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首页> 外文期刊>Oceanography and Marine Biology: An Annual Review >IMPLICATIONS OF LONG-TERM CLIMATE CHANGE FOR BIOGEOGRAPHY AND ECOLOGICAL PROCESSES IN THE SOUTHERN OCEAN
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IMPLICATIONS OF LONG-TERM CLIMATE CHANGE FOR BIOGEOGRAPHY AND ECOLOGICAL PROCESSES IN THE SOUTHERN OCEAN

机译：长期气候变化对南海生物地理学和生态过程的影响

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Understanding the long-term consequences of climate change for Southern Ocean ecosystems is important because this is one of the last remaining wildernesses on the planet and because the Southern Ocean is a major driver of global climate. The Southern Ocean is roughly the size of Africa and experiences exceptional seasonality. Its many habitats include the permanently open ocean, sea ice, frontal systems and neritic waters, and different zonal (east-west) and meridional (north-south) regions are on different trajectories in terms of climate, sea ice cover and biological populations. The Western Antarctic Peninsula has experienced substantial warming, loss of sea ice and declining Adelie penguin populations, while eastern Antarctica has cooled, shown increased ice cover and increasing numbers of Adelies. In the ocean itself, warming seems to be concentrated north of the Antarctic Circumpolar Current and at depth rather than in surface waters. Densities of Antarctic krill are correlated with ice cover in the previous winter and in the south-west Atlantic have decreased over the last century while salps have shown increasing numbers south of the Antarctic Circumpolar Current. Even in this example, the mechanisms involved are uncertain, making predictions difficult. The historic loss of an enormous biomass of consumers through fisheries, led to top-down ecological effects including competitive release among predators. These pelagic food webs are, however, strongly physically forced, making them particularly vulnerable to changes in environmental conditions. The size and species composition of the primary producers affect food chain length and the efficiency of the biological pump. Critically, the primary producer community is profoundly shaped by factors influencing the availability of light (e.g. season, ice melt and water column stability), micro and macronutrients. Changes in these will have deeply important bottom-up effects, and this brings us to defining biogeography. In these pelagic systems, biogeographic provinces are defined by the frontal systems that delineate sharp discontinuities in conditions in the water column and the taxa that dominate primary production. Because these are not geographically fixed, changes in biogeography in this context describe the expansion, contraction or simple displacement of biomes. The associated food webs revolve around a small number of key species that differ among habitats and biomes. They are not simple, exhibit considerable flexibility and include a number of taxa, particularly the cephalopods, that are difficult to sample and remain poorly studied. A major difficulty in understanding how climate change is likely to manifest is the brevity of relevant datasets. We have few physical or biological benchmarks to use in separating short-term noise from long-term signal. As a physical example, Southern Ocean fronts can exhibit short-term meridional shifts of >100 km in a matter of weeks. Biologically, regional differences in trajectories of Adelie penguin numbers need to be viewed against the background of substantial variability over the last 45,000 years. Except for ice or sediment cores, such data are available for few variables or species. In addition, research efforts are geographically unbalanced for logistic reasons. Remote sensing and the Argo float programme reduce this problem by increasing spatial coverage enormously for some variables, but not others, and even then offer relatively new time series. Important variables that are undergoing, or will undergo, change include: sea ice cover (essentially habitat loss), sea temperatures, wind and mixing regimes, the positions of fronts, ultraviolet levels and ocean pH. Many of these will have interacting effects, and the areas likely to be exposed to multiple environmental changes, far exceed those already experiencing important changes. Species are potentially vulnerable to stressors at all ontogenetic stages and in many cases suble
机译：了解南洋生态系统气候变化的长期后果很重要，因为这是这个星球上最后一个剩余的荒野之一，因为南洋是全球气候的主要司机。南海大约是非洲的大小，体验出色的季节性。它的许多栖息地包括永久开阔的海洋，海冰，正面系统和内腔水域，以及不同的地区（东西）和子午线（南北）地区在气候，海冰覆盖和生物群体方面采用不同的轨迹。西南极半岛经历了大量的变暖，海冰丧失，达莱企鹅居民跌幅，而东南极洲已经冷却，显示了冰盖的增加和越来越多的亚德利。在海洋本身中，变暖似乎集中在南极圆形电流的北方，深度而不是表面水域。南极磷虾的密度与前冬季的冰盖相关，而西南大西洋在上个世纪下降，而Salps已经显示南极圆形电流南部的数量越来越多。即使在这个例子中，所涉及的机制也是不确定的，使得预测困难。通过渔业巨大消费者的巨大生物量的历史性损失导致了自上而下的生态效应，包括捕食者之间的竞争释放。然而，这些木质食物网是强烈物理迫使的，使其特别容易受到环境条件的变化。初级生产者的大小和物种组成影响食物链长度和生物泵的效率。批判性地，主要生产者社区深受影响光的可用性（例如季节，冰熔体和水柱稳定），微观和常规营养素的因素的塑造。这些变化将具有深刻的自下而上效果，这使我们能够定义生物地理。在这些骨质系统中，生物地理省份由正面系统定义，该额度系统在水柱和统治初级生产中的条件下描绘了急剧的不连续性。因为这些没有地理上固定，因此在这种情况下，生物地理的变化描述了生物群体的扩展，收缩或简单位移。相关的食物网围绕栖息地和生物群落不同的少数关键物种。它们并不简单，表现出相当大的灵活性，并包括许多分类群，特别是难以样本的卡马托，并且仍然仍然很差。了解气候变化可能表现出气候变化的重大困难是相关数据集的简洁。我们有很少的物理或生物学基准，用于将短期噪声与长期信号分开。作为一个物理例子，南洋海洋面前可以在几周内展示> 100 km的短期优势班次。生物学上，在过去45,000年中，需要在大量变异的背景下观察阿德利企鹅数量轨迹的区域差异。除了冰或沉积物核心外，这些数据可用于几种变量或物种。此外，对后勤原因的研究努力是地理上不平衡的。遥感和ARGO浮动程序通过增加一些变量的空间覆盖，但不是其他变量来减少这个问题，甚至可以提供相对较新的时间序列。正在进行的重要变量或将发生变化包括：海冰盖（基本栖息地损失），海水温度，风和混合制度，前面，紫外线水平和海洋pH的位置。其中许多将具有相互作用的效果，并且可能暴露于多种环境变化的区域，远远超过了已经存在重要变化的环境。物种可能易受所有围粒体阶段的压力源，并且在许多情况下

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