Nutrient pollution is still the major pending issue in the conservation of the ecological status of European lakes
Nutrient pollution is still the major pending issue in the conservation of the ecological status of European lakes, according to an international study involving the expert Cayetano Gutiérrez, of the Research Group Freshwater Ecology, Hydrology and Management (FEHM) of the Faculty of Biology from the University of Barcelona. Fortunately, in general these aquatic ecosystems did not respond negatively to the presence of other impact factors, and this suggests that promoting priority strategies with stricter nutrient control could significantly improve the ecological quality of European lakes.
The new study, published in the journal Nature Ecology & Evolution, reveals what happens when rivers and lakes are affected by several ecological impacts simultaneously and identifies possible strategies to improve the ecological status of European waters.
The new work is led by experts Sebastian Birk and Daniel Hering, from the University of Duisburg-Essen (Germany), and involves international researchers integrated into the European project MARS (Managing Aquatic Ecosystems and Water Resources under Multiple Stress). Specifically, the pairs of impacts that commonly affect European rivers and lakes have been analyzed in order to identify those combinations of factors that should be avoided to preserve the ecological quality of aquatic ecosystems. Among these impacts, the study has studied the effects of nutrient pollution, altered flows, or increased temperature due to climate change.
"In 33% of cases, these mixtures gave rise to effects that require complex management strategies and different from those that currently exist, which focus on mitigating one-off impacts," reveals Cayetano Gutiérrez, member of the FEHM-UB led by Professor Núria Bonada, from the Department of Evolutionary Biology, Ecology and Environmental Sciences and the UB's Biodiversity Research Institute (IRBio).
According to the conclusions, rivers present a more complex situation that would require specific action depending on the pair of impacts studied. "Of course, this is not good news - he continues - as 43% of European rivers suffer from two or more impacts that may require joint mitigation, including diffuse pollution by nutrients and other toxins and altered flows and the shape of the channels. This is especially important for areas such as the Iberian Peninsula where the presence of toxins is linked to overexploitation of water and climate change, while seriously deteriorating the ecological health of many rivers.
Although much work remains to be done, "this study represents a major step forward in European water management and in identifying the impacts that need to be mitigated as a matter of priority," the experts reveal. In this context, the study highlights the importance of reducing nutrient levels in rivers and lakes and maintaining sufficient flow in rivers to cope with the presence of other impacts such as climate change.
Barcelona, 30 June 2020.
Photos: Cayetano Gutiérrez