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Notes on the vegetation of lakes in the woodland of Lule Lapprnark 231Fig. 3. Plankton of Lake Satisjaure.Large spiral colonies: TabellariaTeilingii; lamp-brush orstar-like colonies: Asterionella formosa;six-horned cells: Staurastrumpingue, St. petsamoense v. minus;dark round bodies: PeridiniumW illei, P. cinctum; branched (barelyvisible) Dinobryon cylindricum;small, cylindrical: Cyclotellabodanica v. lemanensis; large rotatoria:Asplanchna priodonta (left),Conochilus unicornis (right). Ca.120 x . Photo K. Thomasson.the vegetation on the shores is on the whole verysparse.The higher aquatic vegetation is also generallysporadic, partly depending on the rarity of shallowbottoms. But on favourable bottom deposits growsa comparatively rich vegetation of aquatic plants.Locally, on muu bottoms, there occur fairly extensivesubaquatic "meadows" consisting of variousspecies, most frequently Nitella cf. opaca, Oharafragilis, Oallitriche harnulata ( =interrnedia) and0. verna, Myriophyllurn alterniflorurn, Ranunculusconfervoides and R. peltatus. On other bottomsIsoetes echinospora, I. lacustris, Potarnogeton alpinus,P. alpinus x grarnineus, P. grarnineus, P. perfoliatus,Hippuris vulgaris, Sparganiurn hyperboreurn, Subulariaaquatica and Ranunculus reptans grow rathercommonly. In shallow water and on the lowestpart of the shores there is a local, generally sparsevegetation of Oarex aquatilis, 0. rostrata, 0. funcella,Alopecurus aequalis and in a few placesEquiseturn fluviatile.The summer transparency in Satisjaure is 650-850 cm in the eastern part, called Patats. The otherparts of the lake have a transparency from 850 to1250 cm. The colour of the water against theSecchi disc is yellow-green or blue-green. The measurementsof pH show values from 6.6 to 7.0. Thetemperature of the water, determined in summer inconnection with quantitative sampling with aRuttner sampler, is seldom more than + 10°C atthe surface, and at 50 m it is usually + 6 to + 7°C.Samples of water taken for chemical analysis showthe following dataDate20 . 106Electrolytes, mgflNaKCaMgMnClS04Total hardness, dH0Total alkalinity, meq.flColour, mg Ptfl15.8. 196122.31.10.472.60.60