British Antarctic Survey, Natural Environment Research Council, Cambridge, UK.
Department of Life Sciences, Marine and Environmental Sciences Centre, University of Coimbra, Coimbra, Portugal.
Glob Chang Biol. 2021 Nov;27(22):5773-5785. doi: 10.1111/gcb.15839. Epub 2021 Aug 29.
Ocean circulation connects geographically distinct ecosystems across a wide range of spatial and temporal scales via exchanges of physical and biogeochemical properties. Remote oceanographic processes can be especially important for ecosystems in the Southern Ocean, where the Antarctic Circumpolar Current transports properties across ocean basins through both advection and mixing. Recent tracking studies have indicated the existence of two large-scale, open ocean habitats in the Southern Ocean used by grey petrels (Procellaria cinerea) from two populations (i.e., Kerguelen and Antipodes islands) during their nonbreeding season for extended periods during austral summer (i.e., October to February). In this work, we use a novel combination of large-scale oceanographic observations, surface drifter data, satellite-derived primary productivity, numerical adjoint sensitivity experiments, and output from a biogeochemical state estimate to examine local and remote influences on these grey petrel habitats. Our aim is to understand the oceanographic features that control these isolated foraging areas and to evaluate their ecological value as oligotrophic open ocean habitats. We estimate the minimum local primary productivity required to support these populations to be much <1% of the estimated local primary productivity. The region in the southeast Indian Ocean used by the birds from Kerguelen is connected by circulation to the productive Kerguelen shelf. In contrast, the region in the south-central Pacific Ocean used by seabirds from the Antipodes is relatively isolated suggesting it is more influenced by local factors or the cumulative effects of many seasonal cycles. This work exemplifies the potential use of predator distributions and oceanographic data to highlight areas of the open ocean that may be more dynamic and productive than previously thought. Our results highlight the need to consider advective connections between ecosystems in the Southern Ocean and to re-evaluate the ecological relevance of oligotrophic Southern Ocean regions from a conservation perspective.
海洋循环通过物理和生物地球化学性质的交换，将地理上不同的生态系统连接在广泛的时空尺度上。远程海洋过程对于南大洋的生态系统尤为重要，南极绕极流通过平流和混合将性质输送穿过海洋盆地。最近的追踪研究表明，在南大洋中存在两个大型开阔海洋生境，在南大洋，来自两个种群（即凯尔盖朗群岛和安蒂波德斯群岛）的灰海燕（Procellaria cinerea）在非繁殖季节的澳大利亚夏季（即 10 月至 2 月）期间会在此处进行长时间的觅食。在这项工作中，我们使用大规模海洋观测、表面漂流者数据、卫星衍生的初级生产力、数值伴随敏感性实验以及生物地球化学状态估计的输出的新颖组合，研究了这些灰海燕栖息地的本地和远程影响。我们的目的是了解控制这些孤立觅食区的海洋特征，并评估它们作为贫营养开阔海洋生境的生态价值。我们估计，为这些种群提供支持所需的最低本地初级生产力远<1%的估计本地初级生产力。来自凯尔盖朗群岛的鸟类所使用的东南印度洋区域通过环流与富饶的凯尔盖朗大陆架相连。相比之下，来自安蒂波德斯群岛的海鸟所使用的南太平洋中部区域相对孤立，这表明它更多地受到本地因素或多个季节性周期的累积效应的影响。这项工作例证了捕食者分布和海洋学数据的潜在用途，可以突出开阔海洋中可能比以前认为的更具动态性和生产力的区域。我们的研究结果强调了需要考虑南大洋中生态系统的平流连接，并从保护的角度重新评估贫营养南大洋区域的生态相关性。
