WP 3: Nitrate leaching

Task 3.2 — Dual isotope studies at the Afon Gwy: "new" atmospheric versus "old" microbial N in surface water nitrate (Pilot Scheme)

This task comprises a pilot study for the assessment of a technique (new in the UK) for the determination of atmospheric (pathways 1 and 2) versus microbial (pathway 3) nitrate, through the analysis of δ15N and δ18O in nitrate.

The field programme will entail monthly sampling for water chemistry and dual isotope analysis, plus quarterly sampling at up to 6 selected stream sub-catchments, bulk deposition and soilwaters, using zero tension lysimeters. Dual isotope analysis will be performed at BGS Keyworth.