Anomalously low zooplankton abundance in the Ross Sea: An alternative explanation
Anomalously low zooplankton abundance in the Ross Sea: An alternative explanation
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罗斯海浮游动物丰度异常低：另一种解释
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
K. Arrigo
中科院分区：
文献类型：
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作者：
Alessandro Tagliabue;K. Arrigo
罗斯海西南部（南极洲）的罗斯海冰间湖（英语：Ross Sea polynya）中有大量的南极棕囊藻（英语：Phaeocystis anaerotica），这是受浮游动物影响最小的冰间湖，而邻近的特拉诺瓦湾冰间湖（英语：Terra Nova Bay polynya）中有一个较小的硅藻水华，这更容易被放牧。这两个地区之间的放牧压力的差异经常被解释为减少的敏感性P. anastritica放牧，尽管相互矛盾的证据表明，棕囊藻属。很容易被浮游动物吃掉使用罗斯海的三维生态系统模型，我们的目标是确定浮游植物的生长动力学，而不是机械和/或化学防御，是否可以解释（1）在以P. anastritica为主的沃茨中观察到的相对较低的浮游动物丰度，以及（2）罗斯海浮游动物生物量较低。尽管在该模型中，硅藻和南极原甲藻同样容易被放牧（即，没有猎物选择性），Terra Nova湾浮游植物生长较慢，导致浮游植物-浮游动物耦合程度较高，浮游动物丰度较高。相反，罗斯海冰间湖的南极磷虾水华的繁荣/萧条周期被夸大，导致与更高营养水平的脱钩程度更大，浮游动物生物量减少。这表明，在罗斯海冰藻中观察到的低浮游动物丰度可能是它们无法与南极原甲藻的高生长率相匹配的结果。特拉诺瓦湾和罗斯海冰间湖之间浮游动物-浮游植物耦合的不同程度可能对食物网结构和碳输出产生重要影响，特别是在不断变化的分层下。
The southwestern Ross Sea (Antarctica) supports a large bloom of Phaeocystis antarctica in the Ross Sea polynya, which is impacted minimally by zooplankton and a smaller diatom bloom in the adjacent Terra Nova Bay polynya, which are more readily grazed. This difference in grazing pressure between the two regions frequently has been explained by a reduced susceptibility of P. antarctica to grazing, despite conflicting evidence showing that Phaeocystis spp. are readily grazed by zooplankton. Using a three‐dimensional ecosystem model of the Ross Sea, our goal was to determine whether phytoplankton growth dynamics, rather than mechanical and/or chemical defenses, might explain (1) the relatively low zooplankton abundance observed in waters dominated by P. antarctica, and (2) the low overall zooplankton biomass in the Ross Sea. Although in the model, diatoms and P. antarctica were grazed with equal ease (i.e., no prey selectivity), the slower growth of phytoplankton in Terra Nova Bay resulted in a higher degree of phytoplankton‐zooplankton coupling and greater zooplankton abundance. Conversely, the exaggerated boom/bust cycle of the P. antarctica bloom in the Ross Sea polynya resulted in greater decoupling from higher trophic levels and reduced zooplankton biomass. This indicates that the low zooplankton abundance observed in the Ross Sea polynya may be a consequence of their inability to match the high growth rates of P. antarctica. The different degrees of zooplankton‐phytoplankton coupling between Terra Nova Bay and the Ross Sea polynya may have important implications for food web structure and carbon export, especially under changing stratification.