Collaborative Research: Time Series and Process Measurements of Dimethylsulfide dynamics at BATS and in the North Atlantic Subtropical Gyre

生物圈-气候相互作用的特征和量化对于理解和预测气候变化至关重要。生物圈和气候之间的反馈在很大程度上是由具有辐射活性的生物成因微量气体的动力学所调节的。量化这些气体的动态和海气交换是新的国际生物圈-地圈计划SOLAS，即表面海洋低层大气研究的一个主要目标。二甲基硫化物(DMS)的生物生成和随后的通风具有重要的气候意义，因为DMS及其大气氧化产物被认为是连接全球生物圈和气候的云反照率反馈机制的一部分。理解生物圈-气候相互作用的进展在很大程度上受到阻碍，因为难以准确地约束、参数化或验证模型。与适当的辅助数据一起收集的现场观测根本不足以以机械性和预测性的方式评估强迫因素。在这一项目中，伍兹霍尔海洋学研究所和百慕大生物研究所的科学家将收集和研究二甲基硫动态的新的时间序列数据集，包括对评估二甲基硫醚池(和主要相关化合物)的长期变异性至关重要的临界水池和速率测量，以及作为这种长期变异性基础的二甲基磺酸盐类和二甲基磺基丙酸盐(DMSP--海洋中二甲基磺基丙酸的主要前体)的短期动态。通过重访同一大洋环流，这项新的研究将首次对深海中DMS和DMSP的浓度进行长期比较。十多年后，第一项研究中所做的测量将在现在重复进行，此外还将进行一系列更广泛的测量，以解决有关控制DMS动力学因素的新假设。每月的测量将包括使用新的35S示踪剂方法的DMS和溶解的DMSP在地表水中的关键周转动态，水中的DMSO浓度，以及在BATS巡航期间大气DMS的日变化。这一全面的时间序列和过程采样方案将使我们能够机械地描述关键的DMS、DMSP和DMSO周转率的控制，并将作为过去和未来建模工作的唯一验证数据集。广泛影响：本研究的结果将加深我们对控制贫营养水域DMSP和DMS浓度的潜在机制的理解，并为模型校准和验证提供关键变量，从而提高我们模拟和预测未来生物圈-气候反馈的能力。这项研究还将支持一名学生和一名博士后研究员的研究，并鼓励与美国和欧洲几个机构的科学家进行多方面的互动。

ABSTRACTOCE-0425166Characterization and quantification of biosphere-climate interactions is critical to understanding and predicting climate change. The feedback between biosphere and climate is mediated to a significant degree by the dynamics of radiatively active, biogenic trace gases. Quantifying the dynamics and air-sea exchange of these gases is a major objective of the new I.G.B.P. (International Biosphere-Geosphere Program) program SOLAS, the Surface Ocean Lower Atmosphere Study. The biogenic production and subsequent ventilation of dimethyl sulfide (DMS) is climatically important as it has been postulated that DMS and its atmospheric oxidation products are part of a cloud albedo feedback mechanism which links global biosphere and climate.Progress in understanding biosphere-climate interactions is hampered largely because it is difficult to accurately constrain, parameterize, or validate models. There are simply not enough field observations collected in conjunction with the appropriate ancillary data to assess forcing factors in a mechanistic and predictive way. In this project, scientists at the Woods Hole Oceanographic Institution and the Bermuda Biological Station for Research will collect and study new time-series data set of DMS dynamics, including critical pool and rate measurements vital to assess not only the long-term variability of the DMS pool (and major associated compounds) but also the short-term dynamics of DMS and dimethylsulfoniopropionate (DMSP - the main precursor of DMS in ocean water) that underlie this long-term variability. By revisiting the same oceanic gyre, this new study will represent the first long term comparison of DMS and DMSP concentrations anywhere in deep ocean. The measurements made in the first study will be repeated now, more than a decade later, in addition to a broader suite of measurements to address new hypotheses about the factors controlling DMS dynamics. Monthly measurements will include key turnover dynamics of DMS and dissolved DMSP in surface waters using new 35S tracer methods, aqueous DMSO concentrations, and diel variations in atmospheric DMS during the BATS cruises. This comprehensive time-series and process sampling scheme will allow us to describe mechanistically the controls on key DMS, DMSP, and DMSO turnover rates and will serve as a unique validation data set for past and future modeling efforts.Broader Impacts: Results from this study should improve our understanding of the underlying mechanisms controlling DMSP and DMS concentrations in oligotrophic waters and also provide key variables for model calibration and validation, thereby improving our ability to simulate and predict future biosphere-climate feedbacks. This research will also support the research of a student and a postdoctoral investigator, and encourage multifaceted interactions with scientists in several institutions in the US and Europe.