Seasonal Composition of Temperate Plankton Communities: Free Amino Acids1

Abstract

In marine plankton, the patterns of seasonal succession and free amino acid composition reveal several features in common. Free amino acid levels are generally higher in summer than in winter communities: major changes occur during periods of community change in late spring and early winter. These levels also appear to be an index of physiological condition and productive capacity. The variations are quantitative in terms of concentration per unit tissue weight; relative compositions are the same in both the summer and the winter dominant copepods (Acartia tonsa and Acartia clausi). Factor analysis reveals an extremely high degree of intercorrelation within the free amino acid pools. The phytoplankton‐microzooplankton, consisting primarily of diatoms and larval crustaceans in varying proportions, has greater consistency of quantitative change (one amino acid in relation to all others) than does the zooplankton. Furthermore, the amino acid communality of an estuarine phytoplankton‐microzooplankton community is surprisingly high.

Plankton composition and biomass development: a seasonal study of a semi-intensive outdoor system for rearing of turbot

“…The pools of free AA in the seston remained relatively similar (318 nmol L À1 AE 201), except for the peaks in May and August of about 700 nmol L À1 . The rather comparable proportion of EAAs among the pool of free AA (31 AE 12% of the free AA were EAA) indicates homoeostasis among EAA in the seston as has also been observed in copepods (Jeffries 1969;Guisande et al 1999). Moreover, the composition of AA in our study (data not shown) is comparable to pools of AAs observed in phytoplankton in coastal ecosystems (Flynn et al 1994) and in laboratory cultures (Zygmuntowa 1972;Carmento et al 2013).…”

The Seasonal Variation of the Free and Combined Dissolved Amino Acids in the Irish Sea

“…There is a noteworthy similarity between the seasonal variation in the dissolved free amino acids and the seasonal succession found by Jeffries (1969) for the free amino acids of phytoplankton growing in Rhode Island Sound. The principal difference is that the summer maximum of the dissolved amino acids and the subsequent fall-off occurs later than that of the free amino acid of the phytoplankton.…”

Biological considerations in the measurement of dissolved free amino acids in seawater and implications for chemical and microbiological studies

“…Glutamic acid and glutamine are particularly high, probably because these amino acids play essential roles in the ammonium uptake mechanisms of phytoplankton (Syrett 1981). The source of the relatively large amount of taurine (2-aminoethanesulfonic acid; not a component of protein) is probably microzooplankton; this compound is reported to be abundant among the plankton only in animals (Jeffries 1969). The concentrations of DFAAs found in natural seawater result from a balance between the processes that release them into the water (primarily from organisms) and those that remove them (e.g.…”