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Popular Science: Another piece of chrysophycean puzzle

Unlike plants and animals, unicellular organisms seem to be largely unexplored, even in areas that are otherwise widely studied. These unicellular organisms, which we call protists, also include chrysomonads. They are flagellates, some of which bear miniature silica scales of various shapes on the surface of their bodies. Their shape and structure are diagnostic. These algae are an important part of spring phytoplankton, where they can form dense populations until green algae or cyanobacteria overgrow them during the season. Yvonne Němcová from the Department of Botany of the Faculty of Science, Charles University and her colleague E. Rott from the University of Innsbruck in Austria focused on exploring the species richness of Alpine lakes (1,000-2,500 m) in Northern Tyrol. They have extended previous lake studies from lower locations in the same area.

Generally, chrysophytes like nutrient-poor waters and lower pH. However, in the highest lakes, which were extremely poor in nutrients, they were not found at all. Of the 21 analysed lakes, there were no chrysomonads living in 9 of them. The pair of scientists recorded 27 species, one of which is completely new to science. It was named Mallomonas pechlaneri. The silica scales of chrysophytes are observed in an electron microscope and their photographs can then be analysed using the geometric morphometry method. This method makes it possible to compare the shape of the scales of each species with one another and, on the basis of differences, to define new species. These morphologically-defined species very often correspond to the results of molecular genetic analyses. Other species found were among the world’s well-known representatives. Factors that most affected the occurrence and composition of chrysophycean communities were altitude and pH.

New species Mallomonas pechlaneri, source: Yvonne Němcová

From this study, it can be seen that even in such thoroughly researched areas such as Europe, new and new species of unicellular organisms, whose diversity is immense, can still be found. Despite the fact that molecular genetic methods are often necessary for the definition of new protists, in the case of chrysomonads, the shape and structure of the silica scales on their surface appears to be a reliable guide for distinguishing these algae from one another.

Němcová, Y., Rott, E. (2018). Diversity of silica-scaled chrysophytes in high-altitude Alpine sites (North Tyrol, Austria) including a description of Mallomonas pechlaneri sp. nov. Cryptogamie, Algologie 39: 63-83.               

Radka Zelená

Published: Nov 12, 2018 09:45 AM

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