Effects of artificial electric fields on the physiological state of Amphistegina lessonii: Insights from oxidative stress biomarkers and gene expression

Anthropogenic energy infrastructure, including subsea power cables and renewable devices, introduces unexpected artificial electricity into marine ecosystems, potentially acting as ecological stressors on benthic community. The physiological responses of benthic organisms to electric stimulation remain poorly understood. Benthic foraminifera, single-cell organisms widely used as bioindicators in marine environments, are sensitive to environmental stressors. This proof-of-concept study aims to evaluate the effects of different electric current densities on the benthic foraminiferal species Amphistegina lessonii based on single-cell transcriptomic and biochemical (i.e. proteins and enzymes) analyses in short-term exposure experiments. Electrical stimulation leads to the upregulation of mitochondrial metabolic (COQ3, PPOX, and ATP6) genes, as well as TCA cycle pathways. The biomarkers p-p38 MAPK and p-PKC, which are associated with cellular responses to stressful stimuli, are significantly enhanced at 0.86 μA/cm², suggesting that this electric density induced a significant physiological response. These responses indicate that electrical stimulation may enhance mitochondrial energy production, potentially increasing reactive oxygen species (ROS) generation. Following cellular responses to stressful stimuli, antioxidant defence is upregulated as reflected by redox-related (GPX, GGT1) genes. This antioxidant activity is further supported by the levels of multiple biomarkers (GST, GPx, and Se-GPx). This study demonstrates significant metabolic and physiological changes in A. lessonii and its adaptive capability to ensure cell survival under electrical stimulation. These findings also highlight the combined use of cellular biomarkers and single-cell transcriptomic analysis as a promising approach for assessing environmental stress in benthic foraminifera-based biomonitoring.