Bigmack there are over 100 different redox couples in that pool that liberate enough energy to support life. For example the sulfide oxidizes rapidly to sulfate at the surface because there's oxygen present. There are organisms that reduce that sulfate to sulfides. Deeper in the pool there are organisms that do the reverse and oxidize sulfide to sulfate as their energy source. The bubbles that give the pool its name of "Champagne pool" are methane; the whole area is extremely energy rich.
Etacovada: I was told that most of January was rainy and that I picked the exactly correct 2 weeks to go. My grad student's in your part of the country (Wellington) until April. I think next year I'll tour the North island in its entirety and then the year after that go to the South Island. I have a friend in Dunedin who maintains that the Northern Island is crap compared to the South. That's no surprise from someone in that location apparently
