer Station is the smallest of the three US research stations maintained by the United States Antarctic Program. These seaweed forests in this region provide important physical structures to protect and sustain many Antarctic marine organisms.
Because the UAB in Antarctica research group has spent years studying the ecology of the seaweeds and the invertebrates associated with them, we know that these communities stick around for a long time. We also know that the area further south near the British Antarctic Survey's Rothera base does not have these big seaweed forests, but we know very little about the seaweeds, the associated biodiversity, or food web interactions for the shallow coastal region between stations.
To test these hypotheses, in April-May 2019 our collaborative research team (which included members from University of Alabama at Birmingham, University of Alaska Fairbanks, Texas A & M University, Smithsonian Institute, and University of Oregon) collected seaweeds and the invertebrates associated with them along the Western Antarctic Peninsula (see map for site locations).
At each site, we performed underwater video transects (for biodiversity measures) and collected organisms for genetics (to confirm species identifications) and both stable isotopes (Carbon and Nitrogen) and fatty acids to quantify food web interactions.
We are currently in the process of evaluating all of these samples, so stay tuned to find out what we learn!
The sea ice dynamics vary in this region and can be a significant disturbance to shallow water organisms, particularly seaweeds. The presence of sea ice can block seaweed access to the light need for photosynthesis for energy acquisition and it can scrape seaweeds and their associated invertebrate assemblages off of the bottom when it breaks up or moves around, a process called ice scour.
Our group has hypothesized that the seaweed abundance and assemblage biodiversity will change with the sea ice presence (more scouring with more sea ice) and the duration (resulting in less light available for photosynthesis) of that presence.