Collaborative Research: Coupled Ocean-Atmosphere Recycling of Refractory Dissolved Organic Carbon in Seawater

合作研究：海水中难熔溶解有机碳的海洋-大气耦合回收

• 批准号: 1536605
• 负责人: David Kieber
• 金额: $ 23.68万
• 依托单位: SUNY College of Environmental Science and Forestry
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536605&HistoricalAwards=false
• 关键词: Collaborative; Research; Coupled; Ocean; Atmosphere

The oceans hold a massive quantity of organic carbon that is greater than all terrestrial organic carbon biomass combined. Nearly all marine organic carbon is dissolved and more than 95% is refractory, and cycled through the oceans several times before complete removal. Refractory dissolved organic carbon (RDOC) concentrations are uniform with depth in the water column and represent the "background" carbon present throughout the oceans. However, very little is known regarding RDOC production and removal processes. One potential removal pathway is through adsorption of RDOC onto surfaces of rising bubbles produced by breaking waves and ejection via bubble bursting into the atmosphere. Building on prior research, the investigators will evaluate the importance of ocean- atmosphere processing in recycling marine RDOC during a research cruise in the northwestern Atlantic Ocean. Results of the research will provide important insights regarding the coupled ocean-atmosphere loss of RDOC, thereby improving understanding of and ability to predict the role of RDOC in oceanic and atmospheric biogeochemistry, the global carbon cycle, and Earth's climate. The research will involve three early career faculty, and will provide training for undergraduate and graduate researchers.Recent results based on a limited set of observations indicate that the organic matter (OM) associated with primary marine aerosol (PMA) produced by bursting bubbles from breaking waves at the sea surface is comprised partly to wholly of RDOC rather than OM of recent biological origin as has been widely assumed. The injection of RDOC into the atmosphere in association with PMA and its subsequent photochemical oxidation is a potentially important and hitherto unrecognized sink for RDOC in the oceans of sufficient magnitude to close the marine carbon budget and help resolve a long-standing conundrum regarding removal mechanisms for marine RDOC. This project will involve a shipboard investigation and modeling study to (1) quantify the relative contributions of marine refractory dissolved organic carbon (RDOC) to primary marine aerosol organic matter (PMA OM) produced from near-surface seawater in biologically productive and oligotrophic regions and from North Atlantic Deep Water, and to (2) determine the importance of atmospheric photochemical processing as a recycling pathway for RDOC. To test these hypotheses, a high-capacity aerosol generator will be deployed at four hydrographic stations in the NW Atlantic Ocean to characterize (1) the natural abundance of 14C in PMA and in surface and deep seawater; (2) the surface tension and physical properties of bubble plumes; (3) size-resolved production fluxes, chemical composition, organic carbon enrichments, spectral absorbance, and photochemical evolution of PMA; and (4) the carbon content, optical properties, and physical properties of seawater. The importance of RDOC recycling via PMA production and photochemical evolution will be interpreted with model calculations.

海洋拥有大量的有机碳，该有机碳大于所有陆生有机碳生物量合并。几乎所有海洋有机碳都溶解，超过95％是难治性的，在完全去除之前，几次循环在海洋中。难治性溶解有机碳（RDOC）浓度在水柱中均匀，深度为整个海洋中存在的“背景”碳。但是，关于RDOC的生产和去除过程，知之甚少。一个潜在的去除途径是通过将RDOC吸附到通过破裂波和通过气泡突然进入大气而产生的上升气泡的表面上。在先前的研究的基础上，研究人员将评估海洋大气加工在西北大西洋的研究巡游中回收海洋RDOC的重要性。研究结果将提供有关RDOC的海洋 - 大气损失的重要见解，从而提高对RDOC在海洋和大气生物地球化学，全球碳循环和地球气候中的作用的理解和能力。这项研究将涉及三个早期的职业教师，并将为本科和研究生研究人员提供培训。基于有限的观察结果，结果表明，与原代海洋气溶胶（PMA）相关的有机物质（OM）是由于海面破裂波爆裂而产生的爆炸气泡所产生的，而与最近的rdoc构成了OMODICS，而不是OM的OM构成了OMODIDIOD，而不是OM的。将RDOC注入与PMA相关的大气中，其随后的光化学氧化是一种潜在的重要，迄今为止，对于RDOC而言，RDOC在足够大量的海洋中尚未认可，以关闭海洋碳预算，并有助于解决有关海洋RDOC的清除型混合物。该项目将涉及船上的调查和建模研究，以（1）量化海洋耐火性溶解有机碳（RDOC）对从生物学生产性和寡素的杂物型中的近表面海水产生的原发性海洋气雾有机物（PMA OM）的相对贡献，并从东北大西洋的深水和Recigentions condiencation（2）确定了（2）的重要性（2）对于RDOC。为了检验这些假设，将在西北大西洋的四个水文站部署高容量的气溶胶发生器，以表征（1）PMA，地表和深海水中14C的自然丰度； （2）气泡羽的表面张力和物理特性； （3）尺寸分辨的生产通量，化学成分，有机碳富集，光谱吸光度和PMA的光化学演化； （4）海水的碳含量，光学特性和物理特性。通过模型计算，将通过PMA生产和光化学演化来解释RDOC回收的重要性。