Biodegradability of natural dissolved organic matter collected from a UK moorland stream

► We found biodegradability of natural dissolved organic matter (DOM) ranged from 5 to 19% of total DOC. ► This degradable DOC constituted 11% of the annual flux of 77 kg ha−1 yr−1 from the moorland stream source. ► Biodegradable DOM could be predicted by rainfall amount, aromatic character of the DOM and 15N contents.