By Dr Moses Amweelo
Phosphates are chemical compounds that contain phosphorous, a key nutrient that both plants and animals use for growth and development.
While phosphate is essential for plant and animal life, too much of it can cause a form of water pollution known as eutrophication.
Eutrophication is the process that occurs when high concentrations of nitrogen and phosphorus, which are both fertilisers, pollute the water. It becomes a big threat to aquatic life when there is an unnatural increase of phosphorus in a water body, and it boosts plant growth.
After the algal blooming period, the algae die and fall to the bottom of the water and decompose. When they decompose, the nutrients contained in the organic matter are converted into inorganic form by microorganisms. This decomposition process consumes oxygen, which reduces the concentration of dissolved oxygen.
The depleted oxygen levels, in turn, may lead to fish death and a range of other effects reducing marine biodiversity.
Enhanced growth of aquatic vegetation, marine ecology, avifauna and algal blooms disrupts the normal functioning of the ecosystem, causing a variety of problems such as a lack of oxygen needed for fish and shellfish to survive.
Bulk marine sediment mining would have severe and irreversible impacts on marine ecosystems. There are no feasible ways to mitigate these impacts and no standards or protocols that can be put in place to reduce its destruction effect.
One mining company prospecting off the coast of Namibia intends to remove between one and five metres of seabed silt and ship it to the land to extract phosphate deposits before the waste slurry is syphoned off and dumped back into the sea.
Marine scientists and international experts have expressed concern that the dredging of three-metres of the sea floor will cause destruction to the basic building blocks of the marine ecosystem.
Scientists are also concerned about the release of hazardous substances, including radioactive materials, which will directly kill off wildlife and cause many commercial fish stocks to be unmarketable and not sale quality.
Environmental risks and impacts of deep sea mining would be enormous and unavoidable, including seabed habitat degradation over vast ocean areas, species extinction, reduced habitat complexity, slow and uncertain recovery, suspended sediment plumes, toxic plumes from surface ore dewatering, pelagic ecosystem impacts, undersea noise, ore and oil spills in transport, and more according to Conservation biologist, Professor Richard Steiner.
Before any extraction of phosphate in deep-sea moves ahead, we would need much more extensive scientific research – species identification, community ecology, distribution, genetics, life histories, resettlement patterns, resilience, to disturbance, and at least a 10 to 15 years continuous time series of observations to understand dynamics of proposed mining sites over-time.
The international law-based regulations on deep sea mining are contained in the United Nations Conventions on the Law of the Sea from 1973 to 1982, which came into force in1994.
The convention set up the International Seabed Authority (ISA), which requires nations interested in mining to explore two equal mining sites and turn one over to the ISA, along with a transfer of mining technology over a 10-20-year period.
In line with this convention, we need more robust management regimes at ISA and in coastal nations, royalty-sharing and liability agreement, stakeholder engagement, and significant advancements in subsea technology.
According to the article posted May 16, 2012, updated May 27, 2016, by Earth Organisation, marine phosphate mining has never been done anywhere else in the world and if Namibia allows phosphate extraction in our sea, our coastal waters face the risk of becoming testing ground.
Phosphate mining of the seafloor is a major concern for leading marine scientists worldwide, yet these concerns have not yet been adequately considered in Namibia.
In Australia, the concerns are so grave that the Government of the Northern Territory considers all sea seafloor mining as such a threat that moratorium has been imposed until 2015 while further environmental and risk assessments are conducted.
In 2013 the fishing industry, which is the second or third biggest foreign currency earner for Namibia, has strongly opposed the idea of phosphate mining on fishing grounds.
• Dr Moses Amweelo is Namibia’s former minister of works, transport and communication as well as a marine safety expert