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.

Planctonema lauterbornii Schmidle 1903

seems to be a species that occurs when the ecosystem is in stress (Leitão et al 2003, Song et la 2009).

The Dutch TWN-list has 3 "preferred names" for Planctonema: 2 lauterbornii's and Planctonema subtilissimum.

There is Planctonema lauterbornii Schmidle 1903, but then also Pl. lauterbornii sensu M. Watanabe, T. Hori et M. Akiyama 1986. I looked up the article of Watanabe & Co , but - I must say - some of the information did not exactly reach my brain. Maybe it was the Japanese language. So it remains a mystery to me, why Watanabe et al's lauterbornii should be recorded apart.

Hällfors writes about Planktonema subtilissimum in Finnish archipelago (Hällfors 1984). But this species is not mentioned in the Checklist of Baltic Sea Phytoplankton Species. Not on the Helcom species list either. Nor on the Finnish freshwater algae list... I do have to get that article to find out what Hällfors is writing about.

Planctonema lauterbornii one can find on the Finnish freshwater algae list. But on the updated internet version of Tikkanens Plankton guide one can read that this species is in Finland only seen in the brackish water. This is not true. Planctonema lauterbornii Schmidle is also in the Finnish lakes.

The TWN-list gives us two synonyms for Pl. lauterbornii
1: Binuclearia lauterbornii Author: (W. Schmidle 1903) A.I. Proshkina-Lavrenko 1966
2: Geminellopsis fragilis Author: O.A. Korshikov 1939

Also remember that Bourrelly's (1962) Pl. lauterbornii is actually Planctonema subtilissimum (N.G. Von Lagerheim 1900) G. Hällfors 1984.
And to write the genus nam with a "c", not with "k" anymore.

Photo's: Planctonema lauterbornii cells ca. 3x10 µm.

Literature
Hällfors, G. 1984. Filamentous rock-pool algae in the Tvärminne archipelago, S. coast of Finland. – Acta Botanica Fennica 126:1-111
Leitão M., Morata S.M., Rodriguez S., Vergon J.P. 2003. The Effect of perturbations on phytoplankton assemblages in a deep reservoir (Vouglans, France)Hydrobiologia 502: 73–83.
Song X., Liu Z., Yang G., Chen Y. 2009. Effects of resuspension and eutrophication level on summer phytoplankton dynamics in two hypertrophic areas of Lake Taihu, China. Aquat Ecol (2010) 44:41–54
Watanabe, M., Hori, T. & Akiyama, M. (1986): Planctonema lauterbornii Schmidle. Studies on the development of filament organization in Planctonema lauterbornii Schmidle. – Bulletin of the National Science Museum, Tokyo, Ser. B (Botany), 12 (3): 107-115.

Tychonema

Hmm, it's true, then. They are here. Tychonema's. On the Cyanobactria course in Czech Rebublic last August I was quite surprised to hear Prof. Komárek say that Tychonema is quite common in the northern lakes...

As he, together with Anagnostidis, wrote in Süsswasserflora 19/2 (2005) they occur "in the plankton of northern, colder lakes, slightly eutrophicated". Found some in a northern lake.

Tychonema resembles a lot Planktothrix, and is very closely related too. Both belong to the family Phormidiacea and even to the subfamily Phormidioideae. What is different between these genera is that in Tychonema the cell content is pale and whit "holes" These holes are in fact widened thylakoids, a phenomenon called keritomy.

Tychonema bourrellyi (J.W.G.Lund) Anagnostidis & Komárek

Literature:
Komárek, J. & Anagnostidis, K. 2007. Cyanoprokaryota , 2. Teil: Oscillatoriales. Süßwasserflora von Mitteleuropa, Band. 19/2. Elsevier, München.

Pediastrum

Found this Pediastrum integrum C.W. Nägeli 1849 in a sample with almost nothing in it. And yes, Komárek and Jankovská (2001) tell that it's common in oligotrophic and dystrophic cold and clear large and small lakes as well as small peaty basins. Everything fine so far.

What puzzled me was there also was P. angulosum (C.G. Ehrenberg 1834) ex G.G.A. Meneghini 1840, which Komárek and Jankovská (2001) describe as "rather alkalifilic and does not occur in peaty waters an acidic swamps." But then again, I only saw two coenobia, one of each. In 25 ml. And of course they could occur simultaneusly. Water could be oligotrophic, but not so dystrophic and acidic, with some submersed waterplants too, so that they would both feel happy.

Wecktröm et al (2010) wrote a nice article about ecology of the Pediastrum in subarctic lakes. They mention both these species too. P. integrum was the only species in their study, for which they found similar distribution as the earlier studies. For P. angulosum they found that it was most abundant in lakes with the lowest pH and highest DOC concentration. But, then again, their most acidic was 6,4. So not that acidic anyway. Komárek and Jankovská (2001) write, that P. angulosum is known probably more in warm areas. But it's here too, I can tell!

These species were easy ones to identify. More difficult it gets with the many variaties of P. boryanum. According to Komárek and Jankovská (2001) var. breviscorne and var. forcipatum have been seen in tropical countries and they think that data from these varieties from the northern countries very probably are other species. Well, well. Weckström & co write anyway that they have trust in their identification. I would - for my part - be very careful with these varieties.