A Collaborative Study of the Dynamics and Ecosystem Implications of Post-Bloom Production at the Inner Front of the Southeast Bering Sea

加州的Hunt U，新英格兰的Irvine 9819251，Zeeman U，9907097，AK的Whitledge U，Fairbank，9819273。每年数以百万计的短尾剪毛鱼(Puffinus Tenuirostris)从澳大利亚迁徙到白令海，在内陆架觅食。这种每年一次的跨赤道迁徙的演变意味着，白令海的这些鸟类肯定可以随时获得大量的猎物。1997年和1998年，白令海东部的异常天气模式导致水文和水循环发生重大变化。由此产生的生态系统异常包括白令海首次有记录的球藻水华，约10%的迁徙剪切鱼遭受饥饿，以及1997年和1998年布里斯托尔湾红鲑鱼渔业的崩溃。这项研究项目将继续检验这一假设，即白令海东南部内锋的初级生产量增加的时间比非锋面水域的持续时间更长，并且这种生产量为整个夏季为支持剪切鱼、鲑鱼和它们的浮游动物猎物的食物网提供了能源。根据1997年和1998年的研究结果，关于风暴和营养物质平流作用的其他假设将通过季节性和每年一次的比较来检验。这项合作研究将收集和解释对内锋附近的物理和生物特征的观测，以确定：1)真光层营养物质的可用性，2)导致营养物质垂直通量增加的物理过程，3)初级生产力，4)近水面浮游动物和其他大型和微型浮游动物的分布、丰度和营养生态，5)剪切水的分布、丰度和觅食生态，6)通过稳定的同位素浓缩，从浮游植物到锋面以外的剪切水的营养途径。白令海东南部支持着世界上最丰富的渔业之一；大眼鳕鱼、鲑鱼、大比目鱼和螃蟹每年产生超过20亿美元的收入。尽管如此，对于剪毛虫、鲑鱼幼体和一些螃蟹幼虫聚集觅食的沿海区域和内前锋，还没有得到很好的研究。这项研究之所以重要，是因为它将：1)涉及天气模式的变化如何迫使影响生态系统功能的物理过程；2)首次检查夏季内锋面的物理过程以及锋面在水华盛开后初级生产中的作用；3)侧重于扩大生产的生态作用；4)将海鸟跨赤道迁徙模式的演变与产生可预测猎物来源的生物物理过程联系起来。这些问题是通过集中研究人员熟悉的物种和区域来解决的；然而，这些结果可以应用于许多大陆架潮汐前锋和物种。因此，研究结果对于理解和管理一些世界上产量最高的海洋应该具有普遍的适用性。

AbstractHunt U of CA, Irvine 9819251Zeeman U of New England 9907097Whitledge U of AK, Fairbanks 9819273Each year millions of short-tailed shearwaters (Puffinus tenuirostris) migrate from Australia to the Bering Sea to forage over the inner shelf. The evolution of this annual trans-equatorial migration implies that extraordinary amounts of prey must be readily available to these birds in the Bering Sea. In 1997 and 1998, unusual weather patterns in the eastern Bering Sea resulted in significant changes in hydrography and water circulation. The resultant ecosystem anomalies included the first recorded coccolithophore bloom in the Bering Sea, the starvation of about 10% of the migrant shearwaters present, and the collapse in both 1997 and 1998 of the Bristol Bay sockeye salmon fishery. This research project will continue testing the hypothesis that elevated primary production at the inner front of the southeastern Bering Sea continues longer than in non-frontal waters, and that this production provides an energy source throughout the summer for a food web that supports shearwaters, salmon, and their zooplankton prey. Based on findings in 1997 and 1998, additional hypotheses concerning the roles of storms and advection of nutrients will be tested using seasonal and inerannual comparisons. This collaborative study will collect and interpret observations on physical and biological features in the vicinity of the inner front to determine: 1) the availability of nutrients in the euphotic zone, 2) the physical processes responsible for enhanced vertical flux of nutrients, 3) primary production, 4) the distribution, abundance and trophic ecology of near-surface swarms of euphausiids and other macro- and micro-zooplankton, and 5) the distribution, abundance, and foraging ecology of shearwaters, and 6) by stable isotope enrichment, trophic pathways from phytoplankton to shearwaters at and away from the front.The southeastern Bering Sea supports one of the world's richest fisheries; walleye pollock, salmon, halibut and crab generate over 2 billion dollars in revenue each year. Despite this, the coastal domain and inner front, where shearwaters, young salmon and some crab larvae congregate to forage, has not been well studied. The study is important because it will: 1) relate how variation in weather patterns forces physical processes that affect ecosystem function; 2) be the first examination of the physical processes of the inner front during summer and of the role of the front in post-bloom primary production; 3) focus on the ecological role of the extended production, and 4) relate the evolution of trans-equatorial migration patterns of seabirds to biophysical processes that create predictable sources of prey. These questions are addressed by focusing on species and regions with which the investigators are familiar; however, the results can be applied to numerous continental shelf tidal fronts and species. Thus, the results should have a general applicability to understanding and managing some of the world's most productive seas.