Collaborative Research: Dissolved organic phosphorus controls on marine nitrogen fixation and export production

合作研究：溶解有机磷对海洋固氮和出口生产的控制

• 批准号: 1829797
• 负责人: Angela Knapp
• 金额: $ 34.27万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1829797&HistoricalAwards=false
• 关键词: Collaborative; Research; Dissolved; organic; phosphorus

Phytoplankton play an important role in the Earth's elemental cycles of carbon and nitrogen. In addition to sunlight, phytoplankton living in the surface waters of the oceans require the elements nitrogen and phosphorus for growth. Much of these nutrients are supplied in their inorganic forms from mixing of deep waters towards the surface during the winter months when vertical stability of the water column breaks down. However much of the low latitude oceans, 45degS45degN, suffer from limited nutrient input to sunlit surface waters due to strong thermal stratification (vertical stability) of the upper water column. As a consequence, tropical and subtropical phytoplankton have devised alternative ways of acquiring nitrogen and phosphorus. Marine nitrogen fixation is a process by which specialized microbes utilize the abundant nitrogen gas from the atmosphere to convert elemental nitrogen into the bioavailable form ammonia. These nitrogen fixing phytoplankton and many others also use organic forms of phosphorus in the low latitude ocean where inorganic nutrients are often scarce. This project will significantly increase the number of dissolved organic nitrogen and dissolved organic phosphorus concentration measurements, especially from the currently under-sampled Pacific and Indian Oceans. Changes in the concentration of organic nutrients across the surface ocean will be used to infer rates of organic nutrient use by phytoplankton in numerical models. Specifically, the role for the biological uptake of dissolved organic phosphorus to stimulate the processes of marine nitrogen fixation and photosynthesis in the low latitude ocean will be quantified from the combined data and model output. The project will train one graduate student and several undergraduate students in both laboratory chemical analysis techniques and numerical simulation of ocean biological and chemical processes. New scientific knowledge will be shared with the public via a social media campaign and will inform the development of the next generation of global climate models. The marine biogeochemical modeling community has identified the lack of dissolved organic nitrogen (DON) and especially dissolved organic phosphorus (DOP) concentration measurements from the upper 300 m of the global ocean as crucial gaps in our ability to accurately model export production and N2 fixation rates in the subtropics. The proposed work will significantly increase global data coverage of marine DON and DOP concentration measurements, in particular from under-sampled ocean regions in the Indian Ocean, western, central, and eastern tropical South Pacific, Gulf of Alaska, eastern subtropical and subpolar South Pacific, Southern Ocean, subtropical North Atlantic, and tropical South Atlantic Ocean basins. These new measurements will be assimilated in state-of-the-art biogeochemical models to constrain the relative cycling rates of DOP and DON and to quantify the role of preferential DOP consumption as a P source supporting export production and N2 fixation in the low latitude ocean. Model output will solve for the regionally-resolved fraction of new production that accumulates as DON and DOP, autotrophic DOP uptake rates, as well as the remineralization rates for DON and DOP. The model output will also include the first regionally variable rate estimates of euphotic zone DOP consumption sustaining export production and N2 fixation to be constrained by observations from the Pacific and Indian Oceans. Thus, the new concentration measurements and diagnostic modeling will allow us to evaluate the quantitative role for regional variability in DOP consumption and recycling that supports export production and N2 fixation in the low latitude ocean.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

浮游植物在碳和氮的元素周期中起着重要作用。除了阳光外，生活在海洋地表水域中的浮游植物需要氮和磷元素才能生长。这些营养素中的大部分都是无机形式提供的，从冬季水柱的垂直稳定性分解的冬季，深水向表面的混合。然而，由于上水柱的强热分层（垂直稳定性），大部分低纬度海洋，45degs45degn，养分有限的养分输入有限。结果，热带和亚热带浮游植物已经设计了获得氮和磷的替代方法。海洋氮固定是一个过程，专门的微生物利用大气中的丰富氮气将元素氮转化为可生物利用形式的氨。这些固定浮游植物的氮和许多其他氮在低纬度海洋中也使用有机形式的磷通常很少。该项目将显着增加溶解的有机氮和溶解有机磷浓度测量的数量，尤其是从目前采样不足的太平洋和印度洋。整个地表海洋中有机营养素浓度的变化将用于推断浮游植物在数值模型中使用有机养分的速率。具体而言，将从合并的数据和模型输出中量化溶解有机磷的生物学摄取在刺激海洋氮固定过程和光合作用过程中的作用。该项目将在实验室化学分析技术和海洋生物学和化学过程的数值模拟中培训一名研究生和几名本科生。新的科学知识将通过社交媒体运动与公众共享，并将告知下一代全球气候模型的发展。海洋生物地球化学建模界已经确定缺乏溶解的有机氮（DON），尤其是从全球海洋上部300 m的溶解有机磷（DOP）浓度测量中，这是我们准确地模型的差距。拟议的工作将大大增加海洋DON和DOP浓度测量的全球数据覆盖率，特别是来自印度洋，西部，中部和热带南太平洋，阿拉斯加墨西哥湾，东部亚热带和亚极性南太平洋，南太平洋，南部，南部海洋，北部大西洋和热带南部大洋洲的南太平洋，南太平洋，南太平洋，南太平洋，南太平洋，南太平洋和亚极性的南太平洋，南太平洋，南太平洋，南太平洋，南部太平洋，南太平洋，南部和南部的南太平洋地区。这些新的测量结果将在最先进的生物地球化学模型中吸收，以限制DOP和DON的相对循环速率，并量化优先DOP消耗的作用，作为P源支持出口生产和N2固定在低纬度海洋中的P源。模型输出将解决新生产的区域分辨要素，这些分数积累了DON和DOP，自养DOP摄取速率以及DON和DOP的再矿化速率。该模型输出还将包括维持出口产生的急诊区DOP消耗的第一个区域可变率估计值，而N2固定将受到太平洋和印度洋观察的约束。因此，新的集中度测量和诊断建模将使我们能够评估区域变异性在DOP消费和回收中的定量作用，这些作用支持低纬度海洋中的出口生产和N2固定。该奖项反映了NSF的法定任务，并认为通过基金会的知识优点和广泛的crietia crietia criperia criperia criperia criperia criperia criperia criperia criperia rection the Apportiation均值得通过评估。

项目成果

Geochemical signatures of nitrogen fixation in the western subtropical South Pacific: d15N budgets and low-d15N DON

南太平洋西副热带固氮的地球化学特征：d15N预算和低d15N DON

• 发表时间: 2022
• 期刊: 2022 Ocean Sciences Meeting
• 作者: Forrer, H.;Bonnet, S.;Thomas, R.;Grosso, O.;Guieu, C.;Knapp, A.N.
• 通讯作者: Knapp, A.N.

Natural iron fertilization by shallow hydrothermal sources fuels diazotroph blooms in the ocean

浅层热液源的天然铁施肥助长了海洋中的固氮菌水华

• DOI: 10.1126/science.abq4654
• 发表时间: 2023
• 期刊: Science
• 影响因子: 56.9
• 作者: Bonnet, Sophie;Guieu, Cécile;Taillandier, Vincent;Boulart, Cédric;Bouruet-Aubertot, Pascale;Gazeau, Frédéric;Scalabrin, Carla;Bressac, Matthieu;Knapp, Angela N.;Cuypers, Yannis
• 通讯作者: Cuypers, Yannis

Dissolved organic phosphorus (DOP) distributions in the Eastern Indian Ocean and subtropical South Pacific Ocean

东印度洋和副热带南太平洋溶解有机磷（DOP）分布

• 发表时间: 2020
• 期刊: 2020 Ocean Sciences Meeting
• 作者: Liang, Z.;Letscher, R.T.;McCabe, K.;Marconi, D.;Sigman, D.M.;Knapp, A.N.
• 通讯作者: Knapp, A.N.

Global Patterns of Surface Ocean Dissolved Organic Matter Stoichiometry

• DOI: 10.1029/2023gb007788
• 发表时间: 2023-11
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Zhou Liang;R. Letscher;A. Knapp

Dissolved organic phosphorus concentrations in the surface ocean controlled by both phosphate and iron stress

• DOI: 10.1038/s41561-022-00988-1
• 发表时间: 2022-07-21
• 期刊: NATURE GEOSCIENCE
• 影响因子: 18.3
• 作者: Liang, Zhou;Letscher, Robert T.;Knapp, Angela N.
• 通讯作者: Knapp, Angela N.