Answers to ?s from College Students Part II

Note from Joe: Sorry for the delay in getting these answers posted. The field team has been working literally non-stop since Dec 1st and today we are making our final shipboard measurements as we begin our transit northward.  We'll try to have several posts in the next few days with answers to questions from college and junior high students.

Now here are Melissa's answers to some questions from college student's in Ms. Weiss's Introduction to Oceanography course.

3. Why study zooplankton?

Zooplankton are a really important part of the marine ecosystem and the type and quantity of zooplankton that you find in an area can be very indicative of the condition of the local ecosystem. For instance, salps and krill are two dominant types of zooplankton in the Antarctic. Both are common but typically are not found in high abundances in the same location. Krill tend to be more associated with the presence of sea ice, likely because that is what their primary food source is associated with, whereas salps tend to be associated more with open water. Because salps are not predated upon by many other organisms, they are often considered to be the end of the food chain and are not associated with very diverse systems. Krill, on the other hand, are consumed by a vast number of organisms which are in turn consumed by other organisms and are considered to be a key component to marine food webs. They are the primary food source for baleen whales like humpbacks which swim from the tropics in winter to the Antarctic in Austral summer to feed in the highly productive waters. Fish, penguins, and other marine birds also feed on krill and they in turn are fed upon by toothed whales and seals. In recent years salps have been found to be increasing in abundance and krill to be decreasing. With increasing global temperatures, sea ice is on the decline, correlating with a decrease in krill abundance. Because krill are so vital a part of marine food webs, this indicates that there may be a danger of collapse for Southern Ocean food webs which would have serious implications worldwide.

4. What was the most amazing discovery that you have come across while conducting your research?

I can’t say that there is any one thing that I have come across that I find particularly amazing but the experience as a whole has been pretty amazing in itself – learning just how useful acoustics can be in determining what is in the water column, seeing the diverse array of zooplankton species that we catch in the net tows, and seeing how the physical properties of the water in any one area correspond to the types and number of organisms that we find there. I’ve learned about most of it in my classes but it’s entirely different and there is a far greater sense of self fulfillment when you see it all in person and do the science with your own hands rather than just reading about it in a textbook or a paper published in a science journal.

Melissa gives MT Mark a hand with the radio comms.  Depending on how far we are from the ship, having the radio antenna raised higher can improve our reception.

9. Have you seen any penguins or other animals on the cruise?

Yes, we’ve seen plenty of animals on the cruise. We see penguins practically every day. So far we’ve seen all of the common species for the area like chinstraps, gentoos, and Adelies and we’ve spotted one or two emperor penguins which are rare in the islands and generally only come here to molt. We’ve also spotted a few seals – leopard seals and crabeaters – and we occasionally spy humpack whales, minke whales, and orcas. Or course since we’re studying zooplankton we also see plenty of amphipods, krill, salps, pteropods, and other animals when we pull in the net tows.

A leopard seal hauled out on an iceberg with some anxious penguins nearby.  On land, leopard seals aren't very mobile, however in the water they are incredibly fast.

- Melissa