Up until about 10 years ago, the only known organisms in the lakes of the Dry Valleys were microbes, like the ones we've been studying. It was thought that the glaciers expand and retreat and wipe the biotic slate clean each time, with only these microbial communities having the time to recolonize. It was impossible for a scientist to get funding to even investigate the possibility of other, more complicated life forms here because it was thought to be impossible.
Then, about 10 years ago, someone found 2-3 larvae of copepods, a free-swimming crustacean some 2 mm in length. This was a radical finding since they are exactly the type of complex multicellular organism that we used to think could not colonize these lakes. Were these evidence of a contamination, accidentally brought here by people from somewhere else? We didn't know, but curiosity was piqued.
Researchers looked high and low in the lakes of the Dry Valleys, and they found copepods at very bottom of Lake Joyce. After some more sampling and research, it was determined that this species is found only here in Lake Joyce. This discovery was followed by a bunch of questions; How did they get here? Where did they come from? How long have they been here? Why are they not found in other lakes in this region?
It's possible that the copepods have been here ever since Antarctica split from Gondwana 20 million years ago! This would be a radically different idea from our previous notion of glaciers wiping the biotic slate clean much more recently.
Ian is making progress on these questions while he's here and able to dive. He has set up copepod traps to capture some of them. He'll take them back to New Zealand, where their genome will be mapped. Then we'll be able to compare their genetic information with that of their closest relatives to estimate how long its been since they've been separated.
This story represents the way science is frequently done. We were once pretty sure that glaciation would so thoroughly scour a landscape and prevent anything from surviving. We were and also pretty sure that nothing was here but single-celled organisms. These recent discoveries have made us question what we previously thought, and has inspired a new and very interesting line of research.
Copepod with eggs attached.
Ian with copepod trap – a nalgene bottle with rocks duct-taped to it to make it rest on the bottom of the lake, for the copecods to crawl into.
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