Growth optimization of the invasive cyanobacterium Cylindrospermopsis raciborskii in response to phosphate fluctuations

作者：Valentina Amaral, Sylvia Bonilla, Luis Aubriot · 发表于：European Journal of Phycology · 年份：2014 · DOI：10.1080/09670262.2014.897760 · 被引用次数：60 · 研究领域：Aquatic Ecosystems and Phytoplankton Dynamics、Biocrusts and Microbial Ecology、Marine and coastal ecosystems

The role of ecophysiological traits in the success and expansion of the toxic cyanobacterium Cylindrospermopsis raciborskii is still under debate. One key factor appears to be the high physiological flexibility of this organism when obtaining limiting resources. Recent studies have found that filamentous bloom-forming cyanobacteria are able to optimize their growth by adjusting phosphate uptake during fluctuating nutrient conditions. We investigated the growth response of two phosphate-deficient C. raciborskii isolates (MVCC19 from Uruguay and CCMP1973 from USA) to short-term fluctuations in phosphate supply. These isolates were exposed to five phosphate concentrations which were provided in two supply modes: a single pulse (SingleP) versus the same amount divided in 10 pulses (TenP), with one pulse applied every 6 min. Morphological traits and changes in chlorophyll a and phycocyanin fluorescence were also evaluated. Growth rates of CCMP1973 and MVCC19 almost doubled and tripled, respectively, when exposed to multiple rather than single phosphate additions. Different growth rates were observed with the same total added resource, thus contradicting the classical model of dependence of growth rate on absolute external concentration. Phosphate-deficient C. raciborskii showed a remarkable physiological flexibility in adapting to phosphate availability on a timescale from minutes to hours. The TenP mode provided an extension of phosphate exposure time that allowed the energetic o...