Bacteria-Phytoplankton Interactions: The Influence of Marine Bacteria on Alexandrium spp. Blooms in the Gulf of Maine

细菌-浮游植物相互作用：海洋细菌对亚历山大藻的影响。

• 批准号: 0117820
• 负责人: Juliette Rooney-Varga
• 金额: $ 31.79万
• 依托单位: University of Massachusetts Lowell Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-10-15 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0117820&HistoricalAwards=false
• 关键词: Bacteria; Phytoplankton; Interactions; Influence; Marine

Blooms of the toxic dinoflagellates of the genus Alexandrium have become a chronic problem affecting large areas of the Gulf of Maine (GOM) on a near-annual basis. These algae are the causative agents of paralytic shellfish poisoning, a potentially fatal neurological disorder. Concerns for public health have resulted in frequent shellfish quarantines, permanent closure of some shellfish beds, and the implementation of costly PSP toxin monitoring programs in the GOM. Although considerable effort has been made to determine the environmental factors that influence Alexandrium spp. population dynamics in the GOM, the factors that control in situ growth and decline of Alexandrium populations remain poorly understood. Interactions between the marine bacteria and toxic phytoplankton are thought to play a major role in controlling toxic algal blooms, but their potentially important rolein the GOM has received little attention. It is well known that bacteria and phytoplankton dynamics are tightly linked in coastal marine environments, with strong associations frequently observed between bacterial and phytoplankton biomass. In addition, both positive and negative influences of bacteria on specific harmful algal bloom (HAB) organisms have been documented. Initial research results have indicated GOM bacteria capable of dramatically stimulating Alexandrium under laboratory conditions andthat these interactions may vary seasonally. This project will elucidate the role of bacteria in Alexandrium spp. population dynamics in the GOM. Several aspects of bacteria-Alexandrium interactions will be investigated, including: the seasonal and spatial distribution of bacteria that inhibit or promote Alexandrium growth; the specificity of bacteria-Alexandrium interactions; and the biotic and abiotic factors that influence bacterial community dynamics. Field research will be conducted in the southwestern Bay of Fundy with Canadian collaborators. In addition, archived bacterial community samples that were collected from the eastern and southwestern GOM in collaboration with the ECOHAB-GOM sampling program in 1998 and 2000 will be analyzed to determine the geographic distribution of specific bacteria found to interact with Alexandrium. Close collaboration with the ECOHAB-GOM team and the DFO HAB program will provide an extensive array of data and access to research vessels. Experimental methods to analyze bacteria-Alexandrium interactions will include: (1) molecular phylogenetic (PCR-DGGE and MPN-PCR) and cultivation-based analysis of the seasonal and geographic distribution of bacterial assemblages that inhibit or promote Alexandrium; (2) enrichment and isolation of novel bacterial strains that interact closely with Alexandrium; (3) analysis of the influence of Alexandrium- promoting or Alexandrium-inhibiting bacteria on other algal species present in the GOM; and (4) analysis of the isolates' influence on Alexandrium growth in mixed cultures. The study will provide insight into interactions between Alexandrium and bacteria in the GOM and may ultimately improve our ability to simulate and predict Alexandrium dynamics within a given body of water. This research will determine whether certain bacterial assemblages are associated with Alexandrium spp. in the GOM and will also explore Alexandrium -bacteria interactions that may promote or inhibit Alexandrium growth.

亚历山大属的有毒鞭毛藻的花朵已成为一个慢性问题，该问题近年来影响缅因州海湾（GOM）的大面积。这些藻类是瘫痪贝类中毒的病因，这是一种潜在的致命神经系统疾病。对公共卫生的担忧导致贝类频繁隔离，某些贝类床的永久关闭以及在GOM中实施昂贵的PSP毒素监测计划。尽管已经付出了巨大的努力来确定影响Alexandrium spp的环境因素。 GOM中的人口动态，控制原位生长和亚历山大种群下降的因素仍然众所周知。海洋细菌与有毒的浮游植物之间的相互作用被认为在控制有毒藻华方面起着主要作用，但它们的潜在重要责任是GOM很少受到关注。众所周知，在沿海海洋环境中，细菌和浮游植物动力学紧密相连，细菌和浮游植物生物量之间经常观察到牢固的关联。此外，已经记录了细菌对特定有害藻华（HAB）生物的阳性和负面影响。最初的研究结果表明，GOM细菌能够在实验室条件下急剧刺激亚历山大，并且这些相互作用可能会发生季节性变化。 该项目将阐明细菌在Alexandrium spp中的作用。 GOM中的人口动态。将研究细菌 - 埃克萨德里姆相互作用的几个方面，包括：抑制或促进亚历山德里姆生长的细菌的季节性和空间分布；细菌 - 埃克萨德里姆相互作用的特异性；以及影响细菌社区动态的生物和非生物因素。现场研究将与加拿大合作者在西南芬湾进行。此外，将分析从东部和西南GOM收集的归档细菌群落样本，并与1998年和2000年的Ecohab-GOM抽样计划合作，以确定发现与Alexandrium相互作用的特定细菌的地理分布。与Ecohab-GOM团队和DFO HAB计划的密切合作将提供广泛的数据和访问研究船。分析细菌 - 亚卫星相互作用的实验方法将包括：（1）分子系统发育（PCR-DGGE和MPN-PCR）以及基于培养的分析，分析抑制或促进Alexandrium的细菌组合的季节性和地理分布； （2）与亚历山大紧密相互作用的新型细菌菌株的富集和分离； （3）分析亚历山德里群岛促进或抑制亚历山大细菌对GOM中其他藻类物种的影响； （4）分析分离株对混合培养物中亚历山德里姆生长的影响。 这项研究将洞悉GOM中亚历山德里姆和细菌之间的相互作用，并最终可以提高我们在给定的水体内模拟和预测亚历山大动态的能力。这项研究将确定某些细菌组合是否与Alexandrium spp相关。在GOM中，还将探索可能促进或抑制亚历山大生长的亚历山德省 - 细菌相互作用。