Recurrent marine heatwaves compromise the reproduction success and long-term viability of shallow populations of the Mediterranean gorgonian Eunicella singularis.

Mediterranean gorgonians are being threatened by the impact of recurrent extreme climatic events, such as marine heatwaves (MHWs). The white gorgonian Eunicella singularis was suggested to be the most resistant gorgonian species in the NW Mediterranean, mainly due to the presence of symbiotic algae. However, a substantial shift in the conservation condition of the species has been observed in the recent years.

Heterotrophy in marine animal forests in an era of climate change.

Marine animal forests (MAFs) are benthic ecosystems characterised by biogenic three-dimensional structures formed by suspension feeders such as corals, gorgonians, sponges and bivalves. They comprise highly diversified communities among the most productive in the world's oceans. However, MAFs are in decline due to global and local stressors that threaten the survival and growth of their foundational species and associated biodiversity.

Lethal and sublethal effects of thermal stress on octocorals early life-history stages.

The frequency and severity of marine heatwaves causing mass mortality events in tropical and temperate coral species increases every year, with serious consequences on the stability and resilience of coral populations. Although recovery and persistence of coral populations after stress events is closely related to adult fitness, as well as larval survival and settlement, much remains unknown about the effects of thermal stress on early life-history stages of temperate coral species. In the present study, the reproductive phenology and the effect of increased water temperature (+4°C and +6°C above ambient, 20°C) on larval survival and settlement was evaluated for two of the most representative Mediterranean octocoral species (Eunicella singularis and Corallium rubrum).

Reproduction, energy storage and metabolic requirements in a mesophotic population of the gorgonian Paramuricea macrospina.

This study examined the sexual reproductive cycle, energy storage and metabolic requirements of a Mediterranean gorgonian in a mesophotic ecosystem (~70 m depth). Paramuricea macrospina resulted to be a gonochoric internal brooding species with a 1:1 population sex ratio. Oogenesis lasted ~12-14 months, whereas spermatogenesis was significantly shorter, only lasting 6 months.