Deep Sea Mining
As companies move to find valuable resources in more hazardous territory
– oil, gas, minerals – Dr Anjani Ganase asks us to pause and reflect on what
mining the deep ocean means. As humans seek to exploit our most remote and
unknown environments, we need to be mindful of the present threats brought
about by decades of ecological damage from continuous production and
consumption.
Why?
As long as we continue to build and advance our technology industry, there
will always be a need to mine the elements used in our electronics. The iPhone,
and most smart phones, on average are made up of over 75 elements and many have
to been mined, including gold for electrical circuits, lithium for batteries, rare
earth metals used to make up part of the screen and features in the phone. However, it is not just phones, most modern
electronics, battery systems and alternative energy systems, are built using
these earth elements.
Over the last fifty years as our technology has advanced, this has come
with a significant ecological price. Many of the elements mined are
non-renewable, taken from a finite global supply. With limited recycling
options and electronics needing to be replaced every three to four years, this
means that the ecological impacts of mining will only get worse into the future.
Mining for these elements takes place all around the world (China, Chile, US,
Australia and Ghana), and with limited options for sourcing such elements,
companies will continue to mine in countries with sub-standard environmental laws.
As resources on land have already begun to be depleted, exploration for the minerals
is expected to shift to the deep ocean. If environmental damage as result of
mining is already difficult to manage within a country on land, it can be
expected that the management of these deep ocean activities will likely be even
more difficult.
 |
| Midwater animal biodiversity: Squid, fish, shrimp, copepods, medusa, filter-feeding jellies, and marine worms are among the midwater creatures that could be affected by deep sea mining. Photo sourced from Drazen et al (2020). |
How?
Deep-sea mining basically consists of a deep-sea vehicle to scrape and
dig the bottom of the ocean, either on submerged sea mounts (the tops of
submerged mountains, 1 -3 km depth) or in the abyssal plains (the valleys
between these submerged mountains, down to 6 km depth). The material that is dug
will be pumped up to the surface, where water is removed leaving mined sediment,
and all the waste products are discharged into the water column.
Environmental impacts
The areas that will be affected by deep-sea mining include the deep-sea
bottom habitats, as well as the marine life that occupy the water column above
(from the surface to 6 km depth). The area of impact consumes 90 % of the
livable area for any deep ocean dweller. Bear in mind that the deep sea is home to a
large amount of marine life including organisms that grow along the seabed such
as sponges, coral, worms and invertebrates, as well as plankton, fish and large
marine mammals that occupy the water column. The environmental impacts range
from the physical removal of these benthic ecosystems that have existed for
hundreds of years without our even knowing what is there or understanding their
ecosystem, to pollution of large areas of water
Many deep-sea dwellers are slow growing owing to the limitations of food
and other resources at depth and are unlikely to recover from the physical
damage of deep-sea mining. Scientists have already tested this out and showed
that sites mined over 35 years ago showed no recovery. In the water column, loud
mechanical sounds which are likely to travel much farther underwater, as well
as the use of light above and in the water, can be disorienting for marine
life, from the migrating whales to larvae of marine creatures that get
transported on ocean currents, affecting organisms that might be feeding, finding
mates, breeding and communicating. A most damaging activity is the dumping of
sediment in the water column creating a sediment plume that will be released
into the water column at multiple depths. It might be as if the densest plume
of Sahara dust were to stay in our atmosphere. We would not be able to breathe.
The open ocean naturally has very little sediment, and life in the ocean
is adapted to the clear water. Sediment can be transported with the current to
smother bottom habitats large distances from the mining sites. Plumes in the
water column can disorient marine life by altering light and sound conditions.
The sediment particles can overwhelm larvae and filter feeders that are not use
to having sediment settle on their gills and tentacles. For the microbial and planktonic
community, sediment can stick and bombard them. Larger animals will also be
affected as they feed on the animals that then feed on organic particulates.
While this is only what can be conceptualized, the impacts in the larger area
(owing to the transient nature of the open ocean) and over the long-term are
unknown. So many deep-sea locations have not been explored that significant
biodiversity can be lost without our ever having a chance to discover and
understand them. Deep-sea mining will bring additional stress to fisheries,
tourism industry, and exacerbate existing climate-related maladies being
experienced by the ocean – algae blooms, dead zones and global warming and
acidification.
What the future holds
As we continue to push for economic growth, the exploitation of natural
resources will continue to destroy habitats and biodiversity. Currently most electronics that are disposed of
every four years, are not recycled, which means that new resources will
continue to be mined. New technology has been touted as the solution to
fighting climate change, yet we are using the same level of unrestraint in our
resource use to solve the primary problem of over consumption. We are causing climate
change through our abusive consumption patterns: fossil fuels are not bad in
themselves, what is bad is how wastefully we use them. We continue to use
finite resources without consideration of the impacts to our global ecology.
The price to be paid to remedy our voracious consumption habits - to
combat climate change - is very high. If technology is thought to be the
solution to combat climate change, what is the solution for the severe
environmental damage brought about by the tech industry and the pollution from
the e-waste that now plagues many poor nations around the world? Maybe the
solution is to re-evaluate what our economy means to us and make it more
dependent on our wellbeing and resources managed for sustainable use. Let us
actively strive to be a healthy economy where our lives and livelihoods are not
valued in property or money, but rather on the quality of living. As it is now,
we barely know what is in our deep-ocean backyard; how do we expect to mitigate
the damage and impacts of deep-sea mining.
 |
| A schematic showing the potential impacts of deep-sea mining on marine ecosystems. Schematic not to scale. Sourced from Miller et al (2018). |
References:
Drazen JC, Smith
CR, Gjerde KM, et al. Opinion: Midwater ecosystems must be considered when
evaluating environmental risks of deep-sea mining [published online ahead of
print, 2020 Jul 8]. Proc Natl Acad Sci U S A. 2020;202011914.
doi:10.1073/pnas.2011914117
Miller, K. A.,
Thompson, K. F., Johnston, P., & Santillo, D. (2018). An overview of seabed
mining including the current state of development, environmental impacts, and
knowledge gaps. Frontiers in Marine Science, 4, 418.
Comments
Post a Comment