Answers to ?s from College Students - Part III

Note from Joe: The final set of answers to questions from Ms. Weiss's students.  Katie take it away...

Karen and Melissa wash down the net after a tow.

We caught a lot of juvenile krill in this net haul. These animals are about 1" in length and can grow to be 3-4X that size.

Who's got two thumbs and loves bioacoustics ?   Katie!

How do adverse changes to this current such as increasing temperatures and carbon dioxide uptake impact this and other bodies of water that are connected to the flow of Antarctic waters? What changes in other bodies of water might be impacting Antarctic life?

This deep current is unlikely to be adversely affected noticeably by short term increasing temperatures and carbon dioxide. Much of this exchange occurs in the surface waters. One way this current could be affected by these changes is if biomass increases or decreases in the surface waters. This could change the levels of nutrients, through detritus, that rain down into the deeper current. Then, when the deep current is finally upwelled, whether in the Atlantic, Pacific, or Indian ocean, effects of these changes may be realized.

While Antarctica is one of the most remote places on the planet, it is still affected by other bodies of water and land. It is important to keep in mind that the natural world of our entire planet is driven by cycles in a delicate balance. The systems are seemingly resistant to small, gradual changes, but there is evidence, such as geological studies, that the currents have shifted in conjunction with shifting climates.

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

One of the coolest things I’ve learned during my research is how powerful acoustics can be as a tool. I have worked in a bioacoustics lab, studying cetacean vocalizations and acoustic ecology. We left hydrophones on the bottom of Massachusetts Bay to record for a few months, picked them up, and then we able to tell when and where the whales were hanging out! I don’t know how to talk to whales, but I can tell different species apart! This summer I interned with NOAA and worked on a project using active acoustics to survey walleye Pollock. The technology is similar to a fancy fish finder. This trip is particularly exciting for me because we are collecting data to develop acoustic models. It’s pretty cool!

Due to the increase in upwelling and down welling off of Antarctica from the Global Conveyor Belt, do you see any evidence that an increase in phytoplankton is directly proportional to the amount of zooplankton per cubic meter?

An increase in phytoplankton might lead an increase to the amount of zooplankton per cubic meter, but not always. In the Southern Ocean, the Spring phytoplankton bloom happens very quickly each year, and much of the life (zooplankton and upper trophic levels) is governed by this increase. However, an increase in phytoplankton may not always lead to an increase in zooplankton. Some zooplankton only reproduce during certain times of the year and may not be able to opportunistically take advantage of an increase in phytoplankton. Salps are likely an exception to this. With a high filtration rate and growth rate due to alternative generations, Salps have the capacity of consuming very large amounts of phytoplankton leading to a dramatic zooplankton volume increase.

- Katie