Plankton Politics Are Unpredictable -- Pennisi 2008 (213): 1 -- ScienceNOW

http://sciencenow.sciencemag.org/cgi/content/full/2008/213/1 --- Chaos really is a fact of life, but it's not necessarily a bad thing. Researchers analyzing the rise and fall of various plankton species have shown that even under constant conditions, the community never stabilizes, and no single species takes over for long. The results suggest that biodiversity might best be preserved not by keeping the number of particular species high but by preserving complex ecosystem dynamics.

Kevin: reminds me of a line from the movie 28 days later. It was roughly like this.
in the relative age of the planet, humans have only been here in a blink of an eyelid. So what makes you think that humans being gone isn't a return to normality.

there are valid criticisms of this experiment but it does point out that one needs to take note if the change in population are part of a dynamics of the eco system.