Distribution Of Foraging Shearwaters Relative To Inner Front Of SE Bering Sea
Distribution Of Foraging Shearwaters Relative To Inner Front Of SE Bering Sea
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觅食海鸥相对于白令海东南部内前沿的分布
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
G. Hunt
中科院分区：
文献类型：
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作者：
J. Jahncke;K. Coyle;S. Zeeman;N. Kachel;G. Hunt
我们检验了短尾剪水豚聚集到白令海东南部的内锋觅食的假设，因为那里的产量增加了。我们通过比较1997、1998和1999年春末和夏末秋初的初级生产力、磷虾类的分布和剪水相对于锋面的分布来检验这一假设。我们发现，在夏季，但不是在春季在前面和海上的前提高初级生产。初级生产量因季节和年份而异。主要差异与1997年和1998年的异常情况有关。南极磷虾的密度夏季在锋面和锋面近海较高，春季各区域无差异。觅食的剪水聚集在高密度的前端在夏季，但觅食接近海岸在春季。在最前端，剪水类捕食磷虾类Thysanoessa raschii和T。inermis的预期，并在桡足类，积累在该地区。从1997年夏季到1999年夏季，浮游动物在锋面的消耗比例有所下降，而在这一功能的沙矛鱼Hammodytes hexapterus的消耗增加。我们的研究结果表明，在夏季，内锋支持磷虾和海鸟捕食者的聚集。锋面系统支持增强生产和随后的营养转移的手段取决于锋面区域深度处营养物质的可用性和小型浮游动物生物在此功能中的聚集。
We examined the hypothesis that short-tailed shearwaters Puffinus tenuirostris aggre- gate to forage at the inner front of the SE Bering Sea because of enhanced production there. We tested this hypothesis by comparing primary production, the distribution of euphausiids and the dis- tribution of shearwaters relative to the front during late spring and late summer/early fall of 1997, 1998 and 1999. We found enhanced primary production at the front and offshore of the front during summer but not during spring. Primary production varied between seasons and years. Major differ- ences were related to anomalous conditions in 1997 and 1998. The density of euphausiids was higher at the front and offshore of the front during summer, but there were no differences among regions during spring. Foraging shearwaters aggregated in high densities at the front during summer, but foraged close to shore during spring. At the front, shearwaters foraged on euphausiids Thysanoessa raschii and T. inermis as expected, and on copepods that accumulated in the area. The proportion of zooplankton consumed at the front decreased from summer 1997 to summer 1999, while consumption of sandlance Ammodytes hexapterus at this feature increased. Our results show that, during summer, the inner front supports aggregations of euphausiids and their seabird predators. The means by which the frontal system supports enhanced production and the subsequent trophic transfers is dependent on the availability of nutrients at depth in the frontal region and the aggregation of small zooplankton organisms in this feature.