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.

Catalogue of the desmids of Ireland

Wonderful! To be found at AlgaeBase: http://www.algaebase.org/search/bibliography/detail/?biblio_id=47220

The big one

This big (68x80 µm) Cosmarium botrytis lightened up my day just before lunch break.

It was cathed in a lake Kurtinjärvi in Kuusamo, in the north of Finland. West & West (1912) already mention, that it has been seen in Finland. A quite a common species, found all over. West & West describe 7 varieties of this species with "considerable amount of variability": paxillosporum, subtumidum, tumidum, gemmiferum, emarginatum, mediolaeve and depressum. They only mention var. gemmiferum as seen in Finland at that time. Skuja mentions the species in some northern lakes in Sweden in 1948, with 3 varieties: subtumidum, tumidum and depressum. In his Abisko-book from 1963 he mentions only the two first ones.

Lenzenweger lists 5 varieties and one forma, of which var. latum and f. minus he states as taxonomically questionable. He also mentions var. emarginatum. Coesel en Meesters mention 3 varieties above var. botrytis itself: paxillosporum, tumidum and mediolave. And finally, AlgaeBase counts totally 14 varieties, all of them taxonomically accepted names.

The Finnish Algae guide by Tikkanen (1986) does not mention any varieties, while the official Phyto-list includes also var. depressum.

To the species level Cosmarium botrytis Meneghini 1840 ex Ralfs 1848 is easy to identify: just look at the big size, the pyramidal outline, two pyrenoids in each cell half the "pearly" granules, as Ralfs (1848) puts it, which can be - according to him - "sometimes very evident, sometimes obscure".

Literature
Coesel, Peter F.M. & Meesters, Koos (J.) 2007. Desmids of the Lowlands. Mesotaeniaceae and Desmidiaceae of the European Lowlands. KNNV, Zeist.
Lenzenweger R. 1999. Desmidiaceenflora von Österreich. Teil 3. 1999 (Bibliotheca Phycologica 104) J. Cramer, Stuttgart.
Ralfs, J. (1848). The British Desmidieae. pp. [i]-xxii, [i], [1]-226, pls I-XXXV. London: Reeve, Benham & Reeve Skuja H. (1948) Grundzüge der Algenflora und Algenvegetation der Fjeldgegenden um Abisko in Schwedisch-Lappland. Nova Acta Regiae. Soc. Sci. Upsal., Ser 4 18 (3).
Skuja H. (1964) Taxonomie de Phytoplanktons einiger Seen in Uppland, Schweden. Symb. Bot. Upsal. 9 (3).
Tikkanen, Toini 1986. Kasviplanktonopas. Suomen Luonnonsuojeluliiton tuki Oy. Helsinki.
W. & G.S. West 1912 A Monograph of the British Desmidiaceae, Vol. 4., Ray Society, London.

They still love Zooplankton!

In the newest Hydrobiologia (Volume 676, Number 1 / November 2011) there is a bunch of articles about zooplankton. Wonderful! "Cladocera crustaceans: sentinels of environmental change" Eggermont & Martens write in the preface. I do believe they are. Jeppesen et al plead for including zooplankton to the European Water Framework Directive. No objections heard from me. What makes me especially happy is the high number of Finnishs names as authors.