Benthic Dinoflagellate Migration (BenDiM): Occurrence and Processes

大多数应用程序的标准化甲藻昼夜垂直迁移（DVM）假设考虑在白天和地下营养目标在夜间，因为可见的表面水华的表面目标。然而，次表层营养源可以如此之深，以至于甲藻在12小时的上升过程中无法到达表面。至少有三份文献报告记录了一种面向沉积物的表达，这种表达是大陆边界的另一种DVM模式的特征，这种模式具有更宽、更缓倾斜的大陆架，可以产生高生物量、近底甲藻积累。有针对性的甲藻生态位，在这里被称为“底栖甲藻迁移”或“BenDiM”，是受光和营养梯度的影响，但独特的是，DVM之间存在的营养源附近或在沉积物-海洋界面和光强度在较低的真光层，支持人口规模的净增加。该项目具体涉及：1）5月至11月期间，占据佛罗里达州巴拿马城外60 m至20 m等深线之间的大陆架BenDiM生态位的不同甲藻物种; 2）占据BenDiM生态位的不同甲藻物种的光适应、营养吸收能力和行为模式;（3）典型的物理水运动对不同BenDiM甲藻种群的形成、迁移和归宿的影响。该研究包括：1）2008年5月至10月和2009年7月至8月期间，在不同月份进行了三次为期7天的远洋/底栖实地考察; 2）对BenDiM甲藻的光照、营养和行为特征进行了实验室研究，使其能够与近底层远洋硅藻和微型底栖植物成功竞争;以及3）物理-生物建模研究，以规划、整合和扩展现场和实验室结果。巡航方案采用了联合国后勤基地办事处标准的船舶能力，并增加了仪器，包括：1）配备SeaBird CTD-O2系统、Biospheric PAR、SeaPoint叶绿素和CDOM荧光计、SeaPoint Turning、Satlantic ISUS硝酸盐传感器、Brooke-Oceans激光光学浮游生物计数器的波浪起伏系统，和通用海洋流量计，集成了GPS和回声探测定位系统，并实时显示所收集的数据，2）FlowCAM，3）自主式垂直剖面仪（AVP）。实验室的努力适用于一个成熟的运动分析系统，研究甲藻的行为和一个发达的围隔生态系统的能力，研究甲藻的生理，生物化学和行为。建模工作建立在现有的，生物学上强烈的建模方法，采用参数化的甲藻生理，生物化学和行为在一个有代表性的物理领域。知识价值直接适用于“隐形”水华爆发，因为BenDiM生物量的发展通常是看不见的，因为它发生在卫星探测的第一光学深度以下。BenDiM还涉及碳输出的改进估计，因为这种生物量可能会错过在常规的真光层调查和营养关系，因为这种生物量可能会受益或损害食草动物取决于甲藻物种，占主导地位的生态位在给定的地点和时间。更广泛的影响包括：NCSU和UNCW的研究生和本科生教育;通过COSEE进行的高中教师教育;在国家/国际会议上向同事传递信息;以及通过COSEE向公众传递关于巡航工作的DVD。

Most applications of the standardized dinoflagellate diel vertical migration (DVM) hypothesis consider a surface goal in daylight and a subsurface nutrient goal at night because of the visibility of surface blooms. The sub-surface nutrient source, however, can be so deep that dinoflagellates are unable to reach the surface during a 12 h ascent. At least three literature reports document a sediment-oriented expression of an alternative DVM pattern characteristic of continental boundaries with wider, more gently sloping shelves that can yield high biomass, near-bottom dinoflagellate accumulations. The targeted dinoflagellate niche, here termed ''Benthic Dinoflagellate Migration'' or ''BenDiM'', is influenced by light and nutrient gradients but is unique in that a DVM exists between a nutrient source near or at the sediment-sea interface and a light intensity in the lower euphotic zone that supports a net increase in population size. The project specifically deal with: 1) the different dinoflagellate species that occupy the BenDiM niche on the continental shelf off Panama City, FL between the 60 m and 20 m contours between May and Nov; 2) the light acclimation, the nutrient uptake capabilities, and the behavioral patterns required of different dinoflagellate species that occupy the BenDiM niche; and, 3) the effect of representative physical water motion on the formation, transport and fate of the different BenDiM dinoflagellate species populations. The study includes: 1) a pelagic/benthic field program with three 7-day cruises during different months between May and Oct in 2008 and Jul-Aug 2009; 2) laboratory studies on the light, nutrient, and behavioral characteristics of BenDiM dinoflagellates that allow successful competition with near-bottom pelagic diatoms and the microphytobenthos; and 3) a physical-biological modeling study to plan, integrate and extend the field and laboratory results. The cruise program applies standard UNOLS ship capabilities extended with instrumentation that includes: 1) an Acrobat undulating system instrumented with SeaBird CTD-O2 system, Biospherical PAR, SeaPoint Chlorophyll and CDOM Fluorometers, Seapoint Turbidity, Satlantic ISUS Nitrate Sensor, Brooke-Oceans Laser Optical Plankton Counter, and General Oceanics Flow Meter with integrated GPS and echo sounding location system and a real-time graphical display of the collected data, 2) the FlowCAM, and 3) the autonomous vertical profiler (AVP). The laboratory effort applies a proven motion analysis system for studying dinoflagellate behavior and a well-developed mesocosm capability for studying dinoflagellate physiology, biochemistry, and behavior. The modeling effort builds on an existing, biologically intense modeling approach that incorporates parameterization of dinoflagellate physiology, biochemistry and behavior in a representative physical field. The intellectual merit directly applies to "stealthy" bloom initiation since the developing BenDiM biomass generally is unseen because it occurs below the first optical depth of satellite detection. BenDiM also is implicated in improved estimates of carbon export since this biomass may be missed during routine euphotic zone surveys and in trophic relationships since this biomass may benefit or harm grazers depending on the dinoflagellate species that dominates the niche at a given place and time. The broader impacts include: NCSU and UNCW graduate and undergraduate education; high school teacher education through COSEE; information transfer to colleagues at national/international meetings; and, information transfer to the public through a COSEE facilitated DVD on the cruise effort.