Influence of spatial heterogeneity on the type of zooplankton functional response: A study based on field observations

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• 作者：Andrew Morozov ; Elena Arashkevich ; Marit Reigstad ; Stig Falk-Petersen
• 关键词：Zooplankton feeding response ; Holling's types ; Calanus glacialis ; Vertical distribution ; Barents Sea
• 刊名：Deep Sea Research Part II: Topical Studies in Oceanography
• 出版年：2008
• 出版时间：October 2008
• 年：2008
• 卷：55
• 期：20-21
• 页码：2285-2291
• 全文大小：325 K

文摘

Mathematical models of plankton dynamics are sensitive to the choice of type of zooplankton functional response, i.e., to how the rate of intake of food varies with the food density. Conventionally, the conclusion on the actual type of functional response for a given zooplankton species is made based upon laboratory analysis on experimental feeding. In this paper, we show that such an approach can be too simplistic and misleading. Based on real ocean data obtained from three expeditions of R/V Jan Mayen in the Barents Sea in 2003–2005, we demonstrate that vertical heterogeneity in algal distribution as well as active vertical movement of herbivorous zooplankton can modify the type of trophic response completely. In particular, we found that the rate of average intake of algae by Calanus glacialis exhibits a Holling type III response, instead of Holling type I or II found previously in laboratory experiments. We argue that this conceptual discrepancy is due to the ability of the zooplankton to feed in layers with high algal density and to avoid depths with lower algal density. Since theoretical studies would predict enhancing in system stability in the case of Holling type III, our results may be of importance for understanding the main factors controlling plankton dynamics.