On modeling the Southern Ocean Phytoplankton Functional Types
On modeling the Southern Ocean Phytoplankton Functional Types
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DOI：
10.5194/bg-2019-289
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
S. Losa;S. Dutkiewicz;M. Losch;J. Oelker;M. A. Soppa;S. Trimborn;H. Xi;A. Bracher
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文献类型：
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作者：
S. Losa;S. Dutkiewicz;M. Losch;J. Oelker;M. A. Soppa;S. Trimborn;H. Xi;A. Bracher
抽象的。这项研究着重介绍了应用物理-生物地球化学耦合模型研究南大洋主要浮游植物种群分布的最新进展和挑战，这是一个对了解生物地球化学循环和生态系统在当前气候变化下的功能非常感兴趣的领域。我们对各种浮游植物功能类型(PFT)物候的模拟是基于与麻省理工学院(MIT)大气环流模型(Darwin-MITgcm)耦合的达尔文生物地球化学模型的一个版本。生态模块版本适用于南大洋，方法是：1)通过引入对营养物质的高亲和力和逃避球藻放牧控制的能力，提高相对于原始模型的球藻丰度；2)包括两种不同大小(小型和大型)的硅藻；以及3)考虑棕囊藻的两个不同的生活阶段(单细胞和集群)。这一新的模式配置最好地描述了南大洋太平洋自由贸易协定的竞争和共存。与旧版本相比，它显着改善了模拟的球藻和硅藻丰度与亚南极地区扫描电子显微镜原位观察以及通过诊断色素分析获得的巴塔哥尼亚陆架和南极半岛西部沿线的硅藻和半芽藻(包括球藻和棕囊藻)叶绿素a浓度的一致性。模拟的南大洋PFT优势也与基于卫星的PFT信息很好地吻合。
Abstract. This study highlights recent advances and challenges of applying coupled physical-biogeochemical modeling for investigating the distribution of the key phytoplankton groups in the Southern Ocean, an area of strong interest for understanding biogeochemical cycling and ecosystem functioning under present climate change. Our simulations of the phenology of various Phytoplankton Functional Types (PFTs) are based on a version of the Darwin biogeochemical model coupled to the Massachusetts Institute of Technology (MIT) general circulation model (Darwin-MITgcm). The ecological module version was adapted for the Southern Ocean by: 1) improving coccolithophores abundance relative to the original model by introducing a high affinity for nutrients and an ability to escape grazing control for coccolithophores; 2) including two different (small vs. large) size classes of diatoms; and 3) accounting for two distinct life stages for Phaeocystis (single cell vs. colonial). This new model configuration describes best the competition and co-occurrence of the PFTs in the Southern Ocean. It improves significantly relative to an older version the agreement of the simulated abundance of the coccolithophores and diatoms with in situ scanning electron microscopy observations in the Subantarctic Zone as well as with in situ diatoms and haptophytes (including coccolithophores and Phaeocystis) chlorophyll a concentrations within the Patagonian Shelf and along the Western Antarctic Peninsula obtained by diagnostic pigment analysis. The modeled Southern Ocean PFT dominance also agrees well with satellite-based PFT information.