What is the impact of deep-sea mining? | JPI OCEANS

What is the impact of deep-sea mining?


What is the impact of deep-sea mining?

In 2015 research cruises conducted under the framework of JPI Oceans examined the sites of deep-seabed disturbances which left prominent marks on the seafloor that are still clearly visible several decades after. These studies provide essential information about deep-sea ecosystems and the potential impact of mining activities.

The first year of the project "Ecolological aspects of deep-sea mining" was dedicated to field sampling campaigns in the polymetallic nodule areas of the Eastern Equatorial Pacific. The research expeditions focused on investigating different types of seafloor disturbances in the deep sea that were created from a few days and months up to almost 40 years ago. While three expeditions (Sonne 239, 240 and James Cook 120) worked in International Seabed Authority contractor areas of the United Kingdom, Germany, Belgium, France, IOM, and two of the Areas of Particular Environmental Interest (APEIs 3 and 4) located in the Clarion-Clipperton Fracture Zone (CCZ), both legs of the last expedition (Sonne 242) re-visited the DISCOL area in the Peru Basin, where a disturbance experiment has been conducted 26 years ago.
Today both the plough marks in the Peru Basin and the marks of the 37 years old OMOC dredge track were still clearly visible irrespective of their size. Preliminary biological and geochemical results are quite in line with the visual observations. In general, macro- and meiofauna communities show less diversity in the tracks: sessile and also mobile fauna associated to the nodule hard substrate (e.g., sponges, ophiuroids) is largely absent, but also species not associated to nodules (e.g., nematodes) are still significantly impacted. In those areas where the top layer of sediment was removed, the microbial communities still showed reduced metabolic activity and biomass.
Careful analyses of the data is necessary when trying to extrapolate impacts across the CCZ quantitatively and to understand how ecosystem functioning is affected and over which distances this is important. For example, total biomass shows a general correlation with nodule abundance in the CCZ, but is also influenced by the existing gradients in food supply (i.e. organic carbon flux to the seafloor) over large geographic distances from N to S and E to W. What are the dominant and the key species? How does the food web look like? Many  of the collected species were found in very distant working areas, but over which spatial and temporal scales are they connected? Following the cruises which were finalised in October 2015, scientists are processing the samples and evaluating the collected data on-shore in the participating institutes. Afterward scientific data and results will be stored in public world-wide databases and will also be made available to the Legal and Technical Commission of the International Seabed Authority to facilitate implementation into regulations.
The scientists are now analysing the data with regard to different types and levels of disturbance. The effects on community composition and diversity, as well as different types of ecosystem functions will be evaluated and compared between the investigated areas. The first observations show that a recolonization of the disturbed areas takes longer than presumed and will differ to its previous status.  The absence of the hard substrate will not allow the sessile fauna to recolonize. 
In this context it should be noted that commercial nodule mining will differ greatly from these scientific experiments by disturbing continuous areas many times larger in size (200-250 km2 per company per year).

The pilot action ‘Ecological aspects of deep-sea mining’ was initiated by the German Federal Ministry of Education and Research (BMBF) which provided 118 days of ship time for onsite research in the Pacific on the RV SONNE. The project started in January 2015 and will run for 36 months.  The funding of approximately €9.5m was brought together by Belgium, France, Germany, Italy, the Netherlands, Norway, Poland, Portugal, Romania, Sweden and the UK. The project is coordinated by Dr. Matthias Haeckel of the GEOMAR Helmholtz Centre for Ocean Research Kiel.

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