Climate Change Effects on Mediterranean Marine Ecosystems

The Mediterranean Sea is warming faster than most global ocean regions, driving profound shifts in its marine ecosystems. Elevated sea surface temperatures and the increasing frequency and intensity of marine heatwaves have triggered mass mortality events among foundation species such as corals, sponges and gorgonian forests. Warming also alters species distributions, favouring thermophilic organisms and non-indigenous taxa at the expense of cold-adapted endemics. Changes in thermal regimes interact with acidification, deoxygenation and nutrient loading to undermine ecosystem functioning, reducing biodiversity, altering food-web dynamics and compromising services such as coastal protection and fisheries. Trait-based studies reveal that vulnerability to warming depends on species’ life-history characteristics, with long-lived, slow-growing taxa at greatest risk. Ecological modelling predicts shifts in the timing and extent of harmful algal blooms and range contractions for commercially important fish and invertebrates. Despite evidence of resilience pockets in mesophotic refugia, cumulative stressors threaten the capacity of Mediterranean assemblages to adapt. Integrating high-resolution observations, experimental thermal tolerance assays and predictive habitat models is essential to inform climate-smart conservation and spatial planning, ensuring the continued productivity and heritage value of this biodiversity hotspot.

Research from Nature Portfolio

Research on population collapses at the warm edge of species’ distributions highlights how exceptional coastal warming in the Levant basin has driven sustained declines of key invertebrates. Investigations reveal multi-species collapses of sea urchins and reef-building gastropods beyond their physiological tolerance, coupled with a surge of non-indigenous molluscs. This seminal work emphasises the importance of monitoring range-edge populations as early indicators of basin-wide ecosystem change and underscores warming as a primary driver of biodiversity loss in the Mediterranean.

Climate Change Effects on Mediterranean Marine Ecosystems publication trend

The graph below shows the total number of articles in climate change effects on mediterranean marine ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Marine heatwave: A discrete period of anomalously high sea surface temperatures lasting days to months, often causing ecological disruptions.

Mass mortality event (MME): A rapid, unusual die-off affecting multiple species or large portions of a population, frequently linked to extreme thermal anomalies.

Trait-based approach: A method assessing species’ climate risk by combining exposure metrics with life-history and physiological characteristics.

Ecological habitat model (EHM): A predictive tool that links species’ occurrences to environmental variables to forecast distribution under future conditions.

Physiological tolerance: The range of environmental conditions within which an organism can survive, grow and reproduce.

References

1. Marine heatwaves drive recurrent mass mortalities in the Mediterranean Sea. Global Change Biology (2022).
2. Are Mediterranean marine threatened species at high risk by climate change?. Global Change Biology (2023).
3. Harmful Ostreopsis cf. ovata blooms could extend in time span with climate change in the Western Mediterranean Sea. The Science of The Total Environment (2024).
4. Multi-species collapses at the warm edge of a warming sea. Scientific Reports (2016).
5. Footprints of climate change on Mediterranean Sea biota. Frontiers in Marine Science (2015).
6. Temperate mesophotic ecosystems: gaps and perspectives of an emerging conservation challenge for the Mediterranean Sea. The European Zoological Journal (2019).