Climate-related challenges in long-term management of Säkylän Pyhäjärvi (SW Finland)

Säkylän Pyhäjärvi (SW Finland) is an example of a large and shallow lake suffering from eutrophication. During the last 20 years, the quality and general usability of water in Pyhäjärvi have shown considerable variation driven by both a variety of human activities and climate-related factors such as wet and dry years. The lake has been thoroughly studied for decades and has been the object of comprehensive restoration activities both in the catchment and in the lake since the 1990s. Large variety of water protection measures like wetlands, sedimentation ponds and filtering systems have been implemented in the catchment area to reduce external nutrient load. Another important tool for Pyhäjärvi restoration is biomanipulation, done by local commercial fishermen in winter. Twenty-five percent of the annual phosphorus input is removed with fish catch. Currently, restoration work is facing new challenges: short or even nearly missing ice cover period and increased winter time nutrient load from the catchment. In the 2000s, there were 3 years with exceptionally short ice period, allowing only brief winter seining periods. Consequently, the biomanipulation catch was very low in 2007 and 2008 leading to observable food web effects. Phosphorus load was especially high in winters 2006/2007 and 2008/2009. On the basis of the data of 1987–2008, we have tested the hypothesis if climate-related winter time variables like phosphorus load, air temperature and precipitation would affect the water quality of the lake in following summer, here measured as chlorophyll a concentration in the lake water. A linear model has been used and a validation procedure has been performed to select the best variables. Our results indicate some of the linkages between climate-related catchment processes and the ecological status of the lake.     

The food and parasites of fish in some deep basins of northern L. Päijänne

The composition of the fish stock, food and macroparasites were studied in eleven basins (22–100 m) of Lake Jyväsjärvi and North Päijänne in August–September 1976. The fishing was done by means of a series of nets (meshes 15, 21 and 35 mm) laid on the bottom overnight. No fish were found in the two northernmost basins owing to bad oxygen conditions caused by waste waters. Smelt and burbot were the most abundant fish in the catches in other basins but the vendace was rare. Relict crustaceans and some deep water copepods (e.g. Heterocope borealis) played an important role in the food of fish in all basins.Parasites spreading via relict crustaceans were abundant in smelt and burbot, but absent in vendace and ruffe. The most common parasite in smelt was Cystidicola farionis, in burbot Echinorhynchus borealis, in ruffe Triaenophorus nodulosus and in vendace the gill parasite Ergasilus sieboldi. Females of a relatively rare copepod Salmincola lotae were found in the oral cavity of five burbot (at depths of 50 and 100 m).     

The Origin and Evolution of Lake Vähä-Pitkusta, SW Finland – A Multi-Proxy Study of a Meromictic Lake

Lake Vähä-Pitkusta is a 35-m deep meromictic kettle-hole lake in SW Finland. The topmost 15cm of the sediment stratigraphy consists of black gyttja, representing the last ca. 600years. A sediment core from the deepest point was examined with multi-proxy methods to determine the origin and evolution of the basin, the onset of the meromictic conditions and the primary factors that initiated the meromictic processes. The results indicate that Lake Vähä-Pitkusta became isolated from the Baltic basin during the Yoldia Sea stage. After initial unstable sedimentary conditions the development continued steadily until ca. 2500–2300 cal.BP when there is indication of lake level rise and/or increased surface runoff, probably resulting from a cooler and moister climate. The diatom and cladoceran results indicate only a slight rise in the trophic state following the increased erosion. Pollen evidence suggests weak anthropogenic activity in the catchment during the last 1000 years, and this had only little effect on the trophic state, which remained rather low. Thus, it is most unlikely that the trophic state was the primary reason for the origin of meromixis, although it may have contributed to it. We tentatively suggest that the primary reason was the peculiar morphometric dimensions of Lake Vähä-Pitkusta (small, deep, sheltered from winds) which made it very sensitive and that even a very slight increase in soluble electrolytes may push it over the edge into meromixation. It is possible that this did not occur during the cold/moist period around ca. 2300 cal.BP but during the Medieval Climate Anomaly. Studies on sediment geochemistry are needed to verify this assumption.     

Sediment and phytoplankton records of the cyanobacterial genus Anabaena in boreal Lake Pyhäjärvi

Past occurrence and quantities of Anabaena cyanobacteria in Lake Pyhäjärvi, SW Finland, were investigated using sediment and phytoplankton records. A short sediment core covering the past 20 years was examined for Anabaena resting spores (akinetes) in order to assess the utility of akinetes as a paleolimnological proxy. Sedimentary akinetes confirmed the past existence of Anabaena in water, but did not show a direct correlation with the amount of Anabaena spp. in water samples. The amount of planktonic Anabaena spp. correlated with total phosphorus and nitrogen concentrations in Lake Pyhäjärvi, but the number of akinetes was considered to have a relationship with low nutrient concentrations and dominant bloom-forming cyanobacteria. Akinetes are probably suitable for low-resolution and long time scale paleolimnological investigations, where they provide information of past cyanobacteria that cannot be directly attained otherwise.     

Expression and regulation of Spätzle-processing enzyme in Drosophila

The Drosophila melanogaster Toll receptor controls embryonic dorsal-ventral axis formation and is crucial for the innate immune response. In both cases, Toll is activated by the enzymatically cleaved form of its ligand Sp?tzle (Spz). During axis formation, Spz is cleaved by the maternally provided serine protease Easter while the Sp?tzle-processing enzyme (SPE) activates Spz after infection. We confirm the role of SPE in immunity and show that it is a zygotic gene specifically expressed in immune tissues implying that the dual activation of Spz is achieved by differential spatiotemporal expression of two similar but distinct serine proteases.     

Zitronensäuregärung Auf Stärkehydrolysaten

Summary It was the aim of the authors to examine the purification methods of the starch hydrolizate using the following adsorbents: Fuller's Earth, CaSO₄- dead burnt, activated coal, Amberlit IRA-410, Duolit C-20, Kaolin S, Kaolin NS and Al₂O₃ for Chromatography. Fermentation of the purified starch hydrolizate carried out withAspergillus niger C₂, showed that it could be used as a substrate for the citric acid fermentation. We obtained the best results using starch hydrolizates with a concentration of 10,24% of sugars purified with Amberlit IRA-410, 0,1–0,25% activated coal, Fuller's Earth and CaSO₄.     

Stereoselective synthesis of a C-glycoside analogue of N-Fmoc-serine beta-N-acetylglucosaminide by Ramberg-Bäcklund rearrangement

A C-glycoside analogue of N-Fmoc-serine beta-N-acetylglucosaminide 1 was synthesized stereoselectively from a sulfone derivative of serinol thio-N-acetylglucosamide 8 using a Ramberg-B?cklund rearrangement as a key step.     

Utilization of noxious weeds for the management of plant-parasitic nematodes infesting some vegetable crops: Einsatz von schädlichen unkräutern zur bekämpfung von pflanzenparasitären nematoden auf verschiedenen gëmusekulturen

Significant reduction was observed in the population of plant-parasitic nematodes, Meloidogyne incognita, Rotylenchulus reniformis and Tylenchorhynchus brassicae infesting eggplant and cauliflower when given root-dip treatment in the leaf extracts of Argemone maxicana and Solanum xanthocarpum at different concentrations and dip durations. The root-knot development and larval penetration of second stage juveniles of M. incognita were also inhibited, may be due to bare-root dip treatment in leaf extracts of both the weed plants. Leaf extracts of S. xanthocarpum caused more inhibition in root-knot development, nematode multiplication of reniform and stunt nematodes than that of A. maxicana. Plant growth improvement was noted which seems to be due to dip treatment and reduction in the population of parasitic nematodes. The efficacy of root-dip treatment with respect to improvement in plant growth of eggplant and cauliflower and reduction in root-knot development and nematode population, increased with increasing the concentration of leaf extracts and dip durations.     

Factors controlling long-term changes of the eutrophicated ecosystem of Pärnu Bay,Gulf of Riga

Phytoplankton, mesozooplankton, mysids and fish larvae were studied during 15–29 annual cycles measured weekly to monthly in Pärnu Bay, the Gulf of Riga. The monthly variability of the biological data was related to temperature, ice conditions, salinity, influx of nutrients, the North Atlantic Oscillation (NAO) index, cloudiness and solar activity. Phytoplankton development was mainly a function of the NAO index. For the whole study period the abundance of zooplankton increased with increasing water temperature and solar activity. Significant correlations between phytoplankton and zooplankton densities were found until 1990. After the invasion of the predatory cladoceran Cercopagis pengoi in 1991, the zooplankton community was likely to be regulated by the introduced species rather than phytoplankton dynamics. The increased abundances of rotifers and copepods triggered the increase in mysid densities. The development of herring larvae was positively affected by the high density of copepods and rotifers but also by increased eutrophication. Until 1990 there was no significant relationship between the density of zooplankton and herring larvae. A negative relationship between the density of zooplankton and herring larvae in the 1990s suggests that the major shift in zooplankton community resulted in food limitation for herring larvae. The results indicated that (1) atmospheric processes in the northern Atlantic explain a large part of the interannual variation of the local phytoplankton stock, (2) trophic interactions control the development of pelagic communities at higher trophic levels, and (3) the introduction of an effective intermediate predator has repercussions for the whole pelagic food web in Pärnu Bay.     

Electron microscopy of the paracervical (Frankenhäuser) ganglion of the adult rat

Summary The ultrastructure of the paracervical (Frankenhäuser) ganglion in the rat was studied after immersion or perfusion fixation with glutaraldehyde followed by post-osmification. This ganglion is located at the uterovaginal junction in the vicinity of arteria uterina and contains three neuronal cell types. (1) Principal neurons have a fine structure mainly similar to the ganglion cells of other autonomic ganglia. (2) Small granule-containing cells occur in clusters often close to fenestrated capillaries. They are divided into two subgroups according to the size of their cytoplasmic granules; those containing only small granulated vesicles of 800 to 1400 Å in diameter and those having also large granulated vesicles of 2000 to 3000 Å in diameter. (3) Vacuolated nerve cells are large cells that resemble the principal neurons in their cytoplasmic components, except that they contain one to ten vacuoles with corpuscles of different size and shape. The possible physiological significance of the small, granule-containing cells in the uterine function is discussed.     

Nutrient dependence of phytoplankton production in brown-water lakes with special reference to Lake Päijänne

A method for predicting the mean seasonal chlorophyll a concentration, the mean seasonal in vitro phytoplankton primary productivity per unit volume, the maximum daily production per unit volume and the seasonal integral production in brown-water lakes is presented. The production values can be calculated when the mean annual concentration of total phosphorus and the mean annual colour of the water are known. This method has been developed especially for practical water pollution studies to permit rapid and inexpensive estimates of major biological consequences of changes in effluent loads. The method can be applied for brown-water lakes where phosphorus is the limiting nutrient for primary production.     

Die proteolytische Aktivität gebräuchlicher Diastasepräparate

Zusammenfassung In den Speicheldrüsen von Weinbergschnecken zeigen bestimmte, zunächst nur schwach PSL-positive Zellen nach Vorbehandlung mit Diastase, Pepsin oder Papain eine deutliche Intensivierung ihrer Perjodatreaktivität. Als Ursache hierfür wird angenommen, daß bei den vorliegenden Glykoproteinen die Kohlenhydratkomponente größtenteils von einem Proteinmantel umhüllt ist. Somit wird erst nach ausreichender Proteolyse eine optimale PSL-Reaktion möglich. — Die Intensivienmg der PSL-Reaktion nach Vorbehandlung mit Diastase beruht wahrscheinlich auf der Verunreinigung handelsüblicher Diastasepräparate mit Proteasen.

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On the proteolytic activity of common diastase preparations

Summary Certain cells of the salivary gland of Helix pomatia show normally only a weak PAS reaction. However, after prior incubation with diastase, pepsin or papain the same cells show a strong PAS staining. This intensification may be due to proteolysis of a protein-coat which covers the carbohydrate and thus prevents PAS reaction.—The increased PAS reaction after diastase is probably due to contamination of commercial diastase samples with proteolytic enzymes.

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Für technische Unterstützung danke ich Fräulein Jannamaria Frielinghaus und Herrn Hermann Guckes.     

The management of fisheries in Lake Vörtsjärv

L. Vörtsjärv is a eutrophic lake in Central Estonia. The area of the lake is 270 km², the average depth only 2.8 m. The biological productivity of the lake is rather low. Twelve to fifteen years ago the main fish were ruff and perch (80–90% of catch), while the numbers of valuable fish were small. At the same time the total catch of fish was relatively high — about 300 tons a year. Attempts were made to reduce the numbers of undesirable fish by intense trawl-catch but no marked results were achieved. Subsequently trawl-catch was ended, elvers were regularly introduced into the lake and protection of valuable fish was improved. At the present time the total catch of fish has decreased (184 tons in 1979), but pike-perch and eels are now the main game fish (50–60% of catch) and the value of the catch of fish has risen 2–3 times.     

Distribution and development of under-ice phytoplankton in 90-m deep water column of Lake Päijänne (Finland) during spring convection

Distribution and development of phytoplankton were studied in the deep and large Lake Päijänne from mid-winter until the disappearance of ice. Diatoms were an important part of the phytoplankton assemblage and, with cryptophytes and chrysophytes, made up 50–80% of the phytoplankton biomass. In mid-winter, chlorophyll a and phytoplankton biomass were uniformly distributed over the whole water column down to a depth of 90 m. Thus, most of the phytoplankton was in virtual darkness and there was negligible growth. Only motile cryptophytes were concentrated in the layers below the ice and were rare in deep water. After the disappearance of snow, convection developed, but at first cryptophytes were able to resist mixing. When convection turned from penetrative to predominantly horizontal, all phytoplankton were generally uniformly distributed in the water column. In spite of the full under-ice overturn with low average availability of light, the phytoplankton biomass doubled in April. The growth of cryptophytes was higher than that of diatoms, suggesting that motile species gained an advantage by being able to maintain themselves in the upper, illuminated layers. The results show that knowledge of the basic physical framework is essential for interpretation of under-ice phytoplankton results.     

Die häufigsten hämoglobinführenden oligochaeten der mitteleuropäischen binnengewässer

Zusammenfassung Für die häufigsten hämoglobinführenden Oligochaeten der Binnengewässer Mitteleuropas wurde eine relativ unkomplizierte Bestimmungstabelle ausgearbeitet, die es vor allem den Ökologen und Abwasserbiologen ermöglichen soll, die einzelnen Arten der Oligochaeten-Fauna zu identifizieren. Einleitend werden kurz die praktischen Methoden zum Fang und zur Behandlung der Oligochaeten umrissen. Abschließend wird eine Aufstellung über die Häufigkeitsverteilung der behandelten Spezies in den Sedimenten der Fließgewässer gegeben.Vorstand: Prof. Dr. H. Liebmann     

Dominant rotifers of Võrtsjärv (Estonia)

Rotifers form 71% of the zooplankton of the strongly eutrophic (total N 2 g m^–3, total P 53 mg m^–3) Võrtsjärv (Estonia). Altogether 150 taxa of rotifers occur. Species characteristic of oligo- and mesotrophic waters have totally disappeared during the last 30 years, or are disappearing now. Species whose numbers and biomass reached 20% or more of total zooplankton were considered dominants. These were Anuraeopsis fissa, Keratella cochlearis, K. quadrata frenzeli, Polyarthra dolichoptera, P. luminosa, Synchaeta verrucosa and Trichocerca rousseleti. The contribution of dominant rotifers to total zooplankton and its biomass is as follows: S. verrucosa 25% and 39%, P.dolichoptera 34% and 25%, K. cochlearis 25% and 7%, K. quadrata frenzeli 9% and 7%, A. fissa 28% and 0.4%, T. rousseleti 20% and 0.6%, respectively.     

The recovery of L. Vesijärvi following sewage diversion

For 60 years the sewage of the City of Lahti was discharged into L. Vesijärvi. The eutrophication of the lake was observed as early as the 1920s but in the 1960s the pollution became obvious. The sewage was completely diverted in 1976. As a result of the diversion the bacteriological defects were eliminated within one year, restoring the recreational value of the lake. The recovery of water quality was rapid during the first two years. The oxygen content increased markedly but hypolimnetic oxygen depletion persisted. The phosphorus content decreased about 60% and the nitrogen content about 30%. After that period the recovery slowed down. The biomass of phytoplankton decreased but the abundance of heterocystous blue green algae increased causing blooms in July and August. The primary production has lately been reduced despite the lack of improvement in chemical water quality. Hypolimnetic aeration was started in order to accelerate the recovery. The results during winter stagnation have been encouraging.     

Viskositätsänderungen des Protoplasmas während der Narkose

Zusammenfassung Wir können also sagen, daß die Oberflächen-Schichten der Amöbenzelle eine weit höhere Viskosität zeigen als das Endoplasma. Die Auswirkung der eigentlich narkotischen Dosen von Chloroform und Chloreton auf die Viskosität ist eine Erhöhung der Viskosität in den oberflächlichen Schichten und eine Erniedriging der Viskosität im Endoplasma während der ersten Zeit der Narkose.In späteren Stadien der Narkose gibt es auch im Entoplasma eine leichte Erhöhung der Viskosität.Die allerersten Anzeichen der Wirkung der Narkotika ergeben eine Erniedrigung der Viskosität in den oberflächlichen Schichten (verdünnte Lösungen !).Alle diese Änderungen sind reversibel, nur die letzte Auswirkung der Intoxikation, die Koagulation, ist irreversibel.