Abstract：
Harmful algal blooms (HABs) are recurrent in the NW Patagonia fjords system and their frequency has increased over the last few decades. Outbreaks of HAB species such as Alexandrium catenella, a causal agent of paralytic shellfish poisoning, and Protoceratium reticulatum, a yessotoxins producer, have raised considerable concern due to their adverse socioeconomic consequences. Monitoring programs have mainly focused on their planktonic stages, but since these species produce benthic resting cysts, the factors influencing cyst distributions are increasingly gaining recognition as potentially important to HAB recurrence in some regions. Still, a holistic understanding of the physico-chemical conditions influencing cyst distribution in this region is lacking, especially as it relates to seasonal changes in drivers of cyst distributions, as the characteristics that favor cyst preservation in the sediment may change through the seasons. In this study, we analyzed the physico-chemical properties of the sediment (temperature, pH, redox potential) and measured the bottom dissolved oxygen levels in a \"hotspot\" area of southern Chile, sampling during the spring and summer as well as the fall and winter, to determine the role these factors may play as modulators of dinoflagellate cyst distribution, and specifically for the cysts of A. catenella and P. reticulatum. A permutational analysis of variance (PERMANOVA) showed the significant effect of sediment redox conditions in explaining the differences in the cyst assemblages between spring-summer and fall-winter periods (seasonality). In a generalized linear model (GLM), sediment redox potential and pH were associated with the highest abundances of A. catenella resting cysts in the spring-summer, however it was sediment temperature that most explained the distribution of A. catenella in the fall-winter. For P. reticulatum, only spring-summer sediment redox potential and temperature explained the variation in cyst abundances. The implications of environmental (physico-chemical) seasonality for the resting cysts dynamics of both species are discussed.
摘要：
有害藻华（HAB）在西北巴塔哥尼亚峡湾系统中反复出现，并且在过去的几十年中，其频率有所增加。HAB物种的爆发，例如Alexandriumcatenella，麻痹性贝类中毒的病原体,和网状原角菌，一个耶梭毒素的生产者,由于其不利的社会经济后果，引起了相当大的关注。监测项目主要集中在它们的浮游阶段，但是由于这些物种会产生底栖静息囊肿，在某些地区,影响囊肿分布的因素对HAB复发具有潜在的重要意义.尽管如此，缺乏对影响该地区囊肿分布的物理化学条件的全面了解，尤其是与囊肿分布驱动因素的季节性变化有关，由于沉积物中有利于囊肿保存的特征可能会随着季节的变化而变化。在这项研究中,我们分析了沉积物的物理化学性质(温度，pH值,氧化还原电位)并测量了智利南部“热点”地区的底部溶解氧水平，在春季和夏季以及秋季和冬季采样，为了确定这些因素可能作为鞭毛藻囊肿分布的调节剂发挥作用，特别是对于A.catenella和P.reticulum的囊肿。方差分析（PERMANOVA）显示，沉积物氧化还原条件在解释春季-夏季和秋季-冬季（季节性）囊肿组合差异方面具有显着影响。在广义线性模型(GLM)中，沉积物氧化还原电位和pH值与春夏季A.catenella静息囊肿的最高丰度有关，然而，沉积物温度最能解释秋冬季A.catenella的分布。对于网状鱼，只有春夏季沉积物的氧化还原电位和温度解释了囊肿丰度的变化。讨论了环境（物理化学）季节性对这两种物种的静息囊肿动力学的影响。
