Functional changes across marine habitats due to ocean acidification

Abstract

Global environmental change drives diversity loss and shifts in community structure. A key challenge is to better understand the impacts on ecosystem function and to connect species and trait diversity of assemblages with ecosystem properties that are in turn linked to ecosystem functioning. Here we quantify shifts in species composition and trait diversity associated with ocean acidification (OA) by using field measurements at marine CO2 vent systems spanning four reef habitats across different depths in a temperate coastal ecosystem. We find that both species and trait diversity decreased, and that ecosystem properties (understood as the interplay between species, traits, and ecosystem function) shifted with acidification. Furthermore, shifts in trait categories such as autotrophs, filter feeders, herbivores, and habitat‐forming species were habitat‐specific, indicating that OA may produce divergent responses across habitats and depths. Combined, these findings reveal the importance of connecting species and trait diversity of marine benthic habitats with key ecosystem properties to anticipate the impacts of global environmental change. Our results also generate new insights on the predicted general and habitat‐specific ecological consequences of OA.

Elevated heterotrophic capacity as a strategy for Mediterranean corals to cope with low pH at CO2 vents

“…Natural marine volcanic vent systems release CO 2 into the water column, locally acidifying the seawater to pH levels expected later this century [ 16 ]. At CO 2 vents in Papua New Guinea and Ischia, Italy, species richness, habitat complexity, and functional diversity decrease with decreasing pH along natural gradients [ 17 – 19 ], with calcifying species being most affected [ 16 – 20 ]. In Ischia, two species of coral, the symbiotic Cladocora caespitosa and the asymbiotic Astroides calycularis , have recently been found growing near CO 2 vents [ 18 , 21 ].…”