Why do we get massive Juncus bulbosus growth? (completed)
About the project
The hydroelectric power industry has thus far been strongly linked to the problem with mass development of the aquatic macrophyte Juncus bulbosus in regulated freshwaters, although other factors like climate variability, acid rain and liming may also contribute to the expansion of this species. In southern Norway, there is also a remarkable similarity between the deposition pattern of atmospheric nitrogen and the regional distribution of massive J. bulbosus growth. We hypothesise that nuisance growth can be governed by the skewed stoichiometry of nitrogen (N) relative to carbon (C) and phosphorus (P). Our main objective is to explore possible links between mass occurrence of J. bulbosus and regional patterns in the stoichiometry of C, N and P in surface waters, relative to impacts from other environmental gradients and flow-regime regulations. The project includes a synoptic survey of 150 lakes, detailed field investigation in a smaller subset of natural and regulated/non-regulated lakes and streams, and growth experiments under controlled laboratory conditions. These activities will hopefully put us in a good position to generate new knowledge about the factors governing mass development of J. bulbosus.