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> Greetings and Question about temperature changes
Ms. Purser
post Apr 30 2006, 04:03 AM
Post #1


Hi Sam!
Can't tell you how excited I am for you, and for me and my students, that you are headed on this adventure! What a great way for our students to learn about ecology! As you know, we'll be checking your journal often and will be anxious to find out what you're learning. We'll send questions as we have them. I have one for now: So, the fish are starting to move further north because the waters are warmer than they used to be, due to global warming.... How much have water temp's risen over the past ____ years? In other words, how much of a temp change is needed for this type change in the territory of the fish? And, which species of fish are the first ones on the move? I know this is a busy time for you... we'll wait for a response til you have a chance to get on the Healey and get settled! Stay warm... we'll miss you at PCJ!
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Sam Barlow
post May 6 2006, 12:11 AM
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Hi Sue,
Thanks for the great questions you posed. I will have to ask my researchers and get back to youj on that. We won't board the Healy until Sunday. She had to turn around in transit from Seattle to Dutch Harbor for a search and rescue mission.

I have yet to find anything that resembles PCJ here in Dutch. I sat in the hotel restaurant this morning and the waitress seemed confused that I just wanted to take up space by working on my computer and drinking copious amounts of coffee.

Miss you,
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post May 6 2006, 09:53 PM
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Group: TREC Team
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Hi Ms. Purser,

There is a cold pool of water in the north Bering Sea that forms each winter and the water temperature is pretty close to freezing, which for seawater is -1.8 degrees Celsius. This cold pool seems to be shrinking in size and is being displaced by warming waters that are perhaps a couple degrees higher. That may be enough to allow some fish to reproduce and grow in this area, but that is actually one of the things we are interested in finding out during this research cruise, so we may have some more information by the end of the cruise.

Thanks for your question, Lee Cooper
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post May 19 2006, 04:39 PM
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Group: TREC Team
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Hey Ms. Purser!
That’s great that you are having your students access my journal as a resource for an assignment. I am very flattered! Now on to your questions.

What is photosynthetic radiation?
Plants use more than just visible light for photosynthesis. They also use ultra violet light. So, if you want to determine whether plants have enough light in the water column to grow, then you have to measure all the wavelengths that penetrate the water column that plants can use as part of photosynthesis. The chlorophyll will fluoresce when hit with a blue light in the fluorometer. So, if the chlorophyll that uses UV is in the water, then the fluorometer will be able to measure it! I think it gives them a measurement of chlorophyll a concentration. It is all related to finding a quantitative measurement of primary production. I am so putting this in my journal now that I have squeezed it out of my PI. It took me a little bit to try and understand this one.

What are the possible sources for selenium and what would high levels suggest?
Selenium occurs naturally at trace levels in seawater. Saltwater animals can accumulate higher levels than freshwater animals without showing the birth defects. Selenium messes with gene expression, but it does not mutate them. Perhaps you know the vocabulary term (starts with a t?) for that type of chemical. Mallards that have high selenium levels have egg deformities while eiders with high selenium levels do not. Some research suggests that high selenium levels may protect against the toxic affects of mercury and that it may have something to do with the physiology of the animals' salt excretion. It is not very well understood by scientists according to my scientist friend, Marj. Selenium is an essential trace nutrient that humans use to help deal with oxygen radicals in the body, but the FDA does not have a recommended level.
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