The impact of Mid-Ocean Ridges on the Ocean's Iron cycle

大洋中脊对海洋铁循环的影响

基本信息

批准号：
NE/N009525/1
负责人：
Alessandro Tagliabue
金额：
$ 30.14万
依托单位：
University of Liverpool
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FN009525%2F1
关键词：
impact Mid Ocean Ridges Iron

项目摘要

Photosynthesis by marine phytoplankton provides energy to higher trophic levels (such as fish and marine mammals), as well as contributing to the partitioning of carbon dioxide between the atmosphere and the ocean. Iron is essential for phytoplankton growth as it is required for a number of important enzymes that participate in both photosynthesis and respiration. In contrast with terrestrial systems, iron is present at very low concentrations (less than 1 iron atom to every billion water molecules) in the open ocean. Thus phytoplankton photosynthesis is limited by iron over large parts of the ocean. This iron deficiency has important ramifications for the earth system since phytoplankton photosynthesis is an important means by which the ocean regulates global climate. Mid-ocean ridges are an important source of iron with estimates suggesting that ridge-derived iron makes up 25-75% of global ocean iron stocks. These mid-ocean ridges are the deep-sea mountain ranges that form a single global mid-ocean ridge system throughout the world's ocean, making it the longest mountain range in the world. At these ridges, new magma mixes with seawater and is exhaled as a high temperature fluid. While this ridge fluid has been noted to be a large source of iron to the deep-sea, the far field influence of this iron depends on its retention in dissolved forms by ocean chemistry. Our recent work shows that iron from mid-ocean ridges appears to have a much longer lifetime than previously thought and be exported up to 4000km away from the ridge. Despite the emerging role for ridge-derived iron, we do not understand its impact on deep ocean iron stocks, as well as how iron is mixed into surface waters to drive biological activity. We have highlighted that understanding the fate of ridge-derived iron and its ultimate influence on the ocean requires more information on the quantity and chemical form of iron supplied by ridges (e.g. dissolved or particles) and how these change with distance from source. To do this we need to appraise the role of small organic molecules called ligands and so-called iron nanoparticles, which have been invoked to control the lifetime of ridge-derived iron. Accounting for the specificity of iron within hydrothermal systems is key to constraining its wider impact. In addition, recent work by our colleagues has shown that interactions between the deep ocean tide and the ridge itself can elevate rates of physical mixing. If increased vertical mixing typifies mid-ocean ridges it implies that these regions may also exhibit efficient transfer of iron to surface waters. Given the ubiquity of mid-ocean ridges, the synergistic combination of these phenomena may be key to the large-scale supply of iron to surface waters.Sampling and measurement of iron at very low concentrations in seawater is challenging and the applicants are among the few research groups in the world who are able to do this reliably. Our group is at the forefront of representing the role of iron is global ocean models, which are crucial tools for assessing larger scale impacts on biological productivity. This project will participate in a NERC funded research cruise where scientists with expertise in measuring mixing and other macronutrients will be studying the nutrient and carbon pump over mid-ocean ridges. This proposal will therefore benefit from these measurements and will add value to this cruise by determining the associated role for iron.Overall, this project will provide state of the art observational and modelling constraints on two important aspects of the ocean iron cycle: 1) How does the ocean ridge impact physical mixing of iron to the surface and 2) what chemical processes control the large scale influence of the iron directly supplied by mid-ocean ridges. Ultimately we will be able to address the broader question of how the amount and chemical form of iron from mid-ocean ridges can influence phytoplankton growth in the open ocean.

海洋浮游植物的光合作用为较高的营养水平（例如鱼类和海洋哺乳动物）提供了能量，并为大气和海洋之间二氧化碳的分配提供了贡献。铁对于浮游植物的生长至关重要，因为这是参与光合作用和呼吸的许多重要酶所必需的。与陆生系统相反，在开阔的海洋中，铁的浓度非常低（每十亿水分子）。因此，浮游植物光合作用受到海洋大部分地区的铁的限制。由于浮游植物光合作用是海洋调节全球气候的重要手段，因此这种铁缺乏对地球系统具有重要的影响。海脊是铁的重要来源，估计表明山脊衍生的铁占全球海洋铁库存的25-75％。这些海洋中部山脊是深海的山脉，在世界海洋中构成了一个全球中大海山脊系统，使其成为世界上最长的山脉。在这些山脊上，新的岩浆与海水混合，并作为高温流体呼出。虽然已经发现这种脊液是深海的大铁来源，但该铁的远场影响取决于其通过海洋化学以溶解形式的保留。我们最近的工作表明，来自海洋山脊的铁似乎比以前想象的要长得多，并且距离山脊高达4000公里。尽管山脊衍生的铁发挥了新作用，但我们不理解其对深海铁库存的影响，以及如何将铁混合到地表水中以驱动生物学活性。我们强调，了解山脊来源的铁的命运及其对海洋的最终影响需要更多有关脊（例如溶解或颗粒）的铁的数量和化学形式的信息，以及这些形式如何随距离距离的距离而变化。为此，我们需要评估称为配体和所谓的铁纳米颗粒的小有机分子的作用，这些有机分子已被调用以控制山脊衍生的铁的寿命。考虑水热系统中铁的特异性是限制其更广泛影响的关键。此外，我们的同事最近的工作表明，深海潮与山脊本身之间的相互作用可以提高物理混合的速度。如果增加的垂直混合典型的中山脊则表示这些区域也可能表现出铁的有效转移到地表水域。鉴于中山脊的普遍存在，这些现象的协同组合可能是向地表水供应大规模的铁的关键。在海水中，铁的采样和测量很低，申请人是世界上少数能够做到这一可靠性的研究组中的申请人。我们的小组处于代表铁的作用的最前沿，是全球海洋模型，这是评估对生物生产力的较大影响的关键工具。该项目将参加由NERC资助的研究巡游，其中具有测量混合和其他大量营养素的专业知识的科学家将在中山脊上研究营养和碳泵。因此，该提案将从这些测量中受益，并通过确定铁的相关作用来增加该巡航的价值。事后，该项目将对海洋铁循环的两个重要方面的两个重要方面提供最先进的观测和建模约束：1）海洋岭如何影响铁对表面的物理混合以及2）化学过程的范围内的较大尺度影响了中等地位的ridgets ridgets ride ridgets ride ridgets ride ridges。最终，我们将能够解决更广泛的问题，即中山脊中的铁的数量和化学形式如何影响开阔的浮游植物的生长。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Variability in iron (II) oxidation kinetics across diverse hydrothermal sites on the northern Mid Atlantic Ridge

DOI：
10.1016/j.gca.2021.01.013
发表时间：
2021-02-04
期刊：
GEOCHIMICA ET COSMOCHIMICA ACTA
影响因子：
5
作者：
Gonzalez-Santana, David;Gonzalez-Davila, Melchor;Santana-Casiano, J. Magdalena
通讯作者：
Santana-Casiano, J. Magdalena

The unaccounted dissolved iron (II) sink: Insights from dFe(II) concentrations in the deep Atlantic Ocean.

未解释的溶解铁 (II) 沉降：来自大西洋深海 dFe(II) 浓度的见解。

DOI：
10.1016/j.scitotenv.2022.161179
发表时间：
2023
期刊：
The Science of the total environment
影响因子：
0
作者：
González-Santana D
通讯作者：
González-Santana D

Mechanisms Driving the Dispersal of Hydrothermal Iron From the Northern Mid Atlantic Ridge

驱动北大西洋中脊热液铁扩散的机制

DOI：
10.1029/2022gl100615
发表时间：
2022
期刊：
Geophysical Research Letters
影响因子：
5.2
作者：
Tagliabue, Alessandro;Lough, Alastair J. M.;Vic, Clément;Roussenov, Vassil;Gula, Jonathan;Lohan, Maeve C.;Resing, Joseph A.;Williams, Richard G.
通讯作者：
Williams, Richard G.

Constraining the Contribution of Hydrothermal Iron to Southern Ocean Export Production Using Deep Ocean Iron Observations

利用深海铁观测限制热液铁对南大洋出口生产的贡献