Fisheries and Oceans Canada, Freshwater Institute, 501 University Crescent, Winnipeg, MB, R3T 2N6, Canada.
Canadian Food Inspection Agency, Chemistry Laboratory, 1992 Agency Drive, Dartmouth, NS, B3B 1Y9, Canada.
Harmful Algae. 2023 Aug;127:102474. doi: 10.1016/j.hal.2023.102474. Epub 2023 Jun 17.
This study presents the first evidence that a diverse suite of phycotoxins is not only being actively produced by the toxigenic algal communities in the Canadian Arctic waters, but is also entering the marine food web. We detected measurable amounts of Amnesic Shellfish Toxins (ASTs) and Paralytic Shellfish Toxins (PSTs), as well as trace amounts of other lipophilic toxin groups including pectenotoxins, yessotoxins, and cyclic imines, in bivalves collected from the Canadian Beaufort Sea in 2014 and 2018. There appear to be species-specific differences in accumulation and retention of AST by Arctic bivalves, with significantly higher concentrations recorded in Nuculanidae than Propeamussiidae, likely reflecting physiological and allometric differences. We further confirm the omnipresence of potentially toxic taxonomically-versatile phytoplankton communities in the western Canadian Arctic comprising Pseudo-nitzschia delicatissima group, P. obtusa, Dinophysis acuminata, Prorocentrum minimum, Alexandrium tamarense, and Gymnodinium spp. Although measurements of actual toxicity levels and profiles of these species at the time of sampling fall outside of the scope of this study, we show that high abundance and competitive success of known AST-producers, Pseudo-nitzschia spp., are possible in Canadian Arctic waters. In 2014, a strong dominance of Pseudo-nitzschia spp. was observed at a few shallow coastal stations, representing nearly 40% of the total phytoplankton cell abundances with > 10 cells/L at the depth of maximum chlorophyll a. We further describe oceanographic conditions conducive to high abundances of toxin-producing algae, indicating that temperature is likely a key factor. Even though measured AST and PST concentrations in bivalve tissue remained well below the Health Canada's levels at which monitored fisheries would close, i.e., 5% and 4%, respectively, their presence demonstrate that phycotoxin accumulation is occurring in food webs of the Canadian Beaufort Sea. Yet, the phycotoxin production controls and trophic transfer mechanisms remain unknown. Canadian Arctic marine ecosystems are rapidly changing and temperatures are expected to continue to increase. Given that these changes simultaneously affect multiple, and often co-occurring, species of primary producers, adaptive capacity is likely to play an important role in the structure of phytoplankton communities in the Canadian Arctic.
本研究首次表明，加拿大北极水域的产毒藻类群落不仅在积极产生多种藻毒素，而且这些藻毒素还正在进入海洋食物网。我们在 2014 年和 2018 年从加拿大波弗特海采集的双壳类动物中检测到了可测量数量的失忆贝类毒素（ASTs）和麻痹贝类毒素（PSTs），以及痕量的其他亲脂性毒素组，包括扇贝毒素、膝沟藻毒素和环状亚胺，在北极双壳类动物中，AST 的积累和保留似乎存在种间差异，在 Nuculanidae 中记录的浓度明显高于 Propeamussiidae，这可能反映了生理和比例差异。我们进一步证实，在加拿大西部北极地区存在广泛存在的有毒浮游植物群落，包括纤细拟菱形藻组、钝拟菱形藻、塔玛亚历山大藻、鳍藻和夜光藻。尽管在本研究中，采样时这些物种的实际毒性水平和谱的测量不在研究范围内，但我们表明，在加拿大北极水域，已知 AST 生产者拟菱形藻属的高丰度和竞争优势是可能的。2014 年，在少数浅海沿岸站观察到拟菱形藻属的强烈优势，其占总浮游植物细胞丰度的近 40%，在叶绿素 a 最大值的深度超过 10 个细胞/L。我们进一步描述了有利于产生毒素藻类高丰度的海洋条件，表明温度可能是一个关键因素。尽管双壳类动物组织中的 AST 和 PST 浓度仍远低于加拿大卫生部监测渔业关闭的水平，即分别为 5%和 4%，但其存在表明藻毒素积累正在发生在加拿大波弗特海的食物网中。然而，藻毒素产生的控制和营养转移机制尚不清楚。加拿大北极海洋生态系统正在迅速变化，预计温度将继续上升。鉴于这些变化同时影响多种，而且经常同时发生的，初级生产者的物种，适应能力可能在加拿大北极浮游植物群落的结构中发挥重要作用。
