67 / 2025-03-31 00:53:22

Transport of Dissolved Organic Carbon (DOC) Across the Sediment-Water Interface and Microbial Response Mechanisms at Different Developmental Stages of Cold Seeps

coldseep,dissolved organic carbon,sediment water interface,FT ICR MS,microbial enyzmes

Theme 2: Geobiology of Modern Habitable Earth > Session 2a: Microbe-mediated Carbon Cycling on Modern Earth

Deep-sea cold seep environments are often referred to as "oases" on the seafloor, characterized by active organic carbon cycling within sediments. Throughout various developmental stages of cold seeps, significant differences emerge in ecosystem characteristics, leading to variations in the composition and properties of sedimentary dissolved organic matter (DOM). The continuous and intense exchange of materials between cold seep sediments and overlying water, driven by methane emissions, results in substantial DOC fluxes across the sediment-water interface. This process may have the potential to alter the strategies employed by water column microorganisms in organic carbon cycling.

However, systematic comparative studies on the differences in organic matter composition and properties across different developmental stages of cold seeps remain scarce. Consequently, the impact of upward transport from sedimentary carbon pools on deep-sea carbon cycling has yet to be thoroughly elucidated. Given the widespread distribution of cold seeps in the South China Sea, this study collected samples of porewater, overlying water, and bottom water from three distinct cold seep environments: nascent, mature, and waning stages. By calculating DOC fluxes at the sediment-water interface and employing spectroscopic and mass spectrometric methods, we aim to capture vertical variations in the composition and properties of DOM. Additionally, metagenomic techniques will be utilized to analyze microbial carbon cycling mechanisms.

This research seeks to conduct an in-depth comparison of DOC transport fluxes across the sediment-water interface during different stages of cold seep development. It aims to elucidate the differences in sedimentary DOC, microbial composition, and metabolic processes, thereby enhancing our understanding of the connectivity between sedimentary and deep-sea water carbon reservoirs.