- The biochemical composition of ten species of estuarine phytoplankton
was determined. Studies were made of their growth in
various culture media and of their relative value as food for oyster
larvae. Nine of the species were isolated from Yaquina Bay, Oregon.
An attempt was made to select species which commonly occurred in
the 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 determined
using larvae of European and native oysters. Determinations were
based on the mean length of larvae at the end of the feeding period.
Isochrysis, known to be an excellent food source, was used as a
standard for comparison with the Yaquina Bay isolates.
Cylindrotheca gracilis, Navicula abscondita, and an unidentified
centric diatom proved to be adequate food sources for the larvae.
Comparison of total protein, carbohydrate, lipid, and pigment
showed no differences that could be related to the taxonomy of the
organisms. Total protein ranged from 313 μg/mg dry weight to
521 μg/mg. Total carbohydrate ranged from 78 to 316 μg/mg. Total
lipid ranged from 53 to 202 μg/mg. Total pigment ranged from 11
to 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 did
not have leucine. Hydroxyproline was present only in Chlamydomonas
palla. Ornithine was not present in Tetraselmis suecica, Prymnesium
parvum, or the centric diatom.
The three species of Chlorophyta contained chlorophylls a and
b, beta carotene, lutein, neoxanthin, and violaxanthin. Cryptomonas
salina contained chlorophylls a and c, alpha carotene, and three
unidentified xanthophylls. The six species of Chrysophyta contained
chlorophylls a and c, beta carotene, fucoxanthin, and diadinoxanthin.
An unidentified xanthophyll was found in Cylindrotheca. Total chlorophyll
and carotenoid, the ratio of chlorophyll a:b or c, and the ratio
of carotenoid:chlorophyll were estimated for each species.
Twenty-eight fatty acids were found in the ten species. The
fatty 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 of
linolenic acid, 18:3. The diatoms were distinguished by very low
amounts of C₁₈ acids and a high proportion of 20:5. All species
contained a high proportion of palmitic acid, 16:0.
All species were grown in enriched seawater media and artificial
seawater media, and a comparison was made of their growth
in the different media. Growth curves in an enriched seawater
medium were derived for each species.
Detailed descriptions of the nine species isolated from Yaquina
Bay are given.