The importance of oceanographic fronts to marine birds and mammals of the southern oceans
The importance of oceanographic fronts to marine birds and mammals of the southern oceans
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DOI：
10.1016/j.jmarsys.2008.11.022
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发表时间：
2009-10-01
影响因子：
2.8
通讯作者：
Weimerskirch, H.
中科院分区：
文献类型：
--
作者：
Bost, C. A.;Cotte, C.;Weimerskirch, H.
在过去的30年里，对亚热带锋以南海洋的海鸟和海洋哺乳动物的海上研究已经描述了与主要锋面区域的联系。最近，微技术的进步使得跟踪个体和调查这些海洋捕食者如何实际使用额叶区成为可能。从空间分布和碳通量的角度分析了不同额区对顶端捕食者的相对重要性；2)决定其优先使用的过程；3)额叶结构的中尺度动力学如何驱动这些捕食者的海上觅食策略。我们回顾了来自南部水域的已发表结果，并将其置于更广泛的背景下，考虑到我们对更北部海洋锋面的重要性的了解。一些前沿构成了南部水域海鸟群落的重要边界。在中尺度上，海鸟多样性和丰度的最大值与主要锋面的位置相对应。海上调查显示海鸟数量与海面温度之间有很强的曲线相关性。鲸鱼和海鸟的高平均物种丰富度和多样性始终与南极环极流、亚热带锋和亚南极锋的南部水团边界有关：在极地锋的情况下，平均海鸟密度变化更大。在小尺度上，海鸟发生的变化在有限的情况下与锋面的过程直接相关。部分浮游生物取食种类与锋温梯度-浮游植物变量呈显著正相关。遥测研究表明，一些顶级捕食者（企鹅、信天翁、海豹）根据地点的不同，会进行长途、定向的觅食旅行，要么去亚热带锋，要么去极地锋。飞行成本低的海鸟，如信天翁，能够从很远的地方到达前线，表现出不同的觅食策略，这是距离的函数。像王企鹅这样的潜水鸟类，它们的飞行成本更高，速度更慢。依赖于在极锋附近发现的中上层鱼类的可预测空间分布。他们可能会利用与漩涡有关的洋流作为积极寻找锋面区的海洋学线索。一旦进入这些区域，它们优先潜入温跃层深度及其以下，在那里单位努力的渔获量很高。海象的觅食活动主要集中在气旋漩涡的内部或边缘。这些中尺度特征似乎提供了特殊的生产力，有利于各种潜水顶级捕食者的觅食。前沿生物物理参数与捕食者之间的联系可能是通过生物增强来实现的。顶级捕食者似乎在猎物被物理过程平流的地方觅食，也在猎物在当地生产的地方觅食。对海洋顶级捕食者的分布和人口统计参数的长期研究对于评估与全球变暖有关的前沿分布的潜在变化的后果至关重要。这样的环境变化会增加工业化渔业对南方食物网的影响。(C) 2009 Elsevier B.V.版权所有
During the last 30 years, at-sea studies of seabirds and marine mammals in the oceans south of the Subtropical Front have described an association with major frontal areas. More recently, the advancement in microtechnology has allowed the tracking of individuals and investigations into how these marine predators actually use the frontal zones. In this review, we examine 1) the relative importance to apex predators of the different frontal zones in terms of spatial distribution and carbon flux; 2) the processes that determine their preferential use; and 3) how the mesoscale dynamics of frontal structures drive at-sea foraging strategies of these predators. We review published results from southern waters and place them in a broader context with respect to what has been learned about the importance of fronts in oceans farther north. Some fronts constitute important boundaries for seabird communities in southern waters. At a mesoscale the maximum values of seabird diversity and abundance correspond to the location of the main fronts. At-sea surveys show a strong curvilinear correlation between seabird abundance and sea surface temperatures. High mean species richness and diversity for whales and seabirds are consistently associated with the southern water mass boundary of the Antarctic Circumpolar Current, the Subtropical Front and the Subantarctic Front: in the case of the Polar Front mean seabird densities are more variable. At small-scales, variation in seabird occurrence has been directly related to the processes at fronts in a limited number of cases. A significant positive relation was found between some plankton feeding species and frontal temperature gradient-phytoplankton variables.Telemetric studies have revealed that several apex predators (penguins, albatrosses, seals) perform long, directed foraging trips either to the Subtropical front or Polar Front, depending on locality. Seabirds with low flight costs, such as albatrosses, are able to reach fronts at long distances from colonies, showing variable foraging strategies as a function of the distances involved. Diving birds such as King penguins, that travel at a higher cost and lower speed. rely on the predictable spatial distribution of mesopelagic fish found close to the Polar Front. They may use the currents associated with eddies as oceanographic cues in the active search for frontal zones. Once in these areas they dive preferentially in and below the depth of the thermocline where catches per unit effort are high. Elephant seals concentrate foraging activity principally inside or at the boundary of cyclonic eddies. These mesoscale features appear to offer exceptional productivity favourable for foraging by various diving top predators.The connection between biophysical parameters at fronts and predators is likely to be made through biological enhancement. Top predators appear to forage at locations where prey are advected by physical processes and others where prey are produced locally. Long-term research on at-sea distributions and demographic parameters of top predators are essential to assess the consequences of potential shift in front distributions in relation to global warming. Such environmental changes would add to the impact of fish extraction by the industrial fisheries on the southern food webs. (C) 2009 Elsevier B.V. All rights reserved.