Posts Tagged ‘Seaweeds’

Fisk i människans händer – ett Östersjöseminarium. På Östersjöseminariet förra veckan gavs två intressanta presentationer. EN handlade om kopplingen mellan täckningen på bentisk (bottenlevande) vegetation och fiskens rekrytering och produktion. Det andra tog upp den starka påverkan från stora fiskeföretag. Först ut var Johan Eklöf från institutionen för ekologi, miljö & botanik vid Stockholms universitet. Johan presenterade hur kaskadeffekter påverkar och de täta kopplingarna som finns mellan vegetation (rotade akvatiska växter och makroalger) och rekryteringen hos fiskar som exempelvis gädda och abborre i grunda Östersjövikar. Detta har visats i allt fler vetenskapliga studier och experiment.1Large fish -plant benefits

I första figuren ser vi den positiva effekten som stora fiskar har på filamentösa alger (de betar ner dem, så inte så positivt för algen, men för problemet med dem) och hur rotad akvatisk vegetation gynnar rekryteringen hos fisk (här abborre) i de grunda delarna av skärgården.

2PLants juvenlie pike

Fig. 2 visar att det verkar vara en tröskel på ca 20 % täckningsgrad av vegetation som är optimal för rekrytering. Detta följdes av en presentation av Henrik Österblom, från Stockholm resilience centre om den stora påverkan som stora fiskeföretag har på hur man sköter fiskbestånden, både på global skala och inom Östersjön.


Seminariet avslutades med en paneldiskussion gällande frågan om fiskbestånden är i människans händer och om vi någonsin kommer hitta hållbara sätt att utnyttja och sköta världens fiskbestånd.

4panel Balticseminar

Kan kunskapen om de starka kopplingarna mellan vegetation och fiskrekrytering hjälpa till att ta fram bättre skötselplaner av grunda vikar och kustområden? Sofia Wikström och Gustaf Almqvist från Östersjöcentrum på Stockholms universitet breddade diskussionen med behovet av att vidare utveckla och förbättra vår förståelse för dessa komplexa ekosystem för en långsiktigt hållbar hantering av fiskar som gädda och abborre.



Read Full Post »

The number of posters was very large and one poster presented by a PhD student won the award as the best poster, selected by the board of Oikos during the conference. This was number 100 with the title: “Ant larvae as a secret weapon against social parasites” by Unni Pulliainen. During the poster session lots of engaged presentations occurred.

1Winning poster Ants

Winner of ”Best Poster Award”

1 a Ben presents his poster

Ben presents his poster

There were also a number of marine and aquatic posters, for some the author had the possibility to pitch their poster in 3 minutes.

Tiina Salo, now being on a post-doc, showed in her poster that Lymnea stagnalis responds more strongly to a heat wave after exposure to a mixture of micropollutants. But they recovered fast after the heat wave had passed. To feed the snails she used ecological salad. In the future experiments they will be fed leaves from different aquatic plant species.

2Tiina presents her poster

Tiina (left) pitches her poster

Several posters presented different aspects on the hot topic “ top- down – bottom-up” regulation of different ecosystems and impact of cascading effects and interactions between species. One species that creates lots of emotions is the cormorant, when establishing large populations on small islands along the Baltic coast.

4 aPelagic food-web  poster

Top-down fish poster

5Cormorant poster

Bottom-up cormorant poster

From the Department of Ecology, Environment and Evolution two posters were presented, one on the long-term effect of Pilayella on the settlement of Fucus vesiculosus by Susanne Qvarfordt and the other one presented results from a master project on the Swedish west coast about two closely related Littorina snail species behaviour when placing their egg sacs on different fucoid species.

6Pylaiella påverkan på etablering av blåstång

Susanne Qvarfordt show how the effects of Pylaiella can be seen for a long time in the macroalgal community

7Littorina poster

Our poster!

The last poster that I want to present was of high interest dealing with the new crab species, the mud crab, Rhithropanopeus harrisii and its impact on the local fauna. It is just a question when this crab will arrive on the Swedish coast. Keep your eye out for it.
8Mud crab introduced

The conference ended after three intense days.

9Thanks for the conference


Read Full Post »

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.Programme 2016

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.Icelandic Godwit

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!1nutrient reduction has payd off

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.2long term changes in lake vegetation

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.3Spread of water borne

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.4Water-borne herbivore resitance

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.


Read Full Post »