Changes in sediment nutrient content in a subarctic lake subjected to lake fertilization

SUMMARY. 1. Phosphorus and nitrogen concentration in the surface sediment was analysed before, during and after fertilization of a small, stratified, subarctic lake. During stratification most (70%) of the added nutrients were deposited in the epilimnion sediment.
2. After 2 years of fertilization there was a significant increase of both nutrients at all water depths, although values were 30–50% higher per square metre in the shallow areas.
3. Nutrient budget calculations based on the sediment analyses showed that 75% of the added phosphorus and 45% of the nitrogen were accumulated in the sediment after fertilization.