Confocal Raman Microscopy Quantitatively Reveals Subcellular Metabolic Adaptation Mechanisms of Deep-Sea Mussels to Methane Deprivation.

Methane hydrates are a potential energy source, but their extraction may disrupt deep-sea ecosystems that rely on methane. Understanding biological responses to methane fluctuations in cold seep environments remains limited, primarily due to the inability to monitor subcellular metabolic dynamics in real time. This study applied confocal Raman microscopy combined with full-spectrum normalization to investigate subcellular metabolic adaptations in the gill tissues of the deep-sea mussel containing symbionts under methane deficiency. This label-free and nondestructive technique allows high-resolution quantitative analysis of biomolecules. Results demonstrate that methane deficiency induced metabolic reprogramming and structural reorganization, disrupting energy metabolism while enhancing proteolysis and lipolysis. Spatial heterogeneity is evident across cellular regions, with varying degrees of structural recovery and degradation highlighting differential resilience. These findings collectively underscore the indispensable role of methane in maintaining metabolic and structural homeostasis in deep-sea mussels, offering key insights into their adaptation strategies under methane deficiency and fundamental data for assessing the ecological impacts of methane extraction. The successful application of our methodology demonstrates broad potential for real-time metabolic monitoring in diverse organisms and for evaluating subcellular effects of environmental disturbances, establishing a new avenue for noninvasive, high-resolution quantitative metabolic tracking.