Along-shore larval dispersal kernels in a numerical ocean model of the central Chilean coast
Along-shore larval dispersal kernels in a numerical ocean model of the central Chilean coast
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DOI：
10.3354/meps339013
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发表时间：
2007-01-01
影响因子：
2.5
通讯作者：
Castilla, Juan Carlos
中科院分区：
文献类型：
--
作者：
Aiken, Christopher M.;Navarrete, Sergio A.;Castilla, Juan Carlos
扩散核提供了一种有用的方法来量化源自空间中给定点的传播体的平均空间分布。因此，扩散核已被用于海洋无脊椎动物和鱼类的远洋幼虫阶段的短距离和长距离扩散的分析和数值研究。在大多数情况下，分散内核的形状是预先确定的和参数化的知识幼虫的持续时间或平均电流速度均匀地跨越空间。在这里，通过使用智利中部海岸的一段数值海洋模型的近岸物种在一个现实的沿海洋流的浮游幼虫扩散的特点进行了研究。三维原始方程模式是由4年观测到的风从拉斯克鲁塞斯。利用演化模型的速度场模拟了浮游幼虫在平流中的扩散过程。没有先验假设的扩散平流统计。每天从定期间隔位置释放漂流者沿着海岸，并被认为是解决，如果发现在1公里的海岸30天后释放。观察到的分散内核，然后计算每个释放位置，并检查其在空间和时间的变化。这种变化被认为是实质性的空间尺度小于一个典型的幼虫平流尺度，因此，一个空间和时间上平均的分散内核是不够的，作为一个全球性的定居模式。大沿岸的分散内核的形状的变化导致显着的变化，在当地网站之间的连接的空间格局，一些作为净源，一些作为净汇在10公里的尺度。这些结果与沿海岸和海洋环流的季节性变化有关，特别是靠近海岸。局部和全局扩散核被发现是非高斯的，其分布与海洋速度场的分布有关。它的结论是，在现实的流动与复杂的海岸几何形状，相当大的偏离预期的高斯分散内核的基础上均匀的流动条件，可以导致复杂的空间格局的连接和成功的解决沿着一个相对简单的，但真实的海岸线。
Dispersal kernels provide a useful way to quantify the average spatial distribution of propagules originating from a given point in space. Consequently, dispersal kernels have been used in analytical and numerical studies of short- and long-distance dispersal of marine invertebrates and fish with pelagic larval stages. In most cases, the shape of dispersal kernels is pre-determined and parameterised with knowledge of larval duration or mean current velocities homogeneously across space. Here, the characteristics of planktonic larval dispersal for near-shore species in a realistic coastal ocean flow are investigated through the use of a numerical ocean model of a section of the central Chilean coast. The 3-dimensional primitive equation model was forced by 4 yr of observed winds from Las Cruces. Planktonic larval dispersal was simulated by advecting passive drifters using the evolving model velocity field. No a priori assumptions were made about diffusion-advection statistics. Drifters were released daily from regularly spaced locations along the coast and were considered to have settled if found within 1 km of the coast 30 d after release. Observed dispersal kernels were then calculated for each release location, and their variability in space and time was examined. This variability was found to be substantial over spatial scales less than a typical larval- advection scale, and, as a result, a spatially and temporally averaged dispersal kernel was inadequate as a global model of settlement. Large along-shore variation in the shape of dispersal kernels led to significant variation in the spatial pattern of connectivity among local sites, with some acting as net sources and some as net sinks within scales of 10s of kilometres. These results are linked to the alongshore and seasonal variability in ocean circulation, in particular close to shore. Both local and global dispersal kernels were found to be non-Gaussian, with their distribution related to that of the ocean velocity field. It is concluded that, in realistic flows with complicated coastal geometry, considerable departure from the expected Gaussian dispersal kernels based on homogeneous flow conditions can lead to complex spatial patterns of connectivity and successful settlement along a relatively simple but real coastline.