Aggregation Dynamics of Antarctic Krill, Euphausia Superba Dana

南极磷虾、磷虾的聚集动态

• 批准号: 9523748
• 负责人: Mark Huntley
• 金额: $ 14.81万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-11-01 至 1998-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9523748&HistoricalAwards=false
• 关键词: Aggregation; Dynamics; Antarctic; Krill; Euphausia

9523748 Huntley Patchiness of zooplankton and micronekton is a feature of central importance in marine ecosystems. In the Southern Ocean, aggregations of krill (Euphausia superba) are of particular interest. The distribution and dynamics of such aggregations are critical to determining the transformation of organic matter (e.g. carbon flux) and the fate of populations in the sea. These phenomena are especially important in the mesoscale and sub- mesoscale domains, where patchiness is most strongly expressed. If the means to predict patch dynamics is lacking, then so is the means to adequately predict carbon flux and population dynamics at these scales. Traditional models of zooplankton patch dynamics generally treat animals as Lagrangian particles whose aggregations are determined solely by processes of advection and diffusion. This approach ignores behavior induced by biotic and abiotic forces and manifested as purposeful motion - motion that clearly is not governed by advection and diffusion. Attempts to acknowledge behavior in models of plankton motility have been successful at the level of the individual animal, but even the most powerful computers cannot run individual-based models to predict aggregation dynamics of n individuals. This proposal takes a new approach to modeling aggregation dynamics, based on "bio-continuum" theory, and provides for model verification against benchmark field data. Rather than relying on traditional advection-diffusion equations, which ignore behavior, the bio-continuum theory recognizes behavioral forces in the context of statistical mechanics. Model output provides information on animal behaviors, manifest as swimming velocities, that are absent from other models of patch dynamics. All key model variables are measurable using common sampling techniques, such as acoustic Doppler and multiple net systems. The proposed research consists of studying both the internal and external forces that act on aggregations of Euphausia superba. First, the internal forces of autocoherence (that act between animals to maintain patch integrity) will be measured in krill aggregations observed in the Gerlache Strait region in 1992. Our database consists of more than 20 such aggregations observed by ADCP and MOCNESS. Second, the effect of external physical forcing on krill aggregations will be studied by embedding krill swarms of typical scales in numerically modeled flow regimes that are typical of the Gerlache Strait region (Zhou and Niiler 1995), by combining the Princeton circulation model (e.g. Blumberg and Mellor 1987) with our aggregation model. This research provides a novel, dynamic theory of animal aggregations in the sea. A study of the fundamental theory, coupled with model realizations that can be compared to observed aggregations of Euphausia superba, may lead to more realistic predictions of krill patch dynamics in the Southern Ocean. Such predictions are critical to more accurate measurements of carbon flux and the population dynamics of krill.

亨特利浮游动物和微浮游生物的斑块性是海洋生态系统中具有核心重要性的特征。 在南大洋，磷虾（Euphausia superba）的聚集特别令人感兴趣。 此类聚集体的分布和动态对于确定有机物的转化（例如碳通量）和海洋中种群的命运至关重要。 这些现象在中尺度和次中尺度区域尤其重要，在这些区域斑块性表现得最为强烈。 如果缺乏预测斑块动态的手段，那么在这些尺度上充分预测碳通量和种群动态的手段也是如此。 传统的浮游动物斑块动力学模型一般将动物视为拉格朗日粒子，其聚集仅由平流和扩散过程决定。 这种方法忽略了由生物和非生物力量引起的行为，并表现为有目的的运动-运动显然不受平流和扩散的控制。 试图在浮游生物运动模型中确认行为在个体动物的水平上是成功的，但即使是最强大的计算机也无法运行基于个体的模型来预测n个个体的聚集动力学。 该建议采取了一种新的方法来模拟聚集动力学，基于“生物连续”理论，并提供了对基准现场数据的模型验证。 生物连续统理论不依赖于忽略行为的传统对流扩散方程，而是在统计力学的背景下认识到行为力。 模型输出提供了动物行为的信息，表现为游泳速度，这是从补丁动力学的其他模型缺席。 所有关键的模型变量都可以使用常见的采样技术进行测量，例如声学多普勒和多网系统。 该研究包括研究作用于南极磷虾聚集体的内部和外部力。 首先，自相关的内力（动物之间的行为，以保持补丁的完整性）将在1992年在Gerlache海峡地区观察到的磷虾聚集测量。 我们的数据库由ADCP和MOCNESS观测到的20多个这样的聚集体组成。 其次，外部物理强迫对磷虾聚集的影响将通过嵌入典型尺度的磷虾群的数值模拟流态，这是典型的Gerlache海峡地区（周和Niiler 1995），结合普林斯顿环流模型（例如，Blumberg和梅洛尔1987）与我们的聚集模型。 这项研究提供了一个新的，动态的海洋动物聚集理论。 的基本理论的研究，再加上模型实现，可以比较观察到的聚集磷虾superba，可能会导致更现实的预测磷虾补丁在南大洋的动态。 这种预测对于更准确地测量碳通量和磷虾种群动态至关重要。