Freeze coring is a commonly used method for the investigation of the bed sediment fauna of rivers. It is considered to produce quantitative numbers of invertebrate abundance in different depth layers. Calculations of abundance use total volume of the freeze core sample as spatial reference. This definition of sample volume is incorrect. In the present, study freeze core samples...
The presented study investigates the evolution of artificial gravel placements for Atlantic salmon and sea trout in Aurlandselva in Western Norway. Various monitoring methods have been applied including (i) quantifying the spatial extent and dynamics of spawning sites over the monitoring period, (ii) grain size distributions as well as (iii) applying numerical hydraulic and...
Our experimental study was designed to assess the effects of temperature on food isotopic integrity and trophic fractionations (of carbon and nitrogen stable isotopes: Δ13C and Δ15N) in chironomid larvae. A laboratory experiment was run using Chironomus riparius larvae at 15, 18 and 23°C, and under three pulverized food resources. There were significant changes in the stable...
Lakes and reservoirs play key roles in global carbon cycling, especially as a carbon sink. Enrichment of nutrients in lakes and reservoirs (eutrophication) and rising global temperatures favors the proliferation of bloom-forming cyanobacteria. Harmful blooms of cyanobacteria (cyanoHABs) alter carbon and nutrient cycling in freshwater ecosystems. Some evidence suggests the...
Cyanobacteria may limit recreational use of waters and have negative impacts on ecosystem services. The aim of this study was to determine phosphorus (P) thresholds for cyanobacterial taxa, which form toxin-producing blooms (mass occurrences) in boreal lakes. These thresholds help to set robust P reduction targets for restoration measures. We used long-term (> 40 years) June...
The disturbing effect of a short-term cooling period during summer on planktonic bacterial community structure of an alpine lake was investigated using 16S rDNA pyrosequencing. Proteobacteria, Actinobacteria, and Bacteroidetes constituted the most abundant phyla. During the sampling period (from July to August 2010), a sudden cooling period with high precipitation occurred, as...
Forestry-related land use can cause increasing instream sedimentation, burying and eradicating stream bryophytes, with severe ecological consequences. However, there is limited understanding of the relative roles and overall importance of the two frequently co-occurring stressors, increased fine sediments and loss of bryophytes, to stream biodiversity and ecosystem functions. By...
Experimental streams are bounded and partly enclosed lotic units that facilitate the simulation of certain aspects of natural stream ecosystems under controlled conditions. We summarized the current knowledge regarding experimental streams in order to support researchers in designing and undertaking future studies using experimental streams. We observed an increase in the number...
Detailed knowledge on the habitat preference of invasive fishes and the bias of different fishing methods in determining their population dynamic parameters are essential in fisheries management, ecology and conservation. This study was conducted to determine the habitat use and length frequency distribution of the invasive monkey goby and pumpkinseed in the littoral zone of Lake...
Autotrophic lakes are regarded to function as net autotrophic systems in which mobilization of solar energy by phytoplankton, benthic algae, and macrophytes forms the base of primary production. However, they are also subsided by allochthonous inputs. In this paper, we tested three hypotheses explaining the role of allochthonous subsidies as a driving force of autotrophic...
The life cycle of unionids is characterized by a obligatory period of larval parasitism on a fish host, any disturbance of which might cause a large-scale decline in the mussel population. Because the probability of fish infestation is so important, we modelled what would happen to a population (in terms of population growth and probability of extinction), if the same number of...
Freshwater mussels face threats from climate change and changing land use that are dramatically altering their habitat. The health of mussel populations and the state of current and past environmental conditions can be monitored by measuring mussel growth and glycogen levels. In this study, we measured growth and glycogen levels in mussels from two small river basins impacted by...
Effect of freshwater mussels’ (Unionoida) glochidia on the growth of fish host has remained poorly studied. We compared the specific growth rate of the juvenile, PIT-marked brown trout (Salmo trutta) between uninfected controls to those experimentally infected (average initial intensity of infection 8000 fish−1) with Margaritifera margaritifera glochidia, kept in high and low...
The 9th International Charr Symposium convened on 18–21 June 2018, in Duluth, Minnesota, USA, to gather scientists with an interest in charr biology and management from the entire geographical range of the genus Salvelinus. The symposium was attended by 169 individuals from six countries, and included 99 oral and 32 poster presentations, 28 of which were published in the ensuing...
Responsiveness to biotic factors is crucial for the survival of sessile aquatic animals. They cannot escape from danger, but developed a number of defences against predation, usually delayed in time. We checked the initial defence of the freshwater byssate zebra mussel, Dreissena polymorpha, associated with valve gaping. We tested the effect of chemical signals: fish predator...