Anthropogenic Inputs to Biogenic Effects in the Bay of Bengal (AItoBE)

• Applicants: Privatdozent Dr. Bert Engelen; Privatdozentin Dr. Christa Marandino
• Subject Area: Oceanography ; Analytical Chemistry ; Microbial Ecology and Applied Microbiology ; Metabolism, Biochemistry and Genetics of Microorganisms
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 531977795

Ocean biogeochemistry influences atmospheric processes through the exchange of climate-active trace gases and aerosols, which in turn feedback onto ocean biogeochemistry. These ocean-atmosphere interactions influence society, through climate, ecosystem services, and air/water quality. This coupled system is experiencing anthropogenic perturbations, which must be fully studied, to accurately predict system changes. The overarching goal of the proposed project is to understand the impact of anthropogenic inputs on microbial processes and the subsequent effects on the cycling of climate-active trace gases between the ocean and atmosphere. There are no studies, to date, that have investigated the influence of anthropogenic atmospheric inputs on climate-active trace gas cycling between the ocean and atmosphere and we aim to close that gap. A major part of this proposed study will be performed on the BIOCAT cruise in the Bay of Bengal (BoB) on board the R/V Sonne. The BoB region is an optimal area to perform this work, as it is an oceanic region experiencing high pollution and dust loading from land. Since it is considered a low nutrient, low chlorophyll region, processes there are analogous to vast areas of the open ocean. The seasonal monsoon cycle offers interesting opportunities to study this region under more pristine or more polluted conditions, making it an ideal natural laboratory setting. By investigating the aerosols on land and over the ocean, in conjunction with atmospheric trajectories, microbial mediated transformations, trace gas distributions in the ocean and air-sea exchange, we cover the full feedback cycle in the region. The analysis of the microbial community in natural samples in the BoB will help to understand the influence of the anthropogenic inputs on the sulfur cycle, specifically the production of the climate-active gas DMS, as well as other biogenically produced and consumed trace gases (i.e. isoprene, carbonyl sulfide, and carbon disulfide). Comparing microbial communities and genetic information from areas with high anthropogenic inputs with areas of low inputs will provide information about the influence of these factors on key organisms involved in the production and degradation of the trace gases. These findings will be supported by incubation experiments, during which collected atmospheric aerosols will be added to natural water samples. By combining the expertise of German and international scientists across the disciplines of microbial ecology, ocean biogeochemistry, air-sea exchange and atmospheric chemistry, we have the unique opportunity to investigate atmospheric inputs from the Indo-Gangetic Plain and desert areas that influence microbes and trace gas production in the ocean and subsequent feedbacks on atmospheric processes. What we learn in the BoB will be applied to other regions experiencing the effects of high population density and anthropogenic influences, such as the Baltic and the North Sea.

• DFG Programme: Research Grants