Thursday, 12 June 2014

The chamber of earthly delights and a question of scale


Pete, Dave and Philip are unveiling the latest piece of field work kit. A fine example of the different scales at which people work: Pete seems to be taking a remote sensing view point, Dave bit more hands on, Philip going for the fine detail. The item they are revealing should allow us to work at the scale of whole ponds at Hauxley, the new arrival being a perspex chamber manufactured to fit over individual experimental ponds. This will allow Pete to monitor the gas exchanges from a whole pond, in addition to the more fine grained analyses with smaller floating chambers that we can position over small sections of distinct vegetation types. Initial data show that the individual ponds vary markedly, some ponds exhaling CO2 and methane, others acting as sinks for those same gases at the very same time. The chamber looked surprisingly large when it arrived, (it looked surprisingly large when Pete tried to get it in his car at the factory). It is designed to extend either side of the ponds and wedge down into the surrounding vegetation to create a strong seal. Eventually the lure of bubble wrap got the better of us.

Dave, who is no mean craftsman himself is inspecting the workmanship. The chamber is a hefty and stout piece. The next step is to try this out in the field. We will put the chamber over a pond, and connect it up to the portable gas analyser which samples the air inside the chamber and gives real time measures of the changing concentrations. One unexpected outcome of this approach is the very concrete feel for the ecosystem's processes that you get from watching the numbers tick up on a display screen. Suddenly those invisible gases seem very real, the squidgy ground beneath our feet very lively, as if we are standing on some giant creature, submerged in the swamp.

No comments:

Post a Comment