REDEEM – Resilience of anthozoan corals to deep-sea mining, an holobiontic approach


Ana Hilário


Programa Operacional da Competitividade e Internacionalização (02/SAICT/2017)


22/07/2018 - 21/07/2021

Funding for CESAM

239959 €

Total Funding

239959 €


Commercial-scale mining for polymetallic nodules could have a major impact on the deep-sea environment, but the effects of these mining activities on organisms are very poorly known. In addition to the removal of nodules, that are essential for many species, nodule mining will also cause sediment plumes that may bury or smother seafloor organisms and habitats, and prevent larval settlement and colonisation. REDEEM aims to study, for the first time, the impact of such plume on anthozoan corals, one of the most important megafaunal components on the Clarion-Clipperton Zone (CCZ), the main region targeted for nodule mining, with 15 exploration contracts approved by the International Seabed Authority (ISA). The ISA has recently adopted an environmental management plan for the CCZ and it demands that prior to exploitation, a benthic biological baseline study must be undertaken for each exploration contract area. However, the international deep-sea research community has recognized the urgent need for independent research. In this context, the REDEEM team has been invited to participate in a research cruise led by GEOMAR (Germany) within the JPI Oceans project “Mining Impact”. The cruise is designed to monitor the field trial of a nodule collector and to assess its environmental impacts. Samples will be collected before and after the trial from the mined area, its vicinity blanketed by the resettling sediment plume and from a reference area where no impacts are expected. REDEEM will use state-of-the art methodologies developed to study the effects of high sediment loads on shallow-water corals to understand tolerance and response mechanisms of deep-sea anthozoans to sediment plumes resulting from nodule mining. We will investigate and integrate 3 main aspects of coral ecology: feeding, life-cycle and microbiome, following the well accepted hypothesis that coral resilience depends on the intrinsic relationship between the coral host and the associated microbial community (known as the “coral holobiont”). REDEEM puts together a team of deep-sea biologists, with expertise on trophic ecology and reproductive and larval biology, and microbiologists, experienced on molecular microbiology and characterization of communities. Such collaboration will undoubtedly advance our understanding of the nature and scale of the impacts of deep-sea mining. Further, the wide experience on open ocean/deep-sea sampling, and a strong collaboration with the cruise leaders will minimize the inherent risks of working on a remote region at ~5000m depth. REDEEM results will be broadly disseminated to the scientific community but also to different stakeholders. We will ensure fluent communication between science and end users, to inform of novel scientific results and obtain information on the needs and constrains faced by industry and decision makers. In addition, several outreach activities and products will be developed to raise public awareness about deep-sea mining.