Paint it black: Chronic whiting event degrades bottom communities in a Mediterranean coastal lagoon

Abstract

Whiting events, caused by the suspension of fine-grained carbonate particles that give surface waters a milky blue appearance, are generally considered ecologically minor due to their short-lived nature. Their impacts have rarely been explicitly recognized in the scientific literature. We investigated the ecological consequences of a persistent whiting event in the Mar Menor coastal lagoon (SE Spain, SW Mediterranean), which has remained active and spatially stable for over three years. Benthic vegetation within the whiting-affected area exhibited particle leaf deposition and vegetation damage resulting from calcite precipitation and a sustained lack of light, contrasting with unaffected zones that retained normal structural integrity. This disturbance encompassed roughly 9% of the lagoon's surface, including a 6.7 km2 core of unvegetated seabed. Habitat alterations facilitated cascading trophic effects, leading to measurable changes in the composition and diversity of the fish assemblages. Our study provides the first empirical evidence at a global scale that persistent whiting events can drive significant ecological modifications in coastal lagoons. These findings highlight the broader implications of whiting phenomena for the functioning, resilience, and management of shallow coastal ecosystems under increasing anthropogenic and climatic pressures.