Ecosystem Injuries from the DeepWater Horizon Blow-out: A Tale of Two Spills

1. Ecosystem Injuries from the DeepWater Horizon Blow-out: A Tale of Two Spills Ocean Conservancy – GOMURC Workshop April 2012 Charles H. “Pete” Peterson University of North Carolina at Chapel Hill

2. DWH Blowout – Two Types of Oil Spills Type I - Familiar Spill Type II - Deepwater Spill Type I Type II • Composite of nearshore oil spills • Fate: • Oil rises to the surface • Floating oil grounds on shores • Effects: • Surface organism mortality • Intertidal habitats fouled • Shallow subtidal contamination • Sublethal effects induce pop losses • Novel offshore, deep-water blowout of oil and gas • Fate: • Extensive fine dispersion of oil & gas via turbulent pressurized injection into cold seawater • Retention in plumes at depth • Surfacing and grounding of oil • Broad deposition on sea floor • Effects: • Surface organism mortality • Intertidal habitats fouled • Bio exposures in water column • Widespread benthic mortalities NOAA UPI

3. The Deepwater Horizon Spill dispersant oil slick 200 m oil plume finely dispersed subsurface oil plume finely dispersed oil/hydrate plume 500 m 1000 m well head accumulating oil on sediments 1500 m asphaltines 1800 m

4. Oil Spill Oceanography Neritic Oceanic Pelagic Complex Physics and Chemistry Epipelagic Photic Nearshore Estuary 0 to 200 m Continental shelf APhotic Mesopelagic Bathyal 1000 m Bathypelagic Benthic 4000 m

5. Legacy of the Exxon Valdez Oil Spill • Of all oil spills, EVOS impacts are the most thoroughly studied in scope, duration, and roles of ecosystem-based interconnectivity of natural resource impacts • Explicit impact studies of EVOS are relevant to the Type I components of DWH (surface and shorelines), but offer only procedural insights to guide impact assessment of DWH Type II components • EVOS helps guide the processes of impact assessment and restoration by example, good and bad • EVOS brings new insights into ecotoxicological mechanisms and processes – new paradigms only slowly incorporated into injury models Exxon Valdez Oil Spill = EVOS Deepwater Horizon Spill = DWH Photos: Anchorage Daily News

6. Myths Debunked and Emerging Paradigms Created by EVOS Science • Significant toxicity is not limited to acute exposure to BTEXs, but continues for decades via exposure to buried oil sequestered in biologically accessible, but anoxic reservoirs • Toxicity of chronic exposures to PAHs occurs at ppb concentrations, much lower than the ppm water quality standards (based only on acute exposures to water-soluble fractions from fresh oil) • Clean-up and restoration responses can be more injurious than the oil benzene, toluene, ethylbenzene, and xylenes = BTEX polycyclic aromatic hydrocarbons = PAH

7. Novel Scientific Insights from EVOS • Sublethal impacts (affecting individual growth, reproduction, behavior) may have serious effects at the population level and must be incorporated into the injury assessment process • Major physical effects of oil (smothering, fouling of feeding apparatus, etc.) can continue to operate independent of chemical toxicity of the oil • An ecosystem-based approach is critical to account for interactions and indirect effects that ramify through the interaction webs; this coupled with long-term monitoring is the onlyway to understand some delayed and long-term impacts of the oil spill

8. Deepwater Horizon Timeline • April 20 – well blow-out and fire @ 21:45 h • April 22 – first surface oil slick detected • May 1 – surface application of dispersant began • May 14 – injection of dispersant at well-head began • July 15 – oil and gas discharge ended (after 84 d)

9. Comparative Spill Oil Volumes 6 to 8 8 7 6 5 4 3 2 1 0 4.9 million barrels of oil 3.5 0.75 0.1 Kuwait oil field 1991 DWH 2010 Ixtoc I 1979 Exxon 1989 Santa Barbara 1969 DWH: 4.9 million barrels of oil, 14.7 million ft3 of gas • 1.8 million gallons of dispersant added • 1.07 million gallons at sea surface • 0.77 million gallons at the well-head • 1.5 to 1.9 x more gas released than oil by mass

10. Natural Resource Injuries from the Type I Portion of the DWH Incident EPA • The “easy” part – long agency (NOAA) experience/skills directly applicable here to surface and shoreline habitat oiling impacts • Potentially trivial compared to novel subsurface ecosystem impacts ? • May form the vast majority of the focus of restoration because: • Better capacity to infer injuries • Ecosystem values and uses to humans understood • Compensatory restoration is deemed feasible • Political pressure for state “wish list” projects Press-Register

11. Type I Injuries: Species Oiled at Sea Surface Reuters AP • Seabirds found dead in oiled areas in USFWS counts to 12/2011 • gulls = 2901 • brown pelican = 556 • northern gannet = 441 • royal tern = 233 • black skimmer = 233 • Sea turtles – 613 dead (incl. Kemp’s ridleys) in NOAA counts from 4/2010-4/2011 • Marine mammals – 452 dolphin strandings in NOAA data base out of 625 total cetacean strandings from 4/2010-1/2012; abnormally high miscarriage rates • Fish –concerns about impacts on early life stages because of dispersed oil in fine droplets is so highly bioavailable and to nearshoredemersal fish like killifish in contact with oil • Blue crab and penaeid shrimps – still under study but clearly extensive exposure to oil and dispersants • FloatingSargassum community – high risk and likely injury to habitat provider (plant) and associated fish and wildlife – incl. dead hatchling sea turtles; concern over larval & juvenile bluefin tuna, mahi, cobia, etc.

12. Type I Injuries: Shoreline Habitats Oiled (1053 linear miles) • Coastal marsh – especially margins, where below-ground plant mortality also fostered marsh edge erosion but low total acreage lost • Sandy ocean beaches – coatings of mousse, tarballs, and layers of buried oil at depths in the sand with intense disturbance of clean-up • Seagrass beds – some direct habitat loss • Oyster reefs – some mortality from smothering plus possible oyster larval mortality; mass freshwater diversion mortality • Protected mudflats – some loss of benthic invertebrate prey for higher trophic levels • Estuarine muddy bottom and ocean floor – PAH contamination plus persistence of oiled detritus, evident during summer 2011 storms

13. Type I Injuries: Grounded Oil Effects on Shoreline Species AP • Ground- and low-nesting marsh birds (double jeopardy for pelicans etc. = feeding at sea + nesting impacts). • Fiddler crabs, blue crabs, and marsh nekton, esp. shrimps. • Oysters by adult and juvenile mortality, larval losses, and likely slower growth. • Terrapins and marsh mammals. • Nekton, including juvenile and resident fishes (killifish), that use shallow marsh, oyster reef, seagrass habitats. • Seaducks, sea turtles, and demersal fishes that eat benthic invertebrates in shallow estuarine bottom are at risk.

14. Collateral Injuries: from Response Actions AP • Toxicity from chronic exposure to persistent dispersant - alone and with oil • Fine-scale chemical dispersal of oil enhanced bio- availability and kept it sub-surface for longer, thereby magnifying impacts to zooplankton, particle feeders • Physical injuries to marsh from boom groundings and vessel groundings while deploying boom • Waterbird mortalities from “booming in” both oil and birds around marsh islands • Habitat and food-web degradation from beach “nourishment”, which kills benthic invertebrates • Oyster mortality from of freshwater diversions • Air pollution and health effects in wildlife and humans from soot creation during at sea burning

15. Collateral Injuries: from Clean-up Efforts AP U.S. Coast Guard • Vehicle driving on beaches (especially at night) destroyed nests, killed nesting birds/chicks • Birds and other animals killed during uptake into oil skimmers • Construction of coastal barrier berms killed benthic food resources and misguided sea turtles / ground-nesting birds to nest on that rapidly eroding sand • Sea turtle mortalities from intense trawl fishing, perhaps with disabled TEDs, immediately before closures when enforcement attention was diverted • Repeated mortality of benthic invertebrates and consequent loss of prey from demersal surf fishes and shorebirds after beach excavations to remove buried tarballs and oil layers and raking up wrack

16. Injuries: Type II Oil Spill Impacts (Subsurface including Deep Ocean) NOAA NOAA • By far the hardest aspect of the DWH spill to assess, requiring new research on interdisciplinary oil-spill oceanography • Possibly largest portion of the ecosystem impacts of the hydrocarbon release • Effective restoration depends on scientific advances to understand direct and indirect ecosystem impacts and service losses in meso-pelagic, bentho-pelagic, and deep-bottom communities • Failures by government and industry to conduct necessary science for readiness

17. Subsurface Ecosystem Consequences of a Deep-water Blowout • 3 broad categories of subsurface impacts from the DWH • Toxicity of oil and dispersant (includes physical smothering and fouling) – pelagic particle feeders and all guilds of benthos • Implications of organic carbon loading (perhaps 0.5-3.0 x annual production over the spill area) with resultant intense microbial heterotrophic production and CO2 injection into seawater • Indirect effects of food web disruption – likely a widespread fracture of the food-chain linkage from particle feeders to higher trophic levels – including (?) species like sperm whales • 2 ecological compartments outside familiar scope of NRDA • pelagic (mostly deep) water column • deep benthos

18. Type II Effects of DWH Oil Spill:Glimpses of Pelagic Impacts M. Joye • Extensive mortality by fouling the feeding and respiratory organs of pelagic particle feeders such as copepods, salps, and appendicularians, thereby fracturing the food chain linkages to higher trophic levels • Massively elevated heterotrophic microbial production and consequent oxygen sags detected in petroleum hydrocarbon plumes trapped at a pycnocline in 800-1,100 m, but oxygen not depleted enough to induce hypoxia • Microbial production has been associated with marine snow and slime that helped aggregate oil droplets with organic particles and induce transport the oil to the deep sea floor • Study of higher trophic levels could integrate impacts to food chains, taking opportunity to use the spill as an oceanographic experiment • The high likelihood of large indirect food-web effects from DWH oil implies that delayed injuries will emerge, detectable only if focused ecosystem-based injury assessments continue over sufficient time

19. Type II Effects of DWH Oil Spill:Glimpses of Deep Benthos Impacts • Deposition of dark, hydrocarbon-rich sediments mm-cm thick onto sedimentary bottoms appears to have caused widespread mortality of resident soft-bottom benthic invertebrates, perhaps by smothering (Joye) • Some emergent hard-bottom areas exhibit apparent cover by a similar dark material and exhibit mortality of soft corals, sea fans, brittle stars, and other inverts (Fisher) • After the early bloom of heterotrophs, microbial activity now appears grossly suppressed on the sedimentary seafloor

20. Guiding Principles for GoM Ecosystem Restoration from 2011 Pew Report AP • Recognizing that past human and natural perturbations have compromised Gulf ecosystem function and resilience • Acknowledging that dramatic environmental change is inevitable and must be integrated into restoration plans • Treating the Gulf as one interconnected network of ecosystems from the shoreline to the deep sea • Realizing that ecosystem productivity, health, and sustainability of the Gulf and human welfare are intrinsically codependent

21. Acknowledged Contributors NCEAS Working Group: Sean Anderson, Gary Cherr, Rich Ambrose, Shelly Anghera, Steve Bay, Michael Blum, Rob Condon, Tom Dean, Monty Graham, Michael Guzy, Stephanie Hampton, Samantha Joye, John Lambrinos, Bruce Mate, Doug Meffert, Sean Powers, PonisserilSomasundaran, Bob Spies, Caz Taylor, Ron Tjeerdema, Charles Peterson : paper now posted on-line in BioScience May 2012. Ocean Conservancy Team: Stan Senner, Jeff Short, Chris Haney, Bob Spies, Lisa Suatoni, Paul Kemp, Dennis Kelso, Charles Peterson