Nishijima, T., Fukami, K.-1995
Bulletin of Marine Sciences and Fisheries, Kochi University,15: 25-31
Abstract:
Algal growth potentials of deep seawater for a diatom and food alga, Skeletonema costatum and a raphidophycean alga, Heterosigma akashiwo were evaluated. Growth enhancement of these algae by co-incubation with bacteria isolated from deep seawater was also examined.
Deep seawater pumped up from a depth of 320 m had growth potentials of 105 cells/ml for S. costatum and 103 cells/ml for H. akashiwo. These cell yields were about 8-30% for S. costatum and 1% for H. akashimo compared to a 100% of those cultured in nutrient-rich artificial medium. The cell yield of S. costatum in deep seawater was enhanced by the addition of vitamin B12 and or EDTA, but no such enhancements of H. akashiwo by ferric chloride, vitamin Bl2, and or EDTA were found. The growth rates of both S. costatum and H. akashiwo were enhanced by the addition of ferric chloride, vitamin B12, and/or EDTA. Among the eight bacterial strains previously found to enhance the cell yields of Chaetoceros ceratosporum, six bacterial strains enhanced the cell yields and or growth rates of S. costatum and five bacterial strains enhanced those of H. akashiwo. The growth enhancement by co-incubation with those bacterial strains could result from the vitamm B12 and/or chelater excreted into the medium by the bacteria.
(Faculty of Agriculture, Kochi University, Monobe, Nankoku City, Kochi 783, Japan)
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