Cyst-forming dinoflagellates in a warming climate
Cyst-forming dinoflagellates in a warming climate
复制标题
DOI：
10.1016/j.hal.2019.101728
复制
发表时间：
2020-01-01
期刊：
影响因子：
6.6
通讯作者：
Anderson, Donald M.
中科院分区：
文献类型：
--
作者：
Brosnahan, Michael L.;Fischer, Alexis D.;Anderson, Donald M.
许多浮游植物物种，包括许多有害藻华（HAB）物种，通过形成底栖休眠阶段在水华之间存活很长时间。由于它们对这些物种的持续存在和新水华的开始至关重要，因此必须考虑底栖生物阶段的生理学，以准确预测对气候变暖和相关环境变化的反应。甲藻的底栖阶段，称为休眠孢囊，在适宜的温度，氧气供应和解除休眠的组合下萌发。后者是一种即使在氧气和温度条件有利时也会阻止发芽的机制。在这里，温度介导的控制休眠持续时间的证据，从甲藻Alexandrium catenella和Pyrodinium bahamense-两个HAB物种，导致麻痹性贝类中毒（PSP）-一起审查和提出新的证据的补充，基于温度的控制孢囊静止（在该状态下，孢囊发芽暴露在有利的条件下）。两个基于温度的机制与气候的相互作用进行了探讨，通过一个简单的模型参数化使用最近的实验结果与A。链状体。模拟结果表明，季节性温度循环的重要性，同步孢囊的解除休眠，并与基于地理的推论，A。链状藻在经历较大范围的季节性温度变化的栖息地中对变暖更有耐受性（即，具有较高的温度季节性）。温度的季节性是更大的浅，长停留时间的栖息地比深，开放水域的。随着气候变暖改变物种的活动范围，在季节性变化较大的浅水近岸生境中，孢囊床可能比在深水近海生境中持续时间更长，从而促进了更局部化和每年更早开始的赤潮。近年来对A. catenella还指出了新的囊肿形成的重要性，这是通过大规模性诱导触发花终止的一个因素。在温度季节性限制新的游泳细胞（幼苗）的流量狭窄的时间窗口的地区，变暖是不太可能促进更长和更激烈的HAB的影响，即使水柱条件，否则会促进长期的水华发展。许多物种可能具有强烈的性别分化驱动力，一旦浓度达到有利于新包囊形成的水平，就会产生新的包囊。这种现象可以施加一个限制，水华加剧，并建议在确定有害藻华风险期的持续时间囊床静止的重要作用。
Many phytoplankton species, including many harmful algal bloom (HAB) species, survive long periods between blooms through formation of benthic resting stages. Because they are crucial to the persistence of these species and the initiation of new blooms, the physiology of benthic stages must be considered to accurately predict responses to climate warming and associated environmental changes. The benthic stages of dinoflagellates, called resting cysts, germinate in response to the combination of favorable temperature, oxygen-availability, and release from dormancy. The latter is a mechanism that prevents germination even when oxygen and temperature conditions are favorable. Here, evidence of temperature-mediated control of dormancy duration from the dinoflagellates Alexandrium catenella and Pyrodinium bahamense-two HAB species that cause paralytic shellfish poisoning (PSP)-is reviewed and presented alongside new evidence of complementary, temperature-based control of cyst quiescence (the state in which cysts germinate on exposure to favorable conditions). Interaction of the two temperature-based mechanisms with climate is explored through a simple model parameterized using results from recent experiments with A. catenella. Simulations demonstrate the importance of seasonal temperature cycles for the synchronization of cysts' release from dormancy and are consistent with biogeography-based inferences that A. catenella is more tolerant of warming in habitats that experience a larger range of seasonal temperature variation (i.e., have higher temperature seasonality). Temperature seasonality is much greater in shallow, long-residence time habitats than in deep, open-water ones. As warming shifts species' ranges, cyst beds may persist longer in more seasonally variable, shallow inshore habitats than in deep offshore ones, promoting HABs that are more localized and commence earlier each year. Recent field investigations of A. catenella also point to the importance of new cyst formation as a factor triggering bloom termination through mass sexual induction. In areas where temperature seasonality restricts the flux of new swimming cells (germlings) to narrow temporal windows, warming is unlikely to promote longer and more intense HAB impacts even when water column conditions would otherwise promote prolonged bloom development. Many species likely have a strong drive to sexually differentiate and produce new cysts once concentrations reach levels that are conducive to new cyst formation. This phenomenon can impose a limit to bloom intensification and suggests an important role for cyst bed quiescence in determining the duration of HAB risk periods.