Distribution of dissolved free amino acids in the Ushant front region

Abstract

Measurements of dissolved free amino acids (DFAA) combined to phytoplankton and particulate matter parameters of water samples are described with reference to spring and summer hydrological conditions offshore the coast of Brittany in the Ushant front region. DFAA were found to exhibit vertical, lateral, diel and seasonal variations. Major differences were due to variations of a limited number of amino acids: aspartic acid, serine, histidine, threonine, glycine, alanine, leucine and ornithine. They were found to be enriched at the boundaries of the halothermoclines and the frontal region. Spectra of amino a c~d s and total DFAA concentrations were rather similar in samples representative of mixed and stratified waters at a given season. There were no significant correlations between total DFAA concentration and phytoplankton pigments. The magnitude of seasonal and diel variations of amino acids suggest that their turnover may be related to a variety of biological, physiological and biochemical processes prevailing in the pelagic ecosystem.

Distribution of phyto- and bacterioplankton growth and biomass parameters, dissolved inorganic nutrients and free amino acids during a spring bloom in the Oosterschelde basin, The Netherlands

“…No quantitatively important differences were observed between stations. The in situ amino acid concentrations were slightly high compared to those measured in coastal waters elsewhere (Dawson & Gocke 1978, Billen et al 1980, Keller et al 1982, Mopper & Lindroth 1982, Poulet et al 1984. Concentrations comparable to those detected in the Oosterschelde basin were found by Jsrgensen (1982) in spring and autumn in a shallow estuary on the coast of Denmark.…”

“…These amino acids constituted at least 60 % of total DFAA. The predominance of these amino acids, sometimes together with ornithine and lysine, is a commonly observed phenomenon in marine or estuarine waters (Bohling 1970, Dawson & Gocke 1978, Billen et al 1980, Amano et al 1982, Jsrgensen 1982, Keller et al 1982, Macko & Green 1982, Mopper & Lindroth 1982, Sigleo et al 1983, Poulet et al 1984. Unfortunately, ornithine and lysine were not detected by our HPLC procedure.…”

“…Dissolved free amino acids (DFAA) may form a substantial part of the small fraction (Jsrgensen 1982). The amount of DFAA released in the marine environment and the contribution of the individual amino acids depend on the algal species involved (Macko & Green 1982, Poulet et al 1984) and on the physiological condition of the algae or the algal population (Riley & Segar 1970, Crawford et al 1974, Hammer & Eberlein 1981, Ittekot 1982, Hammer & Brockmann 1983, Lancelot 1983, Poulet & Martin-Jkzkquel 1983. Amino acids are submitted to rapid recycling (Laane 1983).…”

Oligotrophy and pelagic marine bacteria: facts and fiction

“…A,,, was taken as 1 mg glucose 1-' (Vaccaro et al 1968), 1 mg 1-' of a single amino acid, and 30 mg 1.' of dissolved free amino acids (Mopper & Lindroth 1982. Poulet et al 1984.…”

Dissolved free amino acids in the marine environment: a carbon to nitrogen ratio shift during diatom blooms

“…The spectrum of results is widely extended from no interrelations with phytoplankton (Macko et al 1982, Williams & Poulet 1986) to accumulations of single amino acids at density gradient boundaries (Liebezeit et al 1980, Poulet et al 1984) and die1 variations in distribution patterns (Mopper & Lindroth 1982). More or less fixed patterns of DFAA during phytoplankton development were reported by Laanbroek et al (1985).…”