Trophic Controls on the Life Cycle of Pfiesteria piscicida and the Second Known Toxic Pfiesteria-like Species

最近，在美国大陆最大的河口切萨皮克湾的几条支流爆发的有毒事件中，人们意识到，被称为有毒Pfiesteria复合体的鞭毛藻对鱼类健康和人类健康可能产生微妙但严重的慢性/亚致命影响。在切萨皮克爆发之前的近十年里，第二大河口阿尔伯马尔-帕姆利科也发生了更大规模的鱼类死亡和动物流行病。在拟议的研究中，我们将继续研究Pfiesteria piscicida复杂生命周期的营养控制，并将扩展类似的努力来表征第二种有毒Pfiesteria样物种（尚未正式命名）的生命周期，该物种最近分别在Albemarle-Pamlico河口生态系统和Chesapeake湾的Neuse和Pocomoke河口被发现。利用先进的视频成像和运动分析软件，我们将通过操纵可用猎物（藻类，细菌，贝类，鳍鱼，哺乳动物组织）和改变环境条件（例如，突然的温度和盐度冲击），获得两种鱼类伏击捕食者复杂生命周期阶段变化的完整照片记录。这项研究将极大地提高对鱼类死亡/动物流行病现场样品中Pfiesteria的认识，并将提高对有毒Pfiesteria复群中两种已知物种的阶段转化和丰度的营养控制的一般理解。

Recently, the potential for subtle but serious chronic/sublethal impacts from dino-flagellates known as the toxic Pfiesteria complex on fish health as well as human health was realized during toxic outbreaks in several tributaries of the largest estuary on the U.S. mainland, Chesapeake Bay. Much more massive fish kills and epizootics by Pfiesteria also had occurred in the second largest estuary, the Albemarle-Pamlico, for nearly a decade before the Chesapeake outbreaks. In the proposed research we will continue to examine trophic controls on the complex life cycles of Pfiesteria piscicida, and will extend similar effort to characterize the life cycle of a second toxic Pfiesteria-like species (not yet formally named) that recently was identified from the Neuse and Pocomoke Estuaries in the Albemarle-Pamlico Estuarine Ecosystem and Chesapeake Bay, respectively. Using advanced video imaging and motion analysis software, we will obtain full photographic documentation of the stage transformations in the complex life cycle of the two species of fish ambush-predators, through manipulation of available prey (algae, bacteria, shellfish, finfish, mammalian tissues) and through alteration of environmental conditions (e.g., sudden temperature and salinity shock). This research will greatly improve recognition of Pfiesteria in field samples from fish kills/epizootics, and will also enhance general understanding of trophic controls on stage transformations and abundance of both known species in the toxic Pfiesteria complex.