Metal composition of marine cyanobacteria - an indicator of niche adaptation and cell physiological state?

海洋蓝藻的金属成分 - 生态位适应和细胞生理状态的指标？

• 批准号: NE/F003889/1
• 负责人: Mikhail Zubkov
• 金额: $ 4.79万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF003889%2F1
• 关键词: Metal; composition; marine; cyanobacteria; indicator

The oceans play a major role in determining the world's climate. In part this is due to the production of oxygen and the consumption of carbon dioxide by very small, single celled organisms, which are referred to as the photosynthetic picoplankton. Marine cyanobacteria of the closely-related genera Prochlorococcus and Synechococcus are the prokaryotic components of the photosynthetic picoplankton. Current and previous work in my lab has demonstrated that the in situ community structure of these organisms is fairly complex, with specific ecotypes or lineages occupying different niches to populate the world's oceans, allowing them to grow and photosynthesise under a broad range of environmental conditions. Whilst such molecular ecological studies can effectively map the spatial distributions of specific genotypes, the factors that dictate this global community structure are still poorly defined. This is important because changes in dominant picocyanobacterial lineages indicate major domain shifts in planktonic ecosystems and by observing and interpreting their distributions and physiological states we are essentially assessing changes in the rates of biogeochemical cycles. Athough the role of macronutrients, particularly N and P has received previous attention still there is a relative dearth of data on factors controlling picocyanobacterial community composition. Certainly, little if anything is known of the role of trace metals in this process. Thus, we hypothesise that in oceanic ecosystems genetically distinct picocyanobacteria are restricted to specific niches by their ability to acquire (limitation) or regulate trace metal accumulation (toxicity). In order to address this topic we propose to investigate trace metal (and macroelement) cell quotas in i) representatives of specific marine Prochlorococcus and Synechococcus lineages and to assess the affect of light stress and macronutrient shifts on these quotas and ii) in natural picophytoplankton assemblages using prior flow cytometric sorting, ICP-MS and X-ray microanalysis techniques. In so doing we will also obtain, for the first time, a real indication of picocyanobacterial cell physiological state over large spatial scales / in effect using elemental quotas as a proxy for what environment a given cell/population of cells is experiencing in situ / and hence can realistically begin to determine those macro and trace elements that are potentially depleted in situ and which are potentially restricting growth rate and/or yield.

海洋在决定世界气候方面发挥着重要作用。这部分是由于非常小的单细胞生物产生氧气和消耗二氧化碳，这些生物被称为光合微型浮游生物。海洋蓝细菌的密切相关的属原绿球藻和聚球藻是光合微型浮游生物的原核组成部分。我实验室目前和以前的工作表明，这些生物的原位群落结构相当复杂，特定的生态类型或谱系占据不同的生态位，以填充世界海洋，使它们能够在广泛的环境条件下生长和光合作用。虽然这样的分子生态学研究可以有效地绘制特定基因型的空间分布图，但决定这种全球群落结构的因素仍然很难定义。这是很重要的，因为占主导地位的picocyanobacteria谱系的变化表明主要领域的变化，在亚热带生态系统和观察和解释他们的分布和生理状态，我们基本上是评估的变化率的地球化学循环。虽然大量营养素，特别是氮和磷的作用已经得到了以前的关注仍然是一个相对缺乏的数据控制微蓝细菌群落组成的因素。当然，很少有人知道微量金属在这一过程中的作用。因此，我们假设，在海洋生态系统中，遗传上不同的picocyanobacteria被限制到特定的壁龛，他们的能力，以获得（限制）或调节微量金属的积累（毒性）。为了解决这个问题，我们建议调查微量金属（和大量元素）细胞配额在i）代表特定的海洋原绿球藻和聚球藻谱系，并评估光应力和常量营养素的变化对这些配额的影响和ii）在自然picophytoplankton组合使用之前的流式细胞仪分选，ICP-MS和X-射线微量分析技术。这样我们也将首次获得，在大的空间尺度上的微蓝细菌细胞生理状态的真实的指示/实际上使用元素配额作为给定细胞/细胞群体在原位经历的环境的代表/并且因此可以实际地开始确定那些可能在原位耗尽并且可能限制生长速率的宏量和痕量元素和/或者屈服