期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：41
DOI：10.1073/pnas.2107387118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
The neurotoxin-producing dinoflagellate
Alexandrium catenella is shown to be distributed widely and at high concentrations in bottom sediments and surface waters of the Alaskan Arctic. Future blooms are likely to be large and frequent given hydrographic and bathymetric features that support high cell and cyst accumulations, and warming temperatures that promote bloom initiation from cysts in bottom sediments and cell division in surface waters. As the region undergoes an unprecedented regime shift, the exceptionally widespread and dense cyst and cell distributions represent a significant threat to Arctic communities that are heavily dependent upon subsistence harvesting of marine resources. These observations also highlight how warming can facilitate range expansions of harmful algal bloom species into waters where temperatures were formerly unfavorable.
Among the organisms that spread into and flourish in Arctic waters with rising temperatures and sea ice loss are toxic algae, a group of harmful algal bloom species that produce potent biotoxins.
Alexandrium catenella, a cyst-forming dinoflagellate that causes paralytic shellfish poisoning worldwide, has been a significant threat to human health in southeastern Alaska for centuries. It is known to be transported into Arctic regions in waters transiting northward through the Bering Strait, yet there is little recognition of this organism as a human health concern north of the Strait. Here, we describe an exceptionally large
A. catenella benthic cyst bed and hydrographic conditions across the Chukchi Sea that support germination and development of recurrent, locally originating and self-seeding blooms. Two prominent cyst accumulation zones result from deposition promoted by weak circulation. Cyst concentrations are among the highest reported globally for this species, and the cyst bed is at least 6× larger in area than any other. These extraordinary accumulations are attributed to repeated inputs from advected southern blooms and to localized cyst formation and deposition. Over the past two decades, warming has likely increased the magnitude of the germination flux twofold and advanced the timing of cell inoculation into the euphotic zone by 20 d. Conditions are also now favorable for bloom development in surface waters. The region is poised to support annually recurrent
A. catenella blooms that are massive in scale, posing a significant and worrisome threat to public and ecosystem health in Alaskan Arctic communities where economies are subsistence based.
