Storms are usually named in alphabetical order from the area where they begin. St. Jude was named in England but was re-named by SMHI (Swedish Meteorological and Hydrological Institute) to Simone after the name of the day in the calendar (in Sweden, each day of the year has one or two names) that the storm reached the Swedish west coast. The weather was less severe than expected at Tjärnö, but still quite strong winds and high water levels. I could still see the traces of this a month later, as we took a walk around Saltö.
The clear evidence of how high the water has reached during the last storm can be detected by looking at the size of the beach cast wrack border, and how far up on the beach it is.
This picture shows three clear rows of wrack borders where algae and eelgrass has been gathered by water movements.
During the storm Simone, a lot of algae was washed high up on shore. The material in the wrack border tells us that the entangled algae and some mussel shells were torn away from quite deep locations. Among the species of mussels that I found in the wrack border was the horse mussel (Modiolus moduolus) which looks a bit like the common blue mussel (Mytilus edulis) but is larger and lives at greater depth.
So, how do I tell a Modiolus moduolus from a Mytilus edulis? If you look closely at the picture, you’ll see that the pointy part (the umbo) is not at the tip of the shell as it is on the Mytilus edulis?, but slightly higher up on the shell. The shell of the Modiolus moduolus is also slightly browner than that of the Mytilus edulis, which is typically blue, as the common name denotes.
Other traces on the beach shows that part of the beach cast comes from Norway or even as faraway as from the British Isles, and has been transported all this way before ending up in this tangle of seaweed on Saltö. I found Ascophyllum nodosum, which also grows on the rocky shores around Saltö, but these specimens had much larger vesicles (floating bladders)than the ones at Saltö and were entangled together with reproductive parts of Himenthalia elongata, an algae species that is sometimes referred to as “sea spaghetti”.
Amongst our other exciting finds were several unusually large cuttlefish skeletons. It looked like they had been floating for quite some time in the sea, as they had a lot of green algae growing on them. They are often used as a source of calcium for caged birds. In days of old they were called “whale fish scales”, which is a double fault since the whale is not a fish and hence does not have scales.
There were also remnants of the summer’s fun and games. The lost bucket for catching crabs and a deflated ball. Or the almost ghostly rubber gloves in a bucket of frozen water, which looked like an art installation.
It was a cold but sunny day in November that we made all these discoveries at Saltö, which is part of the Kosterhavet marine national park near the Tjärnö Marine Laboratory. It will be exciting to come back around the New Year and see what coming storms have brought us, and if the bucket with gloves or the ball are still there. Maybe there will be some new species of seaweed from a faraway place, brought here attached to a floating shoe, a log or some other flotsam.
During the summer, the BalticSeaWeed blog did al ot of fieldwork, both at Askö on the east coast and Tjärnö on the west coast.
Among other things, we performed an inventory of algae populations along two transects (laid out measuring tape) outside Tjärnö on the salty west coast.
The scuba diver swims from the beach with a tape measure that has been attached at the waterline down to the depth where no more algae grow. Depending on water clarity, this may vary from a few meters to more than 20 meters depth.
Once the algae end, the diver takes out her slate (the single most important tool for any marine biologist) and begins by noting the depth and how much of the tape measure that’s been rolled out. Subsequently, the diver notes down all the algal species she sees and appreciates how much of them there are, on a 7-point scale (1, 5, 10, 25, 50, 75 and 100%).
When the diver has recorded all of this about the starting point, she swims slowly along the transect (tape measure) and continues to note the depth, length and species when it becomes a visible difference in the species that dominates, in order to produce a map of different “algal belts”.
Each “belt” is also sampled, using frames and bags. The diver uses a fixed size frame, which can be loose or attached to a bag, of a size usually 20×20 or 50×50 cm, depending on how many species and how much algae it is.
The diver puts the frame on the bottom, picks the largest algae by hand and puts them into the bag and then use a scraper to get off all the algae that grows within the frame and whisk them into the bag. It’s harder than it looks to work under water when everything is floating around.
For you to get an idea of how it works, Joakim Hansen, who helped out as dive buddy this summer, shared what he was filming with the BalticSeaWeed blog. Here’s how it looks when you scrape a frame.
Why, then have we done this, except that it’s very nice to go for a dive?
On these two sites, these inventories have been conducted for several years. In ecology, it is very important to have measurements that extend over a long period of time in order to see if there is a genuine change in the environment, or if it is just normal variations between years.
So during the cold, dark months, we will pick up our bags with frozen algae out of the freezer (there were over 30 of them), thaw them, sort them into piles according to species, dry and weigh and record in the protocols, thus getting the number of grams dry weight of each species that grew in each frame. By comparing our data with previous protocols, we can then see if it has become more or less of any species, and if any new species have appeared or if any have disappeared over the years.
At the end of November, I spent a week at Roskilde University in Denmark.
By invitation from fellow marine botanist professor Morten Foldager Pedersen, I went there to start up an experiment on Fucus radicans together with his PhD-student Tiina Salo.
Fucus radicans is named after its ability to reproduce asexually by fragmentation. Radicans is latin for “root-forming”, and although algae do not have roots, they form root-like attachments to the substrate, called rhizoids. So, when a small fragment falls off the mother algae, it can re-attach and form a new thallus, which is a genetically exact copy of its “mother”, i.e a clone.
A fragment of Fucus radicans has formed new rhizoids, attaching to the bottom of a petri dish.
To reproduce in this way is not very common within the Fucus-family. We do not know what favours this mode of reproduction, unlike the sexual reproduction where we know that salinity plays a major role, but light and temperature is also important.
So, in order to find out how Fucus radicans has the best non-sexual reproduction, we designed the experiment in Roskilde.
The parameters we have decided to try are light, temperature and water movement.
Together with Tiina, I spent the better part of the week in the basement of the Biology department, in a temperate chamber filled with algae, sea urchins, a hard-at-work master student and the all-time favourite combination of electricity and water.
The light box is fitted over one of our white tanks.
In order to decide if any of our tested parameters, alone or in any combination, contributes to the formation of rhizoids, you have to plan the setup so that the results can be testad statistically. This means that you have to think hard before you start the experiment, so that you can use the data to actually answer your initial question. I’m in luck. Tiina is a total wiz when it comes to statistics, and two heads are better than one.
To the right can be seen the heater (square box) and the cooler (spiral).
I had brought some Fucus radicans from some different localities with me to Roskilde. We picked off small fragments, no bigger than 1 cm, and placed them on tiles. Tiina bought them at Bauhaus and had had the same experience as me. Why is it considered strange to be more interested in the back of a tile?
Four small fragments on a tile.
Finally, we were all set and could switch on the electricity again. We’ll leave it for approximately seven weeks, then I’ll go back and check the result. Meanwhile, wee keep our fingers crossed, hoping that the seaweed will cooperate and form nice new rhizoids. We’ll keep you updated.