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.

klippor-mars

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.

motsatta-grenar

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.

 

Advertisements

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.

IMG_8099

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.

IMG_8102

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.

IMG_8101

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

IMG_8103

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

 

 

Nordic OIKOS poster sessions

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

 

Two post doc positions on Baltic Sea research

The University of Helsinki and Stockholm University have entered into a strategic partnership where one of the key areas is Baltic Sea research. To strengthen this joint research initiative they are now inviting applications for two post-doctoral positions, one at Tvärminne Zoological Station (University of Helsinki) and one at the Askö Laboratory / Baltic Sea Centre (Stockholm University).

They are looking for candidates with experience and a strong interest in at least one of the following areas, with a particular focus on the coastal zone:
– biodiversity and ecosystem functioning
– benthic and/or pelagic biogeochemical cycles
– modelling of ecosystem processes in the coastal zone

The ideal applicants would have PhD’s in Marine Ecology, Ecosystems ecology, Biogeochemistry, Ecosystem modelling or related disciplines, have strong publication records commensurate with experience, and a demonstrated potential to obtain external research funds.
The successful candidates will be expected to be active in research and publication, advise graduate students, and engage in inter-disciplinary research and public outreach.
Comparative studies at both Askö Laboratory and Tvärminne Zoological Station are expected.

So, if you fit any of the above descriptions and love to be out in the field, this is a wonderful opportunity to experience two beautiful archipelagos of the Baltic Sea.

For more information on the positions, check HERE for the one placed in Finland and klick HERE for the one in Sweden.

Deadline for applicants is March 30th!

Askö boathouse early spring morningAskö boathouse early spring morning
Sunset at Tvärminne in FeburarySunset at Tvärminne in Feburary