Scientists found the cause of the mysterious mass death of dolphins

The ecological tragedy that unfolded in 2013 in the Indian River Lagoon (Florida) claimed the lives of 8% of the bottlenose dolphin population. An international scientific team established the cause of the disaster - ecosystem disruption due to abnormal phytoplankton blooms. The research results were published in the authoritative journal Frontiers in Marine Science.

Microscopic algae that make up phytoplankton are usually the foundation of the marine food chain. However, their excessive reproduction caused a real catastrophe in the lagoon. The overgrown phytoplankton blocked light from reaching the seabed, leading to the death of aquatic vegetation - a key element of the local ecosystem.

The disappearance of seagrass and algae deprived fish of their usual shelters and food. Dolphins, left without their traditional prey, were forced to switch to a less nutritious diet. As Dr. Charles Jacoby from Florida Flood Hub explained: "We established a direct link between dolphin deaths and the decrease in their energy consumption after a forced diet change."

The scale of the disaster was shocking: 64% of dolphins suffered from exhaustion, 5% were in critical condition, and the total number of deaths reached 77 individuals. This case has been officially recognized as an unusual mass mortality event.

Isotopic analysis of dolphin tissues showed that in 2011-2013, the animals switched from nutritious pinfish to less caloric sea bream. To maintain their previous energy levels, dolphins needed to consume 15% more food, which became an impossible task under conditions of general food shortage.

Scientists emphasize: although phytoplankton blooms are a natural phenomenon, their catastrophic scale is often provoked by human activities, particularly the introduction of excessive amounts of fertilizers and wastewater into water bodies.