1 August, 2002
As I prepared to post the journal for July 31 on time (it was actually 11PM on the 31st) we lost our connection to the internet. That makes one more reason for my often tardy journals. I suspected it might happen as the ship suddenly began to move to find a better area (less ice covered) to deploy the CTD. Since that was just before midnight and several people needed to sample, including four hours of pumping, I went to bed. This morning I found that I still had time before my sediment work, so I had a chance to do my laundry and to talk with two more of the scientists on board.
Laura Belicka and Karl Kaiser work in a lab just off the main science lab. They are sampling water to trace the sources and the fate of organic carbon. Remember that organic carbon is that carbon which is found in living things. When Laura and Karl talk about the fate of the carbon, they are looking at how it can be changed into other forms. It might be broken down, eaten, or even end up at the bottom in the sediments. Basically, they want to know where the carbon came from and where it is going. Laura is a faculty research assistant at the Chesapeake Biological Laboratory, a part of the University of Maryland Center for Environmental Science where she works with Rodger Harvey. She collects water from the CTD casts and sediments from a very large box core (see the picture below). Itís much bigger than the van Veen that we use to get mud! She filters the water and examines the parcticles left behind on the filter. Karl then looks at what is left, the dissolved organic matter. Both Karl and Laura are analyzing for special biomarkers. Lipids, one type of biomarker, are fat-like molecules found in all living things. For example, they are always found in the membranes that surround all cells in our bodies. In addition, they contain carbon. A biomarker is a substance that is found only in one type of organism thus making it easier to figure out where it came from. For example, cholesterol is a lipid but itís not a good biomarker since so many different organisms contain it. One lipid bio marker that Laura looks for is dinosterol, a lipid produced by tiny plankton called dinoflagellates.
There are two sources of organic carbon in the Arctic Ocean. One is from within the ocean itself (marine) and one is from land (terrestrial). The marine carbon comes from primary production on the shelf. This is where the phytoplankton come in. Remember that phytoplankton are plants and plant-like plankton that make their own food and food for others by using the carbon dioxide (CO2) in the air or dissolved in the ocean. The process is called photosynthesis. Thereís lots of food production on the shelf because the water is shallow enough for light to reach the phytoplankton (they need the light for photosynthesis), and there are plenty of nutrients there to help the phytoplankton grow. Terrestrial carbon comes into the Arctic Ocean by way of fresh water rivers. The Yukon and the Mackenzie are the two largest Alaskan rivers, but several Russian rivers also empty into the Arctic Ocean. Marine carbon is consumed very fast, but terrestrial carbon is older and resistant to change. Laura and Karl use biomarkers to distinguish between these two sources of carbon.
Lauraís work is with the parcticles that she filters from the water. This parcticulate carbon makes up only 5-10% of the carbon in the ocean. The dissolved carbon with which Karl works makes up almost 90% of the ocean carbon. Karl emphasized that there is a huge amount of organic carbon that we know very little about; the chemical structure is essentially unknown. Laura will filter her water here and collect sediments. Once she is back in her lab, she will extract (take out) the lipids from the parcticles and from the sediments. On ship, her work takes about three hours/sample. At home in her lab, she will separate out the lipids, often getting several hundred different lipids in each sample. To complete the analysis, she will need about three weeks to do each set of 12 samples. The two SBI cruises (spring and summer 2002) combined will give her about 100 parcticle samples and 240 sediment samples. She has a lot to do when she gets home!
Karl is a research associate at the University of South Carolina where he works with Ron Benner. Karlís goal on this cruise is to gather data for comparison with the data from the spring SBI cruise and to look more closely at an unexpected observation from the spring cruise. In the spring, scientists on board the Healy observed an unusual layer of water at a depth of approximately 130 meters, going over the slope and into the basin. Test results tell them that this water is probably 900-1500 years old, and they would like to identify the source. Is it marine or terrestrial? Thereís even a possibility that the source could be fresh water rivers. The question then would be how could it stay that long? There are many questions to be answered about this water mass and about the Arctic Ocean in general. Thatís why this SBI project is so important. Hopefully, after more cruises in 2004 and discussions with scientists from other nations who are conducting research in the Arctic Ocean, scientists will be able to answer some of these questions.
Karl, like Laura, will complete his analysis once he returns to his lab. He estimates he can analyze eight samples in a week, and he will have 200 samples from the two SBI cruises. Many people donít realize that the process of science is often time consuming and repetitive. Scientists gather data, analyze it and repeat their work many times to make sure their results are accurate. Often their work leads not directly to answers but instead to more questions. Even when they find ďanswersĒ new information may cause them to re-examine their findings. While Iíve been on this cruise, Iíve had a chance t observe the day to day work of these scientists as they carefully gather data, start the long process of analysis and document their findings. That often means long days and nights in the lab or on deck. They are working hard while out here for 40 days, and their work will continue once they get home.
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