Abstrakt: |
Concentration patterns of ammonia, nitrate and particulate- and dissolved organic nitrogen in Lake Vechten (The Netherlands) are given. The main processes playing a role in the lake's nitrogen cycle are inventorized. During spring and summer, the uptake of ammonia and nitrate by primary producers, accompanied by sedimentation of organic matter, result in significant nitrogen losses from the 0–6 m stratum. Ammonia accumulates during the stratification in the hypolimnion and after the autumn overturn is recirculated over the whole water column. In winter, release of ammonia from the sediments and nitrification further restore the lake's nutrient supply. The changes in nitrogen content of the different compartments are quantified, giving a basis for more detailed research. |