Size structure and function of phytoplankton communities in a changing ocean

变化海洋中浮游植物群落的规模结构和功能

• 批准号: 1434007
• 负责人: Stephanie Dutkiewicz
• 金额: $ 53.2万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-10-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434007&HistoricalAwards=false
• 关键词: Size; structure; function; phytoplankton; communities

Phytoplankton form the base of the marine food web and are a crucial component in the global carbon cycle. They are also extremely diverse, with different species ranging widely in size, biochemical functions, and light and temperature requirements. How phytoplankton establish communities (mixtures of the different species living in the same place) and how these vary between regions and with time is poorly known. Community structure is important for the type of food webs they can support and the amount of carbon they sequester in the ocean. The diversity within the community may also be essential for stability of the ecosystems under changing environmental conditions. Computer models, grounded by observations, provide an important tool to explore marine ecosystems. Current models however include very limited diversity of phytoplankton, focusing on either their differences in size or function, but not both. This new modelling effort will incorporate substantially more diversity and therefore be able to address how and why different groups of phytoplankton co-exist in space and time and how their community structures change in altered environments. This study will be enhanced by new international collaborations with experts in France and Canada. An ongoing collaboration with the San Francisco Exploratorium and its Living Liquid display will be significantly enhanced as part of the Broader Impacts. This installation is a large touch screen table that allows museum visitors to make their own discoveries about phytoplankton diversity through interaction with the model output. The software developed as part of this project will be freely available, and visualizations of the results will provide unique outreach tools.This unique global modelling effort plans to incorporate multiple dimensions of trait space: size, biochemical function, and adaptation to light and temperature. The new model will be tested and constrained by compiling existing and new empirical data sets. It will then be used to explore how community structure and biogeochemical impact are controlled by the interplay of both organism functional and size trait. In particular the model will be used to explore how the diverse community structure is significant in regulating the resilience of ecosystem structure and function to global change. The compiled data, model, as well as theoretical frameworks will address the hypotheses: 1) a model with multiple dimensions of traits will provide more realistic complex community structures, with a size range within functional groups, and more co-existence between functional groups; 2) community structure will be driven by grazing control within functional groups, but nutrients supply rates will control functional group ranges; 3) patterns of carbon export will be significantly more complex when both size distribution of overlying communities and ballasting by minerals such as calcium carbonate and opal are taken into account; 4) climate change will lead to regionally varying patterns of size shifts within functional groups or shifts between functional groups, and such changes will lead to varying alterations to carbon export fluxes; and 5) the inclusion of size will lead to more stable ecosystems in terms of productivity and export to climate change perturbations.

浮游植物构成了海洋食物网的基础，是全球碳循环的重要组成部分。它们也极其多样化，不同的物种在大小、生化功能以及对光和温度的要求上差异很大。浮游植物如何建立群落(生活在同一地点的不同物种的混合体)以及这些群落如何在不同地区和时间内变化，人们知之甚少。群落结构对它们所能支持的食物网的类型以及它们在海洋中固定的碳量很重要。在不断变化的环境条件下，群落内的多样性对于生态系统的稳定性也可能是必不可少的。以观测为基础的计算机模型为探索海洋生态系统提供了重要工具。然而，目前的模型包括非常有限的浮游植物多样性，侧重于它们的大小或功能差异，但不是两者兼而有之。这一新的建模工作将包含更多的多样性，因此能够解决不同的浮游植物群体如何以及为什么在空间和时间上共存，以及它们的群落结构在变化的环境中如何变化。这项研究将通过与法国和加拿大的专家进行新的国际合作而得到加强。作为更广泛影响的一部分，与旧金山探索博物馆正在进行的合作及其活的液体展示将得到显着加强。这个装置是一个大的触摸屏桌子，允许博物馆参观者通过与模型输出的互动来自己发现浮游植物的多样性。作为该项目的一部分开发的软件将免费提供，结果的可视化将提供独特的推广工具。这一独特的全球建模工作计划纳入特征空间的多个维度：大小、生化功能以及对光和温度的适应。新模型将通过汇编现有和新的经验数据集进行测试和约束。然后，它将被用来探索生物体功能和大小特征的相互作用如何控制群落结构和生物地球化学影响。特别是，该模型将被用来探索多样化的群落结构如何在调节生态系统结构和功能对全球变化的适应能力方面具有重要意义。编制的数据、模型和理论框架将解决以下假设：1)多维特征的模型将提供更真实的复杂群落结构，功能组内的大小范围，以及功能组之间的共存；2)功能组内的放牧控制将驱动群落结构，但营养物质的供给率将控制功能组的范围；3)当同时考虑上覆群落的粒度分布和碳酸钙、蛋白石等矿物的压载时，碳输出的模式将明显更加复杂；4)气候变化将导致官能团内部或官能团之间大小变化的区域模式，这种变化将导致碳出口通量的不同变化；5)大小的纳入将导致在生产力和对气候变化的输出扰动方面更稳定的生态系统。