The culture and biochemical analysis of some estuarine phytoplankton species

The biochemical composition of ten species of estuarine phytoplanktonwas determined. Studies were made of their growth invarious culture media and of their relative value as food for oysterlarvae. Nine of the species were isolated from Yaquina Bay, Oregon.An attempt was made to select species which commonly occurred inthe phytoplankton of the bay. The tenth species, Isochrysis galbana,was obtained from the Culture Collection of Algae at Indiana University.The ten organisms comprised three species of Chlorophyta,one species of Cryptophyta, and six species of Chrysophyta.The relative value of each species as food was determinedusing larvae of European and native oysters. Determinations werebased on the mean length of larvae at the end of the feeding period.Isochrysis, known to be an excellent food source, was used as astandard for comparison with the Yaquina Bay isolates.Cylindrotheca gracilis, Navicula abscondita, and an unidentifiedcentric diatom proved to be adequate food sources for the larvae.Comparison of total protein, carbohydrate, lipid, and pigmentshowed no differences that could be related to the taxonomy of theorganisms. Total protein ranged from 313 μg/mg dry weight to521 μg/mg. Total carbohydrate ranged from 78 to 316 μg/mg. Totallipid ranged from 53 to 202 μg/mg. Total pigment ranged from 11to 40 μg/mg.The amino acid composition of the ten species was similar.The five most abundant amino acids were glutamic acid, alanine,glycine, aspartic acid, and leucine. Only Cryptomonas salina didnot have leucine. Hydroxyproline was present only in Chlamydomonaspalla. Ornithine was not present in Tetraselmis suecica, Prymnesiumparvum, or the centric diatom.The three species of Chlorophyta contained chlorophylls a andb, beta carotene, lutein, neoxanthin, and violaxanthin. Cryptomonassalina contained chlorophylls a and c, alpha carotene, and threeunidentified xanthophylls. The six species of Chrysophyta containedchlorophylls a and c, beta carotene, fucoxanthin, and diadinoxanthin.An unidentified xanthophyll was found in Cylindrotheca. Total chlorophylland carotenoid, the ratio of chlorophyll a:b or c, and the ratioof carotenoid:chlorophyll were estimated for each species.Twenty-eight fatty acids were found in the ten species. Thefatty acids common to all species were 14:0, 16:0, 16:1, 18:0, 18:1,and 18:2. The Chlorophyta were distinguished by a high content oflinolenic acid, 18:3. The diatoms were distinguished by very lowamounts of C₁₈ acids and a high proportion of 20:5. All speciescontained a high proportion of palmitic acid, 16:0.All species were grown in enriched seawater media and artificialseawater media, and a comparison was made of their growthin the different media. Growth curves in an enriched seawatermedium were derived for each species.Detailed descriptions of the nine species isolated from YaquinaBay are given.