Impact of elevated levels of CO2 on animal mediated ecosystem function: The modification of sediment nutrient fluxes by burrowing urchins

► At pH8, urchins reduced sediment uptake of NOx and increased the release of silicate and phosphate. ► Reduced pH significantly affected the relationship between urchins and sediment nutrient fluxes. ► CCS leaks could alter nutrient cycling by disrupting key animal-microbial relationships.