The overall project, to determine reference conditions for phosphorus runoff from forested areas with arable soil properties is funded by the Norwegian Research Council. Bioforsk has sub-contracted ENSIS to undertake a palaeolimnological survey of three lake sediment cores from Lake Vastadtjern in Norway.


The main objective of this project is to develop a methodology to assess the contribution of phosphorus runoff from clay-rich soils at reference conditions, for use as a management tool in the implementation of the European Water Framework Directive (WFD) in agricultural river basins. Additionally the project seeks to
  1. estimate levels of P losses from forested arable areas with clay-rich soils
  2. estimate the bioavailability of P in runoff from clay-rich soils, soil-water/ground water, and surface water in forested areas
  3. evaluate reference conditions in areas dominated by clay-rich soils based on palaeolimnological studies, and
  4. develop an improved methodology and management tool for estimating background contributions of P in areas dominated by clay-rich soils.


ENSIS is analysing three sediment cores taken by Bioforsk from Lake Vastadtjern providing a total sediment core length of around 600 cm. The intention is to extend the record back to pre-human impact (approx 6000-7000 yrs BP). The cores were as follows;

  1. a Gravity core (c. 30 cm long)
  2. a Russian core (c. 340 cm long) and
  3. a deeper Russian core (c. 270 cm long) which continues on from the previous core.

The Gravity and Russian cores have been dated using 210Pb and the deeper Russian core has been carbon dated. ENSIS is analysing c.20 sub-samples for diatoms macrofossils and cladocera distributed throughout the whole sequence to determine the aquatic flora and fauna at various stages in the lake’s history.


The project is still ongoing



Vastadtjern Russian core