Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.

Inhalt: - Frank Holl: Vorwort / Prefacio - Ottmar Ette: Entre mundos - vías de Alexander von Humboldt hacia la conciencia universal - Eberhard Knobloch: Alexander von Humboldts Weltbild - José Ángel Rodríguez: El culto a Humboldt en Venezuela - Christian Durisch Acosta: Die Humboldt-Rezeption in Ecuador - ein kulturgeschichtlicher Beitrag zum ecuadorianischen Nationsbildungsprozess - César W. Astuhuamán Gonzáles: Incas, Jívaros y la obra de Humboldt Vues des Cordillères - José Enrique Covarrubias: La recepción de la figura y obra de Humboldt en México 1821-2000 - Helga von Kügelgen: Klassizismus und vergleichendes Sehen in den Vues des Cordillères - Hector Pérez Brignoli: Alexander von Humboldt en Centroamérica y en el Río de la Plata - Tobias Kraft und Katharina Einert: Das ganze Werk in einem Netz? Bibliographie online verfügbarer Alexander-von-Humboldt-Digitalisate

Esta contribución analiza la estela de influencia dejada por la obra escrita de Alexander von Humboldt en Venezuela. Su recorrido científico expuesto en su obra Viaje a las regiones equinocciales del Nuevo Continente se convirtió en fuente de consulta e inspiración para otros viajeros que, por razones diversas, recorrieron el país a lo largo del siglo XIX. No fueron pocos los visitantes decimonónicos, alemanes y de otras nacionalidades, que tomaron la obra de Humboldt como una referencia para enfrentar los nuevos paisajes que tenían como objetivo visitar. Se destaca especialmente los casos de los alemanes Louis Glöckler, Friedrich Gerstäcker y Carl Geldner, así como del húngaro Pál Rosti. Hubo, en definitiva, viajeros que vinieron a observar lo que ya el sabio alemán había visto con anterioridad, destacando los prodigios de la naturaleza venezolana, tanto por vía de la escritura como de la pintura y la fotografía.