Wallace Marcella Kretz, Kudela Raphael M, Gobler Christopher J
School of Marine and Atmospheric Sciences, Stony Brook University, Southampton, NY, United States.
Ocean Sciences & Institute for Marine Sciences, University of California Santa Cruz, Santa Cruz, CA, United States.
Harmful Algae. 2025 May;145:102860. doi: 10.1016/j.hal.2025.102860. Epub 2025 Apr 8.
Estuaries are dynamic ecosystems that are an important habitat for bivalves. The freshwater bodies that discharge into estuaries can introduce cyanobacteria and cyanotoxins that may accumulate within food webs. Microcystin is a hepatotoxin that causes adverse health effects in humans and can be harmful to terrestrial and aquatic organisms. Microcystin has been detected in marine bivalves and the rate of microcystin accumulation and depuration differs between bivalve species. No study has explored the presence or dynamics of microcystins in bivalves in the Northeast US, where they represent a major fishery. This study quantified levels of microcystins in wild and cultured bivalves as a time series from 2017 to 2021 in three of the largest US East Coast estuaries (Chesapeake Bay, the Hudson River Estuary, and Long Island Sound) that have hosted microcystin-producing cyanobacterial harmful algal blooms (CHABs) within their watersheds. During this study, microcystins were rarely detected in bivalves across Chesapeake Bay but were commonly quantified in multiple bivalve species in the Hudson River estuary and within two harbors of Long Island Sound, Stony Brook Harbor and Conscience Bay. Microcystins were detected in clams (Mercenaria mercenaria and Corbicula fluminea), Eastern oysters (Crassostrea virginica), and mussels (Mytilus edulis and Geukensia demissa). Eastern oysters (C. virginica) had significantly higher levels of microcystin than other bivalve species (p < 0.05) and often contained microcystin even when other bivalves sampled concurrently did not, suggesting oysters may be a vector for hepatotoxic shellfish poisoning in estuaries. Microcystins were detected in oysters even in fall months after water column cyanobacterial biomass and microcystins had decreased to low levels, suggesting toxin depuration slows during colder months. Collectively, this study demonstrates that microcystin accumulation in estuarine bivalves, particularly Eastern oysters (C. virginica), occurs within several of the larger US East Coast estuaries and could represent a public health risk.
河口是动态生态系统，是双壳贝类的重要栖息地。流入河口的淡水水体可能会引入蓝藻和蓝藻毒素，这些毒素可能会在食物网中积累。微囊藻毒素是一种肝毒素，会对人类健康产生不良影响，对陆生和水生生物也可能有害。海洋双壳贝类中已检测到微囊藻毒素，不同双壳贝类物种中微囊藻毒素的积累和净化速率有所不同。在美国东北部，双壳贝类是主要渔业资源，但尚无研究探讨微囊藻毒素在当地双壳贝类中的存在情况或动态变化。本研究对美国东海岸三个最大河口（切萨皮克湾、哈得逊河河口和长岛海峡）2017年至2021年期间野生和养殖双壳贝类中的微囊藻毒素水平进行了时间序列量化，这些河口流域内曾出现过产生微囊藻毒素的蓝藻有害藻华（CHABs）。在本研究期间，切萨皮克湾的双壳贝类中很少检测到微囊藻毒素，但在哈得逊河河口以及长岛海峡的两个港口（石溪港和良心湾）的多种双壳贝类中经常检测到微囊藻毒素。在蛤蜊（硬壳蛤和河蚬）、东部牡蛎（弗吉尼亚牡蛎）和贻贝（紫贻贝和偏顶蛤）中检测到了微囊藻毒素。东部牡蛎（弗吉尼亚牡蛎）中的微囊藻毒素水平显著高于其他双壳贝类物种（p < 0.05），而且即使同时采样的其他双壳贝类未检测到微囊藻毒素，牡蛎中也常常含有该毒素，这表明牡蛎可能是河口地区肝毒性贝类中毒的一个载体。即使在水柱中蓝藻生物量和微囊藻毒素降至低水平后的秋季月份，牡蛎中仍检测到微囊藻毒素，这表明在较冷月份毒素净化速度会减慢。总体而言，本研究表明，美国东海岸几个较大河口的河口双壳贝类，特别是东部牡蛎（弗吉尼亚牡蛎）中会积累微囊藻毒素，这可能构成公共健康风险。
