Last week we analysed the various pollutive aspects of oil rigs and the production of the lucrative ‘black gold’ but did you know that these rigs play an important role in maintaining marine biodiversity? To be honest, I was just as surprised as you when I learned of this just last week during my lecture for GES1021 – The Natural Heritage of Singapore! It’s a really interesting module – almost on par with GE3246 of course erhmm – and to our fellow NUS students who haven’t cleared their GES pillar, please do consider it 😀

Now enough of the shameless promotion, and let’s get back to business. Prepare your diving gear as we plunge into the depths of the oceans!

Down Under

It is estimated that there are over 7,500 offshore oil and gas platforms located around the world (Zeldovich, 2018) and many of these are aging relics, with wells that have run dry and awaiting dismantling. We often interact with information about these offshore rigs through their utility, in that they are constructed for the purpose of drilling petroleum and other hydrocarbon products, yet these are just the tip of the iceberg. The University of California – Santa Barbara (2019) posits that these pillars and accompanying structures extending all the way to the ocean floor are teaming with life while providing spawning sites for fish. This is so as when the shellfish attached to the structures die, they fall to the base of the platforms, forming enormous shell mountains attracting rockfish and other animals to make their nursery grounds and lay their eggs there. 

Moreover, as the oil rigs operate for decades, it provides opportunities for barnacles, oysters, mussels, hydroids, sponges, and corals to attach to the underwater frame, which attracts mobile invertebrates and fish species. This in turn lures larger fish that feed upon them, and so on, forming a highly complex and interrelated food chain. Isn’t it fascinating? 

Take a look at the video to catch a glimpse of the world beneath!

Rigs to Reef: Transecting Borneo (Trailer) from Matador Network on Vimeo.

Protecting the Flourishing Biodiversity

Since the late 1980s, there have been calls to preserve these structures, culminating in the launch of the ‘Rigs-to-Reef’ programme that started in Mexico (Kaiser & Pulsipher, 2007). It provides an alternative to complete platform removal, enabling oil companies to modify their platform structures to continue to support marine life as an artificial reef. 

Apart from the ecological benefits, preserving these structures brings about economic gains too. Rigs-to-Reefs can save oil companies millions of dollars in decommissioning costs, however, not all platforms are suitable as reefing candidates. Each platform must undergo extensive ecological evaluations to assess any potential value it might add to the local ecosystem. Moreover, local fishermen are able to benefit from enhanced commercial fishing (American Petroleum Institute, n.d.) as schools of fish tend to congregate around the rigs due to the presence of shellfish and other sources of food (Hazelwood & Sparks, n.d.).

For a better understanding of the programme, let’s turn to the current initiatives that the present in the Gulf of Mexico 😀

Case Study: Artificial Reefs – Gulf of Mexico

Rigs-to-Reefs was introduced in the late 1980s in the Gulf of Mexico by the National Marine Fisheries Service, and according to the Bureau of Safety and Environmental Enforcement (BSEE, n.d.) as of April 2018, 532 platforms have been converted into reefs. In Asia, the program has been implemented in Malaysia and Brunei Darussalam too!

Before the implementation of the program in the 1980s, the costs of decommissioning an entire oil rig can run as high as US$200 million in the deep waters of the Gulf of Mexico, with daily costs amounting to US$700,000 per day to transport the structure to its final disposal site (Hazelwood & Sparks, n.d.). Preserving these sites thus eliminates such costs while protecting the biodiversity that lies beneath the surface.

These structures are touted to house more than 14,000 fishes by providing 2 to 3 acres of habitat for hundreds of marine species (BSEE, n.d.). The image above just illustrates a portion of an oil rig, and it’s already teaming with schools of fish! As the natural seafloor of the Gulf of Mexico is a flat plain of clay, mud, and sand, offering very little natural hard bottom and reef habitat, artificial reefs thus provide habitat that supports marine life.

How are the artificial reefs formed?

There are 3 general methods that can be utilised for removing and reefing a retired structure (BSEE, n,d,):

1. Tow-and-place: severing the structure from the seafloor either using explosives or mechanical cutting techniques and then towing it to the selected reef for deployment.
2. Topple-in-place: detaching the structure from the seafloor using explosives or mechanical cutting and topple it onto its side for it to sink.
3. Partial removal: generally doesn’t use explosives. The platform is severed at a permitted navigational depth, typically 85 feet deep, and placed on the seafloor next to the base of the remaining structure.

However, this doesn’t come without potential threats to the environment. As aforementioned, certain reefing techniques might require the use of explosives, which might result in the creation of debris and result in the mortality of marine life. Additionally, there is a major concern regarding the leaking potential of the capped well and from the metal structures themselves (Callahan & Jackson, 2017). That being said, Callahan and Jackson (2017) posit that the metals from the steel structure of the platform jacket and the anodes attached to them have a fundamentally low leaching rate and the available concentrations of metal ions resulting from corrosion typically fall to reduced levels due to marine currents and circulation. Therefore, it can be expected that there would be few negative impacts resulting from the leaching of metals from the jacket’s structural steel.

Till Next Time

Repurposing oil platforms as reefs evidently presents an opportunity to save costs while minimizing impacts to the environment. Moreover, local communities are able to benefit from commercial and recreational fishing and recreational scuba diving due to the enriched marine habitat. This can act as a catalyst for the growth of sustainable ocean development projects in the future.

For our next post, you have heard about global warming, but what about global cooling? And no, I am not talking about cooling due to natural events such as volcanic eruptions or changes in sunspot activity. But rather global cooling as a result of anthropogenic activity. Seems impossible? Well stay tuned for our next post to find out how 😉

 

References:

American Petroleum Institute. (n.d.). Rigs to Reef Programs Create Valuable Fish Habitat. Available from: https://www.api.org/oil-and-natural-gas/environment/environmental-performance/environmental-stewardship/rigs-to-reef-programs [Accessed 16 September 2020]

BSEE. (n.d.). Rigs to Reef. Available from: https://www.bsee.gov/what-we-do/environmental-focuses/rigs-to-reefs [Accessed 16 September 2020]

Callahan, E., & Jackson, A. (2017). Viewpoints: Rigs to Reefs. Mission Blue. Sylvia Earle Alliance. Available from: https://mission-blue.org/2017/07/viewpoints-rigs-to-reefs/ [Accessed 16 September 2020]

Hazelwood, E., & Sparks, A. (n.d.). How Oil Rigs Can Help Preserve Marine Life. Development Asia. Available from: https://development.asia/explainer/how-oil-rigs-can-help-preserve-marine-life [Accessed 16 September 2020]

Kaiser, M. J., & Pulsipher, A. G. (2007). Rigs-to-Reef Programs in the Gulf of Mexico. Ocean Development and International Law. 36(2), 119-134. Available from: doi: 10.1080/00908320590943990

Images:

BSEE. (n.d.). Rigs to Reef. Available from: https://www.bsee.gov/what-we-do/environmental-focuses/rigs-to-reefs [Accessed 16 September 2020]

Grace, R. (n.d.). Viewpoints: Rigs to Reef. Mission Blue. Sylvia Earle Alliance. Available from: https://mission-blue.org/2017/07/viewpoints-rigs-to-reefs/ [Accessed 16 September 2020]

Platko, J. (n.d.). Marine life thriving under oil rigs off the coast of Long Beach California. Development Asia. Available from: https://development.asia/explainer/how-oil-rigs-can-help-preserve-marine-life [Accessed 16 September 2020]