1993-1

Transport and retention of nitrogen and phosphorus was studied in a small (51 km2), agricultural watershed in southern Sweden. The article deals predominantly with: – comparison of different methods for nutrient transport calculation; – estimation of nutrient retention in a meandering part of the stream; – analysis of two similar tributaries with different nutrient transport. […]

A hydrochemical model (PULSE) has been used to simulate liming activities in Ljustorpsån, a tributary to river Indalsälven in central Sweden. The PULSE-model is a conceptual runoff model with possibilities to simulate some chemical variables, such as alkalinity and pH. The PULSE-model treats alkalinity as a function of the calculated groundwater level in the model. […]

During the winter ice-cover an inverse thermal stratification arises in dimictic lakes because cold surface water overlays the warmer and deeper lake water owing to differences in density. This condition can create so-called overflows in lakes, with the result that cold inflow water will only mix with the surface water immediately below the ice-cover. Changes […]

The immune defence of arthropods is specifically and efficiently turned on after infection with fungi or bacteria. Different proteins in the blood of the animal are activated by the addition of cell wall polysaccharides from these microorganisms, and the activation can be studied in vitro with commercial substrates that form coloured products after enzymatic reaction […]

The presence of compounds inhibitory to nitrification in sewage treatment is a severe problem when introducing biological nitrogen removal at municipal treatment plants. These compounds often have their origin in industrial wastewaters connected to the municipal sewage works. One way to decrease the risk for inhibition of the nitrifying microflora in the treatment plant is […]

The artificial groundwater recharge has been studied in order to earn knowledge about the processes active in this kind of drinking water production. Water and soil samples were taken from the infiltration basin and analyzed for their content of iron, manganese and organic carbon. The quality of the infiltrating water was rapidly improved with 95 […]