HR: 13:35h
AN: U23B-02 INVITED     [Abstracts]
TI: Enabling the assessment of a high CO2/low pH ocean: Is a Free Ocean CO2 Enrichment (FOCE) experiment possible?
AU: Brewer, P G
EM: brpe@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road , Moss Landing, CA 95039 United States
AU: Kirkwood, W
EM: kiwi@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road , Moss Landing, CA 95039 United States
AU: Barry, J
EM: barry@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road , Moss Landing, CA 95039 United States
AU: * Dunk, R M
EM: dura@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road , Moss Landing, CA 95039 United States
AB: Free Air CO2 Enrichment (FACE) experiments are now commonplace on land, and a large international network of sites exists. In sharp contrast there is as yet no equivalent ocean network. Yet it is in the ocean where the effects of elevated CO2 levels may have the greatest ecosystem impact. The ocean already holds some 500 billion tons of fossil fuel CO2, and the current invasion rate from the atmosphere is approximately 1 million tons CO2 per hour. Ocean surface pH values are already 0.1 pH units lower than pre-industrial, and a drop of 0.3 pH units is predicted by the middle of this century. The promise of cabled observatories in the ocean, which can provide the power and communications necessary for experimental control, opens the door to a new class of ocean experiments to investigate these impacts. The challenge is large both technically and scientifically. In air CO2 simply mixes, with no chemical reactions of concern. In sea water a series of reactions occurs, with significant kinetic lags, which present complex detection and control problems. We have initiated an attack on this problem. We have designed and are field testing a prototype system in which the H+ and CO2 concentration in a free volume of sea water may be elevated to simulate the conditions predicted for the later part of this century. This requires active feedback of current velocity and pH data to a controller to maintain experimental stability. This system should enable the study of important biogeochemical systems such as coral reefs, benthic fauna, and carbonate dissolution studies. For short term testing small volumes of acid or CO2 may be delivered from self-contained packages. For long term experiments a small bore pipe would be required to deliver the required volumes.
DE: 1615 Biogeochemical processes (4805)
DE: 1635 Oceans (4203)
DE: 1694 Instruments and techniques
DE: 4806 Carbon cycling
SC: Union [U]
MN: 2005 Joint Assembly