Biocomplexity in the Environment (BE), Coupled Biogeochemical Cycles (CBC): Complex Molecular to Global Interactions and Feedbacks in the Marine Dimethylsulfide (DMS) Cycle

Matrai 0221748海洋生态系统是一个复杂的生态-地球化学网络的一部分，它转换物质和能量，并为生命创造条件。这个网络的不同部分之间的反馈是介导的重要程度上通过交换辐射，生源微量气体。其中一个反馈涉及海洋浮游生物、挥发性硫化合物二甲基硫（DMS）和全球气候。在这种反馈中，海洋浮游植物和食物网产生的二甲硫醚进入对流层，并在那里被氧化成硫酸盐颗粒，影响云层的湿度，从而影响气候。大规模气候变化反过来又影响海洋中浮游植物的丰度和食物网进程，从而关闭反馈回路。这种反馈回路的强度甚至是信号仍然没有得到解决，这主要是因为影响DMS浓度的地球化学和生态过程的极其复杂的网络。在这个周期中，新的快速相互作用仍在被发现，具有一定的规律性，但这个系统的机械和预测数学模型还没有纳入许多这些发展。此外，还没有实地研究同时测量海洋二甲硫醚循环中的所有相关速率和浓度，也没有包括复杂的相互作用或重要的地球物理或化学参数的测量，这妨碍了模型准确绘制地表二甲硫醚浓度时空变化图的能力。这一努力将：1）在对两个海洋生物群落（亚热带环流和南大洋）进行深入实地研究期间，测量二甲硫醚和相关物种浓度的所有已知相关通量并建立模型; 2）在拟议的实地测量和其他现有测量和模型的基础上，建立全球海洋二甲硫醚模型; 3）使用这种模型评估气候与海洋二甲硫醚循环之间的反馈潜力。DMS地球化学系统是一个易于处理的研究课题，有助于理解区域和全球范围内生物圈-地圈调节的复杂性。DMS系统也是一个很好的，研究可访问的模型，食物网依赖的生态地球化学过程。对二甲基硫循环的复杂控制的调查应有助于了解影响海洋生物生态分布和主要营养元素生态地球化学循环的关键因素。提高对DMS地球化学的认识，将有助于更好地预测地方、区域和全球尺度对预期气候变化的反应，并对维持地球生命的地球化学-地球物理网络内的联系提供有价值的见解。

Matrai0221748Ocean ecosystems are part of a complex geophysical-biogeochemical web that transforms matter and energy and sets the conditions for life. Feedback between different parts of this web is mediated to a significant degree by the exchange of radiatively important, biogenic trace gases. One such feedback involves marine plankton, the volatile sulfur compound dimethylsulfide (DMS), and global climate. In this feedback, DMS produced by marine phytoplankton and the food web enters the troposphere and is oxidized there to sulfate particles, which influence cloud albedo and, consequently, climate. Large-scale climate change, in turn, affects phytoplankton abundance and food web processes in the oceans and thereby closes the feedback loop. The strength-and even the sign-of this feedback loop is still unresolved, largely because of the exceedingly complex network of biogeochemical and ecological processes that affect the concentration of DMS. Fascinating new interactions in this cycle are still being discovered with some regularity, but mechanistic and prognostic mathematical models of this system have yet to incorporate many of these developments. Furthermore, there have been no field studies in which all of the relevant rates and concentrations in the marine DMS cycle have simultaneously been measured, nor have complex interactions or measurements been included for important geophysical or chemical parameters, hampering the ability of models to accurately map spatial and temporal variations in surface DMS concentrations. This effort will: 1) Measure and model all known relevant fluxes of concentrations of DMS and related species during intensive field studies in two ocean biomes: a subtropical gyre and the Southern Ocean; 2) Develop a global marine DMS model built upon the proposed field measurements and other existing measurements and models; and 3) Use such a model to evaluate the potential for feedbacks between climate and the marine DMS cycle. The DMS biogeochemical system represents a tractable research subject that can aid in understanding the complexities involved in biosphere-geosphere regulation at the regional and global scales. The DMS system also serves as an excellent, research- accessible model for food-web dependent biogeochemical processes. This investigation of the complex controls on the DMS cycle should shed light on the critical factors influencing the ecological distributions of organisms in the sea and the biogeochemical cycles of major nutrient elements. Advancing the knowledge of DMS biogeochemistry will allow better predictions of the local, regional and global scale responses to anticipated shifts of climate, and provide valuable insights into the connections within the biogeochemical-geophysical web that sustains life on Earth.