International Journal of Marine Science, 2024, Vol.14, No.5, 312-320 http://www.aquapublisher.com/index.php/ijms 317 produced in marine sediments through microbial methanogenesis and can be released into the water column and eventually the atmosphere. However, various microbial processes, including aerobic and anaerobic oxidation, significantly mitigate these emissions. For instance, aerobic methane-oxidizing bacteria (methanotrophs) in the water column can oxidize methane, preventing its release into the atmosphere (Bornemann et al., 2016). In eutrophic coastal areas, the interplay between methanogenesis and methane oxidation is influenced by factors such as organic matter input, oxygen availability, and the presence of alternative electron acceptors like metal oxides and nitrate (Żygadłowska et al., 2023). Additionally, microbial communities in methane seeps and pockmarks play a crucial role in methane oxidation, further highlighting the complex interactions within marine methane cycling (Taubert et al., 2019). 6.3 Impact of climate change on marine methane dynamics Climate change has profound effects on marine methane dynamics, potentially increasing methane emissions through various mechanisms. Rising temperatures can enhance methanogenesis in marine sediments and reduce the solubility of oxygen in surface waters, leading to increased stratification and hypoxia, which favor methane production (Dean et al., 2018). Eutrophication, driven by increased nutrient inputs, can exacerbate these conditions, further promoting methane emissions (Qian et al., 2022). Additionally, sea level rise and changes in hydrology can alter the redox conditions in sediments, affecting the availability of electron acceptors for methane oxidation. The feedback loop between methane emissions and climate change is a critical area of study, as increased methane emissions can further accelerate global warming, creating a positive feedback mechanism. 7 Technological Advances in Methane Measurement 7.1 In situ sensors for methane detection In situ sensors for methane detection have significantly advanced our ability to monitor methane concentrations directly within marine sediments and water columns. These sensors provide real-time data, which is crucial for understanding the dynamics of methane fluxes in various marine environments. For instance, the study by utilized a dynamic transport-reaction model to predict methane concentrations in marine sediments (Wallenius et al., 2021), demonstrating the importance of accurate in situ measurements for robust carbon budget estimations. Additionally, the research conducted at a methane seep near Elba, Italy, highlighted the role of in situ sensors in measuring methane oxidation rates, which were found to be up to 871 nmol of methane per gram of sediment per day (Żygadłowska et al., 2023). 7.2 Stable isotope techniques for tracing methane sources Stable isotope techniques have become a powerful tool for tracing the sources and processes affecting methane in marine environments. By analyzing the isotopic compositions of methane (δ13C and δ2H), researchers can distinguish between different methane production and oxidation pathways. For example, the study on Lake Biwa utilized stable isotope measurements to determine that excess methane in oxic surface waters originated from the littoral zone via lateral transport (Tsunogai et al., 2020). Similarly, proteomic stable isotope probing (SIP) has been employed to track protein synthesis in methane-impacted microbial communities, revealing the active synthesis of enzymes involved in anaerobic oxidation of methane (AOM) (Marlow et al., 2016). These techniques provide detailed insights into the biogeochemical cycling of methane and the specific microbial processes involved (Meister et al., 2019). 7.3 Advancements in modeling methane fluxes Modeling methane fluxes in marine sediments and water columns has seen significant advancements, allowing for better predictions and understanding of methane dynamics. The development of dynamic transport-reaction models, as presented in the study by (Rahmati-Abkenar et al., 2021), enables the prediction of methane concentrations without requiring initial values, thus providing a robust tool for carbon budget estimations. Another study modified a biofilm model originally developed for wastewater treatment to simulate microbial kinetics and substance conversions in aqueous surface sediments, revealing the complex interactions between different microbial communities and environmental factors (Chen, 2024). These models are crucial for explaining phenomena that are difficult to resolve experimentally, such as the alternation between atmospheric methane
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