Desperate Times for Doñana: The Disappearing Lagoons Amid Climate Crisis
Santa Olalla, the largest lagoon in the natural area of Doñana in Huelva, has closed the summer of 2023 in a critically dry state for the third consecutive year, reducing to just a thin layer of residual moisture and mud. According to experts from the Doñana Biological Station (EBDCSIC), this lagoon, which holds the title of the largest in the region, completely dried up during the summers of 2022 and 2023—a phenomenon that had never occurred since data collection began 50 years ago.
The Doñana region is enduring exceptionally difficult years. Eloy Revilla, the director of EBDCSIC, highlighted that the brutal combination of a prolonged and intense drought alongside the ongoing overexploitation of the aquifer is severely impacting the lagoon systems within this protected area. Reports detailing a continuous decline in water levels in aquifers and the disappearance of half of the lagoons indicate a dire future for one of Europe’s largest ecological reserves.
As the hydrological cycle of 2023-2024 commenced, Santa Olalla was completely dry, with this barren state persisting for two months until mid-October, when the first rains helped to elevate the aquifer level and allowed water to flow back into the lagoon basin. Maximum flooding was achieved by the end of February, as reported by Javier Bustamante from EBDCSIC. However, starting in April, sensors from ICTSDoñana recorded a significant boom in filamentous algae due to elevated nutrient ratios spurred by high temperatures and stagnant water, culminating in an alarming count of over 280,000 cyanobacteria cells per milliliter by late June. While not all these cyanobacteria are toxic, levels exceeding 100,000 cells per milliliter are deemed excessive, creating increased toxicity risks for local fauna, including birds and fish.
July brought further challenges, as rising temperatures and a diminishing inundated surface area fostered an overgrowth of phytoplankton across the lagoon's surface. As the summer continued, increasing salinity levels were noted due to evaporation and substantial water loss.
As alarm bells ring in Doñana, the organization's representatives from SEO/BirdLife have called for immediate and effective actions to counteract the degradation of these wetlands, a vital habitat for migratory birds, that have suffered significantly due to the adverse environmental conditions. The Environmental Monitoring team of ICTSDoñana recently found themselves unable to collect representative water samples due to the diminutive water content, only moisture and mud remaining in the lagoon.
The Dulce lagoon, previously classified as a permanent lagoon, followed suit, drying completely during the second week of September, only slightly later than the previous year. In contrast, the Hondón lagoon has managed to maintain water levels throughout the summer.
PCs and experts from EBDCSIC have reported that, astonishingly, 60% of lagoons that existed in the 1980s have vanished entirely. The remaining lagoons are seeing diminished flooding frequency and duration, exacerbated by years of below-average precipitation. Scientific research indicates that the deterioration of the lagoon ecosystems is also profoundly affecting the diverse fauna and flora within Doñana, especially amphibians and aquatic reptiles, who face particular vulnerability in these changing conditions.
In a related note, recent developments in governance indicate a shift in policy regarding the natural park. The Junta de Andalucía and the government have reached an agreement to halt the contentious proposal from the PP regarding the legalization of irrigation in Doñana. Their commitment to listening and collaborative efforts under Vice President Teresa Ribera marks a new phase in the prolonged discourse surrounding the preservation of this critically endangered ecosystem.
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