Data_Sheet_9_Environmental DNA Metabarcoding for Simultaneous Monitoring and Ecological Assessment of Many Harmful Algae.CSV

Harmful algae can have profound economic, environmental, and social consequences. As the timing, frequency, and severity of harmful algal blooms (HABs) change alongside global climate, efficient tools to monitor and understand the current ecological context of these taxa are increasingly important. Here we employ environmental DNA metabarcoding to identify patterns in a wide variety of potentially harmful algae and associated ecological communities in the Hood Canal of Puget Sound in Washington State, USA. Tracking trends of occurrence in a series of water samples over a period of 19 months, we find algal sequences from genera with harmful members in a majority of samples, suggesting that these groups are routinely present in local waters. We report patterns in variants of the economically important genus Pseudo-nitzschia (of which some members produce domoic acid; family Bacillariaceae), as well as multiple potentially harmful algal taxa previously unknown or poorly documented in the region, including a cold-water variant from the genus Alexandrium (of which some members produce saxitoxin; family Gonyaulacaceae), two variants from the genus Karlodinium (of which some members produce karlotoxins; family Kareniaceae), and one variant from the parasitic genus Hematodinium (family Syndiniaceae). We then use data on environmental variables and the biological community surrounding each algal taxon to illustrate the ecological context in which they are commonly found. Environmental DNA metabarcoding thus simultaneously (1) alerts us to potential new or cryptic occurrences of algae from harmful genera, (2) expands our knowledge of the co-occurring conditions and species associated with the growth of these organisms in changing marine environments, and (3) suggests a pathway for multispecies monitoring and management moving forward.

有害藻类可对经济、环境与社会造成深远影响。随着有害藻华（harmful algal blooms, HABs）的发生时间、频次及严重程度随全球气候变化发生改变，高效的监测工具与解析这些类群当前生态背景的手段愈发重要。本研究采用环境DNA宏条形码（environmental DNA metabarcoding）技术，对美国华盛顿州普吉特海湾胡德运河区域内多种潜在有害藻类及其关联生态群落的分布模式进行鉴定。通过对19个月内采集的系列水样中的藻类出现趋势进行追踪，我们在绝大多数样本中均检测到携带有害物种的藻类属的基因序列，表明此类藻类在当地水域中常年存在。本研究记录了经济价值显著的拟菱形藻属（Pseudo-nitzschia）的变种分布模式——该属部分物种可产生软骨藻酸（domoic acid），隶属于脆杆藻科（Bacillariaceae）；同时还报道了该区域此前未被发现或记录匮乏的多种潜在有害藻类类群，包括来自亚历山大藻属（Alexandrium）的冷水型变种（该属部分物种可产生石房蛤毒素（saxitoxin），隶属于膝沟藻科（Gonyaulacaceae））、卡尔藻属（Karlodinium）的两个变种（该属部分物种可产生卡尔藻毒素（karlotoxins），隶属于凯伦藻科（Kareniaceae）），以及寄生性血孢藻属（Hematodinium）的一个变种（隶属于原多甲藻科（Syndiniaceae））。随后，本研究结合环境变量数据与各藻类类群周边的生物群落数据，阐明了这些藻类常见的生存生态背景。由此可见，环境DNA宏条形码技术可同时实现三大目标：（1）预警有害藻类属潜在的新种或隐蔽种出现；（2）拓展我们对变化海洋环境中与这些藻类生长相关的共现条件及伴生物种的认知；（3）为未来的多物种监测与管理提供可行路径。