So the tanks are set up.
Lisa and Kristin are inspecting the overall status and health of the gibberfrons, aka Gibbys, that we caught on our fishing trip.
We've been experimenting with the temperature controls, the water, and the equipment all weekend to get it ready for the fish. Our team is actually working on a few different things. So I'll explain one at a time. The primary experimentation centers around thermal tolerance amongAntarctic fishes, i.e. how well they can tolerate changes in temperature - in this case a rising temperature and what is the mechanism that determines that. The western Antarctic peninsula (which is where we are) is one of the most rapidly warming areas on the planet right now. You may want to research the 2002 collapse of the Larsen Ice Shelf. That was a big deal. There are parts of the Arctic that are experiencing relatively rapid change as well. If you think about it, there is a feedback effect. White, as my students should now know, reflects light (remember our photosynthesis discussions and the various spectra). As the ice melts, less light is being reflected and in turn more heat is absorbed by the earth.
So, this warming brings us to the icefishes and our investigation down here. The icefish, which have no hemoglobin, the protein that carries oxygen in the blood. This mutation (no production of the protein hemoglobin) occurred around 2.2 - 5 million years ago. Because the cold Antarctic waters have high levels of dissolved oxygen this mutation was not deleterious. So naturally one might wonder if and how much warming temperatures might affect the survival of cold water organisms. Still with me? Good. Let's look at the actual experiment...
Hypothesis In a nutshell - the hypothesis we are testing is that the significant factor in thermal tolerance (the fishes' ability to survive in warming water) is lack of oxygen to the tissues (hypoxia). Some people hypothesize that it is 'neuronal' - yes, look that up :)
The Set Up In earlier experiments that Bruce Sidell and Jody Beers have done, it was established that increased temperature was deleterious for the survival of these coldwater fishes, particularly the icefish with no hemoglobin. They don't do so well if you know what I mean. But Wait! When the water gets warmer, there are two variables - temperature and levels of dissolved oxygen because the two go together. Warmer water has less available oxygen for the fish. Sooooo, Bruce, Kristin, and Jody had a great idea. Put the fish in a tank that is getting warmer but pump in more oxygen.
Here's how we are going to do it. We have four tanks that are hooked up to heaters and we can bubble in oxygen as desired.
Here are a couple of the tanks that we will be using. They have a fresh flow of seawater if we choose to turn it on.
Each tank has a heater attached to warm the water and we have portable oxygen pumps to put into the tanks. We also have fish - a must, actually a number of fish (sample size makes a difference). Right now we only have red-blooded fish (remember the broken winch?) But that is okay because we need to test this on both white-blooded and red-blooded fish. Remember, good science rules out (or in) all the possible variables.
Here are some of the Notothenia coriiceps that we caught on our fishing trip. These are red-blooded Antarctic fish.
This is a Notothenia gibberifrons, the famous Gibby. Notice its buggy eyes and big fleshy lips. It gives them a distinctive look. Very lovable, don't you think?
Well, that is certainly enough for today. We'll continue and you all can follow along as we investigate this. Everybody is busy. And as you can see from the picture, I have my share of work to do along with guiding you through our journey. What are your thoughts? Any questions? Ideas about what we will find? Don't go far. We have a lot ahead.
Hey look - they even trust me to figure stuff out and get it ready for our experiments! I'm rigging up the temperature loggers for the tanks. I've been monitoring and graphing the data from these.