title: Exposure to Deepwater Horizon weathered crude oil increases routine metabolic demand in chub mackerel, Scomber japonicus.
abstract: During the 2010 Deepwater Horizon incident, the continuous release of crude oil from the damaged Macondo 252 wellhead on the ocean floor contaminated surface water habitats for pelagic fish for more than 12weeks. The spill occurred across pelagic, neritic and benthic waters, impacting a variety of ecosystems. Chemical components of crude oil are known to disrupt cardiac function in juvenile fish, and here we investigate the effects of oil on the routine metabolic rate of chub mackerel, Scomber japonicus. Mackerel were exposed to artificially weathered Macondo 252 crude oil, prepared as a Water Accommodated Fraction (WAF), for 72 or 96h. Routine metabolic rates were determined pre- and post-exposure using an intermittent-flow, swim tunnel respirometer. Routine energetic demand increased in all mackerels in response to crude oil and reached statistical significance relative to unexposed controls at 96h. Chemical analyses of bile from exposed fish revealed elevated levels of fluorescent metabolites, confirming the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in the exposure WAF. The observed increase in metabolic demand is likely attributable to the bioenergetic costs of contaminant detoxification. These results indicate that short-term exposure (i.e. days) to oil has sub-lethal toxicity to mackerel and results in physiological stress during the active spill phase of the incident.
authors.affiliation: Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA 94305, USA. Electronic address: dhklinger@stanford.edu.
authors.forename: Dane H
authors.initials: DH
authors.lastname: Klinger
authors.affiliation: Biology Department, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Dale
authors.affiliation: Biology Department, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA.
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Machado
authors.affiliation: Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Incardona
authors.affiliation: Tuna Research and Conservation Center, Monterey Bay Aquarium, Monterey, CA 93940, USA.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Farwell
authors.affiliation: Biology Department, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Block
mesh_terms: D000818:Animals; D001646:Bile / Q000737:chemistry; D054750:Ecotoxicology / Q000379:methods; D004781:Environmental Exposure / Q000009:adverse effects*; D010473:Perciformes / Q000378:metabolism* / Q000502:physiology; D010578:Petroleum / Q000032:analysis / Q000633:toxicity*; D059392:Petroleum Pollution / Q000009:adverse effects* / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000493:pharmacokinetics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity
chemical_list: D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
keywords: Aerobic metabolism; Biliary metabolites; Oil spill; PAHs; Scomber japonicus; WAF