Tag Archives: Algae

Friday Fellow: Irish Moss

by Piter Kehoma Boll

Growing abundantly along the North Atlantic coasts, our newest Friday Fellow is a cartilaginous red alga commonly known as Irish moss or scientifically as Chondrus crispus, which means something like “curly cartilage”.

chondrus_crispus

The Irish moss usually appears as a mass of curly cartilaginous and soft seaweed with a red or purple tinge. Photo by Wikimedia user Kontos.*

Reaching about 20 cm in length, the Irish moss is attached to the substrate by a discoid base and its thallus branches dichotomously four or five times. The width of the branches may vary from about 2 to 15 mm and the color is even more variable, ranging from green or yellowish to dark red, purple, brown or even white. As with all plants, the Irish moss has a gametophyte (haploid) and a sporophyte (diploid) form. The gametophytes have a blue iridescence (as seen in the photo above), while the sporophytes show a dotted pattern (seen above as well).

The Irish moss is edible and relatively well known among the communities living where it grows. In Ireland and Scotland, it is boiled in milk and sweetened to produce a jelly-like product. The cartilaginous or jelly-like appearance of this alga and its derivatives are due to the presence of high amounts of carrageenan, a polysaccharide that is widely used in food industry as a thickening and stabilizing agent and as a vegan alternative to gelatin.

Due to its economic importance, the Irish moss is cultivated in tanks for the extraction of carrageenan and other products. Both gametophytes and sporophytes produce carrageenans of different types that can be used for different purposes.

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References:

Chen, L. C.-M.; McLachlan, J. (1972) The life history of Chondrus crispus in culture. Canadian Journal of Botany 50(5): 1055–1060. http://doi.org/10.1139/b72-129

McCandless, E. L.; Craigie, J. S.; Walter, J. A. (1973) Carrageenans in the gametophytic and sporophytic stages of Chondrus crispus. Planta 112(3): 201–212.

Wikipedia. Chondrus crispus. Available at < https://en.wikipedia.org/wiki/Chondrus_crispus >. Access on August 1, 2017.

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Friday Fellow: Common Stonewort

ResearchBlogging.orgby Piter Kehoma Boll

It’s always hard to introduce a less charismatic species here. Not because they are less interesting to me, but because I cannot find good information available. But I try to do my best to show all aspects of our amazing biodiversity.

Today I’m introducing another alga, one of the most complex ones, the common stonewort, scientifically known as Chara vulgaris.

...armleuchteralgen

A “field” of common stoneworts in a pond. Photo by Markus Nolf.*

Found worldwide in freshwater environments, especially marshes and swamps, the common stonewort may actually be a complex of species. Its name “stonewort” comes from the fact that the plant may become encrusted in calcium carbonate, giving it a stony appearance. Growing up to 120 cm in length/height and having a central articulated stalk with several branches coming out from each node, it may look similar to a horsetail, but its structure is much simpler.

If you look closer, you’ll see that the stalk is formed by a simple mass of chained cells, but very big ones. Actually, the cells of species in the genus Chara are among the largest known plant cells. And having such large cells, stoneworts have become experts in cytoplasmic streaming, a phenomenon by which organelles and fluids flow throughout the cytoplasm guided by an interaction of myosin molecules that slide along actin molecules. And in case you didn’t know, myosin and actin are also the molecules responsible for muscular contractions in animals.

chara_vulgaris

A closer look at a stalk of the common stonewort. Photo by Kristian Peters.*

The common stonewort is very common in rice fields and serves as a substrate for nitrogen-fixing bacteria. Thus, although usually considered a weed in the fields, the presence of the common stonewort may actually help to increase the soil fertility in rice fields.

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References:

Ariosa, Y., Quesada, A., Aburto, J., Carrasco, D., Carreres, R., Leganes, F., & Fernandez Valiente, E. (2004). Epiphytic Cyanobacteria on Chara vulgaris Are the Main Contributors to N2 Fixation in Rice Fields Applied and Environmental Microbiology, 70 (9), 5391-5397 DOI: 10.1128/AEM.70.9.5391-5397.2004

Wikipedia. Charales. Available at <https://en.wikipedia.org/wiki/Charales&gt;. Access on December 15, 2016.

Wikipedia. Cytoplasmic streaming. Available at < https://en.wikipedia.org/wiki/Cytoplasmic_streaming>. Access on December 15, 2016.

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Friday Fellow: Wheel Necklace Diatom

ResearchBlogging.orgby Piter Kehoma Boll

Most of you likely know what diatoms are, microscopic algae with a silica shell that are very abundant in the world’s oceans and one of the main oxygen producers. You may have seen images like the one below, showing the diversty of diatoms, but can you name a single species?

diatoms

The beautiful, yet largely neglected by non-experts, diversity of diatoms. Photo by Wikimedia user Wipeter.*

Today I decided to bring you a diatom Friday Fellow and let me tell you: it was not at all easy to select a nice species with a considerable amount of available information and a good picture. But at the end the winner of the First Diatom Friday Fellow Award was…

Thalassiosira rotula!

thalassiosira_rotula

Three connected individuals of Thalassiosira rotula. Photo by micro*scope.**

As with most microorganisms, this species has no common name and, as it is a tradition here, I decided to make one up and chose wheel necklace diatom. Necklace diatom seems to be a good common name for species in the genus Thalassiosira, as they are formed by several individuals connected to each other in a pattern that resembles a necklace. I decided to call this particular species wheel necklace diatom because of its specific epithet, rotula, which means little wheel in Latin.

The wheel necklace diatom is a marine species found worldwide close to the coast. It is very abundant and the dominant species in some areas, so it is of great ecological importance. Small planctonic crustaceans, such as copepods, usually feed on the wheel necklace diatom and, as those crustaceans are used as food for much larger animals, the wheel necklace diatom is responsible for sustaining a whole food chain.

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References:

Ianora, A., Poulet, S., Miralto, A., & Grottoli, R. (1996). The diatom Thalassiosira rotula affects reproductive success in the copepod Acartia clausi Marine Biology, 125 (2), 279-286 DOI: 10.1007/BF00346308

Krawiec, R. (1982). Autecology and clonal variability of the marine centric diatom Thalassiosira rotula (Bacillariophyceae) in response to light, temperature and salinity Marine Biology, 69 (1), 79-89 DOI: 10.1007/BF00396964

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Friday Fellow: Witch’s Jelly

ResearchBlogging.orgby Piter Kehoma Boll

I wonder how many people can say they have a bacterium that reminds them of their childhood. Well, at least I can say that I have.

When I was a boy and started to know about the amazing world of living beings that fill our planet, I spent most of my time outdoors looking at every small corner of the backyard and nearby woods in search for interesting lifeforms. And one that always caught my attention was a strange brownish green gelatinous mass that appeared on the ground in the rainy season.

nostoc_commune

Have you ever found something like that on the ground? Photo by flickr user gailhampshire.*

At first I thought it was some species of green alga, but was unable to identify the species. Many years later I finally found out what it is, a colony of cyanobacteria called Nostoc commune and commonly known as star jelly, witch’s butter, witch’s jelly and many other names. It is found worldwide, from the tropics to the polar regions.

As in other cyanobacteria, the witch’s jelly is formed by a colony of unicellular organisms connected in chains. Those are embedded in a gelatinous matrix of polysaccharides that gives the colony its jelly appearance.

nostoc_commune

Chains of Nostoc commune in the matrix of polysaccharides seen under the miscroscope. Photo by Kristian Peters.**

During dry periods, the colonies of witch’s jelly dessiccate and become an inconspicuous thin layer on the ground. They may remain in this state for decades, maybe centuries, until the ideal conditions come back.

In some places, especially Southeast Asia, the witch’s jelly is consumed as food, being a traditional food in the Chinese Lunar New Year.

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References:

Lipman, C. (1941). The Successful Revival of Nostoc commune from a Herbarium Specimen Eighty- Seven Years Old Bulletin of the Torrey Botanical Club, 68 (9) DOI: 10.2307/2481755

Tamaru, Y., Takani, Y., Yoshida, T., & Sakamoto, T. (2005). Crucial Role of Extracellular Polysaccharides in Desiccation and Freezing Tolerance in the Terrestrial Cyanobacterium Nostoc commune Applied and Environmental Microbiology, 71 (11), 7327-7333 DOI: 10.1128/AEM.71.11.7327-7333.2005

Wikipedia. Nostoc commune. Available at: < https://en.wikipedia.org/wiki/Nostoc_commune >. Access on September 19, 2016.

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Friday Fellow: Red Euglene

by Piter Kehoma Boll

Don’t be as fool as the Egyptian Pharaoh in the myth of the Plagues of Egypt. If you happen to find a lake with red water, as in the picture below, it is certainly not blood. It’s simply… a toxic alga!

Sometimes one may find the waters of a like turned red. Photo extracted from naturamediterraneo.com/forum/, posted by user Carlmor.

Sometimes one may find the waters of a lake turned red. Photo extracted from naturamediterraneo.com/forum/, posted by user Carlmor.

The creature responsible for this coloration is today’s Friday Fellow: Euglena sanguinea, or the red euglene, a microscopic freshwater protist with a worldwide distribution. This unicellular organisms has a red color due to the presence of astaxanthin, a pigment also found in some fish, like salmon, and in crustaceans, like shrimp and crayfish. Some birds may also have this pigment in their feathers. In red euglenes, astaxanthin acts as a protection against ultraviolet radiation, so that the higher the amount of UV radiation, the redder the algae become.

A fraction of a population of red euglenes under the microscope. Photo extracted from naturamediterraneo.com/forum/, posted by user Carlmor.

A fraction of a population of red euglenes under the microscope. Photo extracted from naturamediterranea.com/forum/, posted by user Carlmor.

When the conditions are adequate, usually due to high temperatures and high amounts of nutrients, the red euglene may overpopulate and cover the entire surface of water bodies, making it appear red. Water pollution, especially from domestic wastewater, is one of the main causes of nutrient increase in water bodies and thus a direct cause of many algal blooms.

The red euglene is known to produce euglenophycin, a very potent ichthyotoxin, i.e., a compound that is toxic to fish. As a result, red euglene blooms can lead to high fish mortality, making it an organism of major concern to fish breeders.

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References:

Gerber, S.; Häder, D-P. 2006. Effects of enhanced UV-B radiation on the red coloured freshwater flagellate Euglena sanguineaFEMS Microbiology Ecology, 13(3): 177-184. DOI: 10.1111/j.1574-6941.1994.tb00064.x

Wikipedia. Euglena sanguinea. Available at <https://en.wikipedia.org/wiki/Euglena_sanguinea&gt;. Access on  January 07, 2016.

Zimba, P. V.; Rowan, M.; Triemer, R. 2004. Identification of euglenoid algae that produce ichthyotoxin(s). Journal of Fish Diseases, 27: 115-117.

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Filed under Algae, Conservation, Ecology, Friday Fellow, Pollution