Combined and single effects of pesticide carbaryl and toxic Microcystis aeruginosa on the life history of Daphnia pulicaria

The combined influence of a pesticide (carbaryl) and a cyanotoxin (microcystin LR) on the life history of Daphnia pulicaria was investigated. At the beginning of the experiments animals were pulse exposed to carbaryl for 24 h and microcystins were delivered bound in Microcystis’ cells at different, sub-lethal concentrations (chronic exposure). In order to determine the actual carbaryl concentrations in the water LC–MS/MS was used. For analyses of the cyanotoxin concentration in Daphnia’s body enzyme-linked immunosorbent assay (ELISA) was used. Individual daphnids were cultured in a flow-through system under constant light (16 h of light: 8 h of dark), temperature (20°C), and food conditions (Scenedesmus obliquus, 1 mg of C l−1). The results showed that in the treatments with carbaryl egg numbers per female did not differ significantly from controls, but the mortality of newborns increased significantly. Increasing microcystin concentrations significantly delayed maturation, reduced size at first reproduction, number of eggs, and newborns. The interaction between carbaryl and Microcystis was highly significant. Animals matured later and at a smaller size than in controls. The number of eggs per female was reduced as well. Moreover, combined stressors caused frequent premature delivery of offspring with body deformations such as dented carapax or an undeveloped heart. This effect is concluded to be synergistic and could not be predicted from the effects of the single stressors.

Analizying MOOCs from an educational perspective in Spain

ABSTRACT: This article is the result of a Teaching Innovation Project funded by the University of Cantabria’s Vice-Rectorate for Teaching Staff. Its goals are to analyze the phenomenon of MOOCs with pedagogical criteria and to develop a Best Practice Guide. The project was developed by the Universities of Cantabria and Oviedo, all the work was divided into three phases: 1) Theoretical review and the design of classroom activities, 2) The implementation of classroom activities and analysis of the main results and 3) The development of a MOOC Best Practice Guide. The results of the second phase at the University of Cantabria are presented here. They demonstrate the need to introduce these massive open online courses into degree programmes in Education, updating higher education studies and providing valuable knowledge for understanding the educational potential (not just technological or financial) of this online training

Small Scale Distribution and Diel Vertical Migration of Zooplankton in a Shallow Lake (Lake Naardermeer, the Netherlands).

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

The effect of small doses of toxic cyanobacterial food on temperature response of Daphnia galeata: Is bigger better?

1.Growing evidence shows that cyanobacterial blooms thrive in warmer temperatures, underlining the importance of understanding the relationship between cyanobacterial food, temperature and performance of the key freshwater herbivore Daphnia. 2.To evaluate potential effects of toxic cyanobacterial food and warmer temperatures, we first offered populations of Daphnia galeata a mixture of a low dosage of toxic non-colony-forming cyanobacteria [Microcystis aeruginosa (PCC7806 strain) and non-toxic, good-quality food (Scenedesmus obliquus) and S. obliquus as a sole food source]. After 2 weeks on the different diets, we exposed the daphnids to different temperatures (15 °C, 20 °C and 25 °C) for 2 weeks. 3.We expected that short-term exposure to toxins would reduce population growth, but populations would consist of larger individuals (‘bigger is better’). Upon long-term exposure, however, daphnids switched to higher temperature would be forced to mature at a smaller size and produce smaller, more vulnerable, offspring with subsequent reductions in population size (‘hotter is smaller’). Conversely, populations of daphnids switched to lower temperature should be able to cope better with prolonged exposure to toxins by producing more and larger offspring, less vulnerable to toxins (‘bigger is better’). 4.The amount of the toxin microcystin incorporated in the Daphnia tissue decreased in the first 7 days of exposure, suggesting triggering of detoxification mechanisms upon first exposure. In the remainder of the experiment, the amount of microcystin incorporated in Daphnia tissue increased to high levels, showing the differences between short-term exposure and long-term exposure to low-dosage toxins. 5.Contrary to our expectations, short-term exposure to low dosages of toxic Microcystis resulted in daphnids attaining a higher population density on the mixed diet. Furthermore, on mixed diets daphnids did not increase their body mass (‘bigger is not better’), but rather decreased strongly compared to daphnids growing on pure Scenedesmus diets. A potential explanation for this observation could be a positive hormetic response on short-term exposure to low-dosage toxin, leading to individuals living longer. 6.Prolonged exposure (>14 days) to low-dosage Microcystis resulted in a strong decrease in population densities, regardless of temperature. This decrease in population densities seemed to show a lagged response to the observed decreases in clutch size. On average, clutch size was much smaller on a low-dosage Microcystis diet than on a pure Scenedesmus diet. However, this difference in response between the two diets was smaller when daphnids were exposed to higher temperatures, as daphnids growing on pure Scenedesmus diet at higher temperatures had reduced clutch size. 7.Our observations indicate that the population-level responses to prolonged exposure to low-dosage cyanobacterial toxin mask potential responses to changes in temperatures. Warmer temperatures and toxins in diet seem to trigger similar responses in Daphnia populations: smaller individuals with smaller clutch sizes. The combined effect of toxic cyanobacteria and warmer temperatures on Daphnia populations might be additive rather than synergistic.

Lesson Study: professional development (PD) for beginning and experienced teachers

Central in this study is the professional development of beginning and experienced teachers collaborating in Lesson Study teams. Two high school teacher teams participated, a chemistry and a multidisciplinary team. Each team consisted of a beginning and an experienced teacher. Both teams went through the Lesson Study cycle twice. What and from what the beginning and experienced teachers learned, differences in teacher leaning and what Lesson Study elements contributed to this learning were studied in a qualitative multiple case study using interviews, reflective journals, and recordings . The Extended Interconnected Model for Professional Growth was used to interpret teacher learning. Our results show that two Lesson Study teams materialized in which participants shared experiences, thoughts, and ideas related to teaching and learning. Lesson Study contributed to both beginning and experienced teachers’ PCK development. The combination of two phases in this professional development program proved instrumental for this PCK development: a development phase in which participants meet new pedagogies, discuss these in the perspective of student learning, design a lesson plan and prepare for class use. Followed by a class enactment phase where the designed lesson is enacted, students are observed, subsequently salient results are discussed and the lesson plan revised

The distribution of chydorids (Branchiopoda, Anomopoda) in European shallow lakes and its application to ecological quality monitoring

This study describes the chydorid (Branchiopoda, Anomopoda) assemblages from 66 European shallow lakes, and presents data relating the assemblages to lake type and ecological quality. Forty species, out of a total recorded European fauna of 60 species, were found in the study sites. No significant differences were found between chydorid assemblages associated with rock and plant substrata. Patterns of distribution were best explained primarily by latitude and pH. Chlorophyll-a, total phosphorus, water temperature and Secchi depth were also correlated with assemblage descriptors. Alonopsis elongata, Alona rectangula, Alonella excisa and Pleuroxus uncinatus were shown to have higher prevalence in certain lake types. The dominance of Chydorus sphaericus in a third of the study sites was linked to eutrophication and high levels of chlorophyll-a. The relationship between chydorids and lake ecological quality was more apparent at species rather than community level. This study identifies important typological factors affecting chydorid distribution, and confirms that patterns of chydorid distribution previously reported from regional studies hold true across Europe.