So Called Healthy Chalk Streams Are Damaging The Environment± Scientists
English chalk streams are less healthy than scientists have thought and might even contribute to global warming, says a UK scientist. The scientist looked at plants in the streams and says they help methane to escape from below the surface into the air.
Dr Mark Trimmer, who works at Queen Mary, London University told journalists that he studied a plant that covers up to three quarters of the surface of some streams in the UK.
He found that the plant contributes to methane production. The methane which resides in the sediment beneath the plant's roots was escaping into the atmosphere, he said.
“We found similar emissions [in various] UK peat bogs” said Dr Trimmer from Queen Mary, University of London. “This changes our perception of the health of the ecosystem. [Now] there is climatic concern for [this] unquantified potential source of methane.”
Over 90% of the methane emissions from the river Frome in Dorset that reach the atmosphere do so via the stems of water crowfoot, Trimmer said. The plant also causes a build-up of sediment from neighbouring farmland, which aids the production of methane by bacteria in the stream.
Chalk streams are a British specialty habitat and a priority under the UK’s Biodiversity Action Plan. They have a high status but there is growing concern about their ecological decline.
Dr Trimmer estimates that the total area of chalk streams in the UK is around 20 km2. The situation he observed in Dorset is likely to be widespread, but Dr Trimmer said more research is needed to understand methane emissions fully.
This work is licensed under a Creative Commons Attribution 3.0 License.