Figure 2From: Alkaline fluid circulation in ultramafic rocks and formation of nucleotide constituents: a hypothesisDissolved nitrate concentrations in sediment pore fluids at open-ocean ODP Sites 1225 and 1231. The nitrate values show that fresh seawater is channelled upwards into deep-sea sediments via the rocks underneath (from D'Hondt et al., 2003 [59]).Back to article page