Application of Benthic Microbial Fuel Cells in Systems of Year-Round Monitoring of Water Environment Parameters

The bioelectrogenic activity of sediments of the natural microbial assemblage of Peter the Great Bay, Sea of Japan, was studied in a year-round experiment with parallel temperature, illumination, and water electrical conductivity monitoring using benthic microbial fuel cells (MFC) and automatic online monitoring. Several variants of underwater devices, including benthic microbial fuel cells, monitoring water environment sensor, information collection and transmission systems, have been developed. This device has an electrical voltage of up to 216 mV and a specific power of up to 239 mW/m 2 . The electrogenic activity of natural microflora depends on water temperature and reaches a maximum in summer with a temperature of about 20–25°C. The introduction of toxicants such as hydrocarbons and cadmium into sludge led to suppression of microbial electrogenesis. However, the introduction of inductor substances of microbial sulfidogenesis stimulated microbial electrogenesis. The possibility of functioning of the benthic MFC in the field of Peter the Great Bay in different climate periods is shown. It is demonstrated that such experimental devices can be a basis for autonomous stations monitoring the state of the marine environment over a long time period and in a wide range of changing conditions. Automatic recording of water temperature, illumination, and salinity with a frequency of 48 times a day was done over 13 months (November 28, 2019–December 31, 2020). The electrogenic activity of this microbiota upon MFC scaling can potentially become a new renewable energy source for low-power marine electronics, including those used in mariculture.