Offshore platforms as novel ecosystems: A case study from Australia’s Northwest Shelf
Sean van Elden | February 2022
New publication
Offshore oil and gas platforms can function as “novel ecosystems” supporting diverse and abundant marine wildlife, according to researchers from the University of Western Australia. Six surveys were conducted over three years at the Wandoo oil field, 70 km offshore of Dampier, Western Australia, and at two nearby natural sites.
The study, published in Ecology and Evolution, found that the abundance and diversity of marine life at the Wandoo oil field were higher than they would have been pre-installation. Additionally, the fish community inhabiting the platform area was distinct from that of a nearby natural reef, with a novel ecosystem emerging at the platform.
Lead author Dr Sean van Elden collected thousands of hours of video footage over the course of three years, from which the team at UWA’s Marine Futures Lab documented over 35,000 animals from 358 different species. These animals ranged from tiny baitfish to large minke whales, and included sharks, manta rays, sea snakes and turtles. Several species were observed exclusively at Wandoo, including rainbow runner, Malabar grouper and tawny nurse sharks.
Dr van Elden said that Australia should allow for offshore oil and gas platforms to be left in place once they are decommissioned, if it can be demonstrated that they are of significant ecological value, similar to the Rigs-to-Reefs program in the United States.
“These platforms are artificial reefs that have been in place for decades. Removing these structures from the ocean destroys a thriving reef community.”
“There are thousands of platforms around the world which face decommissioning. We should at least be considering the ecological role these structures play, and whether removing them could do more harm than good.”
Co-author Jessica Meeuwig, Director of the Marine Futures Lab at UWA, said the exclusion of fishing activity around offshore platforms is a key component of these diverse and abundant ecosystems.
“In Australia, offshore platforms are surrounded by a petroleum safety zone which prohibits entry of unauthorised vessels, including recreational and commercial fishing vessels. This effectively means that a marine protected area exists around each of these platforms, providing refuge for the animals associated with them.”
Citation: van Elden S., Meeuwig JJ and Hobbs RJ. 2022. Offshore platforms as novel ecosystems: A case study from Australia’s Northwest Shelf. Ecology and Evolution. https://doi.org/10.1002/ece3.8496
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Study sites
Location of the three study sites, Wandoo, Control Reef and Control Sand, approximately 75 km north-west of Dampier, Western Australia
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Wandoo field
Wandoo oil field schematic adapted from Vermilion Oil and Gas Australia (2014). The infrastructure at the Wandoo field includes the unmanned monopod Wandoo A, the concrete gravity structure Wandoo B, the pipeline end manifold (PLEM), and the catenary anchored leg mooring (CALM) Buoy. Not to scale
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Biological measures
Mean values with standard errors (SE) for taxonomic richness (TR), and logged values of total abundance (TA), total biomass (TB) fork length (FL) by survey for demersal (left) and pelagic (right) communities at the three sites: Wandoo (green); Control Reef (dark blue) and Control Sand (light blue). Solid bars indicate autumn surveys while broken bars indicate spring surveys
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Canonical analysis
Canonical analysis of principal coordinates (CAP) for abundance of (a) demersal and (b) pelagic taxonomic assemblages at Wandoo (green); Control Reef (dark blue) and Control Sand (light blue). Species clockwise from top in (a) are: bluespotted emperor Lethrinus punctulatus, northwest blowfish Lagocephalus sceleratus, brushtooth lizardfish Saurida undosquamis, galloper Symphorus nematophorus, spot-cheek emperor Lethrinus rubrioperculatus, bluespotted tuskfish Choerodon cauteroma, and turrum Carangoides fulvoguttatus. Taxa clockwise from top in (b) are: live sharksucker Echeneis naucrates, scads Decapterus sp., silky shark Carcharhinus falciformis, herrings Clupeidae sp., great barracuda Sphyraena barracuda, and rainbow runner Elegatis bipinnulata.
Funding and Acknowledgements
This research was supported by Vermilion Oil and Gas Australia, owners and operators of the Wandoo oil field, via provision of access to site, project and logistics support, and a PhD scholarship. The research was conducted independently by UWA with no further input from Vermilion