How the ocean got its genome

MIT’s Stefan Helmreich gave a very interesting talk here last Monday titled “How the ocean got its genome.”

It was a blend of his work in Alien Ocean: Anthropological voyages in microbial seas and the new directions his research is taking. If you haven’t come across Alien Ocean yet, it is an excellent book. Here is the blurb from the publisher (UC Press):

Alien Ocean immerses readers in worlds being newly explored by marine biologists, worlds usually out of sight and reach: the deep sea, the microscopic realm, and oceans beyond national boundaries. Working alongside scientists at sea and in labs in Monterey Bay, Hawai’i, the Woods Hole Oceanographic Institution, and the Sargasso Sea and at undersea volcanoes in the eastern Pacific, Stefan Helmreich charts how revolutions in genomics, bioinformatics, and remote sensing have pressed marine biologists to see the sea as animated by its smallest inhabitants: marine microbes. Thriving in astonishingly extreme conditions, such microbes have become key figures in scientific and public debates about the origin of life, climate change, biotechnology, and even the possibility of life on other worlds.”

The one aspect of Helmreich’s new work that I found particularly fascinating was the trouble that ocean microbes present for definitions of species. In particular, the evolutionary ‘tree of life’ idea (where parents pass on their traits to progeny) gets very confused in the lateral transfer of genes amongst microbes. And this presents a big problem for identifying species as different “branches” that link to a common “trunk” in the tree of life.

It seemed to me that this lateral transfer essentially shifts the philosophy of biology from an inductive enterprise to an abductive one. This is not a really new argument, since the very idea that inferential bases for species classifications are abductive has already been proposed. But what is interesting is that when we give up on the inductive project of mapping individuals to general classes, that it is not just our ordering schema that gets confused. In the case of the oceans, for instance, where the great depths are frequently imagined to hold the earliest life forms (not always the case) what we get is a new set of problems over life itself.

I asked Dr. Helmreich what he made of this logical shift given his work interviewing scientists and following these debates. His answer was very interesting: that explanations for species were increasingly being sought based on what works – a functional, perhaps even pragmatist view of things. Latour’s new book “Modes of Existence” starts out with a similar anecdote, where a scientist responds to a skeptic not by an appeal to what is or is not the case, but with an appeal to the institution of science.