Collaborative Research: Identification of nitrogen sources for toxic Alexandrium blooms using a novel species-specific tracer, d15N-saxitoxin

合作研究：使用新型物种特异性示踪剂 d15N-石房蛤毒素识别有毒亚历山大藻华的氮源

• 批准号: 1233057
• 负责人: Juliette Smith
• 金额: $ 45.38万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-11-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1233057&HistoricalAwards=false
• 关键词: Collaborative; Research; Identification; nitrogen; sources

The US and other countries throughout the world are affected by harmful algal blooms (HABs) that negatively impact human health, marine ecosystems, fisheries resources, and local economies. Anthropogenic nutrient loadings have been linked to expanding HAB incidence, but the relationship is site- and organism-specific, and is still poorly understood. The main challenge in this regard is to determine the relative importance of natural versus anthropogenic nutrient sources in the development of an individual HAB species. Given the diverse nature of the planktonic assemblage in which HABs occur, and the lack of appropriate measurement techniques, this is exceedingly difficult to accomplish.In this project, research teams at the Woods Hole Oceanographic Institution and University of Texas at Austin will take a novel approach to this challenge: They use use the nitrogen isotopic signature (del15N) of a species-specific HAB toxin to identify the nitrogen source and chemical form that promotes cell growth and toxin production. The bloom-forming dinoflagellate Alexandrium fundyense and its class of bioactive compounds, saxitoxins (STXs), are an ideal model system as STXs are nitrogen-rich and are typically only produced by a single species in mixed plankton assemblages. The guiding overall hypothesis is that the isotopic signature of a HAB-specific toxin can be used to discriminate between anthropogenic and natural sources of N and provide more details than bulk material del15N on the source, chemical form, and processing of N that lead to blooms of a particular toxic species. This hypothesis is based on the principle that human and animal waste in groundwater and sewage become 15N-enriched and inorganic fertilizers 15N-depleted, relative to natural sources of N in catchment waters. While the use of the isotopic ratio del15N of bulk biomass to identify nitrogen sources to coastal waters is a widely accepted practice, this use of a toxin as a species-specific tracer or marker is new and will provide details on the explicit source, chemical form, and processing of nitrogen that results in blooms of a particular HAB species. Broader Impacts: This project addresses fundamental issues underlying the most widespread of all HAB poisoning syndromes, paralytic shellfish poisoning (PSP), a major form of shellfish poisoning that affects countries throughout the world. Project results can also assist in policy decisions about pollution control and other bloom mitigation strategies, and can be applied to a range of HAB species - those that produce saxitoxins, as well as those that produce other toxins that are nitrogen rich. Project results will be broadly disseminated through scientific papers, presentations at workshops, domestic and international conferences, and departmental seminars, and discussions with the media.

美国和世界其他国家受到有害藻华 (HAB) 的影响，对人类健康、海洋生态系统、渔业资源和当地经济产生负面影响。人为营养负荷与 HAB 发病率的增加有关，但这种关系是因地点和生物体而异的，而且人们仍然知之甚少。这方面的主要挑战是确定自然营养源与人为营养源在单个 HAB 物种发育中的相对重要性。鉴于发生 HAB 的浮游生物组合的多样性，以及缺乏适当的测量技术，这是极其难以实现的。在这个项目中，伍兹霍尔海洋研究所和德克萨斯大学奥斯汀分校的研究团队将采取一种新颖的方法来应对这一挑战：他们使用物种特异性 HAB 毒素的氮同位素特征 (del15N) 来识别氮源和化学形式， 促进细胞生长和毒素产生。形成水华的甲藻亚历山大氏藻及其一类生物活性化合物石房蛤毒素 (STX) 是理想的模型系统，因为 STX 富含氮，并且通常仅由混合浮游生物组合中的单一物种产生。 指导性的总体假设是，HAB 特异性毒素的同位素特征可用于区分人为和天然的氮来源，并提供比散装材料 del15N 更多的细节，包括导致特定有毒物种大量繁殖的氮的来源、化学形式和加工。该假说基于以下原理：相对于流域水域中的天然氮源，地下水和污水中的人类和动物排泄物富含 15N，而无机肥料则缺乏 15N。虽然使用大量生物质的同位素比率 del15N 来识别沿海水域的氮源是一种广泛接受的做法，但这种使用毒素作为物种特异性示踪剂或标记物的做法是新的，并将提供有关导致特定 HAB 物种大量繁殖的氮的明确来源、化学形式和加工的详细信息。更广泛的影响：该项目解决了所有HAB中毒综合症中最普遍的麻痹性贝类中毒（PSP）的基本问题，这是影响世界各国的贝类中毒的一种主要形式。项目结果还可以协助有关污染控制和其他水华缓解策略的政策决策，并可应用于一系列 HAB 物种 - 那些产生石房蛤毒素的物种，以及那些产生其他富含氮毒素的物种。项目成果将通过科学论文、研讨会报告、国内和国际会议、部门研讨会以及媒体讨论等方式广泛传播。