Iron requirements of Heterosigma akashiwo(Raphidophyceae), Heterocapsa circularisquama(Dinophyceae) and two common centric diatoms

DOI HANDLE Web Site Open Access

Search this article

Description

Iron is increasingly recognized to play a key role in the growth of microalgae in various marine systems, but there is a paucity of knowledge about the physiological iron requirements of harmful algal species. This study aimed to elucidate the halfsaturation constant for growth(Ks) and the maximum growth rate(μmax) of four phytoplankton species with regard to iron concentrations. The four species were the fish-killing raphidophyte Heterosigma akashiwo, the bivalve-killing dinoflagellate Heterocapsa circularisquama, and the centric diatoms Ditylum brightwellii(large sized) and Chaetoceros didymus(small sized). We conducted incubation experiments with axenic cultures of the four species using a chemically defined synthetic medium. Compared with Heterocapsa circularisquama(0.59 day-1) and Heterosigma akashiwo(0.50 day-1), the two diatom species exhibited high μmax values(0.68 day-1). The smaller diatom had the lowest Ks value of 7.5×10-9M, while the larger diatom had the highest Ks value of 2.1×10-7M. The Ks values of Heterosigma akashiwo and Heterocapsa circularisquama were 5.1×10-8 and 3.1×10-8M, respectively. Smaller-sized phytoplankton showed better affinity to lower concentrations of iron in the sea.

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top