Here in Wilhelmina Bay, it’s not all whale watching and penguin gazing. We’re out here to explore the science behind these amazing organisms–mostly, the small and abundant animals and marine algae supplying the food and energy for the “charismatic megafauna.” We’ve been pulling out all of the stops, deploying all of our instruments into the water to sample the krill, phytoplankton, and even the sediment at the bottom of the ocean, in order to get a clear sense of the food web dynamics in this amazing ecosystem.
One of our krill experts on the ship, Meng, has estimated the abundance of krill in this single Antarctic bay to be 3.7 million tons!!! 3.7 MILLION TONS! This information is based on extensive surveys of the area that can detect the acoustic reflectance of krill swarms using ADCP, or Acoustic Doppler Current Profiler.
We know who’s eating the krill (our whale and penguin friends), but we want to know: what are all of these krill eating?!
Here’s a first glimpse at some of the ways that we’ve been sampling the environment in order to answer this question:
We use nets. LOTS of nets! By deploying these off of the ship, we can catch everything from krill to the phytoplankton that they feed on. Here’s an example of one type of net that is used for sampling the Antarctic water column.
We also use something called a MOCNESS–basically, a series of nets that allow us to sample krill at different depths.
We’ve also been sampling the sediment. It has been suggested that, during times of the year when phytoplankton are less abundant, the krill may feed on sediment rich in nutrients. This sampling is fun…and VERY muddy! Here’s a picture of our sediment “MEGA CORE”!
This instrument is put over the side, and dropped to the bottom of the ocean (here, about 520 meters), where it sinks into the sediment to collect large columns of mud, bringing an intact sample to the surface.
We use a CTD (conductivity, temperature, depth) that can measure important properties of the water, and collect water samples at different depths, bringing the water to the surface for the scientists on board to analyze.
Once on board, we can use this water to conduct experiments that examine rates of algal growth, and the grazing of single-celled predators. We use these on-deck incubators to conduct our experiments, while keeping the organisms cool.
We’ve also been conducting some REALLY COOL filming of the krill in the water! We’ll update more on that later. Also, stay tuned for an update on some krill experiments in progress–these involve tethering the krill (putting them on a leash!) and filming their response to different prey items.
This is a first glimpse at some of the cool sampling that we’ve been conducting. Stay tuned for more pictures and updates as our findings emerge.
And, don’t worry Mom, we’re always wearing our hard hats on the back deck🙂