摘要
世界范围的珊瑚礁石逐渐地正在变得并且有害地影响在之上由包括的许多因素，重要气候变化，例如全球温暖和增加的 El Nino 南部的摆动活动。通常，珊瑚礁石的坚持，在特别低纬度，部分地，海运被管理不超过集体死亡能在发生的批评限制(∼30 ° C ) 的表面温度。因此，它被想珊瑚那生活在高纬度(即，当前更凉爽的海表面温度) 将多半比珊瑚生活在对假设未来温度增加更有利作出回应低纬度(即，当前更温暖的海表面温度) 。因而，高纬度的珊瑚社区可以有潜力在面临潜在的未来时为许多珊瑚种类充当 refugia 的区域全球温暖。Daya 海湾(22 ° 3 1 ′22 ° 5 0 ′N ) ，北华南海，包含几个高纬度的 non-reefal 珊瑚社区并且在这个区域以内代表 scleractinian 珊瑚的最在北方的分布之一。显著地， Daya 海湾经历了在整个过去的 50 年的在空和海表面温度中的戏剧的温暖。在这篇论文，我们在 Daya 海湾珊瑚社区分析 25 年变化，把两个基于历史性的调查并且我们的最近 2006 2008 地区性的生态的调查。我们的结果建议与预言相反，在过去的 25 年期间在在 Daya 海湾以内的珊瑚盖子有重要衰落(即，在到在 2008 的 15.3% 仅仅珊瑚盖子的 1983/1984 的 76.6% 珊瑚盖子) 。如此的变化也在最丰富的珊瑚种类反映重要移动，从 Acropora pruinosa 到 Favites abdita。大多数现代珊瑚社区变得以前在 15 和 30 年之间建立了，相应于增加的冬季海表面温度的一个时期。然而，很少的殖民地变得在最后 15 年以内建立了，尽管有温暖的一个更强烈的时期。由考虑另外的因素，我们假设那直接人为的影响，而非气候的事件，限制了发展，并且驾驶了衰落，最后 15 年里的 Daya 海湾珊瑚社区。Daya 海湾也在过去的 50 年期间受到了偶尔的极端冷事件，与最近的发生在 2008 年初(13 年 1 月 13 日 2 月) 。在 2008 冷事件期间，最低空气温度到达仅仅 6.6 ° C，和吝啬的海表面温度 2 月秋天，包括在 12.3 ° C 的六连续的天 【 14 ° C。显著地，海表面温度在通常在 scleractinian 珊瑚社区导致集体死亡的假设批评更低的温度阀值(∼13 ° C ) 下面掉落。令人惊讶地，我们的珊瑚社区调查，以前进行了两个(2007 年 8 月) 并且在以后(2008 年 2 月下旬) 极端 2008 冷事件，证明 Daya 海湾珊瑚生态系统恰好被影响在之上在冷时期期间。那些观察建议 Daya 海湾 scleractinian 珊瑚社区开发了改编到低海表面温度。总的来说，我们的数据支持高纬度的珊瑚社区例如 Daya 海湾，有的假设在潜在的未来的来临为 scleractinian 珊瑚充当 refugia 的区域的潜力全球温暖。
Coral reefs worldwide are becoming increasingly and detrimentally impacted upon by a variety of factors including significant climate changes, such as global warming and increased El Nino-Southern Oscillation activity. Generally, the persistence of coral reefs, especially at low-latitudes, is governed, in part, by sea surface temperatures not exceeding the critical limit （-30℃） at which mass mortality can occur. Thus, it is thought that corals living at high-latitudes （i.e., currently cooler sea surface temperatures） will likely respond more favourably to hypothesized future temperature increases than corals living at low-latitudes （i.e., currently warmer sea surface temperatures）. Consequently, high-latitude coral communities may have the potential to act as regions of refugia for many coral species in the face of potential future global warming. The Daya Bay （22°31′--22°50′N）, northern South China Sea, contains several high-latitude non-reefal coral communities and represents one of the most northerly distributions of scleractinian corals within the region. Significantly, Daya Bay has experienced dramatic warming in both air and sea surface temperatures throughout the past 50 years. In this paper, we analyze 25 years of change in the Daya Bay coral communities, based both on historic surveys and our latest 2006--2008 regional ecological surveys. Our results suggest that, contrary to predictions, there have been significant declines in coral cover within the Daya Bay during the past 25 years （i.e., 76.6% coral cover in 1983/1984 to only 15.3% coral cover by 2008）. Such changes also reflect a significant shift in the most abundant coral species, from Acropora pruinosa to Favites abdita. Most of the modern coral communities became established between 15 and 30 years ago, corresponding to a period of increased winter sea surface temperature. However, very few colonies have become established within the last 15 years, despite a more intense period of warming. By taking into account additional factors, we hypothesize that direct anthropogenic impacts, rather than climatic events, have both restricted the development, and drove the decline, of Daya Bay coral communities in the last 15 years. The Daya Bay has also been subjected to occasional extreme cold events during the past 50 years, with the most recent occurring in early 2008 （13 January-13 February）. During the 2008 cold event, the lowest air temperature reaches only 6.6℃, and the mean sea surface temperature for February fall to 〈 14℃, including six continuous days at 12.3℃. Significantly, the sea surface temperatures fall below the hypothesized critical lower temperature threshold （-13℃） that commonly leads to mass mortality in scleractinian coral communities. Surprisingly, our coral community surveys, conducted both before （August 2007） and after （late February 2008） the extreme 2008 cold event, demonstrate that the Daya Bay coral ecosystems are barely impacted upon during the cold period. Those observations suggest that the Daya Bay scleractinian coral communities have developed adaptations to low sea surface temperatures. Overall, our data support the hypothesis that high-latitude coral communities, such as Daya Bay, have the potential to act as areas of refugia for scleractinian corals in the advent of potential future global warming.
基金
Supported by Knowledge Innovation Project of the Chinese Academy of Sciences(Grant No.KZCX2-YW-318)
National Basic Research Program of China(Grant No.2007CB815905)
National Natural Science Foundation of China(Grant No.40830852)
the Australian Research Council(Grant No.DP0773081)
