Remote sensing

Kari Kallio defended earlier today his thesis on remote sensing in boreal lakes at the university of Helsinki. I wasn't there, but I took a glimpse at his thesis. Very interesting developments in technical apparatus, indeed. In a country like Finland with thousands of lakes it sure would be handy to be able to get results of many, many lakes without much effort. But. We are not there yet. A lot of algorithms still need to be calibrated. And algae counted. :)


Literature
Kallio, Kari 2012. Water quality estimation by optical remote sensing
in boreal lakes. Monographs of the Boreal Environment Research, No. 39.

Mytilopsis leucophaeata in the Finnish Archipelago

So, now it's confirmed. Conrad’s false mussel has been seen in the South-West Archipel area. Earlier this for Finland alien species was observed in the eastern part of the Gulf of Finland, near Loviisa, like they tell us on the Baltic Sea Portal http://www.itameriportaali.fi/en/tietoa/tulokaslajit/en_GB/mytilopsis_leu/.

And today, they told in YLE news that this Mytilopsis leucophaeta has reached - or otherwise come to - Airisto. It took an American reseacher, Amy Fowler, to find them. At the university of Turku they verified the species using DNA-techniques. This little mussel looks so much like the very common Zebra mussel (Dreissena polymorpha), that it's not really easy to just look at it and greet it with it's right name.

The scientists of course want to know what are the effects of this newcomer on the Baltic Sea ecosystem? Mostly one immediately fears for negative effects, but just some time ago Joanna Norkko from Åbo Akademi and her colleagues found out, that another invasive species (polychaete worms, Marenzelleria spp) has had a very positive effect on the near bottom oxygen conditions in the Northern Baltic Sea, like they write in Global Change Biology

Planktic long bone

Eunotia zasuminensis (Cabejsz.) Körner 1970 is a rather rare diatom species with star-like colonies. It resemlbles the familiar Asterionella and is probably often identified under this name.

E. zasuminensis differs from Asterionella in the form of the cells. Where Asterionella formosa particularly has cells where one end is much smaller than the other, in E. zasuminensis both ends are quite the same size. But in the middle there is a little bubble. Actually it looks very much like the humerus, the long bow in one's arm. Of course you have to see the Eunotia cell from the valve face.

If you can't see the humerus shape and are hesitating wether to call it E. zasuminensis or Asterionella, take a look at the chloroplasts. In Asterionella there are many little chloroplasts after each other, in E. zasuminensis there are fewer, bigger chloroplasts and they are closer to each other:

Asternionella formosa.

Eunotia zasuminensis.

This species has been moving a bit in the house of Taxonomy, as Eloranta writes in his article (see below). It was originally placed in the genus Fragilaria by Cabejszekowna (1937). Lundh-Almestrand (1954) again moved it to the genus Asterionella, while Körner in 1970 finally gave it a place in the genus Eunotia, because it really does have a raphe, albeit a tiny one. The first two genera are members of the class Fragilariophyceae - the ones without a raphe. Eunotia is a member of tha class Bacillariophyceae.


You want to know more? Take a look at Eloranta's article: Eloranta, P. (1986) Melosira distans var. tenella and Eunotia zasuminensis, two poorly known planktonic diatoms in Finnish lakes. Nordic Journal of Botany
Volume 6, Issue 1, pages 99–103.

Or if you are as fortunate as being able to understand Finnish, you can visit the Finnish plankton guide on the net: http://www.jyu.fi/bio/kasviplankton/uusin/index.php

Literature:
Cabejszekowna, I. (1937) Fragilaria zasuminensis n. sp. w jeziorze Zasuminskim na Pollesiu. Arch. Hydrobiolö Rybactwa 10: 423-425.
Lundh-Almestrand, A. (1954) Some remarks on Fragilaria zasuminensis. Bot. Notiser 1954 (2): 179-182.
Körner, H. (1970) Morphologie und Taxonomie der Diatomeegattung Asterionella. Nova Hedwigia 20 (3-4): 557-724.

The one with the warts

As a good start for a new plankton year I had the pleasure of meeting Crucigenia mucronata in the Dutch waters. Quite a rare species, but easy to recognize because of the warts. As the name says - mucro (Latin) = point, wart.

Size of the cells: 5x7,5 µm.

It is mentioned on the Dutch TWN-list, so it must have been seen in the Netherlands earlier. Komárek and Fott (1983) list France, Guadeloupe (who has been there collecting algae!?), India and Iowa in the USA as places where it has been recorded. They also tell us that the species like eutrophic water.

In Algaebase we can see that also Spain and Portugal can be added to this list of places of observation. Probably Germany too, because the Dutch TWN-list mentions as literature for this species also Tsarenko's and Krienitz's study on the coccal green algae of lake Tollensee, Germany. Unfortunately I don't have this article. Yet.

In Europe the species is further also recorded at least in Poland (Kozak et al 2007). It is not on the Finnish phytoplankton list.

Some surfing on the net gave also result in Taiwan.

Have you seen this little fellow?

Literature
Cambra Sánchez, J., Álvarez Cobelas, M. & Aboal Sanjurjo, M. (1998). Lista florística y bibliográfica de los clorófitos (Chlorophyta) de la Península Ibérica, Islas Baleares e Islas Canarias. pp. 1-614. Burgos: Asociación Española de Limnología.

Komárek, J. & Fott, B. (1983): Chlorophyceae (Grünalgen). Ordnung: Chlorococcales. - In: G. Huber-Pestalozzi (†). Das Phytoplankton des Süßwassers. Systematik und Biologie. 7. Teil, 1. Hälfte. In: Elster, H.-J. & Ohle, W. (red.). Die Binnengewässer. Einzeldarstellungen aus der Limnologie und ihren Nachbargebieten. Band XVI. E. Schweizerbart’sche Verlagsbuchhandlung (Nägele u. Obermiller), Stuttgart. X + 1044 pp., incl. 253 pls. ISBN 3-510-40023-2.

Kozak, A., Gołdyn R., Tymek, K. (2007). Long-term changes in the phytoplankton of a shallow storage reservoir. International Journal of Oceanography and Hydrobiology. Vol. XXXVI, Supplement 1. (87-93)

Tsarenko, P.M. & Krienitz, L. (1997). The flora of coccal green algae of Lake Tollensee and its tributaries (Baltic Lake District, Germany). – Archiv für Hydrobiologie / Supplementband 120, Algological Studies 86: 91-106.