Sichttiefen und Wasserfarben der oberen Seen der Feldberger Seenlandschaft im Jahre 1983

At the Schmaler and Breiter Luzin and at the Haus lake there were carried out monthly measurements of the depth of visibility with a white and a black Secchi disk and with Secchi disks of the colours blue, green, yellow, orange, red and reddish brown. The depths of visibility are 0.55… 5.8 m with variation widths for the colours referred to white of 0.05… 2.1 m. The diagram developed by SAUBERER , ELSTER and ?TěPÁNEK for the colour determination is extended empirically on the basis of measurements in the Feldberg lakes and then the water colour of the investigated lakes was determined in the annual variation. The thus obtained classification of the water in a ten-step scale of colours shows a good agreement with the simultaneously determined colours according to FOREL and ULE . Of particular interest is the representation of the change of colours of the three lakes in the annual variation, which shows an individual distribution of colours for each lake—proceeding from a relatively uniform colour in December.     

Veränderungen der Diatomeenflora der Werra unter dem Einfluß des Salzgehaltes

Under the influence of the wastewaters of the potash industry the Werra river shows considerably varying salt contents (0.47 … 28.2 g/l Cl^?, annual means 4.4 … 11.4 g/l Cl^?) in dependence on the hydrological situation. Between 1982 and 1988 a total of 112 taxa of diatoms were observed. Of special interest is the occurrence of Stauroneis constricta (EHRENBERG) CLEVE, which is new for the river Werra. Its spreading upstream was observed. Compared with earlier findings as well as within each annual cycle there are observed clear changes in the species present and in the colonization structures in dependence on the salt content. The close relations between the salt content and the diatom communities are truly expressed by the index of halobic organisms. Diversity indices of 1.048 … 3.259 as well as values of 0.074 … 0.817 for evenness verify the imbalance of the colonization, without, however, revealing a relation to the salt content, except for variations of concentration which may be too sudden.     

Zum Sauerstoffhaushalt der Gewässer der Feldberger Seenplatte an Hand ausgewählter sommerlicher Tiefenprofile seit 1924 und 1962 Teil 3: Scharteisen,Wasch-See,Dolgener See

This paper presents the depth profiles of 1951 … 1980 for the Scharteisen, the investigations of the last years for the Wasch lake and the Dolgen lake, for the oxygen regime with the representation of the oxygen concentration, transparency, water temperature and the upper limit of the occurrence of hydrogen sulphide. The profiles demonstrate the eutrophication having occurred for the Scharteisen and the present state for the three lakes. The general situation of the drainage areas and the causes to be derived from it concerning changes of the water quality as well as possible measures and aims of sanitations are discussed. Also the most important data are given on the hydrography of these waters and on their utilization for obtaining drinking water and by fishery up to now.     

Hämatologische,enzymatische und histologische Untersuchungen an Fischen der Weser im Mai 1983

The momentary condition concerning the haematological, physiological, macro-and microscopical constitution of the fishes of the Weser at Grohnde was investigated. The fishes were caught electrically at 22 positions in front of and behind the power-station at Grohnde. In the experiments the blood parameters, the biochemical, enzymatical, parasitological and microscopical changes of several species of fishes were analysed. You can see the details of these changes in the figures and pictures of the publication. It is supposed that organic toxic substances are given into the river in front of the power station, because in this region an industrial undertaking is posted. But also the general water quality of the Weser shows a significant toxicological degree, though the content of salt had been reduced in the former time. One can see that at all positions the blood parameters have changed, we also found haemorrhages in the gills, liver, kidney and spleen, little blood swellings, lymphocysts, necrosis, external and internal parasites, enzymatical changes and inflammations of the liver, kidney and myocard in the fishes. The investigations are being continued.     

Über die Verbreitung von Colikeimen im Bodensee und ihre Zunahme während der letzten zehn Jahre

Zusammenfassung Es gelangen heute rund fünfmal so viele Colikeime in den Bodensee wie vor zehn Jahren. In den nachkontrollierten Einzugsgebieten kommen aber auch gleichzeitig von rund fünfmal mehr Menschen die Abw?sser in den See. W?hrend der Sommerstagnation sind in der obersten Wasserschicht mehr Colikeime zu finden als in der Tiefe. Im Winter bestehen keine vertikalen Differenzen. Bei den niederen Wassertemperaturen im Winter werden mehr coliforme Bakterien nachgewiesen als im w?rmeren Wasser im Sommer. Der in den letzten Jahren stark zunehmende Wasserpflanzenbestand hemmt den Wasseraustausch von Ufer- und Seewasser. Die eingeschwemmten F?kalbakterien verbleiben am Ufer.     

Der Kohlendioxid-Gehalt und die Kalzitsättigung der Ilm, einschließlich einiger Vergleichsuntersuchungen im Thüringer Raum

The CO₂ content, air saturation and calcite equilibrium of the River Ilm and some of its tributaries were analysed. CO₂ content was measured by degasing the CO₂ from water. The CO₂ level is a very sensitive indicator for a low pollution in oxygen saturated waters. Clean running waters have a CO₂ content close to the air saturation of 0.1–0.3 mg C l⁻¹. Ground water and springs are rich in CO₂. Polluted waters are characterised by higher CO₂ contents, also organic pollution can result in high values of CO₂. Carbon dioxide concentration of streams and brooks is limited by re-aeration.

The headwater region (softwater) of the River Ilm is unsaturated, the hard water in the middle- and underflow is oversaturated. In summer and autumn high saturation could be found, but without autochthonous calcite precipitation like in hard water lakes.     

Die Massenentwicklung der Geißelalge Uroglena americana (Alk.) Lemm in Trinkwassertalsperren Thüringens und ihre Bekämpfung

A mass development of Uroglena americana with cellular densities of up to 13.5 · 10⁶ and 86.10⁶ cells/l, was observed in two drinking-water reservoirs. In the first case the development remained confined to the upper 20 m, in the second case there occurred a gradual shift of the maximum to deeper zones from May to July with decreasing cellular densities down to a depth of 35 m. Laboratory experiments for the control of the algae development were performed in order to protect the drinking-water resources from potential impairments of odour and taste. Samples of the storage-reservoir water with 20.10⁶ cells/l of Uroglena were concentrated up to 1.25 … 12.5 mg/l Ca(OH)₂ (pH-values of 7.2 … 9.6) by addition of calcium hydroxide and observed for 39 h. First impairment of the cells of Uroglena is detectable at 5 mg/l Ca(OH)₂ after 15 h, an immediate effect can be observed at 7.5 mg/l Ca(OH)₂ together with increased sedimentation, also Gymnodinium and Cryptomonas having been damaged. Thereupon a successful control of Uroglena by liming up to pH-values above 8.0 is possible. The application of lime to outdoor areas was not necessary, in the final analysis, since the drinking-water quality could be secured by the optimum choice of the intake depth of raw water with a maximum of 4.10³ to 77.10³ cells/l.     

Mikroskopische und elektronische Zählung von Sestonpartikeln im Wasser der Warnow — ein Vergleich

In 37 samples from the river Warnow in the course of one annual variation the seston particles were counted in the inverted microscope in three size classes: A <8 μm, B 8 … 25 μm C>25μm. Parallel to that, counting was performed with the electronic particle counting device Picoscale 4, which is used for the counting of blood cells, in the setting WBC for leucocytes with a nozzle 200 μm in diameter, so that the setting approximately corresponded to the size range B of the microscopic count. The microscopic particle numbers per ml were 800,000 … 5,200,000 for A, 10,000 … 96,000 for B and 2,000 … 21,000 for C. In principle, there is a correlation between microscopic and electronic results for the particles B and C. The regression analysis, however, produces a considerable residual scattering because of the morphological variety of the particles and its changes in the course of the seasonal change of mass. Therefore, the conclusion of the particle density from results of electronic counting is connected with considerable indistinctness, so that the electronic counting can be used only as a supplementary method for the estimation of the density of suspended matter.