Ocean Sciences Department, 1156 High Street, University of California, Santa Cruz, CA 95064, United States.
Ocean Sciences Department, 1156 High Street, University of California, Santa Cruz, CA 95064, United States.
Harmful Algae. 2020 Feb;92:101617. doi: 10.1016/j.hal.2019.05.010. Epub 2019 Nov 26.
San Francisco Bay (SFB), California, USA is the largest estuary in the western United States and is home to more than 7 million people in nine counties and 101 cities. It is highly nutrient enriched and is directly connected to the Gulf of the Farallones and coastal Pacific ocean through the Golden Gate strait. The Gulf of the Farallones is one of several "hotspots" for the neurotoxin domoic acid, produced by members of the genus Pseudo-nitzschia. Despite the close proximity, SFB has few reports of harmful algal blooms and low concentrations of domoic acid, suggesting that SFB is somehow resistant to toxic blooms. Here we evaluate the potential growth and toxicity of the dominant toxigenic species in California coastal waters, P. australis and P. multiseries, to directly test the hypothesis that SFB waters confer resistance to blooms. We specifically evaluate the effect of varying temperature, salinity, and to a lesser extent, nutrients on growth and toxin production. Results show equivalent growth in SFB water (maximum growth rates of 0.71 and 1.35 d for P. multiseries and P. australis) compared to open-coast water, and comparable or greater toxicity (0 to >100 pg DA cell). The historical resistance to blooms in SFB is hypothesized to be caused by a combination of insufficient acclimation time for advected Pseudo-nitzschia populations to become established and suppression of toxin production in warm waters.
美国加利福尼亚州旧金山湾（SFB）是美国西部最大的河口，是九个县和 101 个城市的 700 多万人的家园。它富含营养物质，通过金门海峡与法拉隆湾和太平洋沿海直接相连。法拉隆湾是几种神经毒素软骨藻酸的“热点”之一，软骨藻酸由拟菱形藻属的成员产生。尽管距离很近，但 SFB 有害藻类大量繁殖的报道很少，软骨藻酸的浓度也很低，这表明 SFB 以某种方式对有毒藻类大量繁殖具有抵抗力。在这里，我们评估了加利福尼亚沿海水域中占优势的产毒物种——澳大利亚拟菱形藻和多列拟菱形藻的潜在生长和毒性，以直接检验 SFB 水域赋予其抗毒藻大量繁殖的假说。我们特别评估了温度、盐度和在较小程度上营养物质对生长和毒素产生的影响。结果表明，与开阔海域相比，SFB 水（多列拟菱形藻和澳大利亚拟菱形藻的最大生长率分别为 0.71 和 1.35 d）中的生长情况相当，而且毒性相当或更大（0 至 >100 pg DA 细胞）。SFB 历史上对藻类大量繁殖的抵抗力据推测是由于以下两种情况的综合作用：输送的拟菱形藻种群适应时间不足，以及在温暖水域中抑制毒素产生。
