Baltic Sea Science Conference 2019 in Stockholm

Next week, between the 19th to 23rd of August, the Baltic Sea Science Conference 2019 is held in Stockholm, Sweden.

This is THE conference for anyone working with the Baltic Sea, ecologists, hydrologists, geologists…you name it, they will be there.

Are you attending? If not, you can still check the programme and abstract book for the conference to get a good overview of the topics that will be discussed.

There will also be a workshop by the FunkVeg collaboration on free-living Fucus vesiculosus on the Tuesday 20th afternoon for anyone who is interested to hear more about the mysterious red-listed habitat that seems to be quite abundant in the Baltic Sea.

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Free-living bladder wrack on a shallow soft bottom with vascular plants

Tvärminne field station wants research technician

Tvärminne Zoological fieldstation, belonging to Helsinki University in Finland, is looking for a new research technician (permanent position).

Tvärminne is beautifully located just where the Gulf of Finland meets the Baltic Proper, near the picturesque town of Hanko/Hangö.

Are you a dab hand at duct-tape resolutions? Do you know the 456 uses of cable ties? Would you like to work with solving problems and fixing stuff? Are you, or would you like to become, a connoisseur of sauna? Apply! Or inform anyone else that might be interested.

Swedish: https://www.helsinki.fi/sv/lediga-anstallningar/forskningstekniker-tvarminne

English: https://www.helsinki.fi/en/open-positions/research-technician-tvarminne

Alga of the month – in March the rocks, boulders and reeds turn brown and green

The spring is in full bloom in the sea even though there is still ice and snow covering rocks and boulders up on land. Light is returning and the algae begin to grow.

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It is frightfully cold to stick the hands into the water and fetch some rocks, all covered with algae by the jetty at the Askö Laboratory. Overwintering tufts of the brown alga Pylaiella littoralis are only 4-5 cm long but have started to grow even though the water temperature is little more than + 2 or 3 °C. The name littoralis is well suited, since it is often found in the shallow zone near the shore, as littoral means shore.

The Pylaiella is about to reproduce for the first time this year, so that in  2-3 months when many of you go out to your summer-houses by the sea, large areas of the shallow hard or rocky bottoms will be covered with the next generation of  Pylaiella. The reproduction consists of lots and lots of spores being released from single-roomed sporangia, which look like beads on string in the single-cell branches.

pylasporangier

Many of the branches have transformed into sporangia and will be completely emptied of their content. Under a microscope, we can tell that this is Pylaiella littoralis and not the very similar species Ectocarpus siliculosus, since the branches on Pylaiella are situated opposite each other. The brances on Ectocarpus siliculosus are strewn. Also, this species does not occur until later in the year, so I will get back to you with some pictures of that. Ectocarpus siliculosus was actually the first brown algae to get its whole genome sequenced.

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On the branches of the Pylaiella can also be seen clusters of pointy, narrow diatoms. Later in spring, there will be enormous amounts of diatoms. They are also species that thrive in colder water. On many rocks by the shore, we can also see the pretty green alga Monostroma grevillei, which is only one layer of cells thick. The species name monostroma means ”one cellular layer”.

monosten

Monostroma grevillei is a common green alga, with a narrow base and broadening leaf, which splits in the top, forming long bands. It is of a marine origin and grows on any substrate that it can attach itself to, such as rocks, shells and other large algae. It is also an early spring species, reaching about 5-10 cm in size. It reproduces during March-May. After reproduction, the new offspring lives as a microscopic stage until late winter-early spring the following year.

monostroma

The family Monostroma is one of the most farmed green algae in Asia and is marketed as ”hirohano-hitoegusa nori”. Perhaps something for you to try as a salad, if you find some fresh green Monostroma during your walk along the shore, far away from pollution sources.

 

A wee in the Baltic Sea?

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.

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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.

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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.

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The control treatment has no added urine, and the Cladophora glomerata has a light green colour.

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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.

Vegetation is beneficial for fish recruitment

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.

1Large fish -plant benefits

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.

2PLants juvenlie pike

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.

3fishmarket

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.

4panel Balticseminar

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.

Fucus radicans takes to the Royal Dramatic Theatre stage

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.
1Dramaten

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.
4Smal o blåstång

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.

5sjögräsäng

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.

6Kungen tackar

Artificial algalbelt created by ferry traffic

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 …

algzonering ovan ytanSvallvågor

3Spirogyra i luppen

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.

erosionsstrand