The pictures show Heather Reader, post doc from Canada working in my group, sampling water from River Emån and River Lyckebyån. Both waters enter the Baltic Sea on the southeastern coast of Sweden and are brown as they drain catchments with coniferous forest and peat bogs. The watercolor of Lyckebyån is not far from that of Coca-Cola! In fact this water as used as a drinking water resource for the municipality of Karlskrona in Southern Sweden. The color of the water comes from organic matter from the catchment – incompletely degraded plant material mainly – and iron. The diagrams show how water color, organic matter and iron has increased strongly over time in River Lyckebyån. This is a general phenomenon in Sweden and many other areas of the northern hemisphere

In our project we try to understand why organic matter in iron has increased and what the consequences can be to the receiving systems. In this particular case we are interested in understanding what will happen to this organic matter as it enters the Baltic sea. Will it aggregate and sediment, will it be utilized by bacteria and phytoplankton and in that sense "fuel the Baltic foodweb" or will it remain in solution and reduce the light penetration in the Baltic water and potentially reduce primary production? Experiments will be carried out to provide some answers to those questions.