• Ashley Hann

Building an Antarctic Ocean Observing System

Updated: Apr 11

In order to understand the physical mechanisms that drive the biological hotspot at Palmer Deep Canyon, we need to first establish a system that can take measurements and recordings of what is occurring in the study area. Our first week in Antarctica was spent setting up an ocean observing system in the area that included constructing a remote High Frequency Radar (HFR) site, deploying moorings, and fixing and deploying gliders. Needless to say, we had a busy first week! Luckily, in the spirit of Antarctic research, we received loads of support from the R/V Laurence M. Gould and Palmer Station so that our equipment could be up and running, gathering data, as soon as possible. By the end of the week we had a functioning ocean observing system operating in and over Palmer Deep Canyon that consists of three HFR sites, three moorings, and three gliders. Keep reading below for more information and pictures regarding the installation and deployment of our equipment and what data will hopefully be gathered from it all!


SWARM member Hank and marine tech TR carefully help the crane guide the mooring off the back deck of the vessel. Photo Credit: Ashley Hann

Moorings

We deployed three subsurface moorings on a transect across canyon at Palmer Deep from the R/V Laurence M. Gould upon our arrival at Palmer Station. Two of the moorings will be gathered during our field season (austral summer 2020) while one, placed in the middle of our mooring transect, will remain out all year! The moorings are equipped with a variety of instrumentation that will provide acoustic

data along with other measurements about the physical, chemical, and biological elements of the water column.








HFR Sites

High frequency radars allow surface ocean current velocity (speed and direction) to be measured in real-time. While one radar site is powered by Palmer Station because of proximity, the other two are located on remote islands. Luckily, we had the expertise of SWARM team member, Hank Statscewich of University of Alaska Fairbanks, on our side. Hank is one of a few researchers who has pioneered the design and implementation of remote power modules to deploy HFR sites in remote polar locations. The modules that we helped him put together acquire power from wind turbines, solar panels, and a battery bank in case wind or sun isn’t available to generate energy. In order to construct the sites, all materials had to be carried over by zodiacs (small inflatable boats) and assembled by hand. That included carrying around 11,000 lbs of equipment from the zodiacs to their set up location - talk about a workout! Despite the need for a sturdy and self-sufficient set up to survive the irregular and harsh Antarctic weather, after the study is completed the sites will be taken down with no traces left. Once power was established at the sites, we have been able to see actual surface currents that could be impacting the biota of the region!

Clockwise from the top left, the progression of the construction of the module: the site as we started bringing supplies up, working on securing the platform and setting up the hut in which all electronics would be protected from the elements, the team inside the hut, and the final product! Photo Credit: Matt Oliver, Josh Kohut, Hank Statscewich, and Ashley Hann


Gliders

Our SWARM team members at Rutgers, University of Delaware, and the University of Alaska Fairbanks all brought Slocum Gliders, autonomous underwater vehicles that use buoyancy to drive their motion. After testing the gliders to make sure they were seaworthy and performing some glider “surgery”, we were able to deploy them on their individual missions. Each glider has its own mission or transect that it will fly over the next few months and each glider is equipped to dive to different depths. All gliders will provide us with data about a suite of biological and physical variables with spatial and temporal elements.

From left to right: carefully carrying the glider to the zodiac it will be deployed from, grad students from OSU (Ashley Hann and Nick Mehmel) and University of Delaware (Katie Hudson) aboard a zodiac as the glider performs test missions, Katie watching the glider as it sends data to its pilots at Rutgers.

Now that our ocean observing system has been up and running for a few weeks, we are excited to take a closer look and compare the variety of data that is coming in about the ever-interesting Palmer Deep Canyon region. The real-time nature of the information has also allowed us to be adaptive in other surveys that we conduct from Rigid Hull Inflatable Boats (RHIBs) to assess the presence of krill and their predators.