TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 66 (No. 4), pp. 571-580, 2010

Short Contribution

Effects of Seawater Acidification by Ocean CO2 Sequestration on Bathypelagic Prokaryote Activities

Namiha Yamada*, Nobuo Tsurushima and Masahiro Suzumura

National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba AIST West, Onogawa, Tsukuba 305-8569, Japan

(Received 28 October 2009; in revised form 3 February 2010; accepted 29 April 2010)

Abstract: We investigated the effects of seawater acidification induced by ocean CO2 sequestration on bathypelagic prokaryotes. We simulated acidification conditions by bubbling high-CO2 air or adding chemical buffer solutions to seawater samples in order to examine changes in total cell counts, heterotrophic production rate, direct viable cell count, and relative abundance of Bacteria and Archaea. Considerable suppression of prokaryotic activities was observed at pH 7.0 or lower, especially in samples enriched with organic matter. The relative abundance of Archaea increased with increasing CO2 concentration. We found that seawater acidification can potentially alter heterotrophic activities and community structure of bathypelagic prokaryotes.

*Corresponding author E-mail: namiha-yamada@aist.go.jp

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