The Mediterranean Sea’s record water temperatures threaten marine biodiversity
Recent heat waves in the Mediterranean Sea have led to record high water temperatures, affecting local marine life and creating favorable conditions for invasive species. According to Dr. Justino Martinez from the Barcelona Institute of Marine Sciences, the average daily sea surface temperature on August 15, 2024 reached an unprecedented 28.9°C, surpassing the record of 28 Last year’s .71°C was set on July 24.
Increasing sea temperatures in the Mediterranean are directly threatening local fish and marine plants. At the same time, this warming trend is promoting the growth of invasive species that thrive in these new conditions. Additionally, higher evaporation rates are increasing the risk of severe storms in a region already affected by global climate change.
Notably, sea water temperatures measured offshore near Monaco, Corsica and Valencia (Spain) have exceeded 30°C. In Nice, France, sea temperatures have been 3 to 4°C higher since July 15, depriving locals of their usual cool evenings. These heat waves are disastrous for native marine species, including fish, oysters, mussels, sea urchins and coral reefs, while some invasive species are thriving.
Among the invasive species that currently pose a significant threat is the lionfish, native to the Indian and Pacific oceans and known for its venomous spines. This aggressive invader is disrupting local ecosystems. Additionally, the white sea harefish is spreading throughout the kelp forests, further destabilizing the ecological balance of the Mediterranean. According to Jean-Pierre Gattuso, Director of the Center for Scientific Research (CNRS) at the Villefranche-sur-Mer Oceanographic Laboratory, these species are disrupting the local food chain and endangering native marine life. land.
These invasive fish species have entered the Mediterranean via the Suez Canal from the Red Sea, thriving on warming waters. Unlike native species, these invaders are resilient to marine heat waves.
The Mediterranean has long been identified as a “climate change hotspot” by the Intergovernmental Panel on Climate Change (IPCC). Federico Betti, an invasive species expert at the University of Genoa, notes that the average temperature of the Mediterranean has increased by about 1.2°C over the past 40 years.
A 2022 study published in the journal Global Change Biology highlighted significant declines in about 50 species, including corals, sea urchins and molluscs, during marine heat waves since 2015. by 2019. Tropical species are taking advantage of rising temperatures, with blue crabs replacing native crabs, for example. shellfish in northern Italy’s Po Delta and fireworms disrupt fishing.
The IPCC warns that if global temperatures rise more than 1.5°C above pre-industrial levels, more than 20% of fish and invertebrates harvested in the eastern Mediterranean could face danger. risk of local extinction by 2060. Furthermore, revenue from fisheries could decrease by up to 30%. by 2050, highlighting the urgent need for climate action to protect the Mediterranean’s marine biodiversity.
