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Project Overview

High-CO2 Seas: Assessing the Impacts of Ocean Acidification on
Marine Biodiversity and Species Adaptation

The aim of the High-CO2 Seas project is to assess the effects of ocean acidification (OA) on marine biodiversity across different habitats affected by CO2 vents and to estimate acclimation/adaptation's role in the responses to OA on the endemic Mediterranean coral Astroides calycularis.

To achieve these scientific objectives, High-CO2 Seas created a highly cooperative, multi-disciplinary and international consortium with skills in marine biogeochemical cycles, marine ecology, mineralogy, genetics, and communication. The consortium is formed by seven research institutions from Italy, France, and the US. This project is funded by the Total Foundation and will last two and half years.

Ischia as a natural laboratory to assess the impacts of OA on marine biodiversity and species adaptation

OA is a change in seawater chemistry due to the uptake of excess anthropogenic CO2 by the ocean and a concomitant decline in seawater pH. The oceans absorb the excess atmospheric CO2 and play a key role in regulating the climate. OA is expected to profoundly alter the diversity and function of marine ecosystems, as well as the services they provide to society. There are places scattered throughout the ocean where CO2-rich water bubbles from volcanic vents lowering the pH in the surrounding waters. Scientists use these unique CO2 systems as natural laboratories to study and predict the effects of OA on marine organisms and ecosystems. Recently, various new vent systems have been discovered along the coast of Ischia (Italy) across different marine habitats, which are hotspots of Mediterranean marine biodiversity.

The new CO2 vent sites along the coast of Ischia. These vent sites span a variety of different habitats such as Posidonia oceanica seagrass meadows, gravel and sandy bottoms, semi-dark caves, and coralligenous outcrops.

Video images provided by Pietro Sorvino


High-CO2 project will integrate three major objectives: 1) characterize water chemistry and pH variability, 2) assess the vulnerability of marine benthic biodiversity using a trait-functional approach; and 3) determine the role of acclimation/adaptation in the responses to OA of the coral Astroides calycularis. Moreover, we will use virtual reality technology to increase public understanding and awareness of OA.

Objective 1

Objective 1: Characterizing water chemistry and pH variability

The High-CO2 Seas project will perform field surveys to characterize water chemistry and pH measurements at the newly discovered CO2 vents and at reference sites that lack vent activity with normal pH values. We will use in situ pH sensors to monitor seawater pH conditions that allow us to study spatial and temporal variation in seawater pH. We will also collect water samples for biogeochemical characterization of the water column.

Objective 2

Objective 2: Assessing the vulnerability of marine biodiversity

In addition to conducting classic analyses of change in taxonomic diversity and community structure with OA, the High-CO2 Seas project will apply a functional trait approach to cover data of benthic species. Functional traits are defined as any trait directly influencing an organism's performance and examples include: growth forms, solitary versus colonial species, seasonality, size ranges, or the presence of calcareous skeletons and shells. The functional-trait based approach will allow us to assess the responses of functional diversity and redundancy to OA.

Objective 3

Objective 3: To assess the role of acclimation/adaptation in determining responses to OA by the coral Astroides calycularis

With ocean acidification, corals cannot absorb the calcium carbonate they need to build their skeletons. The coral Astroides calycularis is an orange, long-lived species with SW distribution in the Mediterranean Sea. It is considered to be vulnerable on the IUCN red list. Interestingly, there is one population of the coral A. calycularis that naturally occurs at the Magician's Cave (Grotta del Mago in Italian). We will test the degree of genetic adaptation (natural selection that occurs within a population) and acclimation (which occurs in individuals) of the coral by performing reciprocal transplant experiments in the field.

Objective 4

Objective 4: Virtual Reality to communicate Ocean Acidification

High-CO2 Seas will use virtual reality to teach the changes in diversity associated with ocean acidification. Virtual reality exhibitions for the public will be presented in various museums and aquariums in France and Italy. News will be posted on our Facebook and Twitter accounts.


Valeriano Parravicini

Ecole Pratique des Hautes Etudes, USR 3278 CNRS-EPHE CRIOBE University of Perpignan, France

Jean-Pierre Gattuso

Laboratoire d'Océanographie de Villefranche, University Pierre and Marie Curie- Paris 6, France

Samir Alliouane

Laboratoire d'Océanographie de Villefranche, University Pierre and Marie Curie- Paris 6, France

Stefano Goffredo

Marine Science Group, University of Bologna, Italy

Erik Caroselli

Marine Science Group, University of Bologna, Italy


Total Foundation

This project has received funding from the Total Foundation under Grant Agreement BIO_2016_081_4.
High-CO2 Seas is coordinated by the Stazione Zoologica Anton Dohrn, Naples (Italy)