225 years of Bering Sea climate and ecosystem dynamics revealed by coralline algal growth-increment widths
225 years of Bering Sea climate and ecosystem dynamics revealed by coralline algal growth-increment widths
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DOI：
10.1130/g31996.1
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发表时间：
2011-06-01
期刊：
影响因子：
5.8
通讯作者：
Wanamaker, A. D., Jr.
中科院分区：
文献类型：
--
作者：
Halfar, J.;Williams, B.;Wanamaker, A. D., Jr.
白令海的气候和生态系统动态最近经历了重大变化，影响了季节性海冰分布和海洋生物，包括具有重要商业价值的鲑鱼渔业。不幸的是，人们对白令海的长期动态知之甚少，这主要是因为缺乏高分辨率的海洋代理档案。在这里，我们提出了第一个记录，收集了横跨整个阿留申群岛的浅水栖息地收集的长寿珊瑚藻类的年生长增量宽度。虽然阿留申群岛的藻类生长与区域温度呈现出不同的关系，但它强烈地受到到达海底的太阳辐射变化的推动。因此，它提供了一个特殊的长期光动力学档案，在白令海，这归因于阿留申低(AL)强度的变化，阿留申低(AL)是亚北极北太平洋的主要气候模式。AL与白令海云量和风力呈正相关，这反过来又促进了上层海洋的混合。混合提高了地表水的营养物质浓度，刺激了浮游生物的生产，这与阿拉斯加鲑鱼的丰度呈正相关。云层和浮游生物产量的增加增加了浅海底的阴影，减少了藻类的生长。从1782年起，光驱动的藻类生长速率跟踪替代来源的鲑鱼丰度，但与20世纪之前以温度为主导的太平洋年代际涛动(PDO)的变异性关系不大。藻类记录表明，目前AL和PDO的关系在历史上是不同的，鲑鱼种群通过对浮游生物丰度的影响而不是与PDO相关的温度与AL强度有更密切的关系。
Bering Sea climate and ecosystem dynamics have recently undergone major changes that have affected seasonal sea ice distribution and marine life, including commercially important salmon fisheries. Unfortunately, long-term Bering Sea dynamics are poorly understood, largely because of an absence of high-resolution marine proxy archives. Here we present the first record compiled from annual growth-increment widths of long-lived coralline algae collected in shallow-water habitats spanning the entire Aleutian Islands. While algal growth in the Aleutians exhibits a variable relationship with regional temperatures, it is strongly driven by changes in solar radiation reaching the seafloor. Therefore, it provides an exceptional archive of long-term light dynamics, which in the Bering Sea is attributed to changes in strength of the Aleutian Low (AL), the dominant climate pattern of the subarctic North Pacific. The AL is positively related to Bering Sea cloudiness and wind strength, which in turn fosters upper-ocean mixing. Mixing raises surface-water nutrient concentrations and stimulates plankton production, which is positively linked to Alaskan salmon abundance. Enhanced clouds and plankton production increase shading on the shallow seafloor and reduce algal growth. Light-driven algal growth rates track proxy-derived salmon abundance from 1782 onward, but are poorly related to temperature-dominated Pacific Decadal Oscillation (PDO) variability prior to the twentieth century. The algal record suggests that the present-day relationship of AL and PDO varied historically and that salmon stocks have been more closely related to AL strength via its effect on plankton abundance rather than PDO-related temperatures.