Tångbloggen

Here is the first report from the Baltic Sea Weed blog participating in the OIKOS conference. The conference was opened by professor Gunilla Rosenqvist. She has been engaged in Baltic Sea research for many years and is the Coordinator of the Baltic Sea Region at Uppsala University. Professor Mikko Mönkkönen from Turku University gave some information about the conference, the importance of net-working and pointed out that the Nordic countries have a strong tradition in long-term studies and the high value of these data sets, which should be regarded as national assets for ecological research and management. A panel discussion “Open science” was chaired by him after the coffee break.

During the conference a broad range of research subjects were presented. In the first plenary lecture by Tómad Grétar Gunnarsson I learned about the dynamics of Godwit populations and how their migration and increased populations may be affected by volcanic dust deposition on Iceland during their breeding period together with feeding on polychaetes and Macoma on the large mudflats during overwintering in England and Scotland, linking these two ecosystems together.

This presentation was followed by a talk on how water quality changed during the last 20 years (1990- 2010) in Danish lakes focusing on benthic vegetation and species richness. The interesting question addressed by Lars- Baastrup-Spohr was if it has been worth while all the costs put into cleaning the sewage water? The answer was YES!

Alga biomass has decreased in the polluted in lakes but it was not possible to record as an increase in Secchi depth. The number of species had increased since 20 years ago and more species had spread and were found in more of the lakes. This has resulted in the lakes becoming more similar. One functional group that had increased in abundance were Lemnids, small species floating on the surface. So the tremendous effort in restoring lakes in Denmark is starting to pay off. Still, there seems to be some time-lag effects possibly from the sediments containing large stores of nutrients.

Next talk was given by Fiia Haavisto. She presented together with professor Veijo Jormalainen cage experiments testing the spread of water-borne herbivore resistance in natural marine environment.

There is good evidence for such induced resistance in land plants and has also been found in macroalgae, especially in dense stands among other species, Ascophyllum nodosum, Fucus vesiculosus, and several red algal species. You find some references in the picture.

Cage experiments were performed in a shallow sandy bay at Seili during 25 days in May. The results presented showed a resistance in the Fucus thalli being less grazed by Idotea balthica and increased phlorotannin content. The conclusion from the study was that resistance spreads to undamaged not grazed thalli near by but that currents will result in strong spatial variation in water borne substances. One question from the audience was related to how fast do Idotea move between thalli and what could the effect be since the induction takes a few days? Issues that still will have to be studied further. After a presentation or study you are usually left with more questions.

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