by InTrieste
The recent Bora winds drove mucilage far out to sea, offering a temporary reprieve to the Adriatic Coast. Yet despite its intensity, the wind has only partially alleviated the issue, leaving behind diminished but still problematic quantities of the sticky substance in small ports, marinas, and lagoon entrances.
This weekend, Sacchetta saw lingering mucilage affecting local waters. Residents and tourists alike remain concerned as the viscous material disrupts boating and aquatic activities, prompting calls for more robust cleanup efforts and long-term solutions to prevent further environmental and economic impact.
A dense layer of mucilage has emerged near the Gulf of Trieste’s shores last week and then was swept away by the bora winds. According to analyses conducted by Arpa FVG and the National Institute of Oceanography and Applied Geophysics (OGS), the presence of the dinoflagellate Gonyaulax fragilis—a common but typically benign microalga—has been significant. This species, while non-toxic to humans, has proliferated to unusual levels.
“The phenomenon is very widespread,” said Maurizio Spoto, head of the Miramare Marine Protected Area. “It involves Grado, Lignano, and there are reports from Slovenia and Croatia as well. It usually lasts a short time and not with this intensity. Probably, it has to do with favorable weather conditions and stratified waters because there is a significant difference between the surface waters and the bottom. The abundant freshwater inputs from recent rains have also probably favored the growth of these polysaccharide aggregates.”
These mucilaginous blooms are often linked to sudden nutrient surges from river runoff, which appear to have been exacerbated by recent heavy rainfall. The influx of freshwater, combined with nutrient overload, has likely triggered the rapid proliferation of these microalgae, resulting in the extensive marine bloom now witnessed.
Pelagic mucilaginous aggregates are amorphous clumps of organic and inorganic material that can trap bacteria, phytoplankton cells, zooplankton organisms, inorganic detrital material, “fecal pellets,” and suspended materials. Mucous substances can be secreted by a wide variety of plants, animals, and microbial flora. Further controls will be carried out in the coming days to monitor the phenomenon.
