AP Biology class blog for discussing current research in Biology

Tag: Antartica

Climate Concerns and Rising Sea Levels: Antarctic Edition

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   Climate change has been a recent concern as it affects all aspects of human life. More evidence to climate change and the rise of sea levels was expressed in a very recent study conducted by IMAS PhD student: Alessandro Silvano. By doing so, he ultimately found that this process quickens the rate that ice melts and sea levels rise.

The study was conducted using ocean measurements off the coast of east Antartica. The study showed that glaciers are freshening the ocean, as the glaciers do not consist of salt. This dilutes the natural salt content of the ocean. He found that the melted water from the glaciers causes the ocean’s surface layer less salty and more buoyant, which prevented deep mixing during the winter months. Therefore it allowed warm water to retain its heat and melt glaciers from below. This process allowed the water to exist in layers, similar to when one attempts to mix oil and water. The study found a positive feedback mechanism, in which glacial melt water caused further melting of ice shelves, leading to an increase in sea level.

In some areas around Antartica, the study also found fresh meltwater decreased the formation and sinking of dense water. This results in decreasing the rate of ocean circulation, which stores heat and carbon dioxide. Because the cold glacial melt waters cause a slowing of the currents, which then decrease the ocean’s ability to decrease carbon dioxide and heat from the atmosphere. These two processes feed off of each other and induce and speed up climate change.

I enjoyed reading this article because I am personally passionate about decreasing the rate of climate change and educating myself on global warming. Backing global climate change due to its concerning effect – only one of which is sea level – with scientific evidence is important for gaining support of our communities.

Secondary Source Article: The Washington Post: One of the most worrisome predictions about climate change may be coming true

Proteins Keeping Fishes Alive



Words To Know:

notothenoids: the arctic ice fish

practical application: how organisms adapt through natural selection

superheating: solid is above its melting point but does not actually it to melt at this point


     Fish in Antarctica have been forced to evolve natural antifreeze proteins to stay alive.  These proteins are mainly found in the notothenoid fishes, which are found in freezing temperatures. Arthur DeVries discovered these fish, their ice- binding-proteins and also figured out how they work in the 1960s . The proteins bind to small crystals and also protect cells by binding to their cell membranes. They are anti-freezing proteins that allow fish to survive and adapt to harsh and cold conditions of arctic waters.

Recent Discoveries:

          Paul Cziko, among other researchers in the United States and New Zealand, published in The Proceedings of the National Academy of Sciences that these ‘anti freeze’ proteins’ are also ‘anti melting’. Cziko and his team wanted to understand the antifreeze ability and examined if an anti-freeze protein (that was attached to an ice crystal inside the fish) would melt when the temperature rose. Instead, they found that the ice crystals did not melt. Ice above the melting is point is considered superheated. Cziko’s research basically says that even when it is way past its melting point, the ice (that’s latched on to the protein) still stays frozen inside the fish. These ‘anti-freezing’ proteins are also ‘anti-melting’ proteins that cause ice crystals to accumulate in the fish’s body.

The study shows evolution, not practical application, and this is a typical case of ‘evolutionary trade off’. There are difficulties that get solved, but there’s also a price to pay. Cziko’s research has not indicated any unfavorable effect due to the crystals, but the crystals could potentially block up the blood vessels of the fish and provoke an inflammatory reaction.

Personal Statement: 

      Personally, I really liked the NY Times article. I actually didn’t realize that we had to find additional articles until I re-read the assignment sheet. I found other articles because I was genuinely curious as to how this worked and came about. I was initially attracted to the word ‘protein’ in the article’ title -since it relates to what we are learning in class- but stayed because of the evolutionary aspect. It has always been hard for me to think of evolution as something. It is such a difficult-to-grasp concept since you can’t really see it happening . But, in some way- this made me think that I did see evolution. Instead of making me think of evolution as a concept or theory that I learn at school, it made me think of it as a reality, and as something that actually happens.     

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