Collaborative SGER: Domoic Acid Toxins in the Oceanic Pacific in Iron Enrichment Studies

该项目解决了一个与全球变暖有关的新问题：减少大气中温室气体水平的必要性。几十年前提出的一个解决方案是对海洋中广泛的、铁有限的、高营养的、低叶绿素（HNLC）的区域进行施肥，减少二氧化碳，否则二氧化碳将与大气交换。这种解决方案是非常有吸引力的，因为它相对较低的成本和铁施肥确实促进浮游植物在这些地区的水华的证据。然而，一些研究人员对铁的补救措施表示担忧，认为这可能会对生态系统的组成和功能产生意想不到的负面影响。在这个项目中，研究人员假设HNLC区域的铁施肥导致产生软骨藻酸（DA）的伪菱形藻的生物量增加，这是一种神经毒素。在HNLC地区增加DA的后果可能与在沿海地区观察到的后果相似，即污染，有时甚至导致这些生态系统中捕食者的死亡。一个探索性研究（SGER）的小额赠款是基于研究人员最近在Pseudo-nitzschia turdigula中发现的DA提供的，Pseudo-nitzschia turdigula经常在HNLC地区的沃茨的铁富集实验中开花。研究人员开发了一种新的毒素检测方法，用于测量从亚北极西北太平洋的HNLC沃茨收集的P. turdigula样本中的DA。该SGER使调查人员能够参加2007年8月NSF资助的研究巡航，测量阿拉斯加湾（果阿）沿着HNLC（缺铁）地区和含陆源铁的自然富集涡流的断面的沃茨中的铁。研究人员将测量果阿样带和生长实验中相关的P. turdigula沿着的丰度和DA水平，并确定与DA生产相关的伪菱形藻物种。所有样本的拟菱形藻将有相关的营养和海洋学数据，以提供背景的细胞DA配额在海洋学和生理背景。研究结果对确定富铁的生态效应具有重要意义。

Abstract The project addresses an emerging issue related to global warming: the necessity to reduce levels of greenhouse gases in the atmosphere. A solution proposed several decades ago is to fertilize the extensive, iron-limited, high nutrient, low chlorophyll (HNLC) regions of the sea, drawing down carbon dioxide that would otherwise exchange with the atmosphere. This solution is highly attractive due to its relatively low cost and evidence that iron fertilization does indeed promote phytoplankton blooms in such regions. Some researchers, however, have expressed alarm about the iron remedy that could result from unanticipated negative effects on the composition and functioning of ecosystems. In this project, the investigators hypothesize that iron fertilization of HNLC regions results in biomass increases of Pseudo-nitzschia that produce domoic acid (DA), a neurotoxin. The consequences of increased DA in HNLC areas could be like those observed in coastal regions, namely contamination and sometimes deaths of predators in those ecosystems. A Small Grant for Exploratory Research (SGER) is provided based on the investigators recent discovery of DA in Pseudo-nitzschia turdigula, which often blooms in iron enrichment experiments in waters of HNLC regions. The investigators developed a new toxin assay to measure DA in samples of P. turdigula collected from HNLC waters of the subarctic NW Pacific. This SGER enables the investigators to participate in an August 2007 NSF-funded research cruise measuring iron in waters of the Gulf of Alaska (GoA) along transects in HNLC (iron poor) regions and naturally enriched eddies containing terrestrially-derived iron. The investigators will measure the associated abundance and DA levels of P. turdigula along the GoA transect and in the grow-out experiments, and to determine the Pseudo-nitzschia species associated with DA production. All samples for Pseudo-nitzschia will have associated nutrient and oceanographic data to provide context for the cellular DA quotas in an oceanographic and physiological context. Results of the research are important in determining ecosystem effects iron enrichment.