Effect of light, CO2 and nutrient limitation on photosynthesis in marine diazotrophic cyanobacteria.

光、二氧化碳和养分限制对海洋固氮蓝藻光合作用的影响。

• 批准号: NE/F002971/1
• 负责人: Tracy Lawson
• 金额: $ 41.62万
• 依托单位: University of Essex
• 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%2FF002971%2F1
• 关键词: Effect; light; CO2; nutrient; limitation

The ocean plays a central role in the global carbon cycle. Uptake of carbon dioxide by the oceans has reduced the increase in atmospheric carbon dioxide that has arisen from fossil fuel burning and deforestation. It has long been know that the ocean biota play a major role in sequestering carbon dioxide on very long time scales (>1000 years). Recent evidence also suggests that the ocean biota play an important role on shorter time scales (10-100 years) as well. The balance between phytoplankton photosynthesis and community respiration determines the ability of the oceans to take up carbon dioxide. Nitrogen is generally considered to be the nutrient that limits phytoplankton photosynthesis. But what limits the amount of N in the ocean? Unlike most phytoplankton, which are N-limited, nitrogen fixing cyanobacteria have an unlimited supply of N. This is the N2 gas that is dissolved in seawater. Nitrogen-fixing cyanobacteria play a significant role in ocean nutrient and biogeochemical cycles as they are a major source of N, providing N for up to 50% of primary productivity in the most nutrient impoverished regions of the ocean. Nitrogen fixation is a key process that modulates the ability of the oceans to sequester carbon dioxide on time scales of 10 to 10,000 years. Limitation of nitrogen fixation results in lowered N availability for other primary producers reducing the potential of oligotrophic oceans to sequester carbon. This brings us to the issue of 'What limits the amount of nitrogen fixation in the ocean?' Amongst the environmental factors that may limit nitrogen fixation are temperature, light, carbon dioxide concentration and P- or Fe-limitation. It is argued that whereas N is the proximate limiting nutrient for phytoplankton photosynthesis in the sea, the ultimate limiting nutrient is either P (or Fe) because this nutrient limits the amount of nitrogen fixation. This proposal will examine the effects of light, carbon dioxide, P-limitation and Fe-limitation on photosynthetic properties and nitrogen fixation of nitrogen-fixing cyanobacteria. Research will be conducted under defined culture conditions in two species. One of these species, Trichodesmium, is documented to be of global significance. In addition, nitrogen fixation by unicellular cyanobacteria has recently been recognized to be significant. Therefore, the second species is one of these unicellular nitrogen fixers, Crocosphaera. The outcomes of this study will provide new insights into the mechanisms by which phosphorous and iron limit photosynthesis and nitrogen fixation in cyanobacteria. It will also provide new insights into the interaction with environmental factors such as light and carbon dioxide. This research will ultimately assist with several aspects of oceanographic studies on nutrient cycling and modeling the future importance of the oceans as C sinks.

海洋在全球碳循环中发挥着核心作用。海洋对二氧化碳的吸收减少了因化石燃料燃烧和森林砍伐而导致的大气二氧化碳的增加。人们早就知道，海洋生物群在很长的时间尺度（>1000 年）内封存二氧化碳方面发挥着重要作用。最近的证据还表明，海洋生物群在较短的时间尺度（10-100 年）内也发挥着重要作用。浮游植物光合作用和群落呼吸之间的平衡决定了海洋吸收二氧化碳的能力。氮通常被认为是限制浮游植物光合作用的营养物质。但是什么限制了海洋中氮的含量呢？与大多数氮受限的浮游植物不同，固氮蓝藻的氮供应无限。这是溶解在海水中的氮气。固氮蓝藻在海洋养分和生物地球化学循环中发挥着重要作用，因为它们是氮的主要来源，为海洋营养最贫乏地区高达 50% 的初级生产力提供氮。固氮是调节海洋在 10 至 10,000 年时间尺度上封存二氧化碳的能力的关键过程。固氮的限制导致其他初级生产者的氮利用率降低，从而降低了寡营养海洋固碳的潜力。这给我们带来了“什么限制了海洋固氮量？”的问题。可能限制固氮的环境因素包括温度、光照、二氧化碳浓度以及磷或铁的限制。有人认为，虽然氮是海洋中浮游植物光合作用的最直接限制养分，但最终限制养分是磷（或铁），因为这种养分限制了固氮量。该提案将研究光、二氧化碳、磷限制和铁限制对固氮蓝藻的光合特性和固氮的影响。研究将在两个物种的特定培养条件下进行。据记载，这些物种之一，Trichodesmium，具有全球意义。此外，单细胞蓝细菌的固氮作用最近被认为具有重要意义。因此，第二个物种是这些单细胞固氮菌之一，Crocosphaera。这项研究的结果将为磷和铁限制蓝藻光合作用和固氮的机制提供新的见解。它还将为与光和二氧化碳等环境因素的相互作用提供新的见解。这项研究最终将有助于营养循环海洋学研究的几个方面，并模拟海洋作为碳汇的未来重要性。

项目成果

A Key Marine Diazotroph in a Changing Ocean: The Interacting Effects of Temperature, CO2 and Light on the Growth of Trichodesmium erythraeum IMS101.

• DOI: 10.1371/journal.pone.0168796
• 发表时间: 2017
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Boatman TG;Lawson T;Geider RJ
• 通讯作者: Geider RJ

Heme b in marine phytoplankton and particulate material from the North Atlantic Ocean

• DOI: 10.3354/meps10367
• 发表时间: 2013-01-01
• 期刊: MARINE ECOLOGY PROGRESS SERIES
• 影响因子: 2.5
• 作者: Honey, David J.;Gledhill, Martha;Achterberg, Eric P.
• 通讯作者: Achterberg, Eric P.

Pyrenoid loss in Chlamydomonas reinhardtii causes limitations in CO2 supply, but not thylakoid operating efficiency.

• DOI: 10.1093/jxb/erx197
• 发表时间: 2017-06-01
• 期刊: Journal of experimental botany
• 影响因子: 6.9
• 作者: Caspari OD;Meyer MT;Tolleter D;Wittkopp TM;Cunniffe NJ;Lawson T;Grossman AR;Griffiths H
• 通讯作者: Griffiths H

Direct estimation of functional PSII reaction center concentration and PSII electron flux on a volume basis: a new approach to the analysis of Fast Repetition Rate fluorometry (FRRf) data

• DOI: 10.4319/lom.2012.10.142
• 发表时间: 2012-03-01
• 期刊: LIMNOLOGY AND OCEANOGRAPHY-METHODS
• 影响因子: 2.7
• 作者: Oxborough, Kevin;Moore, C. Mark;Geider, Richard J.
• 通讯作者: Geider, Richard J.

The trade-off between the light-harvesting and photoprotective functions of fucoxanthin-chlorophyll proteins dominates light acclimation in Emiliania huxleyi (clone CCMP 1516).

岩藻黄质-叶绿素蛋白的光捕获和光保护功能之间的权衡主导着艾米利亚赫胥黎（克隆 CCMP 1516）的光适应。

• DOI: 10.1111/nph.12373
• 发表时间: 2013
• 期刊: The New phytologist
• 作者: McKew BA