The Legal and Technical Committee of the ISA is currently developing environmental standards. It is essential to establish verifiable indicators and limits to protect sensitive deep-sea species and their habitats, but this has not yet been done.
The ecosystems of the deep-sea bed are very sensitive. Scientific investigations proved that they may be considerably impaired by even minor disturbances. Damages are partly irreversible. In particular, the presence of long-living and slow-growing organisms makes deep-sea habitats especially vulnerable to external interference. New scientific studies also showed that even smallest impaired benthic habitats recover only over centuries, if at all.
The harmful environmental impact of the mining activities is due, among other things, to the extraction of the hard substrate from the deep seabed. Not only numerous organisms living at the sea floor, but also the entire habitat and their communities are eliminated. With respect to manganese nodules not only organisms living on and between these nodules (e.g. sponges, stock-forming polyps, crustaceans, mussels, annelids, snails or fish), but also those embedded therein are affected. Contrary to former ideas of a rather monotonous deep sea, especially the habitats and species are unique. They would be irretrievably lost if they were removed.
In the course of resources extraction, a cloud of fine-particulate sediment disperses in the water column depending on the amount, flow behaviour, and duration of its dispersion. The consequences are either death by suffocation due to a too thick layer of deposit on the bottom or impaired ingestion of food and communication of the benthic and aquatic fauna, for example. Mud clouds in the lighted upper water layers affect the phytoplankton which is, as basis for food webs and agent to CO2 sequestration, quite important.
Tests of the mining equipment conducted so far are expected to result in sediment inputs of several hundred tons per hour, depending on the mining technique used. Subject to grain size, water depth and flow regime, these sediments could remain in the water column for up to 100 years and drift over long distances.
The discharge of production water accumulating on the vessels after the initial processing of the ores is a third kind of negative environmental impact. The potential environmental damages depend on the contamination of the production water and the location of its discharge (on the seabed or in the water column). Adverse effects may also be due to light and noise.
There are some people who consider these environmental impacts to be acceptable as long as extraction only affects a "small part" of the deep seabed as a whole (according to Michael Lodge , Secretary General of the IMB, at several events). But so far, exploration and mining projects are not planned to be spatially limited, nor are there any stipulations on the number of projects. In addition, mining in the area usually affects the ecologically particularly valuable areas of the deep seabed, since, for example, areas with a high nodule density often are of extraordinary biodiversity.
In order to ensure effective protection of ecosystems in the sea and on the deep seabed, suitable assessment criteria (e.g. indicators or environmental quality standards) are needed. They should also take into account the given uncertainties and therefore be committed to the precautionary principle. Such assessment criteria are currently not available.
The German Environment Agency has commissioned a research project aiming at the development of scientifically sound concepts that can be used in deliberations on the compilation of regulations, standards and guidelines for the ISA's environmental management. In this context, the most important aspect concerns both the practical implementation of the ecosystem approach and the precautionary principle.
Continuous monitoring of the effects of mining activities on marine ecosystems is also of high importance. Either the ISA or the respective "sponsoring state" (i.e., the respective states that support individual projects) could do such monitoring. So far, monitoring concepts regarding compliance with environmental requirements and their financing are lacking. In addition, a system is needed to continuously observe the effects on the marine ecosystems of the region.
The ISA contracting states are currently negotiating initial environmental standards.