High acrylate concentrations in the mucus of Phaeocystis globosa colonies

Abstract

Acrylate produced from dimethylsulphoniopropionate (DMSP) by Phaeocystls has been claimed to inhib~t bactenal growth However, the concentrations of acrylate measured In seawater dunng Phaeocystls blooms are not high enough to expect i n h ~b i t ~o n of bactenal growth In this study, the total acrylate m Phaeocyshs cultures free from bacteria was measured The concentration found m the exponenbal phase of growth was similar (0 1 to 1 0 PM) to earher field reports, but the amount found in the stationary phase of growth was much higher (1 to 4 pM) Acrylate in cultures, as well as in field samples, was found to be located in the mucous layer of the colony 'Microscale' concentrations in that layer were more than 1000-fold higher (1 3 to 6 5 mlvl) than the total concentration found in the unfractionated culture Such h ~g h concentrations could have a n antimicrobial effect However, acrylate appears to be adsorbed to the mucus and may be inaccessible to bactena including those that consume acrylate As soon as the colonies started to decay, acrylate was released ~n t o the surrounding envlronment, and since it is not detected In bloom samples, ~t is apparently consumed by bactena KEY WORDS.