Collaborative Research: Gas Hydrate Contribution to the Ross Sea Carbon Budget; Shallow Sediment to Water Column; Present and Future

要了解地球上的气候变化，需要对两极地区和介于两者之间的许多环境中的地球化学和地球生物循环有深刻的了解。甲烷是一个主要的焦点，因为其大量的沉积物负荷和作为温室气体的高大气热吸收。虽然北极一直是甲烷研究的主要气候变化焦点，但南极的罗斯海被认为拥有广泛的海底海洋层-沉积物界面，是地球上变暖最快的地区之一。罗斯海蕴藏着巨大的短暂碳库。需要进行新的研究，以测试罗斯海可能存在的巨大暂时性气体水合物碳储量的重要性，并对南大洋的甲烷储量进行彻底评估。最近的钻探探险证明了对罗斯海的关注是合理的，这表明罗斯海对气候波动的敏感性。广泛传播的地震证据表明，这一巨大的碳储量似乎是以天然气水合物的形式封闭的。有趣的是，最近对类似地震数据的识别表明，由于深层沉积物水合物中的碳储存，这个碳库被低估了。拟议的项目将作为改进未来海洋碳模拟和解释过去古海洋循环的基础。在该项目中，提出了在罗斯海沉积物中勘探可能广泛的天然气水合物储集层的计划，并确定气候变化是否会影响该地区。关键的地震数据证明，这一巨大的碳储量似乎以天然气水合物的形式存在。这种气候变暖和冰川融化的迹象，再加上高的生热气体水合物负荷，表明罗斯海是决定当前和未来潜在的甲烷、石油和冰川碳对浅层沉积物和水柱碳循环的贡献的基本环境。该项目将比较浮游植物、冰川冰、浅层沉积物中的碳、深层沉积物中的石油以及天然气水合物中的甲烷的碳源(S)和循环。数据收集将包括通过罗斯海的两个实地活动进行的地震剖面、地球化学和地球微生物学参数，暂定于2022年12月/1月和2024年2月/4月进行。这个多元化的团队包括地球物理、地球化学、海洋化学、地球微生物学和同位素地球化学方面的专家。最终，该项目的目标是创建罗斯海当前状况的基线数据，为评估未来人类活动对碳循环的影响提供能力。除了科学活动外，该项目还有广泛的教育活动，因为与气候变化有关的教育需要在所有学术级别、政府和公众中全面提供信息。该项目将资助四名研究生，并支持本科生研究人员的培训。将通过实地博客、PI网站、各种教育和外展活动向非科学受众传播成果，并将其纳入研究生和本科课程。最后，这个项目将为西班牙裔服务机构的本科生、研究生和早期职业研究人员提供培训和支持。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding climate change on Earth requires significant insight on geochemical and geobiological cycles in both polar regions and many environments in between. Methane is a major focus because of its substantial sediment loading and its high atmospheric heat absorption as a greenhouse gas. While the Arctic has been the primary climate change focus for studies on methane, the Antarctic’s Ross Sea, embedded with a vast ephemeral reservoir of carbon, has been recognized to have an extensive bottom ocean layer – sediment interface that is one of the most rapidly warming regions on Earth. New studies are needed to test the significance of potentially vast transitory gas hydrate carbon reservoirs present in the Ross Sea and provide a thorough assessment of methane reservoirs in the Southern Ocean. The focus on the Ross Sea is justified by recent drilling expeditions, which suggest a susceptibility of the Ross Sea to climatic fluctuations. This large carbon reserve appears to be sealed in the form of gas hydrate as evidenced by wide-spread seismic evidence. Intriguingly, recent recognition of similar seismic data indicates that this carbon reservoir has been underestimated due to carbon storage in deep sediment hydrates.The proposed project will serve as a foundation for improving both future simulations of oceanic carbon and the interpretation of past paleo-oceanographic cycles. In this project, plans are presented to explore a possible extensive gas hydrate reservoir in Ross Sea sediment and determine whether climate change could be influencing this region. This large carbon reserve appears to be held in the form of gas hydrate as evidenced by key seismic data. This indication of warming and ice melting coupled with high thermogenic gas hydrate loadings suggest the Ross Sea is an essential environment to determine contributions of current day and potential future methane, petroleum, and glacial carbon to shallow sediment and water column carbon cycles. The project will compare carbon source(s) and cycling within phytoplankton, glacier ice, shallow sediment carbon, oil sourced from deep sediment, and methane trapped in gas hydrates. Data collection will include seismic profiling, geochemistry, and geo-microbiology parameters conducted via two field campaigns in the Ross Sea, tentatively planned for December/January 2022/2023 and February/April 2024. The diverse team includes experts in geophysics, geochemistry, ocean chemistry, geo-microbiology and isotope geochemistry. Ultimately, the project aims to create baseline data of present-day conditions in the Ross Sea to provide capability for assessing future anthropogenic influence on carbon cycling. In addition to the scientific activities, the project has extensive educational activities, since education related to climate change requires thorough provision of information across all academic levels, government and the public. The project will fund four graduate students and support the training of undergraduate researchers. Results will be disseminated internationally to non-scientific audiences through field blogs, PI Websites, numerous education and outreach activities, as well as being incorporated into graduate and undergraduate courses. Finally, this project will provide training and support for undergraduate, graduate, and early career researchers at a Hispanic Serving Institution.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.