We wish all our readers a very happy new 2017. During 2016, we had no less than 2434 visitors.
2017 will be a year full of activity in our seaweed resarch on bladderwrack (Fucus vesiculosus) in the Baltic Sea. We hope to share lots of our exciting experiments and resluts with both old and new readers.
As winter seems to finally have decided to arrive in full here in Sweden, we treat you to a film showing the marine life at the Swedish west coast. Diver Edvin Thörnholm filmed all this material during one year in the Gullmar Fjord. The movie consists of material from 150 dives, showing the marine life at different depths and types of substrate in the fjord.
With this movie, Edvin wants to share the beauty of the underwater world and show how it varies with both season and time of day. The speaker voice is in Swedish, but if you see something and wish to know what it is, just mail us and state at what time in the film the organism is shown, and we’ll get back to you with a name in Latin and English. Enjoy!
The Gullmar fjord is the only threshold fjord in Sweden and by many regarded as the best dive site for marine biology. The local divecenter in the town Lysekil, DiveTeam, has many skilled marine biologists in their staff for those who whish for a guided “veggie-dive”.
For two weeks, the bachelor course “Environment of the Baltic Sea” from Stockholm University have been stationed at the Askö Laboratory for field studies. The course includes many relevant methods for new biologists. Among other things, the students have been fishing with survey gillnets, dug the mud of soft bottoms, and done meticulous inventories of vegetation and animal community in three shallow bays.
Enthusiastic students snorkle out to make an inventory of the flora in a Baltic Sea shallow bay.
Part of the course also focuses on how humans affect the Baltic Sea ecosystem. For an easy way to show how urine in the sea affects the growth of phytoplankton, i.e. eutrophication, the students were instructed to set up 4 pieces of plastic tanks of 1 m3 (1000 liters) and fill with seawater. One tank was used as control and nothing else was added to it. In the other three 3dl, 6 dl and 12 dl of urine was added in order to study the phytoplankton response to different nutrient levels.
0,3 permille urine and a week of sun clearly demonstrates how the phytoplankton thrive in response to nutrients.
This year I also put a piece of the filamentous alga Cladophora glomerata in the tanks. This algae grows just below the surface and thrives in nutrient-rich waters. When grown in high nutrients, it gets a darker green color. This is clearly seen in the most eutrophic tank with 1.2 liter of urine per 1,000 liters of water.
The control treatment has no added urine, and the Cladophora glomerata has a light green colour.
In the tank with the highest concentration (1,2 dl), the Cladophora glomerata has grown well and is dark green. The water is full of phytoplankton and does not exactly make one keen to take a bath.
Fish in the hand of humans – a Baltic Seminar. At the Baltic seminar last week two interesting presentations were given, one about the linkage between benthic vegetation cover and fish recruitment and production and the other one the strong impact by large fishing companies.First, Johan Eklöf, Department of Ecology, Environment and Plant Sciences, Stockholm University, presented the impact of cascading effects and the close interaction between rooted aquatic plants and seaweeds and fish recruitment of for instance pike and perch in shallow Baltic Sea bays. Shown both in more and more scientific studies and experiments.
In the first figure the positive effect of large fish is shown on the filamentous algae and how rooted aquatic plants benefit the recruitment of fish .e.g perch in shallow parts of the archipelago.
Fig. 2 shows that there seems to be a threshold of 20 % cover that is optimal for recruitment.This was followed by a presentation by Henrik Österblom, from Stockholm resilience centre about the large impact of big companies managing the fish stocks, both, on a global scale and in the Baltic Sea.
The seminar ended with a panel discussion addressing the question if the fish stocks are in the hand of humans and if we will be able to find ways of sustainable use of and management of fish stocks.
Can the knowledge of the strong link between vegetation and fish recruitment be transferred to better management of shallow bays and coastal areas? Sofia Wikström and Gustaf Almqvist at the Baltic Sea centre, Stockholm University added to the discussion about the need of further improving our understanding of these complex ecosystems for a long-term sustainable management of fish species like pike and perch.
To celebrate the 70th birthday of His Majesty King Carl XVI Gustaf, a unique show “An evening about the Baltic Sea- Hopes and threats” was given in his honour at the Royal Dramatic Theatre on the 25th of April. On stage was more than 10 scientists together with leading dignitaries from several authorities and politicians who gave lively narratives of what is happening in the Baltic Sea. Everything from the slow geological changes over the years to the formation of new species all the way to the political situation today.
A truly dramatic moment was when Ett mycket dramatiskt ögonblick var när professor emeritus Ragnar Elmgren from Stockholm University spoke of what species can be found in the Baltic Sea today. Suddenly, a large Ascophyllum nodosum falls down from above, landing just behind him!
Professor Elmgren cooly states that this species has not managed to migrate into the Baltic Sea due to the low salinity. The common seaweed species that most people reckognise, the bladderwrack, is an important foundation species for life in the Baltic Sea. Many species find shelter or food in the bladderwrack.
This is the moment when Fucus radicans enters the stage, from the pocket of Ragnar. Fucus radicans has formed an own species from Fucus vesiculosus in less than a couple of thousand years. It is the only known endemic species in the Baltic Sea, which means it is not found anywhere else i the world seas.
Seaweed smells of the sea and is also edible. Someone who has tried Fucus radicans canapées (se tidigare inlägg) is the Swedish king, on a visit to the Askö Laboratory.
It is relatively easy to separate Fucus radicans and Fucus vesiculosus when they grow together in sympatry. Fucus radicans appropriate common name is narrow wrack. The thallus is much narrower that that of Fucus vesiculosus and Fucus radicans lacks the bladders that have given Fucus vesiculosus its name.
Between the presentation on stage, we the audience were entertained with beautiful music from the orchestra and songs. Amonst them an interpretation of ”Rönnerdal han dansar över Sjösala äng” (Rönnerdal is dancing over Sjösala meadow)by Evert Taubes, where the background was a lovely seagrass meadow.
The show ended with all participants on stage and His Majesty the King expressed his thanks for a rewarding evening, emphasizing his own keen interest in environmental questions in general and those of the Baltic Sea in particular.
h3>In the non-tidal Baltic Sea, the daily wash from the regular ferry traffic along the archipelago shores creates an algal zonation similar to a tidal shore. The regular wash of the rocky shores bordering the ferry route results in marked green algal zone. In the springtime it is composed of e.g. Spirogyra species and in the summer by Cladophora glomerata and Enteromorpha/Ulva species. Just below the green algal belt a zone of Fucus vesiculosus is found. The swell created by the ferry traffic is enough to keep the thalli wet and not drying out. The daily wash from the ferry traffic also affects the communities in rock pools. If you want to know more about these changes have a look at the article by Östman and Rönnberg Effects of ships’ waves on rock-pools in the Åland …
A stone with Spirogyra spp. collected from the Askö laboratory a week before.
This algal belt could be observed from the ferry last week when I was travelling from Mariehamn, Åland to Stockholm,Sweden. The other less positive effects from the traffic is the strong erosion of sandy coastal parts where threes are falling down and the shores are disappearing, leaving larger stones and boulders along the shore.
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.
Winner of “Best Poster Award”
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.
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.
Top-down fish 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.
Susanne Qvarfordt show how the effects of Pylaiella can be seen for a long time in the macroalgal community
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.
The conference ended after three intense days.
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.