Saturday, February 05, 2011

Chernobyl Birds

This report from BBC says that birds in the hot area have 5% smaller brains, and that mammals are decreasing, and that insect diversity is less.

The insect diversity they claim to understand: "the same researchers found a way to predict which species there are likely to be most severely damaged by radioactive contamination, by evaluating how often they renew parts of their DNA." That surprised me a little--I'd previously surmised that the driving mechanism would be the rate of protein recycling. I don't think I explained my reasoning, so I'll do it here even if it is wrong: if radiation is applied uniformly, since there's more protein in a cell than DNA it will be damaged more often, and become unusable until it is recycled. Recycling proteins faster will require more food and implies a slower rate of growth. If renewing DNA and recycling proteins correlate, then I'll claim a partial verification, anyway. (They already thought of it, and call it "oxidative stress.") I still predict slower growth and overall smaller size. (Larger size would probably be better for them, but stress isn't conducive to growing big.)

But small brains... They're going to go back and look at other organs now. I wonder if there's some region that is smaller than normal, or if the shrinkage was uniform. Might be hard to tell--this is only a 5% effect, and bird brains are small, so dissection would be pretty time-consuming.

As to the fewer mammals--if I recall correctly there was a boom in population for some of the larger ones when people abandoned the area. Maybe the population wasn't at equilibrium, and they're looking at normal fluctuations. Time should tell.

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