Description: In the Western Baltic Sea, climate change is happening at much faster rate than in most other seas and organisms are additionally exposed to a steep and variable salinity gradient. Climate change has previously been shown to affect parasite transmission in other marine ecosystems, yet little is known about potential effects of warming and desalination on parasite–host interactions. In laboratory experiments, we determined the combined effects of projected seawater warming and freshening on the emergence, activity, survival, and infectivity of cercariae (free-swimming infectious stage) of the trematode Himasthla elongata (Mehlis 1831), shed from its first intermediate host, the periwinkle Littorina littorea (Linnaeus 1758), in the Baltic Sea. We also assessed the susceptibility of the second intermediate host, the mussel Mytilus edulis Linnaeus, 1758, to cercarial infections. Generally, salinity was the main driver, particularly of cercarial activity, infectivity, and mussel susceptibility to infection. At the lowest salinity (13), cercariae were 50% less active compared to the highest salinity (19). Infection success and host susceptibility followed a similar pattern, with 47% and 43% less metacercariae (encysted stage) present at salinity 13 than at salinity 19, respectively. In contrast, effects of simulated warming were found only for cercarial survival, with cercarial longevity being higher at 19 than at 23 °C. No significant interactions between temperature and salinity were found. In contrast to the literature, the results suggest that a climate change-driven freshening (partly also warming) may lead to a general decline of marine trematodes, with possible beneficial effects for the involved hosts.

Description: Environmental factors shape the structure and functioning of benthic communities. In coastal zones of the southwestern Baltic Sea, boulder fields represent one of the most productive habitats, supporting diverse benthic communities that provide many ecosystem services. In this study, the influence of the geological characteristics of boulder fields on the biodiversity of associated hard-bottom communities was investigated at two different spatial scales (few kilometers and tens of kilometers). The analyses on overall richness (taxonomic and functional) and community composition revealed how: (i) locally the size of boulders and (ii) regionally site-specific factors like the boulder density distribution and the sediment distribution can act as environmental driving forces. The overall richness of assemblages was shown to increase with increasing surface area of boulders, by up to 60% for species and up to 40% for functional richness. At both investigated scales, differences in compositional variability (β diversity) of the communities were detected. Locally, smallest boulders hosted more variable communities (β diversity up to 2 times higher), while at the regional level, indications of a larger habitat heterogeneity featuring the highest β diversity were observed. This study exemplifies how geological habitat characteristics shape the biodiversity of boulder field communities. The obtained information could be considered in assessment strategies, in order to avoid misclassifications of habitats naturally limited in biodiversity, making a step forward to the desired objective of protecting, conserving, and managing boulder field communities in the study area and at other comparable sites.

Description: Interactive computer simulations and hands-on experiments are important teaching methods in modern science education. Especially for the communication of complex current topics with social relevance (socioscientific issues), suitable methods in science education are of great importance. However, previous studies could not sufficiently clarify the educational advantages and disadvantages of both methods and often lack adequate comparability. This paper presents two studies of direct comparisons of hands-on experiments and interactive computer simulations as learning tools in science education for secondary school students in two different learning locations (Study I: school; Study II: student laboratory). Using a simple experimental research design with type of learning location as between-subjects factor (NStudy I = 443, NStudy II = 367), these studies compare working on computer simulations versus experiments in terms of knowledge achievement, development of situational interest and cognitive load. Independent of the learning location, the results showed higher learning success for students working on computer simulations than while working on experiments, despite higher cognitive load. However, working on experiments promoted situational interest more than computer simulations (especially the epistemic and value-related component). We stated that simulations might be particularly suitable for teaching complex topics. The findings reviewed in this paper moreover imply that working with one method may complement and supplement the weaknesses of the other. We conclude that that the most effective way to communicate complex current research topics might be a combination of both methods. These conclusions derive a contribution to successful modern science education in school and out-of-school learning contexts