Constraining the microbial carbon pump by characterising the chemical composition and functionality of autochthonous dissolved organic matter

通过表征本地溶解有机物的化学成分和功能来约束微生物碳泵

• 批准号: NE/M018806/2
• 负责人: Claire Evans
• 金额: $ 12.93万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FM018806%2F2
• 关键词: Constraining; microbial; carbon; pump; characterising

The oceans contain a massive amount of carbon (hundreds of times as much as the atmosphere) which, because it is not in the atmosphere, can't contribute to trapping heat inside the Earth system via the greenhouse effect. Therefore, we want to understand how big this pool is, what makes it and whether it is getting bigger or smaller. There are several separate processes which regulate the size of this carbon store: 1) The solubility pump: Carbon dioxide from the atmosphere just dissolves into the ocean, 2) the biological carbon pump: small marine plants grow in the surface ocean, sink and then dissolve back to carbon dioxide in the deep ocean and 3) the microbial carbon pump: some of the carbon-containing matter that marine plants make during photosynthesis is so hard to break down (recalcitrant) that it just sits in the ocean for thousands of years. Of these three we know the least about the microbial carbon pump. Because the recalcitrant matter pool is so old and the flux into it is very small we have tended to concentrate on 'pumps' other than the microbial carbon pump which have larger fluxes. But the recalcitrant matter pool is actually very big, certainly big enough that if it stopped then carbon dioxide levels in the atmosphere would increase enough over time to impact our climate. So what are the chances of it changing? Well, we don't know. We do know the pool is big and ancient, on average the matter it contains is 5,000 years old, but what we don't know in detail is how it is made. For example, do small marine plants just leak a tiny amount of their cell contents into the water or do they release a bit when they get eaten? Or do viruses and pathogens in the sea infect and kill them and cause this material to be formed? Could it be that recalcitrant matter is only made when the tiny microbes abundant in the sea eat part of the plants and release unwanted molecules? The answers to these questions are important, because the oceans are likely to change and it might be, that the key process which keeps this pool topped up gets smaller. In my proposal I plan to answer the question 'how does it get made?'. I will take common species of plants and microbes from around the oceans, especially the ones that make a lot of carbon and which form signals you can see from outer space, grow them in the lab and then kill them in a variety of ways. These include starving them to death in the dark, feeding them to their predators and infecting them with pathogens; the same ways they would die in the real world. Then I will see what sort of matter they make when they die in these different ways. My research has indicated that the way they die will affect what they release into the water column. For example, if they get eaten then whatever eats them will probably take all the nutritious matter and excrete low value waste material. I will compare this to the sort of matter found at the bottom of the ocean to see which processes are making the recalcitrant pool. One complication when doing this work is that I don't know exactly which characteristic of the organic matter will be the most suitable to use for the comparison. Because of this I will use some powerful analysis techniques that allow me to characterise the chemical makeup of every single carbon-containing molecule in a massive pool made up of thousands of different chemicals. My project will tell us which processes are important in production of recalcitrant matter and which aren't. In collaboration with modelling experts this information will be used in mathematical models which help us understand how the ocean carbon cycle works. The data I generate will help to make these models more realistic and fast and hence answer the question 'what will happen to the microbial carbon pump in a changing world?'.

海洋中含有大量的碳（大气的数百倍），因为它不在大气中，因此无法通过温室效应在地球系统内部捕获热量。因此，我们想了解这个池有多大，是什么使它变得更大还是更小。有几个单独的过程调节该碳储存的大小：1）溶解度泵：来自大气中的二氧化碳只是溶解到海洋中，2）生物碳泵：小型海洋植物在地面海洋中生长，下沉，然后溶解回到深海中的碳含量：在碳中，碳含量是碳含量的，这是碳含量的：在碳中，碳含量是碳含量的，因此在碳中散发出碳含量，因此在碳中散发出碳含量，因此，在碳中，碳含量是在碳中，因此在碳中散发出碳含量，因此，马里群是在碳含量的，所以马里群是在碳含量。 （顽固的）它只是在海洋中持续了数千年。在这三个中，我们对微生物碳泵了解最少。因为顽固的物质池是如此古老，并且进入其中的通量很小，所以我们倾向于集中在具有较大通量的微生物碳泵以外的“泵”上。但是，顽固的物质池实际上很大，当然足够大，如果它停止，那么大气中的二氧化碳水平会随着时间的推移而增加，以影响我们的气候。那么它有什么变化的机会呢？好吧，我们不知道。我们确实知道游泳池又大又古老，平均而言，其中包含的事情已有5，000年的历史，但是我们不知道它是如何制作的。例如，小型海洋植物只是将一小部分的细胞含量泄漏到水中，还是在吃掉时会释放一点？还是海洋中的病毒和病原体感染并杀死它们并导致这种材料形成？只有只有在海中丰富的微生物吃一部分植物并释放不良分子时，才能做出顽固的物质？这些问题的答案很重要，因为海洋可能会发生变化，并且可能是，使该池充满的关键过程变得更小。在我的提议中，我计划回答“如何制作？”这个问题。我将从海洋周围采取常见的植物和微生物，尤其是那些制造大量碳并从外太空中看到的信号的植物和微生物，在实验室中种植它们，然后以多种方式杀死它们。这些包括在黑暗中饿死他们死了，将它们喂入捕食者并用病原体感染它们。他们在现实世界中将死的方式相同。然后，我将以这些不同的方式死亡时，他们会做什么样的事情。我的研究表明，他们死亡的方式会影响他们释放到水柱中的东西。例如，如果它们被吃掉，那么吃任何食用的东西都可能会吸收所有营养物质并排泄低价值废料。我将其与海洋底部发现的物质进行比较，以查看哪些过程使顽固池。做这项工作时的一个并发症是，我不知道有机物的哪种特征最适合使用。因此，我将使用一些强大的分析技术，使我能够表征由数千种不同化学物质组成的大量池中每个含碳分子的化学构成。我的项目将告诉我们哪些过程在生产顽固的物质中很重要，哪些过程不是。与建模专家合作，此信息将用于数学模型，这些模型有助于我们了解海洋碳循环的工作原理。我生成的数据将有助于使这些模型更加现实，更快，因此回答了一个问题：“在不断变化的世界中，微生物碳泵会发生什么？”。

项目成果

Evaluating the Sensor-Equipped Autonomous Surface Vehicle C-Worker 4 as a Tool for Identifying Coastal Ocean Acidification and Changes in Carbonate Chemistry

• DOI: 10.3390/jmse8110939
• 发表时间: 2020-11-01
• 期刊: JOURNAL OF MARINE SCIENCE AND ENGINEERING
• 影响因子: 2.9
• 作者: Cryer, Sarah;Carvalho, Filipa;Evans, Claire
• 通讯作者: Evans, Claire

Shift from Carbon Flow through the Microbial Loop to the Viral Shunt in Coastal Antarctic Waters during Austral Summer.

• DOI: 10.3390/microorganisms9020460
• 发表时间: 2021-02-23
• 期刊: Microorganisms
• 影响因子: 4.5
• 作者: Evans C;Brandsma J;Meredith MP;Thomas DN;Venables HJ;Pond DW;Brussaard CPD
• 通讯作者: Brussaard CPD

Control of Antarctic phytoplankton community composition and standing stock by light availability

通过光照控制南极浮游植物群落组成和现存量

• DOI: 10.1007/s00300-022-03094-5
• 发表时间: 2022
• 期刊: Polar Biology
• 影响因子: 1.7
• 作者: Biggs T

Overestimation of prokaryotic production by leucine incorporation-and how to avoid it

• DOI: 10.1002/lno.12032
• 发表时间: 2022-02-08
• 期刊: LIMNOLOGY AND OCEANOGRAPHY
• 影响因子: 4.5
• 作者: Giering, Sarah L. C.;Evans, Claire
• 通讯作者: Evans, Claire

Plasticity in dormancy behaviour of Calanoides acutus in Antarctic coastal waters

• DOI: 10.1093/icesjms/fsaa042
• 发表时间: 2020-09-01
• 期刊: ICES JOURNAL OF MARINE SCIENCE
• 影响因子: 3.3
• 作者: Biggs, Tristan E. G.;Brussaard, Corina P. D.;Pond, David W.
• 通讯作者: Pond, David W.