Species area curves in machine oil wells

Ever since I was a grad school young’un, I’ve been interested in the extent to which theories from classical ecology, which mostly seem to have been developed from observations of clams and trees and other big living things I know nothing about, can be extended to microbial ecology. Now, I should make clear that I also know very little about microbial ecology – I’m a DOC chemist, basically – and this interest is not strong enough to drive me to do something extreme, like trying to get a PhD by studying it. It is not even the sort of interest that would make me wish I was studying it full time, even as I actually study something much safer for my PhD work. No, this is the sort of interest that I think about occasionally while I’m eating Doritos, before I get distracted by something more interesting .

With that made clear, check out this paper (Van der gast et al 2005, environmental microbiology 7(8) 1220 - 1226, email us for the pdf), which tests the species-area relationship in a new system. The species-area relationship, as you’ll remember, posits that the species richness of an island (or other discrete area) is related to its area, by s=cA^z, where s is species richness, c is a species-specific scaling parameter, A is island area, and z is a constant that turns out to be fairly stable across taxa and location.

The neat thing about this paper is that they organisms they looked at were bacteria, and the “islands” were reservoirs of lubricant for different machines in a machine shop at Oxford University. The fluid reservoirs vary from 9-180 liters, and species diversity was measured by denaturing gradient gel electrophoresis (reservoir volume was used instead of area). Niftily, not only did the relationship hold, but z was around 0.25, right in the middle of the typical range for parrots and bugs and whatnot on real islands.

I think there might be some bigger implications to this paper – for one thing, the species-area relationship implies the possibility of local extinctions, which are not usually thought to be likely for bactera – but mainly I like it because the authors saw lubricant reservoirs, and thought about islands.

Cheers,
Drew

An addendum:

Cell density in the lubricant reservoirs was typically 10^10 cells per liter, or one hundred billion to 1 trillion “individuals” per reservoir. That seems like a pretty big number to me – in classical studies of the species-area hypothesis, were there anywhere near this many individuals per island? I discount social insects, by the way, since they reproduce as a unit and can’t function individually. What do you think?