Takashi Ishimaru

An improved method for the determination of phytoplankton chlorophyll using N, N-dimethylformamide

Non volatile N, N-dimethylformamide (DMF) at room temperature is proposed as a new solvent for determining the chlorophylla in cultured and natural phytoplankton samples. Advantages of DMF compared to the solvents ordinarily used are (1) higher extraction efficiency, (2) rapid extraction time of 30 min, (3) simple extraction procedure requiring neither extra heating nor grinding, but soaking, and (4) a long stable life of chlorophylla (at least one month at 5°C in the dark).

Effect of water temperature and light intensity on growth rate and toxicity change in Protogonyaulax tamarensis

The effect of water temperature and light intensity on the growth rate and the toxicity of Protogonyaulax tamarensis was examined using a monoclonal culture isolated from Ofunato Bay, Japan in March, 1984. The growth rate decreased with the decrease of either light intensity or temperature. The amount of toxin produced increased concomitantly with the decrease of the growth rate. However, the increase of the toxicity under low growth rate was less remarkable when the growth rate was lowered by the decrease of light intensity. This indicates that photosynthesis plays an important role in the production of toxin in P. tamarensis.

Toxin production in the dinoflagellate Protogonyaulax tamarensis

Many clones of Protogonyaulax tamarensis were collected from Ofunato Bay in the same season and cultured under the same conditions. The toxicity of the cultured cells of these clones was remarkably different from each other (maximum of 100-fold). Significant differences (maximum of 20-fold) in toxicity of cultured cells were also observed among subclones isolated from a single clonal culture. It is unlikely that this variation in toxicity among subclones is due to mutation during culture. From these observations we suggest that toxin production in P. tamarensis is not a hereditary characteristic.

In-Water Algorithms for ADEOS/OCTS

AbstractIn-water algorithms for OCTS standard products were developed using in situ data and installed for operationally processing at NASDA/EOC. This paper describes the in-water algorithms Version 1.0 for chlorophylla concentration, pigment concentration, and attenuation coefficient at a wavelength of 490 nm. The selected OCTS standard algorithms (Ver. 1.0) are as follows:

Upwelling plumes in sagami bay and adjacent water around the Izu Islands, Japan

Chl = 0.2818 \left( {\frac{{L4 + L5}}{{L3}}} \right)^{3.497 }

OCTOPUS, an octo parameter underwater sensor, for use in biological oceanography studies

Pig = 1.568 \left( {\frac{{L2}}{{L4}}} \right)^{ - 2.079 } \left( {\frac{{L3}}{{L4}}} \right)^{ - 3.498 }