Carbon Storage in Mangrove Ecosystems via Abiotic Sulfurization

通过非生物硫化在红树林生态系统中进行碳储存

• 批准号: 2053163
• 负责人: Morgan Raven
• 金额: $ 49.76万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2053163&HistoricalAwards=false
• 关键词: Carbon; Storage; Mangrove; Ecosystems; via

Mangrove forest sediments are important hotspots of organic carbon preservation, and they have the potential to sequester substantial amounts of atmospheric CO2. Currently, however, is it not fully understood why these environments are able to bury so much organic carbon, or how they will respond to future changes in sea level, land use, and climate. This project will investigate a mechanism that may help explain this carbon burial: organic matter sulfurization, the transformation and effective ‘pickling’ of sedimentary organic matter by sulfide. Its central aim is to understand what controls the extent of sulfurization in mangrove sediments, and to estimate the contribution of organic matter sulfurization to sediment carbon storage in different parts of the environment. By providing some of the first constraints on how, when, and where organic matter sulfurization happens in mangroves, the results of this work will guide decisionmakers managing coastal watersheds and carbon stocks in the face of land use, climate and sea level change. As part of this work, four undergraduate students and one PhD student at UC Santa Barbara will gain field and research experience. And, in collaboration with local groups associated with the field site, the team will produce a season of ‘Ocean Solutions’ podcast episodes related to conservation and human impacts of Caribbean mangroves. The overarching goal of this project is to understand how microbial sulfur cycling affects organic matter preservation in vegetated coastal sediments, which have substantial leverage to impact the global carbon cycle on decadal to millennial timescales. It specifically investigates organic matter sulfurization, which can transform fresh, easily respired organic matter into recalcitrant, polymerized carbon stocks with long-term preservation potential. Although organic matter sulfurization is known to occur in mangrove sediments, the scale of its impact is essentially unknown. A pair of field expeditions will be conducted at a mangrove forest on the southwestern coast of Florida. In the first field season, geochemical profiles will be used to quantify organic matter sulfurization in sediments and its relationships with carbon storage, iron mineralogy, and the characteristics of sedimentary organic matter inputs. In the second field season, cyclic voltammetry will be used to target redox dynamics at the millimeter scale. Laboratory experiments will be conducted to test the susceptibility of various local organic matter sources to sulfurization and characterize their sulfurized forms. Throughout, the project applies a holistic approach to sedimentary organic matter by characterizing the dissolved, lipid, protein/carbohydrate, and proto-kerogen pools with isotopic and spectroscopic techniques. This work will yield a first quantitative, mechanistic framework for predicting the extent of organic matter sulfurization in coastal vegetated habitats and its likely response to changes in ecology, land use, or sea level.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.

红树林沉积物是有机碳保存的重要热点，它们有可能隔离大量的大气二氧化碳。但是，目前，目前尚不完全了解为什么这些环境能够掩埋如此多的有机碳，或者它们将如何应对未来的海平面变化，土地利用和气候。该项目将调查一种可能有助于解释这种碳埋葬的机制：硫化物的有机物硫化，硫化物有机物质的转化和有效的“腌制”。它的核心目的是了解是什么控制红树林沉积物中硫化程度的原因，并估计有机物硫化对环境不同部分中沉积物碳储存的贡献。通过在红树林中提供一些关于有机物硫化发生的方式，何时和何时发生的限制，这项工作的结果将指导决策者在面对土地使用，气候和海平面变化时管理沿海流域和碳库存。作为这项工作的一部分，加州大学圣塔芭芭拉分校的四名本科生和一名博士生将获得现场和研究经验。并且，与与现场现场相关的当地团体合作，该团队将制作一个季节的“海洋解决方案”播客剧集，与加勒比红树林的保护和人类影响有关。该项目的总体目标是了解微生物硫循环如何影响植被沿海沉积物中的有机物保护，这具有很大的杠杆作用，以影响全球碳循环对千禧年时间表的十年型。它特别研究了有机物硫化，这些硫化可以将新鲜，易于呼吸的有机物转化为具有长期保存潜力的顽固，聚合碳储备。尽管已知有机物硫化发生在红树林沉积物中，但其影响的规模本质上是未知的。将在佛罗里达州西南海岸的一座红树林森林进行两次野外探险。在第一个野外季节，地球化学曲线将用于量化沉积物中的有机物硫化及其与碳储存，铁矿学和沉积有机物输入的特征。在第二个野外季节，循环伏安法将用于以毫米尺度靶向氧化还原动力学。将进行实验室实验，以测试各种局部有机物来源硫化和表征其硫化形式的敏感性。在整个过程中，该项目通过表征具有同位素和光谱技术的溶解，脂质，蛋白质/碳水化合物和原始核池，将整体方法用于沉积有机物。这项工作将产生第一个定量的机械框架，用于预测沿海植被栖息地中有机物硫的程度，并可能对生态学，土地使用或海平面变化的反应可能反应。该奖项反映了NSF的法定任务，并被认为是通过使用基金会的知识和更广泛影响的评估来审查Criteria来通过评估来支持的。