Mesophotic zone as refuge: acclimation and in-depth physiological
response of yellow gorgonians in the Mediterranean Sea
Abstract
The intensification of warming-induced mass-mortalities in invertebrate
populations is a critical phenomenon that affects many regions
worldwide, including temperate ones. Mesophotic zones (from 30 to 150
meters depth) have been hypothesized to provide refuge from climate
change to gorgonian populations, a promise for re-seeding damaged or
destroyed shallow populations. Using a proteomic approach, we
investigated the responses and acclimatization ability of the yellow
gorgonian Eunicella cavolini along an environmental gradient following
reciprocal transplantations between shallow (20m) and mesophotic (70m)
zones. Our results suggested that yellow gorgonians from mesophotic
waters exhibit a more plastic response when transplanted into shallow
waters, compared to shallow gorgonians when placed at 70m. Colonies
transplanted from mesophotic to shallow waters presented a
down-regulation of immune response compared to colonies that stayed at
70m. Despite immunodepression, transplanted colonies displayed no signs
of necrosis or apoptosis, underscoring the potential acclimation
capacity of mesophotic populations. Under future climate change
scenarios, Eunicella cavolini populations could thus exhibit
physiological plasticity in the face of environmental stress, suggesting
that no physiological barrier may limit natural colonization from
mesophotic populations. This analysis provides new insights into the
cellular and molecular responses of gorgonians to environmental changes.