Direct studies of recovery from drilling in deep water are lacking and the cumulative effects of multiple drilling wells are not well-studied. Environmental management takes many forms. We focus on management activities that mitigate the adverse environmental effects of oil and gas development, specifically addressing avoidance- and minimization-type approaches World Bank, Here, we consider three complementary strategies: i activity management, ii temporal management, and iii spatial management Table 1.
In activity management, certain practices or discharges are restricted or banned, or certain technologies are employed to reduce the environmental impact of operations. An example of activity management is the phasing out of drilling muds that used diesel oil as their base. These drilling fluids biodegrade very slowly, have a high toxicity, and exposure to them can result in negative environmental consequences Davies et al.
In addition, many countries have introduced restrictions on the discharge of lower-toxicity organic-phase drilling muds i. The elimination of these discharges has led to demonstrably reduced extents of drilling impacts Figure 4 , from thousands of meters around wells drilled using oil-based muds Davies et al.
Restrictions are also imposed on the discharge of produced water, with produced water typically being expected to be re-injected into subsurface formations, or to be cleaned to meet national oil-in-produced water discharge limits before being disposed into the sea Ahmadun et al. During exploration activities, activity management may be required for seismic surveys, because the intense acoustic energy can cause ecological impacts particularly to marine mammals.
In many countries, including the US, UK, Brazil, Canada, and Australia, mitigation protocols have been developed to reduce the risk of adverse impacts on marine mammals Compton et al.
Activity management may also be applied to oil and gas industry decommissioning. Although some large installations are exempt, most structures must be taken onshore for disposal; however the environmental impacts caused by removing these large structures may outweigh any negative effects of leaving them in place. In many other jurisdictions, such as the US, Malaysia, Japan, and Brunei, decommissioned structures may be left in place as artificial reefs Fjellsa, ; Kaiser and Pulsipher, To date, these rig-to-reef proposals are limited to shallow waters, where they are thought to create habitat for commercial and recreational fisheries species.
Temporal management of oil and gas activities is not yet widely applied in deep-water settings. Temporal management approaches are intended to reduce impacts on the breeding, feeding, or migration of fish, marine mammals, and seabirds.
Furthermore, seismic operations along marine mammal migration routes or within known feeding or breeding grounds may be restricted during aggregation or migration periods in order to reduce the probability of marine mammals being present in the area during the survey Compton et al.
In addition, soft-start procedures may only be allowed to commence during daylight hours and periods of good visibility to ensure observers can monitor the area around the air gun array and delay or stop seismic operations if necessary Compton et al. Temporal management has also been proposed for the cold-water coral L. In the NE Atlantic, this species appears to spawn mainly between January and March Brooke and Jarnegren, and the larvae are thought to be highly sensitive to elevated suspended sediment loads, including drill cuttings Larsson et al.
Special steps to strengthen the oil spill emergency response system, including shorter response times during the spawning season have also been implemented. Spatial management prohibits particular activities from certain areas, for example where sensitive species or habitats are present. This can range from implementing exclusion zones around sensitive areas potentially affected by individual oil and gas operations to establishing formal marine protected areas through legislative processes where human activities deemed to cause environmental harm are prohibited.
The use of EIAs as a tool for identifying local spatial restrictions for deep-water oil and gas operations is widely applied, and specific no-drilling zones mitigation areas are defined by the regulatory authority around sensitive areas known or occurring with high-probability Table 1. The need for spatial restrictions to hydrocarbon development may also be identified at the strategic planning stage.
In Norway, for example, regional multi-sector assessments have been undertaken to examine the environmental and socio-economic impacts of various offshore sectors and to develop a set of integrated management plans for Norway's maritime areas. The plans incorporate information on potential cumulative effects from multiple sectors, potential user conflicts and key knowledge gaps, as well as locations that should be exempt from future hydrocarbon exploration owing to their ecological value and sensitivity to potential effects from offshore drilling Fidler and Noble, ; Olsen et al.
A number of approaches have been used to identify the ecological features and attributes used in setting targets for spatial management, some of which may be relevant in the deep-sea environment. Cold-seep and deep-water coral ecosystems Figure 5 would be considered as VMEs under this framework. However, given that the deep-water oil and gas industry still operates, almost exclusively, within areas of national jurisdiction, and has impacts that differ in extent and character to bottom-contact fishing, the VME concept may not be the most appropriate.
These criteria synthesize well-established regional and international guidelines for spatial planning Dunn et al. Regional cooperation is encouraged in the spatial management of EBSAs, including identifying and adopting appropriate conservation measures and sustainable use, and establishing representative networks of marine protected areas Dunn et al.
Deep-sea habitats that would be considered as VMEs and would also fit many of the EBSA criteria include cold-seep and deep-water coral communities. Both habitats are of particular significance for the management of deep-water oil and gas activities because they frequently occur in areas of oil and gas interest Figure 5.
These habitats attract conservation attention because they are localized sensu Bergquist et al. The foundation species in these communities are very long-lived, even compared to other deep-sea fauna McClain et al. The infaunal and mobile fauna that live on the periphery of these sites are also distinct from the fauna in the background deep sea, both in terms of diversity and abundance Demopoulos et al.
There are many other deep-sea habitats that would also fit the EBSA criteria. These are typically biogenic habitats, where one or several key species ecosystem engineers create habitat for other species. Examples of these include sponges Klitgaard and Tendal, , xenophyophores Levin, , tube-forming protists De Leo et al.
Furthermore, areas of brine seepage, particularly brine basins, may not contain abundant hard substrata, but still support distinct and diverse microbial communities, as well as megafaunal communities e. For spatial management of these sensitive areas to be effective, information on the spatial distribution of features of conservation interest is essential. Mapping these features can be particularly challenging in the deep sea, but advances in technology are improving our ability to identify and locate them e.
Even modest occurrences of deep-water corals can be mapped by both low and high frequency sidescan sonar in settings with relatively low background topography e.
Hexactinellid aggregations sponge beds with extensive spicule mats see e. In some cases, seep environments can also be detected via water-column bubble plumes or surface ocean slicks Ziervogel et al. Relevant oceanographic and environmental datasets can be obtained from local field measurements, global satellite measurements, and compilations from world ocean datasets Georgian et al.
Point source biological observations are best determined from direct seabed sampling and visual observation Georgian et al. Additional data can be derived from historical data e. However, these data must be interpreted with caution as they may include dead and possibly displaced organisms i.
This is often best achieved via visual imaging surveys towed camera, autonomous underwater vehicles, ROVs, manned submersible , which are typically non-destructive and provide valuable data on both biological and environmental characteristics Georgian et al.
Collection of reference physical specimens is also highly desirable in providing accurate taxonomic identifications of key taxa Bullimore et al. Together, mapping through remote sensing, habitat suitability models, and ground-truthing by seafloor observations and collections provide adequate maps of ecological features to better inform the trade-offs between conservation and economic interests in advance of exploration or extraction activities Mariano and La Rovere, Areas requiring spatial management may be formally designated as MPAs through executive declarations and legislative processes, or established as a by-product of mandated avoidance rules Table 1.
In the US, these are in the form of National Monuments Presidential executive order , National Marine Sanctuaries congressional designation , fisheries management areas such as Habitat Areas of Particular Concern, or, in the case of the oil and gas industry, through Notices to Lessees issued by the U.
In many jurisdictions, systems of MPAs are still under development, and oil and gas exploration and development is permitted within these areas. It remains uncommon for setback distances or buffer zone requirements to be specified.
Fundamentally, a firm, widespread systematic conservation plan sensu Margules and Pressey, in the deep sea will be critical in creating MPAs that are representative and effective Kark et al. They can also be networks of smaller areas that may serve as stepping stones across the seascape. There have been numerous reviews of the theory behind these various designs e.
Even when the formal MPA designation process is followed, oil and gas industrial activity may still be permissible, although their proximity typically triggers additional scrutiny of development plans Table 1.
Examples of wells that have been drilled near some important marine protected areas include the Palta-1 well off the Ningaloo reef in Australia and drilling and production in the Flower Gardens National Marine Sanctuary in the U. Gulf of Mexico. In some cases, MPAs may not be formally declared, but sensitive habitats are explicitly avoided during field operations as part of the lease conditions. For example, in Norway, exploration drilling has occurred near the Pockmark-reefs in the Kristin oil field and the reefs of the Morvin oil field Ofstad et al.
Direct physical damage was limited by ensuring the well location and anchoring points including chains were not near the known coral locations. Similarly, in Brazil, impacts to deep-water corals must be avoided, and ROV surveys of proposed tracklines for anchors are typically conducted before or after installation.
Despite the requirements of many jurisdictions to avoid deep-water petroleum activities near sensitive habitats, it remains uncommon for legally mandated setback distances or buffer zone requirements to be specified. For example, there are no mandated separation distances of industry infrastructure and deep-water corals for both the Brazilian and Norwegian case studies, rather the need for spatial restrictions is evaluated on a case-by-case basis as part of the environmental impact assessment process.
BOEM has taken a precautionary approach and defined mitigation areas in which oil and gas activity is prohibited. These areas are determined from interpretation of seismic survey data. Previous studies have demonstrated that these seismic data can reliably predict the presence of chemosynthetic and deep-water coral communities Roberts et al. ROV surveys of the tracklines of anchors are typically conducted, but can occur after the installation of the infrastructure if the plan is approved.
However, if the well is drilled near a known high-density community or archeological site, then visual surveys are mandatory prior to installation. If the ROV surveys reveal high-density chemosynthetic or coral communities, the operator is required to report their occurrence and submit copies of the images to BOEM for review.
Avoidance measures have to be undertaken for all potential and known high-density benthic communities identified during these assessments. Beyond the borders of the BOEM mitigation areas, there are mandated set-back distances for oil and gas infrastructure in US territorial waters. These distances are primarily based on a contracted study of impacts from deep-water structures CSA, The set-back distance for sea-surface discharges of drilling muds and cuttings was originally m, corresponding to the average distance over which impacts were detected in the CSA study.
Following more recent discoveries of abundant deep-water coral communities in and near the hard-ground sites within the mitigation areas, the set-back distance was doubled to m feet. The set-back distance for the placement of anchors and other seafloor infrastructure is m feet from the mitigation areas, but this may be reduced to 75 m feet if a waiver is requested.
In addition to specific targets for avoidance or establishment of protected areas, the use of reference areas can also assist in spatial management, and in the testing of EIA predictions more generally.
Comparison of reference sites with those proximal to industry operations allows the effects of drilling and routine operations to be assessed, properly attribute any changes in the ecological communities, and further inform spatial management practice Iversen et al. Some real-time monitoring and responsive action has also been undertaken in the benthic environment.
In Norway, Statoil has monitored the potential impacts on a coral reef system at the Morvin oil field, which included sediment sampling, video observations, sensors and sediment traps Tenningen et al. The sensor data were available in real time and enabled drillers to observe if selected reef sites were being impacted by drilling activities. Regardless of the structure of the monitoring program, some periodic post-development assessments, both within the development area and in appropriate reference areas, are required to evaluate the efficacy of the implemented protections.
Deep-sea species, assemblages, and ecosystems have a set of biological and ecological attributes e. In general, deep-sea organisms are slower growing and more long lived than their shallow-water counterparts and their distributions, abundance, and species identity remain largely unknown at most locations. The combination of their sensitivity to disturbance and the direct threat posed by industrial activity of any kind should stipulate a precautionary approach to the management of deep-sea resources.
A comprehensive management plan requires accurate environmental maps of deep-sea oil and gas production areas. These maps could be more effectively generated by creating a central archive of industry-generated acoustic remote sensing data, including seismic data and bathymetry, and making these data available to managers and scientists via open-access platforms.
Predictive habitat modeling can also contribute to the development of distribution maps for specific taxa. Baseline surveys should be carried out first at a regional level if no historical data are available. Prior to industrial activity, comprehensive surveys should be carried out within the planning area including along pipeline tracks and in a comparable reference area outside of the influence of typical impacts at least 4—5 km.
Ideally, surveys should include high-resolution mapping, seafloor imagery surveys, and physical samples to characterize the faunal community and ensure proper species identifications, which should consist of a combination of classical and molecular taxonomy.
We also recommend the inclusion of newer high-throughput sequencing and metabarcoding techniques for a robust assessment of biodiversity at all size classes Pawlowski et al.
International collaboration with the oil and gas industry to develop and conduct basic scientific research should be further strengthened to obtain the baseline information required for a robust understanding of the ecology of these systems and the interpretation of monitoring results, both at local and regional scales. We recommend that representatives of all habitat types, ideally based on a strategic regional assessment, should be granted protection.
Any high-density, high-biomass, high-relief, or specialized i. The definition of these significant communities will vary from region to region and will depend on national or international regulations within the region of interest, but the EBSA concept should be generally applicable.
Given the likely proximity of sensitive habitats to oil and gas activities, and the potential for extremely slow centuries to millennia recovery from perturbation in deep waters, an integrated approach to conservation is warranted.
This will include spatial management in conjunction with activity management in the form of restrictions on discharge and the use of water-based drilling fluids, and temporal management in areas where industry activity is near breeding aggregations or seasonally spawning sessile organisms.
Most countries have an in-principle commitment to conservation that typically extends to deep-water ecological features. However, it is rare that mandatory set-back distances from sensitive features or extensions of spatial protections are included to ensure that industrial activity does not impact the habitats designated for protection. This is significant because these habitats, in particular deep-sea coral and cold-seep ecosystems, consist of central, high-biomass sites surrounded by transition zones that can extend at least m from the visually apparent border of the site to the background deep-sea community Demopoulos et al.
Considering the inherent sources of uncertainty associated with the management of deep-sea habitats, from the imprecise placement of seafloor infrastructure, to the variability in discharge impact distances, to the uncertainty in seafloor navigation and the locations of the sensitive deep-sea habitats and species, we strongly recommend that buffer zones be incorporated into spatial management plans. Based on what is known on distances over which impacts have been observed, we can propose a set of recommendations for appropriate buffer zones or MPA extensions from sensitive habitats Table 4.
Following the Deepwater Horizon spill, impacts to the deep-sea benthos were greatest within a 3 km radius with a signal detected within a 45 km radius Montagna et al. While distances derived from the spatial footprints of large spills might offer a solid precautionary approach in regions undergoing development for the first time, they may prove impractical in most settings. Therefore, in regions of active leasing, the focus should be on the protection of suitably large, representative areas, while still allowing for industrial activity in the area.
Table 4. Recommendations for the spatial management of deep-sea ecosystems in the vicinity of oil and gas industrial activity.
The size of the buffer zones around habitats should be based on the available information on the typical distances over which impacts of standard oil and gas industry operations have been documented. Produced water travels 1—2 km on average, elevated concentrations of barium a common component of drilling muds are often detected for at least 1 km from the source, and cuttings and other surface disposed materials, along with changes to the benthic community are often observed on the seafloor at distances of up to — m.
Considering that impacts can extend to 2 km, we recommend that surface infrastructure and any discharge sites should be at least 2 km away from known EBSAs.
A more conservative approach, based on the variability in water column current structure and intensity, would be to set the distance as a function of the water depth of operations, with the 2 km extent of typical impacts observed as the minimum distance. Seafloor disturbances from direct physical impacts of anchor, anchor chain, and wire laying occur within a m radius of activities. Therefore, based on the combination of the typical impact distance and the transition zone to the background deep-sea community, we recommend that any seafloor infrastructure without planned discharges should be placed at least m from the location of these communities.
Temporal management should also be considered, particularly during discrete coral spawning events Roberts et al. Although these recommendations are based on a thorough review of available literature and the authors' extensive experience in several EEZs, the information on potential impact zones is still relatively sparse.
As a result, processes should be implemented that allow adaptive management to be implemented as more data become available. Management plans must clearly communicate quantitative conservation targets that are measurable, the set of environmental and ecological features to be protected, the levels of acceptable change, and any remedial actions required, increasing the capacity of the industry to better cost and implement compliance measures as part of their license to operate.
It is also in the best interests of scientists, managers, and industry alike to arrive at a common, global standard for deep-water environmental protection across EEZs, and it is our hope that this review represents a first step in this direction toward the integrated and comprehensive conservation of vulnerable deep-sea ecosystems. EC and DJ wrote, edited and revised the text, created and edited figures and tables. TS contributed analysis and figures and edited and revised the manuscript.
All authors contributed to the tables, wrote portions of the text, and edited the manuscript. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
The members of the Oil and Gas working group that contributed to our discussions at that meeting or through the listserve are acknowledged for their contributions to this work.
We would also like to thank the three reviewers and the editor who provided valuable comments and insight into the work presented here. This output reflects only the authors' views and the funders cannot be held responsible for any use that may be made of the information contained therein.
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Claisse, J. But public opinion in Florida is decidedly anti—offshore drilling, and for good reason. Brown oil covered 92, square miles of surface water and sullied 1, miles of coastline along five states, including Florida. The disaster killed 11 oil workers, thousands of marine mammals, and millions of birds. Federal waters, however, are a separate story. Last year, the U. The political might of fossil fuels is atrophying, along with its place in the energy landscape.
A year ago, for instance, the idea that the Atlantic Coast pipeline, Dakota Access pipeline, and Keystone XL pipeline projects would screech to a halt within days of one another would be unfathomable. Before a single drop of oil is produced, an offshore oil project harms marine life through seismic surveys, disturbs the seafloor with the construction of rigs and pipelines, and accelerates coastal erosion by channeling through wetlands.
According to government estimates, if no new areas are leased for offshore oil the reduction of potential supply would cause only a small change in prices. Any possible change in price linked to new offshore drilling would likely be over a decade away and only amount to a few cents per gallon.
If companies drill in new places, it will take 10 years or more from leasing until the oil reaches the market. First there is a lengthy process of planning for a lease sale, bidding, applying for and obtaining approvals, followed by exploration for viable well sites and production. The U. As energy efficiency continues to improve and the renewable energy sector grows there is no need to threaten coastal ecosystems with more dirty and dangerous offshore drilling.
A decision to expand offshore drilling today would put in motion decades of production of fossil fuels that contribute to climate change — risking human health and our clean coasts in the process. We should invest in a better future. Large-scale oil spills tend to capture public attention, but smaller leaks and spills regularly pollute our waters.
BP began drilling two relief wells in May, but oil continued to gush from the leak until the capping stack was added in July. Since then, according to Milito, new safety equipment to prevent spills, more capacity to respond to problems, and greater government oversight has led to safer operations.
Before the Deepwater Horizon happened, that type of accident could never happen. The COVID pandemic has implications for offshore drilling, too, as oil prices and demand plummet amid a nearly global shutdown of business as usual. Even though offshore drilling is moving further into uncharted territory, 10 years after Deepwater Horizon, its effects still reach the shore.
Oil from the spill eventually washed up along 1, miles of coastline reaching from Texas to Florida. Tens of thousands of animals perished in the aftermath. And even more people and wildlife were exposed to the lingering toxic effects of the spill. A decade later, the risks of deepwater oil exploration continue to loom just over the horizon.
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