全球海洋生物固氮的控制机制及其速率对全球变化的响应

项目名称： 全球海洋生物固氮的控制机制及其速率对全球变化的响应

项目编号： No.41476093

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 罗亚威

作者单位： 厦门大学

项目金额： 95万元

中文摘要： 海洋固氮为全球海洋提供了约一半的生物可利用氮源，强烈影响着海洋生产力、及对二氧化碳的储藏。因此，研究其控制机制并预测其对全球变化的响应具有重要科学意义。已有研究主要从资源限制角度（即Bottom-Up）对其控制机制提出了一系列假说，但并未能在全球海洋尺度上得到观测数据的较强确认。我们认为：浮游动物捕食和病毒裂解（即Top-Down）也能控制固氮；固氮微生物也可以通过重新分配资源来应对环境变化。本项目计划在数据分析基础上，从Bottom-Up和Top-Down两个角度分析固氮的控制机制；进一步建立生态系统模型以研究不同控制因子对固氮的综合效应，并通过实验室实验对模型进行验证；建立资源最优化分配模型以研究固氮细菌对全球变化的响应。最终将以上模型与模拟物理场耦合、预测本世纪全球海洋固氮速率的变化。本项目将从新的角度系统阐明海洋固氮的控制机制，提高对未来海洋固氮发展的预测能力。

中文关键词： 海洋固氮；底层向上控制；顶层向上控制；生态系统模型；资源最优化分配模型

英文摘要： Marine nitrogen fixation contributes to about half of the total bio-available nitrogen source to the global ocean. It greatly impacts marine productivity and ocean's capability of storing carbon dioxide. Thus it is important to study the controlling mechanism of marine nitrogen fixation and predict its response to the global change. Previous studies have proposed a series of hypotheses for the controls on marine nitrogen fixation mainly from the aspects of resource limitation (i.e., bottom-up control), which, however, are not strongly confirmed by the observational data on the global scale. We hypothesize that grazing from zooplankton and viral lysis (i.e., top-down control) can also control marine nitrogen fixation; diazotrophs can response to the environmental change by means of reallocating their obtained resources. This project proposes to study both the bottom-up and top-down controlling mechanisms based on data synthesis. Ecosystem model will be constructed to study the synthetic effects of different controlling factors on marine nitrogen fixation, and optimal resource allocation model will also be constructed to study the response of nitrogen fixation to the global change.The models will be valided by in situ sampling and laboratory experiments. These models will be further coupled to simulated physical fields to predict the change of the marine nitrogen fixation rate during this century. This project will explain the controlling mechanisms of marine nitrogen fixation from new aspects, and improve our ability to predict the evolving marine nitrogen fixation in the future ocean.

英文关键词： Marine Nitrogen Fixation;Bottom-up Control;Top-down Control;Ecosystem Model;Optimal Resource Allocation Model