Marine Science Institute, University of Texas at Austin, Port Aransas, TX, 78373, USA.
Marine Science Institute, University of Texas at Austin, Port Aransas, TX, 78373, USA; Laboratoire d'Océanologie et des Geosciences, UMR LOG 8187, Université du Littoral Côte d'Opale, Wimereux, France.
Harmful Algae. 2019 Jun;86:46-54. doi: 10.1016/j.hal.2019.03.013. Epub 2019 May 21.
Paralytic Shellfish Poisoning (PSP) caused by the dinoflagellate Alexandrium catenella is a well-known global syndrome that negatively impacts human health and fishery economies. Understanding the population dynamics and ecology of this species is thus important for identifying determinants of blooms and associated PSP toxicity. Given reports of extensive genetic heterogeneity in the toxicity and physiology of Alexandrium species, knowledge of genetic population structure in harmful algal species such as A. catenella can also facilitate the understanding of toxic bloom development and ecological adaptation. In this study we employed microsatellite markers to analyze multiple A. catenella strains isolated from several sub-regions in the Gulf of Maine (GoM) during summer blooms, to gain insights into the sources and dynamics of this economically important phytoplankton species. At least three genetically distinct clusters of A. catenella were identified in the GoM. Each cluster contained representatives from different sub-regions, highlighting the extent of connectivity and dispersal throughout the region. This shared diversity could result from cyst beds created by previous coastal blooms, thereby preserving the overall diversity of the regional A. catenella population. Rapid spatiotemporal genetic differentiation of A. catenella populations was observed in local blooms, likely driven by natural selection through environmental conditions such as silicate and nitrate/nitrite concentrations, emphasizing the role of short-term water mass intrusions and biotic processes in determining the diversity and dynamics of marine phytoplankton populations. Given the wide-spread intraspecific diversity of A. catenella in GoM and potentially elsewhere, harmful algal blooms will likely persist in many regions despite global warming and changing environmental conditions in the future. Selection of different genetic lineages through variable hydrological conditions might impact toxin production and profiles of future blooms, challenging HAB control and prediction of PSP risk in the future.
麻痹性贝类毒素（PSP）是由甲藻亚历山大藻引起的一种全球熟知的综合征，对人类健康和渔业经济产生负面影响。因此，了解该物种的种群动态和生态学对于确定赤潮爆发和相关 PSP 毒性的决定因素非常重要。鉴于亚历山大藻属物种的毒性和生理学存在广泛的遗传异质性的报道，了解有害藻类物种如亚历山大藻的遗传种群结构也可以促进对有毒赤潮发展和生态适应的理解。在这项研究中，我们使用微卫星标记分析了在夏季赤潮期间从缅因湾（GoM）的几个次区域分离的多个亚历山大藻属菌株，以深入了解这种具有经济重要性的浮游植物物种的来源和动态。在 GoM 中至少鉴定出了三个具有遗传上明显不同的亚历山大藻属种群。每个种群都包含来自不同次区域的代表，突出了整个区域的连通性和扩散程度。这种共享的多样性可能是由以前的沿海赤潮形成的休眠囊形成的，从而保留了该地区亚历山大藻属种群的总体多样性。在当地赤潮中观察到亚历山大藻属种群的快速时空遗传分化，这可能是由环境条件（如硅酸盐和硝酸盐/亚硝酸盐浓度）下的自然选择驱动的，强调了短期水团入侵和生物过程在确定海洋浮游植物种群多样性和动态方面的作用。鉴于 GoM 中以及其他地方的亚历山大藻属具有广泛的种内多样性，尽管未来全球变暖以及环境条件的变化，有害藻类赤潮仍可能在许多地区持续存在。不同遗传谱系通过可变的水文条件选择可能会影响未来赤潮的毒素产生和特征，从而对未来的 HAB 控制和 PSP 风险预测提出挑战。
