Scientists are studying a range of species and habitats to understand how wildlife populations and the environment may have been affected by the accident, as part of the Natural Resource Damage Assessment (NRDA) process
Since May 2010, more than 200 initial and amended work plans have been developed to study resources and habitat by state and federal trustees and BP, and by the end of 2012, BP had paid $973 million to support the assessment process, including cooperative and independent studies. The study data will inform an assessment of injury to the Gulf Coast natural resources and the development of a restoration plan to mitigate the identified injuries. Detailed analysis and interpretation continue on the data that has been collected.
Scientists are studying a range of species, including marine mammals, birds, fish and plants to understand how wildlife populations may have been affected by the accident. Teams of experts are also studying habitats such as wetlands and beaches, with the goal of returning these resources to their baseline condition – the condition they would be in if the Deepwater Horizon accident had not occurred. In addition, experts are looking at how recreational uses of natural resources may have been affected so that lost opportunities to enjoy those activities can be addressed through restoration.
Sharing the information
In 2012 BP produced a second progress report on the NRDA effort and made presentations at scientific conferences to describe studies that are under way. The trustees have already made some of the data sets from these studies available online while others are still being finalized. BP seeks to share data and information collected from the cooperative NRDA studies with stakeholders and members of the public once these have been approved for release by the trustees.
A sample of the studies is introduced here, with access to the fuller information via the links below.
In one NRDA study, birds in the potential area of impact were fitted with transmitters to provide data about survival rates. Of the species tested, four – brown pelican, black skimmers, clapper rail and seaside sparrow – had survival rates equal to or higher than birds in areas not affected by the spill. Two species – American oystercatcher and great egrets – had survival rates somewhat less than birds in areas not affected by the spill.
In an independent BP productivity study of colonial waterbird nesting areas, scientists studied 40 bird colonies in the northern Gulf of Mexico and made 52,000 nest tracking observations. The preliminary results of the study indicate that productivity rates (the number of fledglings per active nest) in 2011 remained within or at the high end of the normal ranges for colonial waterbirds.
Through the cooperative NRDA process, we are studying two Gulf Coast sea turtle species, the Kemp’s Ridley and loggerhead, to determine potential exposure to oil and dispersants, and possible associated injuries to the adult, hatchling and egg life stages of the sea turtle.
Data was gathered over 4,700 miles of shoreline and included tracking 52 turtles via satellite tags and collecting more than 1,100 egg, tissue and body samples. While this data is still being analyzed, preliminary nesting results for Kemp’s Ridley suggest nesting was at or above historical averages in 2011 and the Florida Fish and Wildlife Commission found loggerhead sea turtle nest counts in Florida in 2011 were close to the average for the preceding five-year period.
Numerous studies are under way to assess potential injury to marine mammals as part of the cooperative NRDA process, including live dolphin health assessments, population assessments and the collection of environmental and food chain data.
The National Oceanic and Atmospheric Administration (NOAA) is investigating an ‘unusual mortality event’ involving a series of dolphin deaths that began in the Gulf of Mexico in February 2010, before the Deepwater Horizon oil spill started, and was still ongoing at the end of 2012. Unusual mortality events occur with some regularity in the Gulf of Mexico and around the world. NOAA has identified the cause of approximately half of the 56 declared since 1991, and past causes have included toxic algal blooms, infectious diseases like brucellosis, malnutrition, and human interaction (including injuries caused by fishing vessels and boat collisions). Information about NOAA’s investigation is available on NOAA websites.
BP also participated in studies of sperm whales and other large oceanic marine mammals from 2010 to 2012. The studies include aerial surveys, vessel-based observations, acoustic recordings and satellite tracking. Most of the data from those studies is still being evaluated.
Fish and aquatic organisms
Through the NRDA process, approximately 50 studies were conducted to investigate thousands of species of aquatic organisms, ranging from single-celled phytoplankton to large game fish. The aquatic habitats studied extended from the shallow water along the shoreline out into the deep water environment, which is over 5,000 feet (1,524 metres) deep and located over 40 miles (64 km) from shore. Laboratory analysis of the data is ongoing.
Data about shrimp population and possible contaminant exposure has been collected through studies conducted both cooperatively through the NRDA process and independently, including the Louisiana Inshore Shrimp Survey, Marsh Edge Sandy Shores Plan, and multiple predator prey investigations, and data analysis is under way.
More than 200 marsh sites in Louisiana, Mississippi and Alabama are being studied to document potential injury and recovery of marshes exposed to oil by examining above- and below-ground biomass, plant cover, leaf chlorophyll content, soil nutrient levels and marsh erosion. The marsh sampling programme is testing for the presence of oil at different depths in the soil profile and assessing the benthic invertebrate community that may potentially have been exposed to oil.
Coral is an important habitat for an array of species and has been the subject of studies to identify potential injury – ranging from shallow-water coral accessible by scuba divers to deep-sea coral, where little or no sunlight can reach. The studies have made significant advances in identifying coral communities within proximity to the Macondo well.
BP, the trustees and academic institutions are studying the Gulf’s deepwater environment to gain a better understanding of how the current quantity and composition of deep sea marine species compare to those prior to the accident. Preliminary observations of the sea floor have identified marine life in, on and above the sea floor, both before and after the accident. Work to identify and document changes in species abundance and density are ongoing.
Naturally occurring oil seeps
Naturally occurring oil and gas seeps are part of the Gulf of Mexico ecosystem. The National Research Council estimated in 2003 that the Gulf’s natural seeps release 560,000 to 1.4 million barrels of oil annually. Current studies of these seeps are helping scientists identify natural seeps in the vicinity of the Macondo well and understand how seeps affect the Gulf ecosystem.
Several natural seeps are in close proximity to the Macondo well. Scientists use geochemical fingerprinting techniques to differentiate between Macondo oil and naturally occurring seeps in the Gulf. A strong geochemical correlation was found between oil released from the Macondo well and oil from nearby natural seeps, and further work is under way to establish the chemical features that may be used to distinguish the oils within this family.
Scientists are also studying microorganisms that have the ability to use oil as a food source. Research suggests that during the accident, these oil-eating microbes played a role in breaking down petroleum compounds in the water.
NRDA work plans
Marine mammals - Studies examining whales and dolphins from nearshore coastal environments to offshore waters.
Birds - Studies examining a wide range of birds including secretive marsh birds, colony-nesting birds like pelicans, and coastal birds such as gulls.
Turtles - Studies assessing sea turtles such as the loggerhead and Kemp’s Ridley.
Fish - Studies of populations of fish found in nearshore areas and offshore.
Invertebrates - Studies directed at oysters, crab, shrimp, coral and plankton from coastal waters to deepwater benthic communities.
Plants - Studies examining a range of plant species including salt marsh plants and seagrasses.
Water and sediment quality - Studies examining overall water and sediment quality of the Gulf of Mexico, oil fingerprinting and toxicity, and a range of sampling efforts.
Beach and uplands habitats - These range from the high tide line up to dunes to the hind shore.
Intertidal zones and marsh habitats - These include fresh and saltwater marshes and tidal flats.
Nearshore/shallow water habitats - These include seagrass beds, oyster beds, coral reefs and other shallow water environments.
Offshore/pelagic habitats - These include open water and deep ocean floor environments.
The information on this page forms part of the information reviewed and reported on by Ernst & Young as part of BP's 2012 sustainability reporting.