alga

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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 these 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 to 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.

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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.

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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. Maybe 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.

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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.

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On a plate is where both Petalonia fascia and the closely related species Scytosiphon lomentaria really belong! Were you to visit Japan or other countries where it is common to eat different algae, you will find them dried and for sale under many different names; Kayamo-nori, Hime-kayamo, Ito-kayamo, Mugiwara-nori, Sugara, Yore- kayamo. I am not sure, but maybe they can be purchased at stores specializing in Asian products in Sweden too. Both species are known for their content of antioxidants. Otherwise, you can find your own little “Kayamo-nori” in the spring. It’s fine to eat just as it is. Just make sure they are picked far from discharges of polluted waters and not inside the marina.
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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

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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.

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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.