Gerald McCormack: Deep sea dilemma: More scientific information required
I would like to comment on two recent articles campaigning for a 10-year moratorium on seabed mining: “We know little about our deepest oceans” (August 29, Article A) and “Mysteries of the deep” (September 12, Article B).
Publishing these articles in the Cook Islands News led me to believe the information was meant to apply to the possibility of nodule mining in the Cook Islands. If this was the case, I would like to discuss the main proposed or implied negative effects to assess their local relevance.
Article A stated “The deep sea is a climate regulator. It is where the surface of the ocean is cooled, calmed and recharged” and “it is important to preserve these natural defences against global temperature increase.” The ocean is not cooled in the deep sea; in fact, the bottom water is continuously warming with the heat from the earth below.
The cooling occurs at the poles. In our case, it is cooled at the surface around Antarctica and then being very cold and dense it flows down the flanks of Antarctica to the deep seafloor, and pushes north, mainly towards the Cook Islands. This immense kilometre high current is too dense to flow over the 2000 metre high Manihiki Plateau, so it splits, with about 65 per cent going westward to Samoa and into the North Pacific, while the remainder flows eastward past Palmerston and Aitutaki and northward through South Penrhyn Basin.
This current, known as the Antarctic Bottom Water, is one of the main reasons the Cook Islands has such a high density of spherical nodules lying exposed on the abyssal seafloor, at about 5000 metres below sea level, in the South Penrhyn Basin (between Penrhyn and Aitutaki).
Any suggestion that nodule mining in the South Penrhyn Basin could in some way disrupt such an immense seafloor current is extremely farfetched.
Article A stated nodules have “formed over millions of years, …(and)… are home to a myriad of marine organisms.” The 50 years of research in the immense Clarion Clipperton Zone (CCZ) abyssal nodule field, in the eastern North Pacific, has revealed a lot more biomass and species diversity than was originally expected. However, the ocean surface productivity and resultant sinking organic matter to feed seafloor animals in that Zone is typically three times greater than in the central South Penrhyn Basin (SPB) nodule field. This difference leads to the prediction that the South Penrhyn Basin will have much less biomass than the CCZ, and indirectly much less species diversity.
Consistent with this prediction, seabed research by Japanese scientists (JICA and MMAJ 2001) in the South Penrhyn Basin found very low biomass and species diversity; and, nearby in the deep troughs of the Manihiki Plateau, German scientists (IFM-GEOMAR 2007) were surprised by the scarcity of animals and the lack of diversity.
The idea that nodules everywhere support myriads of organisms is simply untrue. The deepsea environment varies greatly from place to place and the South Penrhyn Basin abyssal plain has a relatively low biomass and limited species diversity.
More important than biomass and diversity is whether any species has a restricted range and could be driven into extinction by nodule mining. The current, rather meagre, evidence is that most species do have wide ranges and will be resilient. However, more biological research is required and this can be obtained under the exploratory phase and be available for independent assessment.
Article A states “nor do we know the potential benefits, including medicine, that could be derived from deep sea biodiversity”. While this is true, it is a very generalised claim. The 2005 UNU-IAS “Bioprospecting for genetic resources in the deep seabed” reported that bioprospecting scientists have little interest in organisms on abyssal plain seabeds, such as the Clarion Clipperton Zone from which many specimens have been retrieved. Instead, bioprospectors mainly focused on hydrothermal vents where animals live under more extreme conditions, and on seamounts where biodiversity is much greater than on the surrounding abyssal plains. The main marine organisms of interest are microbes (Mayer et al. 2010) and sponges (Amjun et al. 2016).
The Cook Islands can access these potential medical benefits by bringing up samples of our abyssal seabed animals and bacteria, and make them available to bioprospecting scientists. This can be done with specimens sampled under exploratory phase licences.
Concerning the non-extractive value of biodiversity, Article B said “The hydrothermal vents of the Pacific Ocean are believed to contain unknown quantities of genetic potential resource.” This is true, but the Cook Islands will not benefit from this bonanza, because there are no hydrothermal vents within our EEZ. The vents have been mapped for the Pacific and they are all in geologically active areas of the seafloor with those nearest to the Cook Islands being: south of Tahiti; a little east of American Samoa; and, in the Lau Basin of Tonga.
Article B states the “Areas targeted for seabed mining are hydrothermal vents, the abyssal plain and seamounts. All of these are known to support a complex, unique and diverse system of marine organisms”. This is a gross generalisation. Hydrothermal vents are known to support more than 300 unique organisms but, as mentioned above, there are none in the Cook Islands.
There are about 80 significant seamounts in the Cook Islands but there are no plans to mine any of them, although as elsewhere they probably have cobalt crusts. Nodules on the abyssal plain, at around 5000 metres below sea level, are the mineral resource of interest in the Cook Islands. And as pointed out above, the present state of the science indicates the Central South Penrhyn Basin will have a much lower biomass and species diversity than in the Clarion Clipperton Zone, the only other area looking towards commercial nodule mining in the near future.
We need more scientific information that is specific to the Cook Islands and I think the best way to obtain this is to give out a few exploratory licenses with the requirement to undertake biological surveys on the seabed, within and around possible mine areas. And, concerning seabed sediment plumes, I think we should allow prospective miners to test their equipment to present real data on plume structure for consideration in the EIA process.
I conclude there is nothing to lose by giving out a few exploratory licenses, and much to gain in terms of knowledge on whether or not to go forward to actual mining.
There is nothing to lose by giving out a few exploratory licenses, and much to gain in terms of knowledge on whether or not to go forward to actual mining.
SOURCE: OPINION PIECE BY GERALD MCCORMACK, CI NEWS