Changes of energy fluxes in marine animal forests of the Anthropocene: factors shaping the future seascape

Abstract

Climate change is already transforming the seascapes of our oceans by changing the energy availability and the metabolic rates of the organisms. Among the ecosystem-engineering species that structure the seascape, marine animal forests (MAFs) are the most widespread. These habitats, mainly composed of suspension feeding organisms, provide structural complexity to the sea floor, analogous to terrestrial forests. Because primary and secondary productivity is responding to different impacts, in particular to the rapid ongoing environmental changes driven by climate change, this paper presents some directions about what could happen to different MAFs depending on these fast changes. Climate change could modify the resistance or resilience of MAFs, potentially making them more sensitive to impacts from anthropic activities (i.e. fisheries and coastal management), and vice versa, direct impacts may amplify climate change constraints in MAFs. Such changes will have knock-on effects on the energy budgets of active and passive suspension feeding organisms, as well as on their phenology, larval nutritional condition, and population viability. How the future seascape will be shaped by the new energy fluxes is a crucial question that has to be urgently addressed to mitigate and adapt to the diverse impacts on natural systems.

Spatial distribution and habitat characterization of marine animal forest assemblages along nine submarine canyons of Eastern Sardinia (central Mediterranean Sea)

“…However, knowing that some coral species can have an extended range of depth distribution (e.g, Corallium rubrum), water depth can be considered as a proxy of other abiotic factors, such as temperature, current regime and trophic supply. Among these factors, water current is the most variable at local scale, as it influences the settlement and the feeding of the corals, as well as the amount of silt coverage (Gori et al, 2015;De Clippele et al, 2017;Rossi et al, 2019). This can be the reason why the contribution of silt coverage and depth in explaining variations in assemblages was different for the three investigated areas.…”

“…Because of their demography (Bramanti et al, 2019;Girard et al, 2019) and tridimensional structure, these animal forests are particularly vulnerable to mechanical injuries inflicted by anthropogenic pressures, such as direct fishing activities (bottom trawling, longlines and trammel nets) and their indirect consequences (Derelict Fishing Gears -DFGs, sediment resuspension and consequently silting), as well as the accumulation of marine litter (Puig et al, 2012;Clark et al, 2016;D'Onghia et al, 2017;Hinz, 2017;Giusti et al, 2019;Gori et al, 2019;Puig and Gili, 2019). Beside fishing activities, other aspects are further impacting…”

Who’s Next? Non-Indigenous Cnidarian and Ctenophoran Species Approaching to the Italian Waters

“…Gametogenesis is fast, taking five months in the case of female colonies and three months in the case of male colonies [101], similar to the parasitic alcyonarian Alcyonium coralloides [102]. This kind of reproduction may be an advantage in a fast-changing sea in which cnidarians may have problems in the stabilization of their populations due to climate change [103]. However, another potential advantage in the species expansion is the relationship with sea urchins and the erosion of the hard bottom substrate [100].…”

Abrupt Change in a Subtidal Rocky Reef Community Coincided with a Rapid Acceleration of Sea Water Warming

“…The community passed from a complex configuration with a dense canopy of large gorgonians (Paramuricea clavata), an understory dominated by long-lived calcified bryozoans (Cellaria fistulosa), and a basal layer of encrusting corallines (Lithophyllum stictiforme), to a simpler configuration with a reduced P. clavata's canopy (due to the mass mortality induced by the heat waves of the 1990s [28]), an understory with soft corals (Parazoanthus axinellae) and a basal layer of filamentous algae (dominated by the alien species Womersleyella setacea and Caulerpa cylindracea). Reduced canopy and decreased abundance of calcified organisms implied loss of topographic complexity, with likely consequences on the whole associate community and ecosystem services [56,57]. The two alternative states remained comparatively stable for many years (1961 to 1990 the previous one, 1996 to 2017 the subsequent one), while the transition between them has been abrupt (between 1990 and 1996) and marked by the quantitative exuberance of a number of species we called 'profiteers'.…”