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.

A multi-sensor and multi-scale monitoring tool for the spatially explicit and periodic monitoring of eutrophication in a small drinking water reservoir is presented. The tool was built with freely available satellite and in situ data combined with Unmanned Aerial Vehicle (UAV)-based technology. The goal is to evaluate the performance of a multi-platform approach for the trophic state monitoring with images obtained with MultiSpectral Sensors on board satellites Sentinel 2 (S2A and S2B), Landsat 8 (L8) and UAV. We assessed the performance of three different sensors (MultiSpectral Instrument (MSI), Operational Land Imager (OLI) and Rededge Micasense) for retrieving the pigment chlorophyll-a (chl-a), as a quantitative descriptor of phytoplankton biomass and trophic level. The study was conducted in a waterbody affected by cyanobacterial blooms, one of the most important eutrophication-derived risks for human health. Different empirical models and band indices were evaluated. Spectral band combinations using red and near-infrared (NIR) bands were the most suitable for retrieving chl-a concentration (especially 2 band algorithm (2BDA), the Surface Algal Bloom Index (SABI) and 3 band algorithm (3BDA)) even though blue and green bands were useful to classify UAV images into two chl-a ranges. The results show a moderately good agreement among the three sensors at different spatial resolutions (10 m., 30 m. and 8 cm.), indicating a high potential for the development of a multi-platform and multi-sensor approach for the eutrophication monitoring of small reservoirs.

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En el trabajo se realiza una caracterización de las variaciones estacionales de la humedad del sustrato de los brezales húmedos de la Serra do Xistral (Lugo, Galicia), y se compara con la humedad de los diferentes ecosistemas que forman la catena vegetacional en la que se enmarcan, así como con la de otros tipos de humedales estacionales. La representatividad de este territorio ha conllevado su inclusión en la Red Natura 2000, mediante la designación del Lugar de Importancia Comunitaria (LIC) Serra do Xistral (ES1120015). Los datos presentados ponen de manifiesto un funcionamiento ecológico homogéneo de los brezales húmedos en relación al resto del complejo húmedo, así como su funcionamiento inequívoco como ecosistemas húmedos. Por tanto, se confirma el diagnóstico de losbrezales húmedos de las Sierras Septentrionales gallegas, vinculados al tipo prioritario Nat-2000 4020*, incluido en el Anexo I de la Directiva Comunitaria 92/43/CEE. El diagnóstico y caracterización de los tipos de hábitat debe considerar la estructura, composición y funcionalidad ecológica, mediante el empleo de conocimientos científicos y técnicos. Esto resulta de vital importancia, sobre todo parala conservación de los tipos prioritarios, evitando la puesta en marcha de planes y proyectos sin una adecuada evaluación de sus repercusiones.