Murphy Eugene J, Trathan Philip N, Watkins Jon L, Reid Keith, Meredith Michael P, Forcada Jaume, Thorpe Sally E, Johnston Nadine M, Rothery Peter
British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, Cambridgeshire CB3 0ET, UK.
Proc Biol Sci. 2007 Dec 22;274(1629):3057-67. doi: 10.1098/rspb.2007.1180.
Determining how climate fluctuations affect ocean ecosystems requires an understanding of how biological and physical processes interact across a wide range of scales. Here we examine the role of physical and biological processes in generating fluctuations in the ecosystem around South Georgia in the South Atlantic sector of the Southern Ocean. Anomalies in sea surface temperature (SST) in the South Pacific sector of the Southern Ocean have previously been shown to be generated through atmospheric teleconnections with El Niño Southern Oscillation (ENSO)-related processes. These SST anomalies are propagated via the Antarctic Circumpolar Current into the South Atlantic (on time scales of more than 1 year), where ENSO and Southern Annular Mode-related atmospheric processes have a direct influence on short (less than six months) time scales. We find that across the South Atlantic sector, these changes in SST, and related fluctuations in winter sea ice extent, affect the recruitment and dispersal of Antarctic krill. This oceanographically driven variation in krill population dynamics and abundance in turn affects the breeding success of seabird and marine mammal predators that depend on krill as food. Such propagating anomalies, mediated through physical and trophic interactions, are likely to be an important component of variation in ocean ecosystems and affect responses to longer term change. Population models derived on the basis of these oceanic fluctuations indicate that plausible rates of regional warming of 1oC over the next 100 years could lead to more than a 95% reduction in the biomass and abundance of krill across the Scotia Sea by the end of the century.
确定气候波动如何影响海洋生态系统，需要了解生物和物理过程如何在广泛的尺度上相互作用。在此，我们研究物理和生物过程在南大洋南大西洋区域南乔治亚岛周围生态系统波动形成过程中的作用。此前研究表明，南大洋南太平洋区域的海表温度（SST）异常是通过与厄尔尼诺-南方涛动（ENSO）相关过程的大气遥相关产生的。这些SST异常通过南极绕极流传播到南大西洋（时间尺度超过1年），在那里，ENSO和与南半球环状模相关的大气过程在短时间尺度（不到6个月）上有直接影响。我们发现，在整个南大西洋区域，这些SST变化以及冬季海冰范围的相关波动，会影响南极磷虾的补充和扩散。这种由海洋学驱动的磷虾种群动态和丰度变化，反过来又会影响依赖磷虾为食的海鸟和海洋哺乳动物捕食者的繁殖成功率。这种通过物理和营养相互作用介导的传播异常，很可能是海洋生态系统变化的一个重要组成部分，并影响对长期变化的响应。基于这些海洋波动得出的种群模型表明，在未来100年内区域升温1摄氏度的合理速率，可能导致到本世纪末斯科舍海磷虾的生物量和丰度减少95%以上。
