Experimental determination of the fate of rising CO2 droplets in sea water.

Brewer, P.G., E.T. Peltzer, G. Friederich and G. Rehder1
Monterey Bay Aquarium Research Institute
7700 Sandholdt Road, Moss Landing, California 95039.

1: Now at GEOMAR, Center for Marine Research
Wischhofstrasse 1-3, D-24148, Kiel, Germany.

Environmental Science & Technology (2002) 36: 5441-5446.

Received: 2002 June 21.
Revision received: 2002 September 20.
Accepted: 2002 October 2.
Published on web: 2002 November 1.


ABSTRACT

Direct oceanic disposal of fossil fuel CO2 is being considered as a possible means to moderate the growth rate of CO2 in the atmosphere. We have measured the rise rate and dissolution rate of freely released CO2 droplets in the open ocean to provide fundamental data for carbon sequestration options. A small amount of liquid CO2 was released at 800 m, at 4.4 C, and the rising droplet stream was imaged with a HDTV camera carried on a remotely operated vehicle. The initial rise rate for 0.9-cm diameter droplets was 10 cm/s at 800 m, and the dissolution rate was 3.0 µmol/sq-cm/sec. While visual contact was maintained for 1 h and over a 400 m ascent, 90% of the mass loss occurred within 30 min over a 200 m ascent above the release point. Images of droplets crossing the liquid-gas phase boundary showed formation of a gas head, pinching off of a liquid tail, and rapid gas bubble separation and dissolution..

© 2002 by American Chemical Society.


Acknowledgements

We thank the pilots of the R/V Ventana for their exceptional skills. This work was supported by a grant to MBARI from the David and Lucile Packard Foundation, and by the U.S. Department of Energy Ocean Carbon Sequestration Research Program Grant De-FC26-00NT40929.


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