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- Hayworth, J.S., Clement, T.P., and Valentine, J.F. Deepwater Horizon oil spill impacts on Alabama beaches. Hydrology and Earth System Sciences 15(12): 3639-3649, 2011.
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From mid June 2010 to early August 2010, the white sandy beaches along Alabama's Gulf coast were inundated with crude oil discharged from the Deepwater Horizon well. The long-term consequences of this environmental catastrophe are still unfolding. Although BP has attempted to clean up some of these beaches, there still exist many unanswered questions regarding the physical, chemical, and ecological state of the oil contaminated beach system. In this paper, we present our understanding of what is known and known to be unknown with regard to the current state of Alabama's beaches in the aftermath of the Deepwater Horizon disaster. Motivated by our observations of the evolving distribution of oil in Alabama's beaches and BP's clean-up activities, we offer our thoughts on the lessons learned from this oil spill disaster.
- Martínez, M. L. et al. Artificial modifications of the coast in response to the Deepwater Horizon oil spill: quick solutions or long-term liabilities? Frontiers in Ecology and the Environment 10(1): 44-49, 2012.
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The Deepwater Horizon oil spill threatened many coastal ecosystems in the Gulf of Mexico during the spring and summer of 2010. Mitigation strategies included the construction of barrier sand berms, the restriction or blocking of inlets, and the diversion of freshwater from rivers to the coastal marshes and into the ocean, in order to flush away the oil, on the premise that these measures could reduce the quantity of oil reaching sensitive coastal environments such as wetlands or estuaries. These projects result in changes to the ecosystems that they were intended to protect. Long-term effects include alterations of the hydrological and ecological characteristics of estuaries, changes in sediment transport along the coastal barrier islands, the loss of sand resources, and adverse impacts to benthic and pelagic organisms. Although there are no easy solutions for minimizing the impacts of the Deepwater Horizon disaster on coastal ecosystems, we recommend that federal, state, and local agencies return to the strategic use of long-term restoration plans for this region.
- Lu, Z. et al. Microbial gene functions enriched in the Deepwater Horizon deep-sea oil plume. ISME Journal 6(2): 451-460, 2012.
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The Deepwater Horizon oil spill in the Gulf of Mexico is the deepest and largest offshore spill in the United State history and its impacts on marine ecosystems are largely unknown. Here, we showed that the microbial community functional composition and structure were dramatically altered in a deep-sea oil plume resulting from the spill. A variety of metabolic genes involved in both aerobic and anaerobic hydrocarbon degradation were highly enriched in the plume compared with outside the plume, indicating a great potential for intrinsic bioremediation or natural attenuation in the deep sea. Various other microbial functional genes that are relevant to carbon, nitrogen, phosphorus, sulfur and iron cycling, metal resistance and bacteriophage replication were also enriched in the plume. Together, these results suggest that the indigenous marine microbial communities could have a significant role in biodegradation of oil spills in deep-sea environments.
- Mitra, S. et al. Macondo-1 well oil-derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico. Geophysical Research Letters 39(1): art. L01605, 2012.
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Mesozooplankton (>200 μm) collected in August and September of 2010 from the northern Gulf of Mexico show evidence of exposure to polycyclic aromatic hydrocarbons (PAHs). Multivariate statistical analysis revealed that distributions of PAHs extracted from mesozooplankton were related to the oil released from the ruptured British Petroleum Macondo-1 (M-1) well associated with the R/V Deepwater Horizon blowout. Mesozooplankton contained 0.03–97.9 ng g-1 of total PAHs and ratios of fluoranthene to fluoranthene + pyrene less than 0.44, indicating a liquid fossil fuel source. The distribution of PAHs isolated from mesozooplankton extracted in this study shows that the 2010 Deepwater Horizon spill may have contributed to contamination in the northern Gulf of Mexico ecosystem.
- Mishra, D.R. et al. Post-spill state of the marsh: remote estimation of the ecological impact of the Gulf of Mexico oil spill on Louisiana salt marshes. Remote Sensing of Environment 118: 176-185, 2012.
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One and a half years after the worst oil spill in U.S. history, we present the first quantitative assessment on the ecological impact of the spill on the salt marsh habitats along the southeastern Louisiana (LA) coast. This research combined satellite and ground data to quantify the impact of the oil and dispersant on the salt marshes in terms of their photosynthetic capacity and physiological status over a large spatial scale. Two of the most important marsh biophysical characteristics, including distribution of canopy chlorophyll content and above ground green biomass, were monitored across the southeastern LA coast during the salt marsh growing season (May–October) of 2009 (pre-spill) and 2010 (post-spill) in order to compare and isolate the spill impacted areas. The initial assessment showed that there was a significant post-spill increase in areas with reduced biomass and canopy chlorophyll (>400 km²) during the 2010 growing season compared to 50–65 km² during the 2009 growing season. Phenological analysis of the post oil-spill data revealed a significant decrease in the magnitude of biomass and canopy chlorophyll during the peak of the 2010 growing season. June was consistently found to be the worst month in terms of salt marsh health across LA over the 2010 phenological cycle followed by the initial signs of recovery along the fringing marsh areas proximal to the shoreline that were first impacted by oil. Interior marsh patches exhibited persistent signs of stress towards the end of the growing season. Extensive reduction in photosynthetic activity was observed during the peak of the growing season, particularly in Plaquemines Parish and St. Bernard Parish. The products generated through this study successfully delineate the critical hotspots of marsh stress so that prioritization of areas needing immediate restoration can be performed.
- Muhling, B.A. et al. Overlap between Atlantic bluefin tuna spawning grounds and observed Deepwater Horizon surface oil in the northern Gulf of Mexico. Marine Pollution Bulletin 64(4): 679-687, 2012.
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The 2010 Deepwater Horizon oil spill impacted the northern Gulf of Mexico (GOM) during the spring spawning season of Atlantic bluefin tuna (BFT). Overlap between BFT spawning habitat and surface oil in the northern GOM was examined using satellite-derived estimates of oil coverage, and spawning habitat models. Results suggested that although eggs and larvae were likely impacted by oil-contaminated waters in the eastern GOM, high abundances of larvae were located elsewhere, especially in the western GOM. Overall, less than 10% of BFT spawning habitat was predicted to have been covered by surface oil, and less than 12% of larval BFT were predicted to have been located within contaminated waters in the northern GOM, on a weekly basis. Our results provide preliminary but important initial estimates of the effects of the spill on larval BFT mortality, as concern continues over the appropriate management responses to impacts of the spill.
- Sumaila, U.R. et al. Impact of the Deepwater Horizon well blowout on the economics of US Gulf fisheries. Canadian Journal of Fisheries and Aquatic Sciences 69(3): 499-510, 2012.
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Marine oil spills usually harm organisms at two interfaces: near the water surface and on shore. However, because of the depth of the April 2010 Deepwater Horizon well blowout, deeper parts of the Gulf of Mexico are likely impacted. We estimate the potential negative economic effects of this blowout and oil spill on commercial and recreational fishing, as well as mariculture (marine aquaculture) in the US Gulf area, by computing potential losses throughout the fish value chain. We find that the spill could, in the next 7 years, result in (midpoint) present value losses of total revenues, total profits, wages, and economic impact of US$3.7, US$1.9, US$1.2, and US$8.7 billion, respectively. Commercial and recreational fisheries would likely suffer the most losses, with a respective estimated US$1.6 and US$1.9 billion of total revenue losses, US$0.8 and US$1.1 billion in total profit losses, and US$4.9 and US$3.5 billion of total economic losses.
- Lin, Q. and Mendelssohn, I.A. Impacts and recovery of the Deepwater Horizon oil spill on vegetation structure and function of coastal salt marshes in the northern Gulf of Mexico. Environmental Science and Technology 46(7): 3737-3743, 2012.
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We investigated the impacts of the Deepwater Horizon (DWH) oil spill on two dominant coastal saltmarsh plants, Spartina alterniflora and Juncus roemerianus, in the northern Gulf of Mexico and the processes controlling differential species-effects and recovery. Seven months after the Macondo MC 252 oil made landfall along the shoreline salt marshes of northern Barataria Bay, Louisiana, concentrations of total petroleum hydrocarbons in the surface 2 cm of heavily oiled marsh soils were as high as 510 mg g-1. Heavy oiling caused almost complete mortality of both species. However, moderate oiling impacted Spartina less severely than Juncus and, relative to the reference marshes, had no significant effect on Spartina while significantly lowering live aboveground biomass and stem density of Juncus. A greenhouse mesocosm study supported field results and indicated that S. alterniflora was much more tolerant to shoot oil coverage than J. roemerianus. Spartina recovered from as much as 100% oil coverage of shoots in 7 months; however, Juncus recovered to a much lesser extent. Soil-oiling significantly affected both species. Severe impacts of the Macondo oil to coastal marsh vegetation most likely resulted from oil exposure of the shoots and oil contact on/in the marsh soil, as well as repeated oiling events.
- McCall, B.D. and Pennings, S.C. Disturbance and recovery of salt marsh arthropod communities following BP Deepwater Horizon oil spill. PLoS ONE 7(3): art. e32735, 2012.
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Oil spills represent a major environmental threat to coastal wetlands, which provide a variety of critical ecosystem services to humanity. The U.S. Gulf of Mexico is a hub of oil and gas exploration activities that historically have impacted intertidal habitats such as salt marsh. Following the BP Deepwater Horizon oil spill, we sampled the terrestrial arthropod community and marine invertebrates found in stands of Spartina alterniflora, the most abundant plant in coastal salt marshes. Sampling occurred in 2010 as oil was washing ashore and a year later in 2011. In 2010, intertidal crabs and terrestrial arthropods (insects and spiders) were suppressed by oil exposure even in seemingly unaffected stands of plants; however, Littoraria snails were unaffected. One year later, crab and arthropods had largely recovered. Our work is the first attempt that we know of assessing vulnerability of the salt marsh arthropod community to oil exposure, and it suggests that arthropods are both quite vulnerable to oil exposure and quite resilient, able to recover from exposure within a year if host plants remain healthy.
- Munilla, I., Arcos, J.M., Oro, D., Álvarez, D., Leyenda, P.M., and Velando, A. Mass mortality of seabirds in the aftermath of the Prestige oil spill. Ecosphere 2(7): art. 83, 2011.
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In the winter of 2002–03 the Prestige tanker spilled 60,000 tons of oil over the northern half of the Iberian Coastal Large Marine Ecosystem (northern Portugal to France). Most (c. 85%) of the 22,981 oiled seabirds reported were alcids (i.e., auks): Common Murres (Uria aalge), Razorbills (Alca torda) and Atlantic Puffins (Fratercula arctica). Here we estimated the mortality of alcids in Galicia (northwestern Spain), the area that received most of the Prestige oil and where half of the oiled seabirds were collected. We performed three experiments that included: (1) a test of several drift block models in open sea, to select the one that best fitted the drift of alcid carcasses; (2) the release of 450 drift blocks at 9 offshore points to assess the recovery rate of oiled alcids and its spatial variation; (3) the assessment of beach survey effort and the detectability of drift blocks. Mean mortality estimates and their bootstrapped confidence intervals were obtained through an estimation model that established: (1) a temporal limit of 23 days to block drifting; (2) spatial differences in the recovery rates of blocks depending on how far away from the coast they were released; (3) a correction factor accounting for detectability, and (4) the distribution pattern of the three alcid species involved according to three distance classes, based on ship surveys. The Prestige oil spill, in terms of acute seabird mortality, was one of the worst oil spills ever reported worldwide. Compared to other major oil spills the estimated mortality for the Prestige oil spill was higher than expected from the number of carcasses retrieved. We recommend that drift block assessments of seabird mortality should be included in contingency response plans to oil pollution emergencies; therefore, a supply of drift-blocks designed to mimic the drifting behavior of the marine bird species of interests should be at hand.
- Bodkin, J.L. et al. Long-term effects of the 'Exxon Valdez' oil spill: sea otter foraging in the intertidal as a pathway of exposure to lingering oil. Marine Ecology Progress Series 447: 273-287, 2012.
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The protracted recovery of some bird and mammal populations in western Prince William Sound (WPWS), Alaska, and the persistence of spilled 'Exxon Valdez' oil in intertidal sediments, suggests a pathway of exposure to consumers that occupy nearshore habitats. To evaluate the hypothesis that sea otter (Enhydra lutris) foraging allows access to lingering oil, we contrast spatial relations between foraging behavior and documented oil distribution. We recovered archival time-depth recorders implanted in 19 sea otters in WPWS, where lingering oil and delayed ecosystem recovery are well documented. Sea otter foraging dives ranged from +2.7 to -92 m below sea level (MLLW), with intertidal accounting for 5 to 38% of all foraging. On average, female sea otters made 16050 intertidal dives per year and 18% of these dives were at depths above the +0.80 m tidal elevation. Males made 4100 intertidal dives per year and 26% of intertidal foraging took place at depths above the +0.80 m tidal elevation. Estimated annual oil encounter rates ranged from 2 to 24 times yr-1 for females, and 2 to 4 times yr-1 for males. Exposure rates increased in spring when intertidal foraging doubled and females were with small pups. In summer 2008, we found sea otter foraging pits on 13.5 of 24.8 km of intertidal shoreline surveyed. Most pits (82%) were within 0.5 m of the zero tidal elevation and 15% were above 0.5 m, the level above which most (65%) lingering oil remains. In August 2008, we detected oil above background concentrations in 18 of 41 (44%) pits excavated by sea otters on beaches with prior evidence of oiling, with total PAH concentrations up to 56000 ng g-1 dry weight. Our estimates of intertidal foraging, the widespread presence of foraging pits in the intertidal, and the presence of oil in and near sea otter foraging pits documents a pathway of exposure from lingering intertidal oil to sea otters foraging in WPWS.
- Monson, D.H., Doak, D.F., Ballachey, B.E., and Bodkin, J.L. Could residual oil from the Exxon Valdez spill create a long-term population 'sink' for sea otters in Alaska? Ecological Applications 21(8): 2917-2932, 2011.
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Over 20 years ago, the Exxon Valdez oil tanker spilled 42 million L of crude oil into the waters of Prince William Sound, Alaska, USA. At the time of the spill, the sea otter (Enhydra lutris) population inhabiting the spill area suffered substantial acute injuries and loss. Subsequent research has resulted in one of the best-studied species responses to an oil spill in history. However, the question remains: Is the spill still influencing the Prince William Sound sea otter population? Here we fit time-varying population models to data for the sea otter population of western Prince William Sound to quantify the duration and extent of mortality effects from the spill. We hypothesize that the patchy nature of residual oil left in the environment has created a source-sink population dynamic. We fit models using the age distributions of both living and dying animals and estimates of sea otter population size to predict the number of sea otters in the hypothesized sink population and the number lost to this sink due to chronic exposure to residual oil. Our results suggest that the sink population has remained at just over 900 individuals (95% CI: 606–960) between 1990 and 2009, during which time prime-age survival remained 2–6% below pre-spill levels. This reduced survival led to chronic losses of ~900 animals over the past two decades, which is similar in magnitude to the number of sea otter deaths documented in western Prince William Sound during the acute phase of the spill. However, the unaffected source population appears to be counterbalancing these losses, with the model indicating that the sea otter population increased from ~2150 individuals in 1990 to nearly 3000 in 2009. The most optimistic interpretation of our results suggests that mortality effects dissipated between 2005 and 2007. Our results suggest that residual oil can affect wildlife populations on time scales much longer than previously believed and that cumulative chronic effects can be as significant as acute effects. Further, source-sink population dynamics can explain the slow recovery observed in the spill-affected western Prince William Sound sea otter population and are consistent with available data.
- Brannon, E.L., Collins, K., Cronin, M.A., Moulton, L.L., Maki, A.L., and Parker, K.R. Review of the Exxon Valdez oil spill effects on pink salmon in Prince William Sound, Alaska. Reviews in Fisheries Science 20(1): 20-60, 2012.
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The Exxon Valdez oil spill that occurred in Prince William Sound, Alaska, in March of 1989 was the largest crude oil spill in the United States at that time, and it was anticipated to have disastrous effects on the ecology and fisheries of that coastal region. The large pink salmon returns to the sound, a major commercial species in Alaska, were of great concern. The Exxon Valdez Oil Spill Trustee Council, a council of government agencies formed to assess the impact of the spill for recovery purposes, concluded that pink salmon in Prince William Sound were damaged by the oil, based on investigations of the Alaska Department of Fish and Game and the National Marine Fisheries Service. Agency scientists claimed that the oil increased incubation mortality of pink salmon and those exposed to oil experienced less growth, higher long-term mortality, and reduced reproductive success. This contrasted with data and conclusions of the non-agency scientists led by the University of Idaho researchers that showed no impact of oil on incubating eggs or on juvenile pink salmon in marine waters, and no reduction in egg viability of returning adults. In this article the authors re-examine the evidence and resolve the problems that resulted in the different interpretation of research conducted by agency and non-agency scientists. The resolution has far reaching implications on ascertaining the impacts of marine oil spills.
- Lv, Y., Zhang, W., Gao, Y., Ning, S., and Yang, B. Preliminary study on responses of marine nematode community to crude oil contamination in intertidal zone of Bathing Beach, Dalian. Marine Pollution Bulletin 62(12): 2700-2706, 2011.
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This study investigated the responses of marine nematodes to crude oil contamination in polluted and relatively uncontaminated sites in Dalian Xingang, China, 40 days after an oil spill. Samples were taken at different tide levels on the beach and at different positions along the beach. We present the results of a comparison of nematode assemblages from undisturbed sediment from the Xiajiahezi Bathing Beach with those from sediment from the Xinghai Bathing Beach contaminated with crude oil. A total of 1666 nematodes from 26 genera were found in this study. Results showed significant differences in nematode assemblages between samples from undisturbed controls and those from the polluted area. Nematode abundance, number of species, diversity and species richness decreased significantly with increasing levels of crude oil contamination. Fifteen genera were eliminated and seemed to be composed of species intolerant to crude oil contamination; only the abundance of Marylynnia sp. increased slightly.
- Incardona, J.P. et al. Unexpectedly high mortality in Pacific herring embryos exposed to the 2007 Cosco Busan oil spill in San Francisco Bay. Proceedings of the National Academy of Sciences [USA] 109(2): E51-E58, 2012.
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In November 2007, the container ship Cosco Busan released 54,000 gallons of bunker fuel oil into San Francisco Bay. The accident oiled shoreline near spawning habitats for the largest population of Pacific herring on the west coast of the continental United States. We assessed the health and viability of herring embryos from oiled and unoiled locations that were either deposited by natural spawning or incubated in subtidal cages. Three months after the spill, caged embryos at oiled sites showed sublethal cardiac toxicity, as expected from exposure to oil-derived polycyclic aromatic compounds (PACs). By contrast, embryos from the adjacent and shallower intertidal zone showed unexpectedly high rates of tissue necrosis and lethality unrelated to cardiotoxicity. No toxicity was observed in embryos from unoiled sites. Patterns of PACs at oiled sites were consistent with oil exposure against a background of urban sources, although tissue concentrations were lower than expected to cause lethality. Embryos sampled 2 y later from oiled sites showed modest sublethal cardiotoxicity but no elevated necrosis or mortality. Bunker oil contains the chemically uncharacterized remains of crude oil refinement, and one or more of these unidentified chemicals likely interacted with natural sunlight in the intertidal zone to kill herring embryos. This reveals an important discrepancy between the resolving power of current forensic analytical chemistry and biological responses of keystone ecological species in oiled habitats. Nevertheless, we successfully delineated the biological impacts of an oil spill in an urbanized coastal estuary with an overlapping backdrop of atmospheric, vessel, and land-based sources of PAC pollution.
- Seuront, L. Hydrocarbon contamination decreases mating success in a marine planktonic copepod. PLoS ONE 6(10): art. e26283, 2011.
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The mating behavior and the mating success of copepods rely on chemoreception to locate and track a sexual partner. However, the potential impact of the water-soluble fraction of hydrocarbons on these aspects of copepod reproduction has never been tested despite the widely acknowledged acute chemosensory abilities of copepods. I examined whether three concentrations of the water-soluble fraction of diesel oil (0.01%, 0.1% and 1%) impacts (i) the swimming behavior of both adult males and females of the widespread calanoid copepod Temora longcornis, and (ii) the ability of males to locate, track and mate with females. The three concentrations of the water-soluble fraction of diesel oil (WSF) significantly and non-significantly affect female and male swimming velocities, respectively. In contrast, both the complexity of male and female swimming paths significantly decreased with increasing WSF concentrations, hence suggesting a sex-specific sensitivity to WSF contaminated seawater. In addition, the three WSF concentrations impacted both T. longicornis mating behavior and mating success. Specifically, the ability of males to detect female pheromone trails, to accurately follow trails and to successfully track a female significantly decreased with increasing WSF concentrations. This led to a significant decrease in contact and capture rates from control to WSF contaminated seawater. These results indicate that hydrocarbon contamination of seawater decreases the ability of male copepods to detect and track a female, hence suggest an overall impact on population fitness and dynamics.
- Incardona, J.P. et al. Potent phototoxicity of marine bunker oil to translucent herring embryos after prolonged weathering. PLoS ONE 7(2): art. e30116, 2012.
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Pacific herring embryos (Clupea pallasi) spawned three months following the Cosco Busan bunker oil spill in San Francisco Bay showed high rates of late embryonic mortality in the intertidal zone at oiled sites. Dead embryos developed to the hatching stage (e.g. fully pigmented eyes) before suffering extensive tissue deterioration. In contrast, embryos incubated subtidally at oiled sites showed evidence of sublethal oil exposure (petroleum-induced cardiac toxicity) with very low rates of mortality. These field findings suggested an enhancement of oil toxicity through an interaction between oil and another environmental stressor in the intertidal zone, such as higher levels of sunlight-derived ultraviolet (UV) radiation. We tested this hypothesis by exposing herring embryos to both trace levels of weathered Cosco Busan bunker oil and sunlight, with and without protection from UV radiation. Cosco Busan oil and UV co-exposure were both necessary and sufficient to induce an acutely lethal necrotic syndrome in hatching stage embryos that closely mimicked the condition of dead embryos sampled from oiled sites. Tissue levels of known phototoxic polycyclic aromatic compounds were too low to explain the observed degree of phototoxicity, indicating the presence of other unidentified or unmeasured phototoxic compounds derived from bunker oil. These findings provide a parsimonious explanation for the unexpectedly high losses of intertidal herring spawn following the Cosco Busan spill. The chemical composition and associated toxicity of bunker oils should be more thoroughly evaluated to better understand and anticipate the ecological impacts of vessel-derived spills associated with an expanding global transportation network.
- Frantzen, M., Falk-Petersen, I.B., Nahrgang, J., Smith, T.J., Olsen, G.H., Hangstad, T.A., and Camus, L. Toxicity of crude oil and pyrene to the embryos of beach spawning capelin (Mallotus villosus). Aquatic Toxicology 108: 42-52, 2012.
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Due to a northward shift in oil and gas activities, there is an increasing need to understand the potential anthropogenic impacts of oil-related compounds on sub-Arctic and Arctic organisms, particularly those in coastal habitats. Capelin (Mallotus villosus), a key fish species in the Barents Sea ecosystem, undertakes aggregated spawning at both intertidal and subtidal coastal localities in northern Norway. To investigate the sensitivity of capelin embryos to oil compounds, newly fertilized capelin eggs were collected from a spawning beach and exposed until hatch (32 days) to either the water soluble fraction of crude oil or the single PAH compound, pyrene. Threshold levels for egg mortality, development and hatching success were determined. Concentrations of 40 μg/L crude oil (S26 PAHs) and 55 μg/L pyrene significantly increased embryonic mortality rates and decreased hatching success, compared with controls, indicating that a potential oil spill in the vicinity of capelin spawning grounds may cause significant impacts. No significant incidence of adverse effects such as yolk sac oedema, pericardia oedema, haemorrhages, craniofacial abnormalities, premature hatch or inhibited growth was observed. Histological studies of hatched larvae did not reveal specific sublethal effects in tissues and organs. Developmental delays and subsequent embryo death were noticed at the period of eye pigmentation in affected groups. Early life-history stages of capelin are sensitive indicators of PAH impacts, but the mechanisms responsible for the toxic effects require further investigation.
- Ingvarsdóttir, A., Bjørkblom, C., Ravagnan, E., Godal, B.F., Arnberg, M., Joachim, D.L., and Sanni, S. Effects of different concentrations of crude oil on first feeding larvae of Atlantic herring (Clupea harengus). Journal of Marine Systems 93: 69-76, 2012.
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Studies have shown that exposure to Polycyclic Aromatic Hydrocarbons (PAHs) and other oil related components alter normal fish larvae development and can cause increased mortality in early life stages. Modelling of results from controlled laboratory exposure experiments will help relate typical oil exposure parameters (biomarkers) to field observations and are valuable tools for oil exposure monitoring and risk assessment. Post yolk sack larval stages of Atlantic herring were exposed to different concentrations of dispersed Arctic crude oil. The selected nominal concentrations were 0.015, 0.040, 0.060, 0.250 and 0.750 mg l-1 raw dispersed oil (0.129, 0.373, 0.496, 2.486 and 6.019 μg l-1 Total Polycyclic Aromatic Hydrocarbons (TPAH) respectively), and control seawater in flow through systems. The larvae were exposed for 12 days and daily mortality recorded in all treatments. Thereafter, the larvae were transported to two large (300 l) rearing tanks, one for control/trace oil and one for oil exposed larvae. The larvae were allowed to recover for 8 weeks after exposure, and mortality and morphological factors then assessed, giving preliminary information on recovery of Atlantic herring larvae after oil exposure. Throughout the testing period, there was a general trend for higher mortality of herring larvae in the oil exposure concentrations than in control, and significantly higher mortality was found in all oil concentrations than in the control after 12 days. We did not detect a clear dose related mortality for our test concentrations, except for the highest concentration. There was no difference found in mortality rates of the herring larvae from either the oil or control/trace oil batch during the recovery phase during the following 60 days. Morphological observations of the herring larvae after 2 months recovery in clean seawater showed that the oil exposed larvae had morphological features that could be described as deformities, and growth was found to be significantly impaired for the oil exposed group when compared to the control/trace oil group.
- Urakawa, H., Garcia, J.C., Barreto, P.D., Molina, G.A., and Barreto, J.C. A sensitive crude oil bioassay indicates that oil spills potentially induce a change of major nitrifying prokaryotes from the Archaea to the Bacteria. Environmental Pollution 164: 42-45, 2012.
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The sensitivity of nitrifiers to crude oil released by the BP Deepwater Horizon oil spill in Gulf of Mexico was examined using characterized ammonia-oxidizing bacteria and archaea to develop a bioassay and to gain further insight into the ecological response of these two groups of microorganisms to marine oil spills. Inhibition of nitrite production was observed among all the tested ammonia-oxidizing organisms at 100 ppb crude oil. Nitrosopumilus maritimus, a cultured representative of the abundant Marine Group I Archaea, showed 20% inhibition at 1 ppb, a much greater degree of sensitivity to petroleum than the tested ammonia-oxidizing and heterotrophic bacteria. The differing susceptibility may have ecological significance since a shift to bacterial dominance in response to an oil spill could potentially persist and alter trophic interactions influenced by availability of different nitrogen species.
- Della Torre, C. et al. Modulation of CYP1A and genotoxic effects in European seabass (Dicentrarchus labrax) exposed to weathered oil: A mesocosm study. Marine Environmental Research 76: 48-55, 2012.
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The aim of this study was to assess medium-term toxicity of weathered oil on European seabass. A mesocosm system reproducing an oil spill at sea was applied. Fish were collected after 48 h, 7, 30 and 60 days. Cyp1a gene transcription, EROD and UDPGT activities, bile PAHs metabolites and micronuclei frequency were investigated. A progressive disappearance of low molecular weight n-alkanes and PAHs in the water of the mesocosm occurred during the experimentation. Fishes exposed to oil displayed a significant increase of cyp1a expression and EROD activity during the entire experiment as well as higher concentrations of PAHs metabolites in bile. Micronulei frequency resulted significantly higher during all experiment in oil exposed sea bass compared to controls. The results highlight the environmental risk associated with the release of oil products at sea and confirm the adopted parameters as useful tools for studying the impact of accidental oil spills on fish.
- Wise, J. and Wise, J.P. A review of the toxicity of chemical dispersants. Reviews on Environmental Health 26(4): 281-300, 2011.
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Chemical dispersants are a mixture of various surfactants and solvents. Most dispersants are proprietary, and the complete composition is not often public knowledge. Chemical dispersants used for the cleanup and containment of crude oil toxicity became a major concern after the 2010 Deepwater Horizon oil crisis in the Gulf of Mexico. During the crisis, millions of liters of chemical dispersants (Corexit 9527 and 9500) were used – the largest known application of dispersants in the field. As of February 2011, 38 peer-reviewed articles were available on the toxicity of 35 different chemical dispersants. Nalco, BP, Shell, and Total Special Fluids manufacture a variety of chemical dispersants. Most notably, Nalco manufactures Corexit 9527 and 9500, and 19 miscellaneous dispersants are manufactured by others. Most studies examined the lethality of the dispersants. Several nonlethal end points were considered, including the effect on predator/prey recognition, enzyme activity changes, effects on hatchability, and the threshold for bradycardia. The animals studied included Daphnia (small planktonic crustaceans), anemones, corals, crustaceans, starfish, mollusks, fish, birds, and rats. Studies in birds and mammals are distinctly lacking. The variety of chemical dispersants, the variability in test methods, and the lack of distinct species overlap between studies make it difficult to compare and deduce which dispersant is most toxic and which is least. Here, we offer some attempt at comparing Corexit 9527 and 9500 (because these have had the largest field application), but significantly more research is needed before clear conclusions can be drawn.
- Jung, S.W., Kwon, O.Y., Joo, C.K., Kang, J.H., Kim, M., Shim, W.J., and Kim, Y.O. Stronger impact of dispersant plus crude oil on natural plankton assemblages in short-term marine mesocosms. Journal of Hazardous Materials 217-218: 338-349, 2012.
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To assess the effects of crude oil and dispersant on marine planktonic ecosystems, analyses were performed in 1000 L mesocosm over a period of nine days. Triplicate experiments were conducted for two different treatments, namely, addition of crude oil alone and oil plus dispersant. In the mesocosm with oil plus dispersant, high concentrations of total petroleum hydrocarbon (TPH) were soon found in the bottom layer. In addition, most planktonic communities responded drastically to the presence of dispersant acting to disperse TPH: total bacterial abundances increased for the first two days and then decreased rapidly for the remainder of the experiment. The abundance of heterotrophic flagellates increased rapidly in association with the increase in bacterial cells. The abundance of phytoplankton and zooplankton communities decreased clearly within two days. Time-delayed relationship also revealed that the TPH concentration had a significant negative relationship with phyto- and zooplankton communities within two days. However, most planktonic communities were affected less adversely in the mesocosms treated with crude oil alone than in those treated with both crude oil and dispersant. The present results demonstrate that the planktonic ecosystem was damaged more severely by the introduction of dispersant than by the harmful effects of crude oil itself. Therefore, caution should be taken when considering the direct application of dispersant in natural environments, even though it has the advantage of rapidly removing crude oil.
- Tamis, J.E., Jongbloed, R.H., Karman, C.C., Koops, W., and Murk, A.J. Rational application of chemicals in response to oil spills may reduce environmental damage. Integrated Environmental Assessment and Management 8(2): 231-241, 2012.
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Oil spills, for example those due to tanker collisions and groundings or platform accidents, can have huge adverse impacts on marine systems. The impact of an oil spill at sea depends on a number of factors, such as spill volume, type of oil spilled, weather conditions, and proximity to environmentally, economically, or socially sensitive areas. Oil spilled at sea threatens marine organisms, whole ecosystems, and economic resources in the immediate vicinity, such as fisheries, aquaculture, recreation, and tourism. Adequate response to any oil spill to minimize damage is therefore of great importance. The common response to an oil spill is to remove all visible oil from the water surface, either mechanically or by using chemicals to disperse the oil into the water column to biodegrade. This is not always the most suitable response to an oil spill, as the chemical application itself may also have adverse effects, or no response may be needed. In this article we discuss advantages and disadvantages of using chemical treatments to reduce the impact of an oil spill in relation to the conditions of the spill. The main characteristics of chemical treatment agents are discussed and presented within the context of a basic decision support scheme.
- Ivanova, M. Oil spill emergency preparedness in the Russian Arctic: a study of the Murmansk region. Polar Research 30: art. 7285, 2011.
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The issue of oil spill emergency response in north-west Russia has become increasingly important following a substantial increase in maritime transport and major offshore developments in Russian waters. This study is an initial effort to outline the public and private agencies and organizations involved in handling oil spills in the Murmansk region and the structure of the oil spill emergency response system in the region. This study examines the formal relationships between federal and regional authorities and between the different subsystems at the regional level. Due to the paucity of academic literature and public documentation on this topic, this study to a large extent bases itself on interview data. A main finding is that the regional oil spill response system has not been fully developed. It further concludes that the system lacks a clearly formulated state policy, a single governing authority and a unified structure. Finally, the study demonstrates that the agencies and organizations involved in tackling oil spill emergencies in the Murmansk region are hampered by insufficient funding, which probably reduces their preparedness to combat oil spills.
- García-Olivares, A., de Pablos, J.L., and Madrigal, R. Sailing the Prestige out to sea. An independent analysis. Scientia Marina 75(3): 533-548, 2011.
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The sinking of the supertanker Prestige off the coast of Spain in November 2002 was one of the most devastating oil spills ever worldwide. During any crisis most of the decisions have to be taken with limited information and they can benefit greatly from a rational methodology based on the available information. The main mechanisms involved in oil spill impacts are reviewed and we propose a decision tree based only on scientific criteria and data that are expected to be available in the first moments of an oil spill crisis. In the Prestige crisis, one of the decisions taken was to sail the Prestige out to sea. This paper makes an independent analysis of that decision to illustrate the methodology proposed, which may help decision making in future emergency situations.
- Schmidt, C.W. Offshore exploration to commence in the Arctic: Can Shell's oil-spill response plans keep up? Environmental Health Perspectives 120(5): a194-a199, 2012.
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- Sylves, R.T. and Comfort, L.K. The Exxon Valdez and BP Deepwater Horizon oil spills – Reducing risk in socio-technical systems. American Behavioral Scientist 56(1): 76-103, 2012.
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One way to assess whether governments and industry (at any level) learn from their disaster experience is to examine two similar events at different points in time. The authors investigate and compare the 1989 Exxon Valdez oil spill disaster with the 2010 BP Deepwater Horizon oil spill disaster to determine whether oil spill prevention and oil spill risk management have advanced over time. The study recounts facts, analyzes features of both incidents, and offers an intergovernmental interpretation of changes in policy and practice over four decades of oil spill management informed by theories of nested sets, distributed cognition, and socio-technical systems.
- Santos, H.F., Carmo, F.L., Paes, J.E.S., Rosado, A.S., and Peixoto, R.S. Bioremediation of mangroves impacted by petroleum. Water Air and Soil Pollution 216(1-4): 329-350, 2011.
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The majority of oil from oceanic oil spills (e.g. the recent accident in the Gulf of Mexico) converges on coastal ecosystems such as mangroves. Microorganisms are directly involved in biogeochemical cycles as key drivers of the degradation of many carbon sources, including petroleum hydrocarbons. When properly understood and managed, microorganisms provide a wide range of ecosystem services, such as bioremediation, and are a promising alternative for the recovery of impacted environments. Previous studies have been conducted with emphasis on developing and selecting strategies for bioremediation of mangroves, mostly in vitro, with few field applications described in the literature. Many factors can affect the success of bioremediation of oil in mangroves, including the presence and activity of the oil-degrading microorganisms in the sediment, availability and concentration of oil and nutrients, salinity, temperature and oil toxicity. More studies are needed to provide efficient bioremediation strategies to be applicable in large areas of mangroves impacted with oil. A major challenge to mangrove bioremediation is defining pollution levels and measuring recuperation of a mangrove. Typically, chemical parameters of pollution levels, such as polycyclic aromatic hydrocarbons (PAHs), are used but are extremely variable in field measurements. Therefore, meaningful mangrove monitoring strategies must be developed. This review will present the state of the art of bioremediation in oil-contaminated mangroves, new data about the use of different mangrove microcosms with and without tide simulation, the main factors that influence the success of bioremediation in mangroves and new prospects for the use of molecular tools to monitor the bioremediation process. We believe that in some environments, such as mangroves, bioremediation may be the most appropriate approach for cleanup. Because of the peculiarities and heterogeneity of these environments, which hinder the use of other physical and chemical analyses, we suggest that measuring plant recuperation should be considered with reduction in polycyclic aromatic hydrocarbons (PAHs). This is a crucial discussion because these key marine environments are threatened with worldwide disappearance. We highlight the need for and suggest new ways to conserve, protect and restore these environments.
- Cheong, H.-K. et al. Hebei Spirit oil spill exposure and subjective symptoms in residents participating in clean-up activities. Environmental Health and Toxicology 26: art. e2011007, 2011.
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Objectives This study was conducted to examine the relationship between crude oil exposure and physical symptoms among residents participating in clean-up work associated with the Hebei Spirit oil spill, 2007 in Korea. Methods A total of 288 residents responded to a questionnaire regarding subjective physical symptoms, sociodemographic characteristics and clean-up activities that occurred between two and eight weeks after the accident. Additionally, the urine of 154 of the respondents was analyzed for metabolites of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) and heavy metals. To compare the urinary levels of exposure biomarkers, the urine of 39 inland residents who were not directly exposed to the oil spill were analyzed. Results Residents exposed to oil remnants through clean-up work showed associations between physical symptoms and the exposure levels defined in various ways, including days of work, degree of skin contamination, and levels of some urinary exposure biomarkers of VOCs, metabolites and metals, although no major abnormalities in urinary exposure biomarkers were observed. Conclusions This study provides evidence of a relationship between crude oil exposure and acute human health effects and suggests the need for follow-up to evaluate the exposure status and long-term health effects of clean-up participants.
- Major, D.N. and Wang, H. How public health impact is addressed: a retrospective view on three different oil spills. Toxicological and Environmental Chemistry 94(3): 442-467, 2012.
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Spanning over a half century, over 38 'major' oil spill accidents have occurred, with the Deep Water Horizon disaster proving to be one of the largest oil spills on record. It is during these environmental disasters where the public community gathers together to participate in the clean-up effort and government entities coordinate various action plans. Whether it is using (1) workers to apply chemical dispersants to facilitate the remediation of oil in impacted areas or (2) volunteers to pick up 'tar balls' from the beach shorelines; public health concerns during an oil spill are warranted for consideration. The purpose of this review was to illustrate a need for increase in scientific advancement and governmental focus on detecting and mitigating public health effects following an oil spill disaster. With focus on the Exxon Valdez, Prestige, and Gulf oil spills, the governmental and scientific community responses were assessed. Using the human-environmental system model, this review illustrates how the model can be used to address human-health concerns following exposure to an oil spill stressor.
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