EXPORTS OF ORGANIC CARBON IN BRITISH RIVERS

✍ Scribed by DIANE HOPE; MICHAEL F. BILLETT; RONNIE MILNE; THOMAS A. W. BROWN

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 288 KB
• Volume: 11
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/(sici)1099-1085(19970315)11:3<325::aid-hyp476>3.0.co;2-i

✦ Synopsis

This study provides the ®rst detailed estimate of riverine organic carbon ¯uxes in British rivers, as well as highlighting major gaps in organic carbon data in national archives. Existing data on organic carbon and suspended solids concentrations collected between 1989 and 1993, during routine monitoring by the River Puri®cation Boards (RPBs) in Scotland and the National River Authorities (NRAs) in England and Wales, were used with annual mean ¯ows to estimate ¯uxes of dissolved and particulate organic carbon (DOC and POC) in British rivers. Riverine DOC exports during 1993 varied from 7 . 7±103 . 5 kg ha À1 year À1 , with a median ¯ux of 31 . 9 kg ha À1 year À1 in the 85 rivers for which data were available. There was a trend for DOC ¯uxes to increase from the south and east to the north and west. A predictive model based on mean soil carbon storage in 17 catchments, together with regional precipitation totals, explained 94% of the variation in the riverine DOC exports in 1993. This model was used to predict riverine DOC ¯uxes in regions where no organic carbon data were available. Calculated and predicted ¯uxes were combined to produce an estimate for exports of DOC to tidal waters in British rivers during 1993 of 0Á68+0Á07 Mt. Of this total, rivers in Scotland accounted for 53%, England 38% and Wales 9%. Scottish blanket peats would appear to be the largest single source of DOC exports in British rivers. An additional 0 . 20 Mt of organic carbon were estimated to have been exported in particulate form in 1993, approximately two±thirds of which was contributed by English rivers. It is suggested that riverine losses of organic carbon have the potential to aect the long-term dynamics of terrestrial organic carbon pools in Britain and that rivers may regulate increases in soil carbon pools brought about by climate change.