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Baltic Sea Weed Blog

The blog about seaweed in the Baltic Sea

European Aquaculture conference in Berlin Day 1: Macroalgae

It is always an uplifting experience to attend a scientific conference. Rooms full of people passionate about their work and, in my line of conferences, the life in the sea. As I am currently “out of office” from the seaweed research, doing a post doc at Gothenburg University, I find myself now in Berlin on the European Aquaculture Conference. It is interesting to see how different conferences are when there is also a strong market and business connected to the research. Here there are up to ten parallel sessions on everything from fish welfare, everything shrimp, genomics, and epigenetics to reproduction and broodstock management and macroalgae.

The first session I attend today is on aquaponics. This is the co-growth of fish, who excrete nutrients, with vegetables, who take up these nutrients. This is something we will see more of in the future, and I have been following the development of these techniques over the years. It was very interesting to hear how far the techniques have come today. There are now free download models that you can use to calculate how much algae you can grow together with fish, depending on what type of food you feed the fish. Super cool!

My favorite presentation was a small pilot study on feeding sea urchins with land grown vegetables (carrots, maize and soy) and then let sea cucumbers eat the waste and faeces. The experiment showed good growth in sea cucumbers and good gonad growth (roe sacks, the bits you eat) in sea urchins. The really good thing is that this shows that you don’t need fish meal in the diet, which has higher negative impact on the environment, and also the vegetables costs less than fish meal. From 9 euros of vegetables, they produced 25 euros worth of sea urchin roe and 40 euros of dried sea cucumber. This is the kind of presentations that gives me inspiration for my own research and also hope for the future food production.

A very interesting presentation by Luca Grosso on how to co-grow sea urchins and sea cucumbers using land-grown vegetables instead of fish meal.

Erik Malta from the Spanish aquaculture center (ctaqua) presented experiments on how to grow the green algae Ulva ohnoi (yes, actual name. Scientists can have a sense of humour) indoors in photobioreactors. Seaweed production have traditionally been limited to countries with traditional harvest, such as Ireland and France. But now other countries are also interested in producing seaweed, but how do you do this if you have little or no coastline suitable? The answer is land based. In this way you can produce large volumes of clean seaweed (no sand in your teeth there) and you can also monitor and to some extent control the nutrient quality of your produce. In this way you can optimize algae for whatever use you grow them for, be it animal feed, biofuel or human consumption. Green algae contain numerous types of oligosugars, as well as lipids (fat) which have a good market. This is underscored by the fact that most talks in this session is about farming green algae.

Siv Etter fron NTNU in Trondheim told of her studies on ammonium uptake in juvenile sugar kelp Saccharina latissima near salmon fish farms in Norwegian fjords. The Norwegian fish farms produce a lot of waste that contaminates the water column, but could be a resource to macroalgae if some calculations and strategical thinking is applied. The study placed small sugar kelp in either nutrient enriched seawater of 7 different concentrations or “clean” seawater, so growth could be compared. The nutrients tested was nitrate, ammonium and a mix of both. The results show a remarkably quick uptake of ammonium by the kelp. In only a matter of hours, the kelp had taken up all ammonium in the test aquaria. They discovered that sugar kelp actual prefers ammonium over nitrate, and only starts taking up nitrate after the ammonium is depleted. This is an extremely interesting and important discovery that shows how integrated systems of several different species is the way to reduce negative environmental impact.

Sofiia Tretiak from Germany has studied how to optimize the antioxidant activity in sea vegetables (a lovely name for macroalgae) when they are grown in RAS (recirculating aquaculture systems). The role of antioxidants in an industrial perspective is to stop the deterioration of fatty acids in produce, as low degradation gives a much longer shelf life and thus reduces food waste. The algae in the study was placed either in normal or high salinity and either also desiccated for some time or not, so in total four different treatment. Measurements were taken for growth rate, where all but the control (normal salinity, no desiccation) decreased in growth. They also measured the photosynthetic activity, showing stress in all but control treatments as well. They then moved on to add light dosage to this. Seaweeds need a certain dose of light per day. They can either get a small dose over a longer period of time, or a high intense short period, the effect on growth will be similar if the total dose is the same. The experiment tried high and low level of light for shorter and longer periods of time. But if given a low level of light for a short time, an extra boost of UV light showed a much increased growth, whereas the same treatment without UV almost completely died. So, why did they stress the seaweed so much? Well, stress is what causes the production of antioxidants, so if you want a seaweed high in antioxidants, you need to stress it real good. There was however, no clear results here on if they actually did produce more antioxidants from these treatments or not.

The final talk before we got to stretch the legs and find some lunch discussed the European seaweed value chains in an international perspective. By now my brain was good and mellow, and this was way too much economy for me to understand fully, so I conclude by stating that it was interesting to see that the seaweed production is globally divided into three different “worlds” regarding how and why. China farms for food, very large scale but with low-paid immigrant work force that is ageing and the whole industry is low tech. This is contrary to Europe, where labour is expensive and technology readily available. But in China, humans consume lots of seaweed, which we still have not begun doing in Europe. Also, the Chinese market is very innovative, looking for new species, new products and new ways to use seaweed. We can really learn a lot from them, and maybe these two different worlds are less different than they seem, as Europe is slowly catching up.

All in all a good and interesting start to the conference. I shall now attempt to dive into the poster display and look at over 500 posters!

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.

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.

2-year full time postdoc in Baltic Sea Ecosystem Change

A 2-year full time postdoctoral position in Baltic Sea Ecosystem Change is available starting 1 February 2018 (or as per agreement) at the Department of Ecology, Environment and Plant Sciences (DEEP). More information on the project and how to apply below (see also a second postdoc opportunity on Molecular Baltic Sea Ecology at the same department).

The project “Temporal change in Baltic Sea coastal, benthic ecosystems” aims to make use of an ‘unearthed treasure’ of data and archived samples from the Swedish national yearly monitoring program of phytobenthic communities in the Baltic Sea paired with existing data on abiotic factors and fish community surveys. The two main research questions are: How have coastal benthic communities along the Baltic Sea coast changed over the past 25 years, and to what extent are those changes driven by abiotic forcing vs. changes in trophic interactions? Have blue mussel diets changed in response to climate or nutrient loading; are changes occurring in both the Baltic proper and in the Bothnian Sea; and what are the consequences of altered diet for mussel body condition?

As most of the data exists, the focus of the work will be on isotope analyses of historical samples and/or causal time series analyses (e.g. multivariate ARIMA analyses).

The successful candidate will work in a team, that apart from the project leader Agnes Karlson, consist of Assoc. Prof Johan Eklöf and Dr Susanne Qvarfordt and Dr. Ellen Schagerström (at DEEP) but also with researchers at the Baltic Sea Centre and Department of Geology (Stockholm University).

The position involves full-time employment for a maximum of two years, with the possibility of extension under special circumstances. Start date 2018-02-01 or as per agreement. Applicants are expected to hold a doctoral degree. The degree should have been completed no more than three years before the deadline for applications. An older degree may be acceptable under special circumstances, which may involve sick leave, parental leave, clinical attachment, elected positions in trade unions, or similar.

Apply at the Stockholm university webpage:

At the Department of Ecology, Environment and Plant Sciences at Stockholm University research and education are conducted in an international environment. The subject areas are marine and plant ecology, ecotoxicology, plant physiology and plant systematics. Some of the research has direct environmental and societal relevance and the approach is often broad and interdisciplinary. About 150 people work at the department, of which ca 60 are teachers and researchers and 50 are PhD students.

Further information about the position can be obtained from Assistant Professor Agnes Karlsson (project leader), [email protected]

See also Postdoctoral Fellow in Baltic Sea Molecular Ecology

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.

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.

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.

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”.

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.

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.

Algae species of the month – February

For February, our Algae species of the Month will be two closely related species of brown algae, both of which belong to the family Scytosiphonaceae.
The first species is Petalonia fascia, also known by the common names Sea Petals or Broad Leaf Weed. It is a marine species that is not able to live in low brackish salinity, so it does not occur inside the Baltic Sea. It is, however, common along the coast of the North Sea and along the Swedish west coast. I found t hese specimens all dried up on one of the plastic containers that were sent ashore by the storm Urd, on a beach near the Tjärnö Marine biological station at Stromstad. So, in order t o investigate what alga species it was that had settled on the container , I carefully removed the thin brown-green flat membranes that were attached to the plastic with only a tiny attachment-disc. The name Petalonia fascia reveals a lot about how the algae looks. Petal means leaf and fascia means ribbon in Italian.

The other marine species is Scytosiphon lomentaria, known as Leather Tube or Chipolata Weed, and is just as Petalonia fascia a species that you can find during the cold season. It can form a belt just below the surface in the outer archipelago on the Swedish west coast in early spring and early summer. It is becoming more rare in the southern Baltic Sea and northwards from the Danish sound up to the Southern Quark, where the salinity is too low for it to survive. The ribbon-like thalli are yellow-brown and can be up to 25 cm long and 1-2 cm wide. They are hollow and have repeated “laced” narrow parts, making them look like a string of sausages, which gave the species its Swedish name, Sausagestring (Korvsnöre). Scytos means skin in Greek, siphon means pipes or tubes and lomentaria means lacing in Latin. So with a little knowledge of the ancient classical languages , the Latin name will provide you with information on how the algae looks.

Both species have a complex life cycle. It is only the major strands of Scytosiphon lomentaria or leaf-shaped pieces of Petalonia fascia that are visible to the naked eye and are found in early spring to early summer. These are the sexual stage of the algae lifecycle, called gametophyte. They grow from a small, millimeter-sized disc with which the algae is attached to the substrate. These small discs are all that is left for the rest of the year, and they form the second stage of the lifecycle, known as the sporophyte.

It is not possible to tell if the small brown spots or membranes you can see on a rock are sporophytes, which will grow in the spring so that the stone is covered by long sausage strings. Just wait and see. M aybe it’s some completely different species that emerges from all the microscopic stages that overwinter on the rocks and shells in anticipation of the return of light and warmth. And for the ice to melt. However, it is amazing how much freezing and dehydration the species living in the littoral zone can withstand.

To determine what species I found dried-up on the red plastic container from Ireland was easy. I just had to put the dry seaweed in a little water on a plate so it was possible to take a photo. You have to take what you can find in order to get a good background. Once re-hydrated, then it was easy to recognize that it was Petalonia fascia, because this is a species I have found before on the Swedish west coast. Also, I found some blue mussel and small saddle oyster-shells which made for a nice image.

Alga species of the month – January

This year we will introduce a new alga every month. Everything from the large brown algae such as the bladderwrack, ( Fucus vesiculosus ) and narrow wrack ( Fucus radicans ) who have been the theme in our research for many years (and will continue to emerge during the studies this year), to small microscopic algae that may not be so famous. We want to show you how exciting alga are and what good they do by producing oxygen and also which products we get from different alga species and what they can do.
The alga of January: Haematococcus pluvialis

In the small rock pools in the archipelago is often found a microscopic unicellular green alga. This alga, Haematococcus pluvialis , is called blood rain alga in Swedish and it is widely spread across Europe, Africa and North America. The latin name comes from the Greek word haema and Staphylococcus , which means blood and seed. pluvialis come from Latin and means rain.
They belong to the group of green algae and swim around by two thin flagella in the front side of the cell. In these small waterbodies of the rockpools, the environmental conditions vary quite a lot and blood rain algae can adapt and survive such different conditions as strong sunlight, drying out and freezing in winter, by forming special immobile resting spores with thick cell walls. The resting spores are filled with starch, fat, and astaxanthin, a red pigment. The spores become a sticky mass, forming a thin red film that sticks to the rock surface. When living conditions become better, for example, after a rain, the spores can transform and return to moving green algae.

Astaxanthin is a substance that protects the cell from degradation by free radicals, which attack the cell during different types of stress, e.g. when the cell is exposed to strong UV radiation. Blood rain alga is cultivated because of its high content of astaxanthin, which can protect the human body’s cells against free radicals and boost the immune system. Today we find astaxanthin in a number of products out on the market, including feed in salmon farming. The substance is for example vital to the salmon’s maturation and spawning and also helps protect against various diseases. Wild salmon ingest astaxanthin through their natural food, small crustaceans who have eaten algae.

Happy New 2017, and a movie.

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”.

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.

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 m 3 (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.

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.

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.

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