TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 60 (No. 4), pp. 797-805, 2004

A Eulerian-Eulerian Physical-Biological Impact Model of Zooplankton Injury Due to CO2 Ocean Sequestration

Baixin Chen*, Yongchen Song, Masahiro Nishio and Makoto Akai

National Research Institute of Advanced Industrial Science and Technology, Namiki, East-Tsukuba, Tsukuba 305-8564, Japan

(Received 2 October 2003; in revised form 4 April 2004; accepted 5 April 2004)

Abstract: To study the biological impacts of CO2 ocean sequestration on floating marine organisms, a full Eulerian-Eulerian scheme model has been developed in a large-eddy simulation (LES) version using one-way coupling of the equations of seawater flow to the transport equations of the bio-scalar variables. Special attention was paid to deriving the transport equation, involving non-conservative scalars to describe the degree of injury to floating organisms due to the change in the pH environment resulting from CO2 dissolution. The source terms of the transport equations of bio-scalar variables are based on experimental data on zooplankton activities affected by lower pH seawater, allowing construction of empirical sub-models of three kinds of floating marine organisms: Gaidius variabilis, Paraeuchaeta Birostrata, and Multi-organisms. An example is given to show the applicability of the model to the assessment of the biological impact of CO2 sequestration in the ocean. Given an initial CO2 droplet diameter of 8.0 mm and an injection rate of 1.0 kg/sec, the model simulation predicts that the zooplanktons lose approximately 90% of their activity when the lowest pH inside the plume decreases from 7.57 to 5.61. These injured zooplanktons then recovered gradually to their normal state within two hours due to dilution of the plume.

*Corresponding author E-mail: b.chen@aist.go.jp

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