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TREC Virtual Base Camp _ Teacher's Journal _ July 12-13, 2006

Posted by: Betty_Carvellas Jul 14 2006, 04:59 PM

July 12 and 13, 2006

You'll soon understand why two days of journals are included in one. We finally started our mud work yesterday afternoon at 2:30 with the first of five SLIP (St. Lawrence Island Polynya) stations. Although we have no ice right now, a polynya is a large area of open water in the ice pack, and we're in just such an area now. I've included the cruise map today so you can see our current position and where we're headed. Each smaller circle represents a CTD station which may or may not include bongos and mud, and each larger circle shows where a mooring will be deployed or retrieved. Our five SLIP stations took us almost 20 hours to complete, with each station lasting about two hours. Once I get someone to come out on deck with us, I'll include some pictures in my journals.

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This the official Arctic Science Plan for the Sir Wilfrid Laurier Cruise 2006-01. You can see where we have just completed our first set of mud stations southwest of St. Lawrence Island.

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Our first mud stations were just southwest of St.Lawrence Island. By the time I woke up, five hours after we had finished, we could easily see St. Lawrence Island in the distance.

I had actually planned to write the journal for the 12th about one of the scientists on board, and even had a draft written. But, I never post a journal until I've had a chance to check it with the person I'm writing about, and she went to sleep while we were doing one of our mud stations. I'll fill you in on her work another day. Once these stations start, things get a bit crazy. It's now 4:30 PM on the 13th, and I've just woken up from a few hours of sleep. After starting on the 12th at 2:30 PM, we finished our lat station just before 10 this morning, and got to sleep around 11. After being up for over 24 hours, with only cat naps during that time, I was feeling pretty tired. While this is indeed a busy schedule, it's not at all unusual for the scientists on board. It's rare to find a time, day or night, when there isn't something going on. Even though the stations are a distance apart, people are working round the clock to launch the XBT's, filter water, run experiments, log data, keep the CTD in running order, or even, in one case, doing underwater sampling every hour. That's one of Dr. Peter Lee's jobs, and it keeps him up for long hours at a time throughout the cruise. Since this is my third trip on the Laurier with Peter, I've written about his work twice before. What I've decided to do this time is to include part of my journal from July 11 last year when I wrote about Peter's work on board. Then, I'm going to do a podcast with Peter and post it once we get off the ship towards the end of July. It will be available on the TREC website.

Dr. Peter Lee is originally from New Zealand, but he's now doing postdoctoral work in biogeochemistry at the College of Charleston in South Carolina. This is the second of three cruises for Peter this year. His first cruise, which lasted 6 weeks and ended in late January, took him to Antarctica where he'll return at the beginning of November for a cruise that will take him through mid December. Peter's work on board involves sampling for DMSP (dimethylsulfoniopropionate), a substance found in the cells of phytoplankton (tiny plants found in the water) and for the pigments found in phytoplankton. DMSP not only helps the phytoplankton regulate salt (it's an osmoregulator), it's also a cryoprotectant (helps them to survive in cold temperatures) and it's an antioxidant. We've all heard about the benefits of antioxidants, so I asked Peter if anyone had thought of using DSMP for humans. He said that some have suggested a teaspoon/day of DMSO (an oxidation product of DMS), but it breaks down and leaves an unpleasant taste of oysters in your mouth. It's easier to eat carrots!

Peter collects his samples in two ways. Every hour that the ship is underway, he uses the ship's seawater pumping system to collect water for horizontal sampling. When we stop for a station and put down the CTD (conductivity depth, temperature) bottles, he'll collect water for vertical sampling. The CTD cast sends down a series of bottles that collect water at specified depths. Peter filters the water and takes the samples, stored at minus 80 degrees Celsius, back to South Carolina for analysis. He estimates that he'll bring back approximately 450 samples this year. At about 20 minutes/sample for the DMSP and 1hour/sample, on an automated system, for the pigment samples, Peter and the lab technicians will be spending a great deal of time analyzing the samples from this relatively short cruise.

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Peter Lee's work on board involves long hours of collecting and filtering water, both while on station and while underway. He's sampling for DMSP, a substance found in phytoplankton, and also for the pigments found in phytoplankton.

Peter will analyze each sample two ways. First, he uses HPLC (high performance liquid chromatography) to identify the pigments and therefore the groups of phytoplankton. Anyone who lives where the leaves change color in the fall knows that, when the chlorophyll dies back, the accessory pigments in the leaves show up to produce the brilliant colors that bring the tourists. Just as you can identify the type of tree by the color of the fall leaves, you can identify the major groups of phytoplankton by their pigments. He'll be able to identify how these groups change over the years due to climate change. For example, there could be a greater concentration of some species, or even new species moving in. That's exactly what happened when, from 1987 - 2002, there was an algal bloom (large production) of a non-native species of phytoplankton in the Bering Sea. Scientists believe a warming trend might have made the conditions more favorable for this new species.

Peter also analyzes DMSP concentrations in each sample using gas chromatography. By looking at this data along with the pigment analysis, he can evaluate how the DMSP concentration responds to the changing phytoplankton community. Since this is the sixth year of sampling at these same stations, Peter is developing a baseline for DSMP concentration and for the phytoplankton present. Scientists in future years will be able to document changes over time.

How does this work relate to climate change? If climate change means warming temperatures, there will likely be additional phytoplankton production, therefore, more DMSP produced. When the phytoplankton die and release the DMSP, it's broken down by bacteria into DMS and eventually to sulfates which are critical to cloud formation. So, it looks like this: warmer temperatures, more phytoplankton, more DMSP, more DMS and sulfates, more clouds, more cloud cover, an increase in the Earth's albedo (ability to reflect back the sun's rays), and cooler temperatures. Just possibly, the ocean's phytoplankton could help to regulate the Earth's climate! If my students are reading this, they may recognize the elements of James Lovelock's Gaia hypothesis. Scientists now refer to this "whole earth as a living organism" idea as geophysiology.

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