Fish carbonates - their nature and fate within the marine inorganic carbon cycle

鱼类碳酸盐 - 它们在海洋无机碳循环中的性质和命运

• 批准号: NE/H010041/1
• 负责人: Rod Wilson
• 金额: $ 50.54万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH010041%2F1
• 关键词: Fish; carbonates; their; nature; fate

This proposal is based on a fundamentally important and previously unexpected change to our understanding of the marine inorganic carbon cycle. It follows our recent revelation that calcium carbonates excreted by fish make a significant contribution but our current estimates vary over more than a 10-fold range (3 to 45 % of global marine carbonate). BACKGROUND: As humans burn more fossil fuels, atmospheric concentrations of the 'greenhouse gas' carbon dioxide (CO2) rise contributing to climate change. Atmospheric CO2 is in balance with CO2 dissolved in the oceans, in something referred to as the marine-atmospheric carbon cycle. Whatever happens to CO2 in the oceans, will ultimately have an effect on CO2 in the atmosphere, and hence can influence global climate. When CO2 dissolves in seawater, it forms bicarbonate ions. An important part of the marine-atmospheric carbon cycle is the reaction of this bicarbonate with seawater calcium to produce a solid precipitate of white calcium carbonate (the mineral found in limestone). These precipitates are very dense, and sink to the ocean bottom in a continuous 'rain' of white crystals. The rate at which they form and sink (or re-dissolve) is important in the marine carbon cycle. The majority of calcium carbonate is generated by marine life that promotes this reaction to make a hard protective 'shell'. The most famous organisms involved in this 'biogenic' calcification are corals. However, those thought to produce the most are actually microscopic phytoplankton called coccolithophores that live in the open ocean. Dense skeletons of these and other microscopic organisms are normally considered to be the only important source of marine carbonates. Scientists collect samples in deep ocean traps, to measure this carbonate 'rainfall' for use in computer models of the carbon cycle. We have recently discovered that marine fish also produce substantial amounts of precipitated calcium carbonate, but for a very different purpose. They produce it in their intestines, by drinking large volumes of seawater and actively promoting the reaction of seawater calcium with bicarbonate ions that are produced by their own metabolism. Fish then excrete the precipitated calcium carbonate into the surrounding seawater, where it probably mixes with all the better known (planktonic) sources. In fact, some tropical fish will excrete calcium carbonate equivalent to its own dry body weight every year! We have conservatively estimated that the contribution of fish may be up to 45% of the total global carbonate production. This novel discovery suggests that fish also contribute to the marine carbon cycle, but scientists who model this cycle have never previously taken this into account. Indeed, the unusual chemistry of fish carbonates (which are more soluble than carbonate from more traditional sources), may explain a phenomenon that has puzzled oceanographers for decades - the rapid dissolution of 'apparently insoluble' carbonates in the upper layers of the ocean. Our research is a multi-disciplinary project that for the first time aims to precisely model how much calcium carbonate is produced by marine fish under different environmental conditions and determine its fate within in our oceans. This will also help with predictions about how carbonate excretion by marine fish will be affected by future environmental changes, such as temperature and CO2. We predict that fish will become even more important in this regard in the future, whereas marine plankton will become less important. Thus a precise understanding of this fish contribution to the global marine carbon cycle is both a novel and environmentally important topic.

该提案基于我们对海洋无机碳周期的理解的根本重要且以前出乎意料的变化。这是我们最近的启示，即鱼排出的钙碳酸钙做出了重大贡献，但我们目前的估计量在超过10倍以上（占全球碳酸盐海洋碳酸盐的3％至45％）方面有所不同。背景：当人类燃烧更多的化石燃料时，“温室气”二氧化碳（CO2）的大气浓度有助于气候变化。大气中的二氧化碳与溶解在海洋中的二氧化碳是平衡的，这被称为海洋 - 大气碳循环。无论海洋中的二氧化碳发生什么，最终都会对大气中的二氧化碳产生影响，从而影响全球气候。当二氧化碳溶解在海水中时，它会形成碳酸氢盐离子。海洋 - 大气碳循环的重要部分是该碳酸氢盐与海水钙的反应，以产生碳酸盐白色钙的固体沉淀物（在石灰石中发现的矿物质）。这些沉淀物非常密集，并在白色晶体的连续“雨”中沉入海底。它们形成和下沉（或重新分解）在海洋碳循环中很重要。碳酸钙的大多数是由海洋生物产生的，该海洋生物促进了这种反应，以制造坚硬的“壳”。这种“生物”钙化涉及的最著名的生物是珊瑚。然而，人们认为产生最多的人实际上是微小的浮游植物，称为居住在开阔的海洋中。这些和其他微观生物的密集骨骼通常被认为是海洋碳酸盐的唯一重要来源。科学家在深海陷阱中收集样品，以测量此碳酸盐“降雨”，以用于碳循环的计算机模型。我们最近发现，海洋鱼类还产生了大量沉淀的碳酸钙，但目的是完全不同的。他们通过喝大量的海水在肠道中产生它，并积极促进海水钙与碳酸氢盐离子的反应，这些碳酸盐离子由自己的代谢产生。然后，鱼将沉淀的碳酸钙排泄到周围的海水中，在那里它可能与所有众所周知的（浮游生物）来源混合在一起。实际上，某些热带鱼会排出碳酸钙，相当于每年其自身的干燥体重！我们保守地估计，鱼的贡献可能是全球碳酸盐总产量的45％。这个小说的发现表明，鱼也有助于海洋碳循环，但是对该周期进行建模的科学家从未考虑过。实际上，鱼碳酸盐的异常化学（比碳酸盐更可溶，来自更传统的来源），可能解释了一种使海洋学家困惑数十年来的现象 - 在海洋上层中，“看似不溶性”的碳酸盐的快速溶解。我们的研究是一个多学科的项目，该项目首次旨在精确地模拟海洋鱼类在不同环境条件下生产的碳酸钙，并确定其在我们海洋中的命运。这也将有助于预测海洋鱼类碳酸盐排泄将如何受到未来环境变化（例如温度和二氧化碳）的影响。我们预测，将来的鱼类将在这方面变得更加重要，而海洋浮游生物将变得不那么重要。因此，对这种鱼类对全球海洋碳循环的贡献的精确理解既是新颖且对环境重要的话题。

项目成果

Animating the Carbon Cycle

碳循环动画

• DOI: 10.1007/s10021-013-9715-7
• 发表时间: 2013
• 期刊: Ecosystems
• 影响因子: 3.7
• 作者: Schmitz O

Marine reserves can mitigate and promote adaptation to climate change

• DOI: 10.1073/pnas.1701262114
• 发表时间: 2017-06
• 期刊: Proceedings of the National Academy of Sciences
• 作者: C. Roberts;Bethan C. O’Leary;D. McCauley;P. Cury;C. Duarte;J. Lubchenco;D. Pauly;A. Saenz-Arroyo;U. R. Sumaila;R. Wilson;B. Worm;J. Castilla

Osmoregulatory bicarbonate secretion exploits H(+)-sensitive haemoglobins to autoregulate intestinal O2 delivery in euryhaline teleosts.

• DOI: 10.1007/s00360-014-0844-x
• 发表时间: 2014-10
• 期刊: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology
• 作者: Cooper CA;Regan MD;Brauner CJ;De Bastos ES;Wilson RW
• 通讯作者: Wilson RW

Temperature, species identity and morphological traits predict carbonate excretion and mineralogy in tropical reef fishes.

• DOI: 10.1038/s41467-023-36617-7
• 发表时间: 2023-02-22
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Ghilardi, Mattia;Salter, Michael A.;Parravicini, Valeriano;Ferse, Sebastian C. A.;Rixen, Tim;Wild, Christian;Birkicht, Matthias;Perry, Chris T.;Berry, Alex;Wilson, Rod W.;Mouillot, David;Bejarano, Sonia
• 通讯作者: Bejarano, Sonia

Body mass and cell size shape the tolerance of fishes to low oxygen in a temperature-dependent manner.

• DOI: 10.1111/gcb.16319
• 发表时间: 2022-10
• 期刊: Global change biology
• 影响因子: 11.6