Modeled spatial-temporal distribution of productivity, chlorophyll, iron and nitrate on the northern Gulf of Alaska shelf relative to field observations
Modeled spatial-temporal distribution of productivity, chlorophyll, iron and nitrate on the northern Gulf of Alaska shelf relative to field observations
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DOI：
10.1016/j.dsr2.2019.05.006
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发表时间：
2019-07-01
影响因子：
3
通讯作者：
Hopcroft, R. R.
中科院分区：
文献类型：
--
作者：
Coyle, K. O.;Hermann, A. J.;Hopcroft, R. R.
阿拉斯加湾北部陆架在空间和时间上都是动态的。由于有两个主要的洋流系统和众多的涡流和曲流，在特定的时间和地点，从船舶观测中获得的现场数据的解释是复杂的。利用区域海洋模拟系统（ROMS）和嵌入式营养浮游植物-浮游动物（GOANPZ）模型，研究了2000 - 2013年在132°W和160°W之间的GOA大陆架上生产力、叶绿素浓度和生物量的时空格局。模型中的碳叶绿素比随光照的变化而变化，以改变生产-辐照度曲线，以符合田间测量结果。模拟结果显示，3 - 5月，阿拉斯加大陆架东南部和威廉王子湾（PWS）与舒马金群岛之间的西部内大陆架生产力较高，而PWS与科迪亚克西部之间的外大陆架生产力较低。该模型在夏季和秋季在果阿西部的外大陆架上产生了生产力升高的区域。这种模式是由影响西部大陆架铁分布的环流驱动的。与2007-2013年相比，2000 - 2006年大陆架上的模拟生产力有所提高，这显然是由于模拟铁浓度的变化。相关性表明，3 - 5月西部果阿陆架的模拟产量可以解释春季净拖带大型桡足类平均生物量变化的65%。模拟结果表明，关于铁浓度和影响铁的过程的详细时空数据对于了解果阿陆架低营养水平产量和生物量的年际时空差异至关重要。
The northern Gulf of Alaska (GOA) shelf is dynamic spatially and temporally. With two major current systems and numerous eddies and meanders, interpretation of field data from ship-based observations at specific times and locations is complicated. We used the Regional Ocean Modeling System (ROMS) with an embedded nutrientphytoplankton-zooplankton (GOANPZ) model to aid in understanding spatial-temporal patterns of productivity, chlorophyll concentration and biomass over the GOA shelf between 132 degrees W and 160 degrees W from 2000 to 2013. Carbon chlorophyll ratios in the model were varied in response to light to alter production-irradiance curves by season to conform to field measurements. Simulations reveal regions of high productivity in March-May on the southeast Alaskan Shelf, and the western inner shelf between Prince William Sound (PWS) and the Shumagin Islands, but with lower productivity on the outer shelf between PWS and western Kodiak. The model produced regions of elevated productivity on the outer shelf of the western GOA during summer and fall. This pattern is driven by circulation affecting the distribution of iron on the western shelf. Simulated productivity on the shelf between 2000 and 2006 was elevated relative to 2007-2013, apparently due to changes in the simulated iron concentration. Correlations indicate that simulated production on the western GOA shelf during March-May can explain up to 65% of the variance in the mean biomass of large copepods from net tows during spring. Simulations suggest that detailed temporal-spatial data on iron concentration and the processes affecting iron are crucial to understanding interannual spatial-temporal differences in magnitudes of production and biomass at lower trophic levels on the GOA shelf.