CO2 mitigation by marine algae


Marine algae as a co2 sink

Journal Water, Air, & Soil Pollution

Publisher Springer Netherlands

ISSN 0049-6979 (Print) 1573-2932 (Online)

Subject Biomedical and Life Sciences and Earth and Environmental Science

Issue Volume 64, Numbers 1-2 / August, 1992

DOI 10.1007/BF00477107

Pages 289-303

Online Date Monday, December 06, 2004

 

Marine algae as a co2 sink

R. L. Ritschard

 

(1) Center for Atmospheric & Biospheric Effects of Technology Lawrence Berkeley Laboratory, University of California, 94720 Berkeley, CA, USA

 

 

Abstract The most effective ways to reduce CO2 emissions are to improve the energy efficiency of each economic sector and to reduce the cutting of tropical and temperate forests around the world. These options, however, may not fully reach their technical and economic potential due to various political and socioeconomic barriers. Other more innovative and less well developed mitigation measures therefore will be required. The most practical of these is to increase CO2 sinks through photosynthesis in both standing tree biomass and in ocean primary producers.

 

In this paper, the use of marine algae as CO2 sinks is reviewed from a technical, engineering/economic, and environmental perspective. Two open ocean options are considered for large-scale CO2 mitigation: the use of phytoplankton through Fe fertilization and macroalgal (kelp) farms, which can be used for both C sequestering and energy production. It has been estimated that these two approaches can sequester from 0.7 to 3 Gt C yr–1 from the atmosphere at an estimated cost of $5 to 300 t–1 C yr–1. Other options currently under study are also mentioned. Numerous questions remain to be answered pertaining to the use of both microalgae and macroalgae for CO2 assimilation before credible estimates of costs of C removal can be made for either system. In addition, there are several key environmental issues raised by the use of algae. A detailed discussion of these variables, including cost estimates, is presented.