A coupled ocean-ecosystem model of the Ross Sea: 2. Iron regulation of phytoplankton taxonomic variability and primary production
A coupled ocean-ecosystem model of the Ross Sea: 2. Iron regulation of phytoplankton taxonomic variability and primary production
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DOI：
10.1029/2001jc000856
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发表时间：
2003-07-16
影响因子：
3.6
通讯作者：
Robinson, DH
中科院分区：
文献类型：
--
作者：
Arrigo, KR;Worthen, DL;Robinson, DH
[1]通过将生物和营养动态纳入海洋环流模型，建立了罗斯海水层生态系统模型。在该模型中，使用来自被动微波卫星数据的20年气候学每日指定的海冰浓度计算表面热通量和盐通量。计算表面光谱辐照度，并通过水柱和海冰传播。生物状态变量包括两个浮游植物群（硅藻和棕囊藻），两个营养盐（NO3和Fe），碎屑和浮游动物。营养物是从富含营养物的深层沃茨的上涌提供给海面的，就铁而言，是从融化的海冰和雪中提供的，这些海冰和雪在前一个秋季和冬季积累了来自风成岩的铁。浮游植物的生长速率是作为光或营养限制的函数来计算的。该模型能够准确地模拟时间演变的两个良好的描述浮游植物水华，占主导地位的西南罗斯海：硅藻水华在浅混合层的西部大陆架（包括特拉诺瓦湾）和P. anaerotica水华在更深的混合罗斯海冰藻区。模拟的浮游植物水华的时间进程，以及它们的初级生产的幅度是在很好的协议与时间序列估计使用卫星海洋颜色数据验证了原位观测。模型结果表明，铁的可用性控制每年的初级生产在罗斯海，只有约三分之二的可用常量营养素在表面沃茨被消耗的过程中的水华，但铁在确定浮游植物群落组成的作用不大。相反，浮游植物水华的分类组成是由适应阴影的P. anaerotica和高光适应硅藻的不同混合（因此光）制度内的罗斯海的差异反应。该模型还预测了一个以前未描述的浮游植物水华沿着东部大陆架的发展，就在罗斯冰架的北部。这第三浮游植物水华的物理环境不同，从西部大陆架和罗斯海冰间湖地区，它收到了更大的输入海冰产生的铁和经验完全耗尽的表面NO3。因此，东部大陆架的年产量高于罗斯海的任何其他地方，并支持了异常庞大的食草动物种群。
[1] A model of the Ross Sea pelagic ecosystem has been developed by incorporating biological and nutrient dynamics into an ocean general circulation model. Surface heat and salt fluxes are calculated in the model using sea ice concentrations that are specified daily using the 20 year climatology derived from passive microwave satellite data. Surface spectral irradiance is calculated and propagated through both the water column and the sea ice. The biological state variables include two phytoplankton groups (diatoms and Phaeocystis antarctica), two nutrients (NO3 and Fe), detritus, and zooplankton. Nutrients are supplied to the sea surface from upwelling of nutrient-rich deep waters, and in the case of Fe, from melting sea ice and snow which have accumulated aeolian-derived Fe during the preceding autumn and winter. Phytoplankton growth rate is computed as a function of light or nutrient limitation. The model is able to accurately simulate the temporal evolution of the two well-described phytoplankton blooms that dominate the southwestern Ross Sea: the diatom bloom in the shallow mixed layer of the western continental shelf (including Terra Nova Bay) and the P. antarctica bloom in the more deeply mixed Ross Sea polynya region. The simulated temporal progression of both phytoplankton blooms as well as their magnitude of primary production are in good agreement with time series estimates made using satellite ocean color data as validated by in situ observations. Model results suggest that Fe availability controls annual primary production in the Ross Sea, with only about two thirds of the available macronutrients in surface waters being consumed during the course of the bloom, but that Fe has little role in determining phytoplankton community composition. Rather, the taxonomic composition of the phytoplankton blooms is determined by the differential responses of shade-adapted P. antarctica and high light-adapted diatoms to the different mixing (and hence light) regimes within the Ross Sea. The model also predicts the development of a previously undescribed phytoplankton bloom along the eastern continental shelf, just north of the Ross Ice Shelf. The physical environment of this third phytoplankton bloom differs from that of the western shelf and the Ross Sea polynya region in that it receives a larger input of sea ice-derived Fe and experiences complete exhaustion of surface NO3. Consequently, annual production on the eastern continental shelf is higher than anywhere else in the Ross Sea and supports an unusually large grazer population.