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Harmful algal blooms: mechanisms, monitoring, and prevention in a rapidly changing world
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In situ HAB observations with biosensors: a decade of challenges, accomplishments, and insights (Invited) Wednesday 9th @ 0930-0950, Multifunction Hall Donald M. Anderson* , Biology Department, Woods Hole Oceanographic Institution Michale L. Brosnahan, Biology Department, Woods Hole Oceanographic Institution Bruce A. Keafer, Biology Department, Woods Hole Oceanographic Institution Presenter Email: danderson@whoi.edu |
The dinoflagellate Alexandrium catenella (=A. fundyense) and diatoms in the genus Pseudo-nitzschia cause frequent harvesting closures of shellfish resources in the Gulf of Maine region of the U.S. due to the threat of paralytic shellfish poisoning (PSP) and amnesic shellfish poisoning (ASP). Blooms can be widespread, covering hundreds of km of coastline, or localized in small embayments and estuaries. In recent years, our studies of harmful algal bloom (HAB) dynamics in both of these systems have incorporated two novel biosensors ¨C the Environmental Sample Processor (ESP) and the Imaging FlowCytobot (IFCB). The ESP uses molecular assays to detect and analyze cells and toxins whereas the IFCB is an automated underwater microscope. Each has presented logistical challenges of different types, requiring new mooring and platform designs, communication protocols, and deployment strategies. This talk will review a decade of deployments, highlighting how these instruments have augmented HAB research in the two hydrographic systems over multiple bloom seasons, emphasizing the unique nature of the data each sensor can provide, correlations with other data such as shellfish toxicity measurements, as well as the engineering and scientific obstacles that were overcome. These studies have taught us that previous laboratory studies produced surprisingly bad estimates of rates and behaviors that are fundamental to predicting bloom dynamics, suggesting that our ability to understand and forecast HABs requires characterization of critical rates and behavioral patterns in natural populations, generated, whenever possible, through in situ observations. Furthermore, given the temporal and spatial patchiness of HABs, we need higher-level strategies that can place sensors where the cells are, rather than putting the instruments in fixed locations, hoping that the HABs will come to us. Mobile and portable platforms, particularly those that enable adaptive, targeted sampling for addressing temporal as well as spatial patchiness, offer great promise for characterizing the evolution of populations through time, and several of these will be described here. In situ sensors can play a major role in HAB research and monitoring, but approaches need to be strategic and flexible in order to meet the challenges posed by highly dynamic blooms. |
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