IKEU – Integrated studies of the effects of liming acidified waters

Data from IKEU (Integrerad kalkningseffektuppföljning , Integrated Liming Effect Monitoring includes biology and water chemistry from a total of over 140 lakes and rivers that are or have been acidified, limed, or serve as references.

IKEU is the Swedish Agency for Marine and Water Management's programme for national monitoring of the effects of liming in lakes and watercourses. The programme includes monitoring of the long-term effects of liming on ecosystems in lakes and watercourses. As emissions of acidifying substances have decreased, lakes and watercourses are no longer limed as much as before. Therefore, the programme now monitors the effects of reducing and stopping liming to see if the changes are damaging the organisms that liming was intended to protect.

The programme started in 1989 and includes sampling of fish, zooplankton, benthic fauna, phytoplankton, and water chemistry. Metals in fish, mainly mercury in perch, are analysed in some IKEU lakes.

A total of 74 lakes and more than 70 watercourses are or have been included in the IKEU sampling programme. Both limed and non-limed lakes and streams are analysed, as well as acidic and neutral references. In addition, the effects in waters where liming has ended are studied. Data are also available from completed measurement programmes of limed lakes, extensive watercourses and extensive lakes.

For the waters included in the IKEU, background information such as size, depth (lakes) and catchment size can be found on the IKEU website. Information on liming is available in the National Lime Database. Temperature and water level (gauge measurements) have also been measured in some of IKEU's lakes and watercourses.

• Data from IKEU is made available via several different databases and is most easily downloaded via links at the IKEU web site.
• The IKEU website also provides background information on the lakes and rivers included.
• Fish data can be downloaded from SLU Aqua's NORS (lakes) and SERS (rivers) databases.
• Benthic fauna, phytoplankton, zooplankton and water chemistry are made available through Miljödata MVM.
• Data on metals are available via the The Geological Survey of Sweden: Datavärdskap för miljö­gifter (In Swedish) which is the data host for environmental toxins.
• Temperature and water level are available on request.
• Information on liming can be found in the national liming database (Nationella kalkdatabasen).