Deep‐water Corallium rubrum (L., 1758) from the Mediterranean Sea: preliminary genetic characterisation

Abstract

The precious red coral Corallium rubrum (L., 1758) lives in the Mediterranean Sea and adjacent Eastern Atlantic Ocean on subtidal hard substrates. Corallium rubrum is a long‐lived gorgonian coral that has been commercially harvested since ancient times for its red axial calcitic skeleton and which, at present, is thought to be in decline because of overexploitation. The depth distribution of C. rubrum is known to range from c. 15 to 300 m. Recently, live red coral colonies have been observed in the Strait of Sicily at depths of c. 600–800 m. This record sheds new light on the ecology, biology, biogeography and dispersal mechanism of this species and calls for an evaluation of the genetic divergence occurring among highly fragmented populations. A genetic characterization of the deep‐sea red coral colonies has been done to investigate biological processes affecting dispersal and population resilience, as well as to define the level of isolation/differentiation between shallow‐ and deep‐water populations of the Mediterranean Sea. Deep‐water C. rubrum colonies were collected at two sites (south of Malta and off Linosa Island) during the cruise MARCOS of the R/V Urania. Collected colonies were genotyped using a set of molecular markers differing in their level of polymorphism. Microsatellites have been confirmed to be useful markers for individual genotyping of C. rubrum colonies. ITS‐1 and mtMSH sequences of deep‐water red coral colonies were found to be different from those found in shallow water colonies, suggesting the possible occurrence of genetic isolation among shallow‐ and deep‐water populations. These findings suggest that genetic diversity of red coral over its actual range of depth distribution is shaped by complex interactions among geological, historical, biological and ecological processes.

Marine Heat Waves Hazard 3D Maps and the Risk for Low Motility Organisms in a Warming Mediterranean Sea

“…rubrum is a slow growing, long lived, gorgonian coral endemic of the Mediterranean Sea. This coral is commonly found on hard substrates, on steep walls and overhangs, below 10 m depth (Rossi et al, 2008) and down to 800 m (Costantini et al, 2010), with the typical range being ∼25-60 m (Rossi et al, 2008). It is associated with the coralligenous communities (Tsounis et al, 2010), a collective term referring to complex biogenic structures made by the outgrowth of encrusting calcareous algae on hard substrate in the mesophotic zone.…”

First report of live deep-water cnidarian assemblages from the Malta Escarpment

“…By and large, the most relevant actors of such aphotic communities are cnidarians and sponges associated with poorly sampled hard bottoms at depths exceeding 200 m. This is primarily the case for the so-called white coral communities documented at bathyal depths in the Strait of Sicily, southern Adriatic, Ionian, Ligurian, Marmara, northwestern Mediterranean and Alboran seas (Tursi et al 2004;Taviani et al 2005aTaviani et al , 2005bTaviani et al , 2011aFreiwald et al 2009;Mastrototaro et al 2010;Vertino et al 2010;Gori et al 2013;Angeletti et al 2014;Fabri et al 2014), the sponge-dominated habitats in the Tyrrhenian, Ionian and Adriatic seas (Bo et al 2012;Calcinai et al 2013), and antipatharian-gorgonacean communities in the Tyrrhenian, Ionian and Adriatic seas and in the Strait of Sicily (Costantini et al 2010;Taviani et al 2010;Bo et al 2011;Angeletti et al 2014;Deidun et al 2014). From this ecological perspective, the Malta Escarpment in the central Mediterranean happens to be one of the least explored in European waters.…”

Overview of the conservation status of Mediterranean anthozoa

“…Often, it coexists with a rich fauna of benthic invertebrates, such as other anthozoan species (gorgonians and hard corals), sponges, as well as calcareous algae (e.g. Ballesteros 2006;Costantini et al 2010). Research has shown that the Mediterranean Red Coral can live more than 100 years and its slow recruitment and growth rate (colonies grow in diameter about 0.25 mm per year, with a higher growth in the early stages of life) hightlight the slow recovery times of disturbed populations (Marschal et al 2004).…”