Nutrient measurements of porewaters in sediment cores collected from the Semenov Hydrothermal Field region of the Mid-Atlantic Ridge during the RRS James Cook cruises JC224 (March - April 2022) and JC254 (October - November 2023)

Porewaters were extracted immediately after sediment cores from the Semenov Hydrothermal Field region of the Mid-Atlantic Ridge were recovered during the RRS James Cook cruises JC224 (March - April 2022) and JC254 (October - November 2023). Aliquots were distributed into various vials and containers with preservation media for different biogeochemical analyses both onboard and onshore. This dataset includes nutrient measurements of porewaters measured at the University of Southampton. These measurements provide a basis for assessing processes such denitrification and nitrate reduction, which can be used as indicators for microbial activity. The data were collected as part of a PhD project funded under NERC's Ultramafic-hosted mineral Resource Assessment (ULTRA) project, grant reference NE/S004068/1, and the sediment cores are currently stored at the BOSCORF for long-term preservation.