March 7, 2013
By Kim Goetz
After our first successful capture and tagging last week, we’ve spent the last several days looking round-the-clock for more emperor penguins. While we’ve found several more, the penguins have either been on ice too thin for us to work, or have gone into the water before we could launch a zodiac to the ice floe.
When our team is not on the lookout, we each find our own activities to pass the time. For some of us, this means catching up on emails, working on our dissertations, or writing manuscripts for publication in a peer-reviewed journal. If these tasks seem too daunting, there are plenty of other activities to keep us busy.
Most recently, the ship crew has asked for volunteers to help keep the incubators running. These incubators are used to house several organisms in their natural seawater environment for further experimentation. As such, they are kept in seawater on the outside deck, exposed to ambient conditions. Because it has been so cold (-48 degrees C / -54 degrees F, wind chill, and 40-knot winds), the seawater being pumped into these tubs is freezing and clogging up the system. Volunteers have been working to keep the tubs ice-free at all hours.
I’ve been spending much of my free time helping other scientific teams filter seawater for zooplankton and sample organisms from net tows. During the net tows, the team usually deploys a 700 micrometer net followed by a smaller 300 micrometer net. The two different sized meshes are designed to capture different organisms. Generally, the larger net captures organisms such as krill and larval fish, while the smaller one captures smaller organisms like algae.
The team in charge of the nets has been very generous in allowing me to collect samples of several krill species, shrimp (also known as mysids), large copepods, amphipods, and juvenile and adult fish for my own research. Seeing these organisms for the first time after the net is brought to the surface has been a highlight for many of us on the ship. The organisms are very interesting and widely diverse—you never know what you’re going to get!
In addition to the penguin work, I am finishing my dissertation on Weddell seal movement and foraging behavior. The samples I’m collecting from the net tows will provide the missing links needed for my analysis of carbon and nitrogen isotopes, chemical information that should provide a better understanding of the seal’s specific diet and role in the food web.
I will be able to compare the carbon and nitrogen isotope ratios from seal whiskers to those found in the fish and invertebrate samples to gain a better understanding of not only where Weddell seals are foraging but also which prey species are most important to their diet across the seasons, even when darkness and heavy ice prevails.