Persistence and Fate of Domoic Acid in the Santa Barbara Basin

圣巴巴拉盆地软骨藻酸的持久性和归宿

• 批准号: 0850425
• 负责人: Claudia Benitez-Nelson
• 金额: $ 44.09万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0850425&HistoricalAwards=false
• 关键词: Persistence; Fate; Domoic; Acid; Santa

Toxic blooms of a variety of algal species (harmful algal blooms -- HABs) have been documented throughout the world?s coastal oceans, ultimately impacting shellfish, finfish, marine mammals and birds over large areas. Several species within the genus of Pseudo-nitzschia, a group of marine diatoms that produce the neurotoxin domoic acid (DA), have been identified as common members of algal assemblages along the coast of California. Key questions in HAB research include not only what causes toxic Pseudo-nitzschia spp. to bloom, but what happens to that bloom after its demise. Causative factors ranging from coastal eutrophication to increased upwelling to resuspension of seed populations from sediments have all been hypothesized, but remain enigmatic, mainly due to a paucity of integrative data. The fate of DA producing Pseudo-nitzschia blooms remains even more elusive, and yet there is increasing evidence of substantial DA concentrations in benthopelagic feeders and benthic organisms both along the coast and offshore. In this project, a research team at the University of South Carolina at Columbia will build upon intriguing and exciting preliminary data that suggests that sinking particles are a major vertical transport mechanism of DA from surface waters to sediments, with DA fluxes exceeding 50,000 ng DA/m2/d at depths in excess of 500 m. They hypothesize that DA is rapidly transported to sediments and likely persists on greater than seasonal timescales, well after the demise of a Pseudo-nitzschia bloom. Their goal is to create a regional observation and modeling program focused on the Santa Barbara Basin (SBB) that specifically: 1) Examines the temporal relationship between Pseudo-nitzschia blooms, DA toxicity, and the vertical transport efficiency of Pseudo-nitzschia and DA to the benthos, 2) Investigates the incorporation of DA into the sediments, and 3) establishes a historical record of DA toxicity spanning the past decade, and potentially, the last century. To achieve this goal, they will use a combination of monthly survey cruises of water column biogeochemistry, two continuously moored sediment traps (150 and 550 m), regional surface and down core sediments records, satellite imagery and develop a numerical model that examines the surface timing of toxic Pseudo-nitzschia blooms and the vertical export of DA to the seafloor. They expect that this research will fundamentally change current views on the persistence of DA toxicity in marine systems and that it will provide the groundwork for similar measurements of other harmful toxins. The proposed research leverages sampling opportunities with a number of ongoing programs off coastal California, such as Plumes and Blooms and the Santa Barbara Coastal LTER Project (water column), the Marine Sediments Laboratory at USC (archived and future sediment trap collections), and the Southern California Coastal Water Research Project Bight 2008 campaign (surface and down core sediment collections). The project is expected to have a number of broader impacts. Beside its obvious relevance to HAB research and marine environmental toxicology, the project will directly support a postdoctoral fellow and one Native American graduate student. Undergraduate students will also participate in the proposed research, supported by internal funds contributed by the University of South Carolina. All students in the principal investigator?s laboratory participate in Science Quest, an after school informal science and technology program geared towards at-risk elementary and middle school students (ages 8 -14).

全世界都有记录表明，各种藻类的有毒水华（有害藻华）？这将对沿海海洋造成严重影响，最终影响到大面积的贝类、鳍鱼、海洋哺乳动物和鸟类。伪菱形藻属（Pseudo-nitzschia）是一组产生神经毒素软骨藻酸（DA）的海洋硅藻，已被鉴定为沿着加州海岸藻类群落的常见成员。赤潮研究的关键问题不仅包括是什么导致有毒的假菱形藻。但是在它消亡之后会发生什么从沿海富营养化到上升流增加，再到沉积物中种子种群的再悬浮，所有这些都被假设为是造成这种现象的原因，但仍然是个谜，主要是由于缺乏综合数据。DA生产伪菱形藻水华的命运仍然更加难以捉摸，但有越来越多的证据表明，大量DA浓度在底栖浮游动物和底栖生物都沿着海岸和近海。在这个项目中，哥伦比亚的南卡罗来纳州大学的一个研究小组将建立在有趣和令人兴奋的初步数据的基础上，这些数据表明，沉降颗粒是DA从地表沃茨到沉积物的主要垂直传输机制，在超过500米的深度，DA通量超过50，000 ng DA/m2/d。 他们假设，DA被迅速转移到沉积物中，并可能在假菱形藻水华消亡后很长时间内持续存在，超过季节性时间尺度。 他们的目标是创建一个以圣巴巴拉盆地（SBB）为重点的区域观测和建模计划，具体包括：1）研究了伪菱形藻水华、DA毒性以及伪菱形藻和DA向底栖生物的垂直迁移效率之间的时间关系; 2）研究了DA在沉积物中的掺入情况; 3）建立了过去十年DA毒性的历史记录，也可能是上个世纪的。为了实现这一目标，他们将结合使用每月一次的水柱地球化学调查巡航、两个连续停泊的沉积物捕集器（150米和550米）、区域表层和下芯沉积物记录、卫星图像，并开发一个数值模型，研究有毒假菱形藻水华的表层时间和DA向海底的垂直输出。他们预计，这项研究将从根本上改变目前对海洋系统中DA毒性持久性的看法，并为其他有害毒素的类似测量提供基础。拟议的研究利用采样机会与一些正在进行的计划关闭沿海加州，如羽和开花和圣巴巴拉沿海LTER项目（水柱），海洋沉积物实验室在南加州大学（存档和未来的沉积物收集），和南加州沿海水域研究项目湾2008年活动（表面和向下核心沉积物收集）。预计该项目将产生一些更广泛的影响。 除了与有害藻华研究和海洋环境毒理学的明显相关性外，该项目还将直接支持一名博士后研究员和一名美洲土著研究生。本科生也将参与拟议的研究，由南卡罗来纳州大学提供的内部资金支持。所有学生都是首席研究员？的实验室参加科学探索，一个课后非正式的科学和技术计划，面向有风险的小学和中学学生（年龄8 - 14）。