Course:EOSC270/2022/Group 19 - Effects of Deep Sea Mining and Offshore Drilling on Apex Marine Predators

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Background Information

The importance of apex predators in marine ecosystems

Figure 1.1 Deep sea food chain demonstrating predator's interactions with lower trophic levels. When marine resource extraction impacts one species, the whole food chain is disturbed.

Apex predators sit at the top of food chains and impact the trophic levels (Figure 1.1) below them[1]. In marine ecosystems, apex predators may be swimmers or birds[2]. Predators mediate energy flow through ecosystems[1] and they stabilize population sizes of species at lower trophic levels[3]. Offshore drilling and deep sea mining destroy the ocean floor[4], release toxic byproducts and introduce noise and light pollution[5]. In these ways, marine resource extraction causes predators to suffer the effects of toxin biomagnification, disturbances to sensory systems, and decreased food availability[5]. Specifically, deep sea predators are adapted to stable conditions and have little tolerance for changes affecting water conditions or their food supply[6].

Ecological significance of deep sea mining

Deep sea mining (DSM) is the extraction of metals and minerals from the seabed[7]. Extracted resources include polymetallic sulphides, cobalt, and manganese[5]. These materials have technological applications such as the manufacture of batteries, cellphones and solar panels[7]. DSM disturbs all levels of the water column[8]. Benthic ecosystems are disrupted by machinery and sediment: both of which destroy habitats and increase water turbidity[8].  Wastewater released from mining operations is warm and rich in toxic metals which can negatively impact ecosystems[5]. DSM also affects hydrothermal vent ecosystems, where sulphide deposits can be mined[5].

Ecological significance of offshore drilling

Offshore drilling is the removal of crude oil and natural gas from the ocean bed[6]. As with DSM, offshore drilling negatively impacts deep sea/seafloor ecosystems by destroying benthic habitats and stirring up sediment[4]. Offshore drilling has the risk of accidents that can affect all trophic levels, particularly if predators with fur and feathers are exposed, additionally, artificial light and noise at oil platforms may impede the sensory systems of predators[6].

Geographical range of offshore drilling and deep sea mining

Figure 1.2 Global distributions of polymetallic sulfides, polymetallic nodules, and cobalt-rich crusts as well as the Clarion Clipperton zone[5]. Image by Miller et al.[5], using information from Hein et al.[9]

As of 2009, 36 countries have offshore drilling rigs[10].  The majority of offshore drilling takes place in Saudi Arabia and in the Gulf of Mexico[10].

Figure 1.2 shows the distribution of polymetallic nodules, polymetallic sulphides/vents and cobalt-rich crusts[5].  These minerals are of commercial interest and would be targeted by mining.  Figure 1.2 also shows the Clarion Clipperton zone (CCZ): a 6,000,000 km2 area with a high concentration of polymetallic nodules[11].  The CCZ is currently being researched to establish baseline data[11].

Problems With Deep-Sea Mining and Offshore Drilling

Altering of the sea floor

Figure 2.1 Deep-sea Mining diagram outlining the environmental impacts of a mining platform and tracked mining vehicle. These include, but are not limited to, altering the seafloor, suspended sediment plumes, and released tailings discharge from the mining platform[12].

To extract resources from the bottom of the ocean, the sea floor must be drastically altered via mining excavation machinery (Figure 2.1) or the establishment of offshore drilling platforms. This can destroy entire ecosystems and potentially lead to the extinction of deep-sea species such as suspension feeders and sea floor macrofauna. Not only does this machinery kill deep-sea predators' food sources, these operations lead to plumes of sediment being suspended in the surrounding ocean. An estimated 40,000 metric tons of sediment is disturbed per day from deep sea mining alone[4]. This increase in turbidity can reduce biological productivity of primary producers by decreasing the sunlight available for photosynthesis, further impacting many predators’ food supply[8].

Toxic waste disposal

Waste disposal is unavoidable if handled incorrectly, can be devastating for marine ecosystems. Although many types of waste are created, oil-based drilling muds (OBMs) are the most toxic[13]. OBMs are comprised of diesel and toxic minerals that have been proven to greatly inhibit the behavior of many marine animals[14]. A 1991 study of sea scallops exposed to concentrated OBMs showed increased mortalities as well as the suppression of reproductive organs[15]. Sea scallops have many predators; therefore, it is possible for the toxins from OBMs to biomagnify up the food chain and become concentrated in the fatty tissues of apex predators. This could be devastating to an ecosystem if its members were inherently sensitive to these chemicals. Additionally, deep sea mining releases wastewater rich with heavy metals into aquatic ecosystems[5]. These heavy metals may bioaccumulate up the food chain, affecting the nervous systems, cellular growth and reproduction of predators[16].

Transportation of extracted resources

To transport excavated materials, large, gasoline powered, tankers are essential. Oil tankers are responsible for approximately 124 million tonnes of CO2 that has been emitted into the atmosphere[17] in addition to noise pollution and oil spills that have directly impacted marine life. Although oil spills can be somewhat rare, the discharge of hydrocarbons from tankers is constant. Discharges can introduce an abundance of marine obligate hydrocarbonoclastic bacteria (OHCBs) which will dominate the microbial community. Although they break down hydrocarbons, OHCBs can dominate other microbes and deplete their nutrients supply, causing an imbalance in bacterial ecosystems and reduction of many microbes' predators’ food supply[18].

Accidents

Figure 2.2 Coast Guard responding to Deepwater Horizon drilling unit disaster (2010)[19].

From assembly, to excavation, to the transportation of materials, there are countless opportunities for large scale accidents to occur in these operations (Figure 2.2). The most impactful of which would be a chemical leak such as an oil spill which would occur if either a tanker or pipe became compromised[20]. The effects of these oil spills can vary depending on location, but it is certain that any animal that encounters the chemicals will be negatively affected. Most notably, animals that enter shallow or surface waters can either become trapped within the oil or mistake it for food and ingest harmful chemicals. Additionally, predators having fur or feathers may become covered in oil and be unable to repel water or insulate themselves from the cold[21].

What Is the Extent of the Problem?

Measurable changes that have occurred

After exploratory gas drilling off the coast of Victoria, Australia, Currie et al. observed decreases in the abundances of common benthic species, supporting the hypothesis that offshore drilling changes community structure[22].  Additionally, a study done in Camden bay recorded elevated levels of Barium, Copper, Chromium, Mercury, and Lead where drilling occurred[16]. The experiment showed a reduction in megafauna richness, particularly in fauna that lived on the polymetallic nodules that were disturbed [23].

Figure 3.1 Echolocation of marine mammals[24]. This figure displays the surface level mechanism of echolocation purpose in marine organisms and its importance in prey or predator detection.

Direct and indirect effects on marine ecosystems

Most deep-sea areas used in mining have extremely fragile ecological characteristics that make them particularly sensitive to disturbance, such as being incredibly diverse, dominated by rare species, and by taking long times to recover[25] . For apex predators specifically, the ability to locate prey largely depends on the predator's ability to recognize its movements against complex backgrounds of shape, colour, and pattern which is threatened by human activity such as deep sea mining and offshore drilling when turbidity, light, and sound levels are altered [26].

Effects on marine apex predators

Sound pollution directly affects organisms that rely on echolocation (the production of sound released by an animal and the subsequent determination of the position of objects based on reflections of the sound [27]) for survival (example of dolphin echolocation use shown in Figure 3.1), and indirectly affects all the other organisms of the ecosystem through food chain dependencies. Apex predators such as whales, orcas and other dolphins all use echolocation to locate and catch prey and to communicate with one another. Specifically in deeper waters where organisms live in low levels of light, organisms rely on sound as their main source of gathering information [28]. Deep sea organisms are well adapted to low to no light levels in their ecosystem and artificial light has been observed to aggregate both small prey fish and larger predatory species [26].

The organisms which are directly affected

Fig 3.2 The Esca is a fleshy growth at the end of a dorsal fin spine of an anglerfish made up of bioluminescent bacteria. The Esca is used as a lure to attract prey to the fish.

Some examples of marine apex predators are seals, sea lions, orcas, polar bears and great white sharks. Their prey, mostly consisting of smaller fish and/or seals, are directly affected by sound and light pollution. Seals and sea lions have been observed to lose their auditory senses due to sound pollution[26]. Prey that lose their auditory senses may be easier to hunt, or more difficult to hunt if they begin avoiding loud areas; causing a range of impacts on their predators. Apart from affecting epipelagic and mesopelagic marine apex predators, deep sea apex predators such as angler fish also become affected by deep sea mining [29]. Angler fish become affected by the change in turbidity that deep sea mining causes. Change in turbidity changes the scattering of light waves that are emitted from an angler fish's esca (shown on an anglerfish in Figure 3.2) in turn interfering with their predatory behaviour and ability to attract their prey. An angler fish’s diet is also season dependent [30] and through light pollution these feeding habits become affected.

Deep-Sea Mining Solutions

Canada and B.C.'s dependence on deep-sea mining

Deep sea mining provides the materials crucial to Canada’s economic infrastructure and reliance on renewable and sustainable energy. British Columbia alone has an 8.4% per-capita rate of electric vehicle registration, the highest in Canada with almost 10% of new car sales being electric[31][32]. These cars are fuelled by a renewable energy source: lithium ion batteries, which are dependent on the metals exploited by deep sea mining[33]. However, recent years have given way to solutions and alternatives to deep sea mining diminishing the need to mine and drill in the deep.

Alternatives

Many deep-sea mining companies and prospectors are adamant that the seabed mining industry is the key to transitioning to an environmentally sustainable lifestyle, but several conservationists disagree since there are sufficient resources accessible terrestrially[34][35]. The most promising source of energy to power the green shift is lithium-ion batteries which require metals like cobalt, nickel and manganese - the targets of deep sea mining, however they are all available terrestrially, negating the need to mine submarine deposits[36][23].

An alternative to oil tanker transportation from offshore drilling would be implementing oil pipelines to transport oil which would decrease the sound pollution produced by oil tankers [37].

Battery alternatives

Renewable energy advancements like solid-state batteries which require no nickel or cobalt, are cheaper and more efficient than the popularized lithium-ion batteries which do[23][38]. Lithium-iron phosphate batteries are also gaining significant success as an alternative to conventional lithium-ion batteries due to their lack of nickel and cobalt which makes them much cheaper as well[34].

Metal Recycling

Figure 4.1 Urban Mining is the reuse and refining of previously used materials. This creates economic circularity so materials are able to be used in other products and do not end up in a landfill. [39]

Recycling methods like urban mining (Figure 4.1) have proven to reduce the need for new virgin metals to be mined by refining and reusing discarded metals[34]. New research has shown that more than 95% of lithium, nickel and cobalt in batteries can be recovered and reused in new batteries and new innovations, meaning a significant decrease in the mining and use of new metals is underway[34].

Policies and regulations

The European Union (EU) has proposed the EU Battery Regulation beginning in 2030, ensuring that batteries entering the EU are sustainable, requiring manufacturers to use recycled metals and encouraging more technological innovations[34]. These regulations will also extend to countries outside of the EU wanting to sell within the market[34].

The International Seabed Authority (ISA) began creating regulations regarding the exploitation of mineral resources in the seafloor in 2013[40]. These regulations include policies on prospecting and protection and preservation of the marine environment[40].

Offshore drilling disasters like the 2010 Deepwater Horizon incident lead the US government to create the BSEE (Bureau of Safety and Environmental Enforcement), which enforces safety and environmental regulations and promotes environmental stewardship and the conservation of resources[41].

References

  1. ↑ 1.0 1.1 Matich, Heithaus P. (2010). "Contrasting patterns of individual specialization and trophic coupling in two marine apex predators". Journal of Animal Ecology.
  2. ↑ Machovsky-Capuska, G.E.; Raubenheimer, D. (2019). "The Nutritional Ecology of Marine Apex Predators". The Annual Review of Marine Science.
  3. ↑ Atwood, T.B.; Hammill, E. (2018). "The Importance of Marine Predators in the Provisioning of Ecosystem Services by Coastal Plant Communities". Frontiers in Plant Science. 9. line feed character in |title= at position 56 (help)
  4. ↑ 4.0 4.1 4.2 Amos, A. F., & Roels, O. A. (1977). Environmental aspects of manganese nodule mining. Marine Policy, 1(2), 156-163.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Miller, K.A.; Thompson, K.F (2018). "An Overview of Seabed Mining Including the Current State of Development, Environmental Impacts, and Knowledge Gaps". Frontiers in Marine Science. 4.
  6. ↑ 6.0 6.1 6.2 Cordes, E.E.; Jones, D.O.B (2016). "Environmental Impacts of the Deep-Water Oil and Gas Industry: A Review to Guide Management Strategies". Frontiers in Environmental Science. 4.
  7. ↑ 7.0 7.1 Cuyvers, L.; Berry, W. "Deep seabed mining: A rising environmental challenge". International Union for Conservation of Nature.
  8. ↑ 8.0 8.1 8.2 Sharma, R. (2015). "Environmental Issues of Deep-Sea Mining". Procedia Earth and Planetary Science.
  9. ↑ Hein, James R.; Mizell, Kira (June 2013). "Deep-ocean mineral deposits as a source of critical metals for high- and green-technology applications: Comparison with land-based resources". Ore Geology Reviews. 51.
  10. ↑ 10.0 10.1 Gamache, Martin (2019). "Drilling for Offshore Oil". National Geographic.
  11. ↑ 11.0 11.1 Jones, Daniel O.B.; Simon-Lledó, Erik (Fall 2021). "Environment, ecology, and potential effectiveness of an area protected from deep-sea mining (Clarion Clipperton Zone, abyssal Pacific)". Progress in Oceanography. 197.
  12. ↑ MimiDeepSea. (2019). Mining implications figure.png. Wikimedia Commons. Retrieved from https://commons.wikimedia.org/wiki/File:Mining_implications_figure.png.
  13. ↑ Nediljka, G. M., Katarina, S., Davorin, M., & Borivoje, P. (2006). Offshore drilling and environmental protection. Energy and Environment, 309-318.
  14. ↑ Holdway, D. A. (2002). The acute and chronic effects of wastes associated with offshore oil and gas production on temperate and tropical marine ecological processes. Marine Pollution Bulletin, 44(3), 185-203.
  15. ↑ Cranford, P. J., & Gordon, D. C. (1991). Chronic sublethal impact of mineral oil-based drilling mud cuttings on adult sea scallops. Marine Pollution Bulletin, 22(7), 339-344.
  16. ↑ 16.0 16.1 Trefry, J.H.; Dunton, K.H. (2013). "Chemical and biological assessment of two offshore drilling sites in the Alaskan Arctic". Marine Environmental Research. 86.
  17. ↑ Walker, T. R., Adebambo, O., Feijoo, M. C. D. A., Elhaimer, E., Hossain, T., Edwards, S. J., ... & Zomorodi, S. (2019). Environmental effects of marine transportation. In World Seas: an environmental evaluation (pp. 505-530). Academic Press.
  18. ↑ Maier, R. (2009). Oil tanker. Oil Tanker - an overview | ScienceDirect Topics. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/oil-tanker
  19. ↑ United States Coast Guard. (2010). Deepwater Horizon offshore drilling unit on fire. Wikimedia Commons. Retrieved from US Coast Guard - 100421-G-XXXXL- Deepwater Horizon fire.
  20. ↑ Ismail, Z., Kong, K. K., Othman, S. Z., Law, K. H., Khoo, S. Y., Ong, Z. C., & Shirazi, S. M. (2014). Evaluating accidents in the offshore drilling of petroleum: Regional picture and reducing impact. Measurement, 51, 18-33.
  21. ↑ Ober, H. K. (2010). Effects of oil spills on marine and coastal wildlife. EDIS, 2010(3).
  22. ↑ Currie, D.R.; Isaacs, L.R. (2005). "Impact of exploratory offshore drilling on benthic communities in the Minerva gas field, Port Campbell, Australia". Marine Environmental Research. 59.
  23. ↑ 23.0 23.1 23.2 Lledó, Simon; Bett, E. (2019). "Biological effects 26 years after simulated deep-sea mining". Nature. Cite error: Invalid <ref> tag; name ":6" defined multiple times with different content
  24. ↑ Achat1999. (2016). Toothed Whale Echolocation.png. Wikimedia Commons. Retrieved from https://wiki.ubc.ca/File:Toothed_Whale_Echolocation.png
  25. ↑ Niner, Holly J. (March 2018). [www.frontiersin.org "Deep-Sea Mining With No Net Loss of Biodiversity—An Impossible Aim"] Check |url= value (help). Frontiers. 5: 12 – via Frontiers.
  26. ↑ 26.0 26.1 26.2 Davies, Thomas W (August 2014). "The nature, extent, and ecological implications of marine light pollution". ESA. 12: 8 – via Frontiers.
  27. ↑ Jones, Gareth (July 2005). "Echolocation". Current Biology. 15 no. 13: 5 – via Department Membrane and Ultrastructure Research.
  28. ↑ Slabbekoorn, Hans (July 2010). "A noisy spring: the impact of globally rising underwater sound levels on fish". Science Direct. 25: 9 – via Elsevier.
  29. ↑ Nielman, Chelsey L.; Brusotter, Jeremy T.; Braig IV, Eugene C.; Gray, Suzanne M. (March 2020). "You can't just use gold: Elevated turbidity alters successful lure color for recreational Walleye fishing". Great Lakes Research. 46: 589–596 – via Elsevier. line feed character in |title= at position 77 (help)
  30. ↑ Crozier, W. W. (May 1985). "Observations on the food and feeding of the angler-fish, Lophius piscatorius L., in the northern Irish Sea". The Fisheries Society of the British Isles. 27: 655–665 – via Wiley Online Library.
  31. ↑ Chan, Kenneth (August 16 2021). "9.4% of BC's new car sales in 2020 were electric models". Urbanized. Check date values in: |date= (help)
  32. ↑ Roy, Lillian (July 29 2021). "Quebecers account for nearly half the sale of electric vehicles in Canada: why?". CTV News. Check date values in: |date= (help)
  33. ↑ "What Type of Batteries do Electric Vehicles Use? (Natural Elements)".
  34. ↑ 34.0 34.1 34.2 34.3 34.4 34.5 "Deep-sea mining: what are the alternatives?" (PDF). Save the high seas. July 2021.
  35. ↑ Mathews, J. A. (2017). Global green shift: When ceres meets gaia. Anthem Press.
  36. ↑ Koschinsky; et al. (2018). "Deep-sea Mining: Interdisciplinary research on potential environmental, legal, economic, and societal implications". Integrated Environmental Assessment and Management: 4(6), 672–691. Explicit use of et al. in: |last= (help)
  37. ↑ Sahebi and Nickel (2014). "Offshore Oil Network Design with transportation alternatives". European J. of Industrial Engineering: 8(6), 739.
  38. ↑ Sun and Kumat (2021). "Advances in solid-state batteries, a virtual issue". ACS Energy Letters: 6(6), 2356–2358.
  39. ↑ Medkova, Katerina (September 2016). "Urban Mining within the Circular Economy".
  40. ↑ 40.0 40.1 "Decision of the Council of the International Seabed Authority relating to amendments to the Regulations on Prospecting and Exploration for Polymetallic Nodules in the Area and related matters" (PDF). July 22 2013. line feed character in |title= at position 52 (help); Check date values in: |date= (help)
  41. ↑ "Regulations | Bureau of Safety and Environmental Enforcement".
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