The effects of global warming have been addressed on coral reefs in tropical areas, while it is still unclear how coral forests are reacting, particularly at temperate latitudes. Here we show how mesophotic coral forests are affected by global warming in the Mediterranean Sea. We highlight how the current warming trend is causing the lowering of the thermocline and it is enhancing mucilaginous blooms. These stressors are facilitating a massive macroalgal epibiosis on living corals, here reported for the first time from different areas in the Western and Central Mediterranean Sea. We provide a focus of this phenomenon at Tremiti Islands Marine Protected Area (Adriatic Sea), were the density of the endemic red gorgonian Paramuricea clavata decreased of up to 47% in 5 years, while up to the 96% of the living corals showed signs of stress and macroalgal epibiosis. Only populations deeper than 60 m depth were not touched by this emerging phenomenon. Spot observations performed at Tuscan Archipelago and Tavolara Marine Protected Area (Tyrrhenian Sea) suggest that this this combination of stressors is likely widespread at basin scale.

Depth range
32- 80 m

Mesophotic “mentions”
10 x (total of 5465 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'temperate mesophotic ecosystem'

Fields
Biodiversity
Climate Change
Disturbances
Ecology

Focusgroups
Algae (Macro, Turf and Crustose Coralline)
Octocorallia (Soft Corals)

Locations
Italy - Adriatic-Ionian
Italy - Ligurian-Tyrrhenian

Platforms
SCUBA (open-circuit or unspecified)
In-situ instrumentation
Surface-deployed sensors and samplers