3 November, 1998

November 3, 1998

Greetings to you from The Ice on another spectacular morning here in McMurdo!

It looks like another very full day for me today including snow-mobile school, learning how to stain and count fish gill chloride cells, and another trip out to Cape Evans (and maybe Royds).

If any of you have e-mailed me and have not heard back from me that means I have not received the e-mail. This might especially be the case if you e-mailed before I got to Antarctica. If so, please try again. I can be e-mailed at either fredatwood@yahoo.com or at the atwoodfr@mcmurdo.gov (which is being forwarded to the yahoo address). QUESTIONS TO THINK ABOUT

1. What is my latitude and longitude here at McMurdo on Ross Island in the Ross Sea in Antarctica?

2. If it is 7:03 AM here (we go on New Zealand time)on Tuesday, what time and day is it there in northern Virginia?

3. Why does the sun never set here at this time of year?

4. If the sun never sets, why does the temperature go up and down each day instead of just getting hotter and hotter?


Yesterday was a learning day for me, as I expect today will be. My project here in the fish lab will be to identify, count, and measure the size of the chloride cells in the gills of two groups of Trematomus bernacchii fish. One group was kept cold at -1.86 degrees Celsius, their normal temperature. The other group was kept warm at 4 degrees celsius for a period of about 4 weeks. It has already been shown that warming these fish up increases the amount of work done by the enzymes called sodium-potassium ATPase (Na/K ATPase), also known as the sodium pumps, which are crucial in regulating the salt concentration of these fish. When it is more active the salt concentration in the blood decreases. Since this enzyme occurs abundantly in the membranes of the chloride cells of the gills we need to know if the warm temperature is increasing the number of cells, the size of cells, the number of sodium pumps in each cell, or just the amount of work done by the sodium pumps that already are present. I am studying the first two parts of this question. The fish have already been caught and have been kept at these temperatures for at least 4 weeks to give time for the complete physiological change to take place. So now I am learning the techniques I will need to do this task.

Yesterday I learned how to use the two photographic microscopes in the lab. One is a regular light microscope with which I will view cross-sections of gills that have been stained with a certain dye called toluidine blue.

The other microscope is a fluorescent microscope that will cause the chloride cells to glow green if they have been stained with a fluorescent dye called DASPE. The enzyme sodium-potassium ATPase needs ATP to work. ATP is an energy-storage molecule that releases the energy the enzyme needs to pump the sodium and potassium. ATP is made by mitochondria, small organelles known as the powerhouses of the cell, found in almost all cells. Since the chloride cells have so much Na/K ATPase, they need lots of ATP, so they need lots of mitochondria. This fluorescent dye is designed to bind to mitochondria, so DASPE-dyed cells with a lot of mitochondria, such as chloride cells glow very brightly when viewed with fluorescent light. The other cells in the gills don't have as many mitochondria so they don't glow much, if at all. This should make it fairly "easy" to count and measure the cells.

So yesterday I learned how to use these microscopes to photograph the microscopic samples to document our results and to double check my counting. I also had to learn how to use the darkroom to develop black and white negatives and print black and white photos. I did a little bit of this back in high school and college and I watched the Photography class at school doing their work in the darkroom before I left for the ice, so the skills came back to me rather quickly.

Also yesterday I visited the aquaria to try to learn how to identify the different types of fishes that can be caught in these frigid Antarctic waters. I will tell you more about these fishes, their marvellous adaptations, and their suspected evolution later. I checked out a digital camera from the stockroom to use for this week and photographed several of the fishes so I hope to get these loaded into the computer and transferred to the journal soon.

Well I'm off to snow-mobile school! I hope you have a good day and do something good for somebody.

Fred Atwood



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