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.