Interactions of Physics and Biology: Gelatinous Predators in Chesapeake Bay

PURCEL 9633607这项研究将与切萨皮克湾正在进行的为期5年的LMER II计划(TIES)对接，该计划将提供后勤和分析支持以及关于水文学、中游动物和浮游鱼类的数据。将收集关于胶状捕食者(水母和鞭毛虫)分布的全海湾数据集，因为它们与水柱中的大规模水文特征有关。特别关注的特征是季节性跃层、锋面、水力控制点和生物斑块。用于密集测绘和面向过程的研究的海湾区域包括多盐类南部海湾和中盐类海湾中部。在以过程为导向的研究中，将测量摄食和繁殖力，以确定水文特征的营养相互作用是否增加。TIES将持续测量中浮游动物的丰度和温度、盐度、叶绿素和溶解氧。深度离散的胶状捕食者样本将使用开放的封闭网系统进行制作。活的胶状生物体的生物体积、数量和大小将在船上确定。小而精致的标本(幼虫、鞭毛虫和水母)将从更多的垂直浮游生物拖网中进行量化。个体标本将被收集并(1)立即保存用于肠道内容物分析，(2)为产蛋而孵化一夜。数据分析将强调水文数据与区域、季节和年际人口数据的三维绘图和相互关系，以及营养和生殖数据与水文特征的比较。胶状捕食者是切萨皮克湾远洋食物网的重要组成部分。水母的聚集是因为它们的行为与水柱的物理特征相互作用而产生的。切萨皮克湾的物理结构很复杂，有许多可能的聚合特征。海湾中只有三种胶状物种的种群数据，但已有30种物种被报告。这项研究将对物理和生物如何相互作用导致前沿的营养相互作用和其他物理特征的加剧进行关键研究。***

Purcell 9633607 This research will interface with the ongoing 5-yr LMER II program (TIES) in Chesapeake Bay, which will provide logistic and analytical support and data on hydrography, mesozooplankton, and ichthyoplankton. A bay-wide data set will be collected on the distribution of gelatinous predators (medusae and ctenophores), as they are related to large-scale hydrographic features in the water column. The features of particular focus will be the seasonal pycnocline, fronts, the hydraulic control point, and biological patches. Regions of the bay for intensive mapping, and process-oriented studies include the polyhaline southern bay and the mesohaline mid-bay. In process-oriented studies, feeding and fecundity will be measured to determine if trophic interactions increase at hydrographic features. TIES will continuously measure mesozooplankton abundances and temperature, salinity, chlorophyll, and dissolved oxygen. Depth-discrete samples of gelatinous predators will be made using an opening closing net system. Biovolumes, numbers, and sizes of the live gelatinous organisms will be determined on board ship. Small and delicate specimens (larval ctenophores and hydromedusae) will be quantified from additional vertical plankton hauls. Individual specimens will be collected and (1) preserved immediately for gut content analysis, and (2) incubated overnight for egg production. Data analysis will emphasize 3-dimensional mapping and correlations of hydrographic data with population data on regional, seasonal, and interannual bases, as well as comparisons of the trophic and reproductive data relative to hydrographic features. Gelatinous predators are important components of the pelagic food web in Chesapeake Bay. Aggregations of jellyfish occur because of interactions of their behaviors with the physical characteristics of the water column. Chesapeake Bay is physically complex, with many possible aggregating features. Population data exist for only three gelatinous species in the bay, but 30 species have been reported. This research will provide critical studies on how physics and biology interact to cause intensification of trophic interactions at fronts and other physical features. ***