Sensitivity of copepod populations to bottom-up and top-down forcing: a modeling study in the Gulf of Maine region
Sensitivity of copepod populations to bottom-up and top-down forcing: a modeling study in the Gulf of Maine region
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DOI：
10.1093/plankt/fbs070
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发表时间：
2013-01-01
影响因子：
2.1
通讯作者：
Davis, Cabell S.
中科院分区：
文献类型：
--
作者：
Ji, Rubao;Stegert, Christoph;Davis, Cabell S.
海洋桡足类的时空变化，像其他水生和陆生生物，是由自下而上（通过食物资源的变化）和自上而下（通过捕食的变化）强迫控制。典型的是，水文、营养化学和循环方面与气候有关的变化可以调节浮游植物的生产，从而对海洋桡足类实行自下而上的控制，而捕鱼等人类活动则可能通过营养级联等食物网重组影响桡足类的捕食死亡率。评估桡足类种群对自下而上和自上而下强迫的敏感性是预测未来海洋浮游生态系统变化的重要一步。在这项研究中，我们使用耦合的水动力学/食物网/人口动力学模型，以确定关键过程控制观察到的季节性和分布格局的两个桡足类群体在缅因州（GoM）地区，包括伪哲水蚤属。和典型刺蛾Centropages typicus。数值实验进行了评估的敏感性模拟物种的浮游植物生物量和水华的时间，以及死亡率制度的变化。结果表明，这两个桡足类群体更敏感的变化，死亡率比食物供应和高峰时间。自下而上的过程本身不能解释所观察到的变化，在Pseudocalanus和Centropages人口规模，而自上而下的控制起着至关重要的作用，在墨西哥湾地区的桡足类种群动态。
The spatio-temporal variability of marine copepods, like other aquatic and terrestrial organisms, is controlled by both bottom-up (through changes in food resource) and top-down (through changes in predation) forcing. Canonically, climate-related changes in hydrography, nutrient chemistry and circulation can modulate phytoplankton production, thus imposing a bottom-up control on marine copepods, whereas human activities such as fishing may affect the predation mortality of copepods through food-web re-organization such as trophic cascading. Evaluating the sensitivity of copepod populations to bottom-up and top-down forcing is an essential step toward the prediction of future marine planktonic ecosystem changes. In this study, we used a coupled hydrodynamics/food-web/population-dynamics model to identify the key processes controlling the observed seasonality and distributional patterns of two copepod groups in the Gulf of Maine (GoM) region, including Pseudocalanus spp. and Centropages typicus. Numerical experiments were conducted to assess the sensitivity of the modeled species to changes in phytoplankton biomass and bloom timing, as well as the changes in mortality regime. The results show that both copepod groups are more sensitive to changes in mortality rates than to food availability and peak timing. Bottom-up processes alone cannot explain the observed variability in Pseudocalanus and Centropages population sizes, while top-down controls play a critical role in copepod population dynamics in the GoM region.