Warming effect in a multiple stressor context: role of thermal variability and resource supply shaping phytoplankton communities’ responses to environmental change

多重压力背景下的变暖效应：热变化和资源供应的作用影响浮游植物群落对环境变化的反应

• 批准号: 465193586
• 负责人: Dr. Miriam Gerhard
• 金额: --
• 依托单位: Departamento de Ecología y Gestión Ambiental
• 依托单位国家: 德国
• 项目类别: WBP Fellowship
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465193586?language=en
• 关键词: Warming; effect; multiple; stressor; context

Freshwater ecosystems provide critical ecosystem services but are threatened by human activities causing modifications in, for example, temperature and nutrients. Changes in mean and variance (i.e. fluctuations) of these factors affect primary producers’ performance. In phytoplankton, responses to temperature are mediated by the nutrient context, and unfavourable nutrient conditions can restrict thermal tolerance or responses to temperature fluctuations. Novel environmental conditions might also interact with community composition according to species-specific traits and biotic interactions shifting the community structure. Since these changes in phytoplankton function and structure are crucial for the maintenance of ecosystem processes and services, as phytoplankton is responsible for almost half of Earth’s primary productivity, it is relevant to understand how phytoplankton communities respond to multiple environmental stressors. Current studies focus mostly on simplified evaluations by either considering changes in temperature mean and variability separately, considering one nutrient concentration but not the balance between multiple nutrients, or are mostly based on single species omitting community interactions. The general aim of this project is to evaluate freshwater natural communities’ responses to expected changes in temperature, considering interactions with local factors, i.e. the nutrient context and thermal history. For that, controlled experiments will be conducted manipulating temperature mean and variance, as well as nutrient availability (concentrations and ratios) using natural phytoplankton communities from different climatic regions, which has not been previously addressed for freshwater systems. This proposal will allow for testing responses to environmental change and the generation of new theoretical concepts for describing and understanding complex processes in natural ecosystems.

淡水生态系统提供关键的生态系统服务，但受到人类活动的威胁，人类活动造成温度和养分等方面的变化。这些因素的均值和方差(即波动)的变化影响初级生产者的业绩。在浮游植物中，对温度的反应是由营养环境调节的，不利的营养条件会限制热耐性或对温度波动的反应。新的环境条件也可能根据物种特有的特征与群落组成相互作用，以及生物相互作用改变群落结构。由于浮游植物功能和结构的这些变化对于维持生态系统过程和服务至关重要，因为浮游植物几乎占地球初级生产力的一半，因此了解浮游植物群落如何应对多种环境压力具有重要意义。目前的研究大多集中在简化评价上，要么分别考虑平均温度和变率的变化，要么只考虑一种营养物质的浓度而不考虑多种营养物质之间的平衡，或者大多基于单一物种而忽略群落相互作用。该项目的总体目标是评估淡水自然群落对预期温度变化的反应，考虑与当地因素的相互作用，即营养背景和热史。为此，将利用来自不同气候区域的自然浮游植物群落进行控制实验，控制温度均值和方差，以及养分可获得性(浓度和比率)，这是以前在淡水系统中没有涉及到的。这一提议将允许测试对环境变化的反应，并产生新的理论概念，以描述和理解自然生态系统中的复杂过程。