期刊
AQUATIC TOXICOLOGY
卷 222, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.aquatox.2020.105454
关键词
Coral; Crude oil; High-energy water-accommodated fraction (HEWAF); Pocillopora damicornis; Pulse amplitude modulated fluorometry; Tissue regeneration assay
资金
- National Oceanic and Atmospheric Administration
- National Centers for Coastal Ocean Science portfolio project [842]
- Coral Reef Conservation Program project [1133]
Recent oil spill responses such as the Deepwater Horizon event have underscored the need for crude oil ecotoxicological threshold data for shallow water corals to assist in natural resource damage assessments. We determined the toxicity of a mechanically agitated oil-seawater mixture (high-energy water-accommodated fraction, HEWAF) of a sweet crude oil on a branched stony coral, Pocillopora damicornis. We report the results of two experiments: a 96 h static renewal exposure experiment and a pulse-chase experiment of three short-term exposure durations followed by a recovery period in artificial seawater. Five endpoints were used to determine ecotoxicological values: 1) algal symbiont chlorophyll fluorescence, 2) a tissue regeneration assay and a visual health metric with three endpoints: 3) tissue integrity, 4) tissue color, and 5) polyp behavior. The sum of 50 entrained polycyclic aromatic hydrocarbons (tPAH50) was used as a proxy for oil exposure. For the 96 h exposure dose response experiment, dark-adapted maximum quantum yield (Fv/Fm) of the dinoflagellate symbionts was least affected by crude oil (EC50 = 913 mu g/L tPAH50); light-adapted effective quantum yield (EQY) was more sensitive (EC50 = 428 mu g/L tPAH50). In the health assessment, polyp behavior (EC50 = 27 mu g/L tPAH50) was more sensitive than tissue integrity (EC50 = 806 mu g/L tPAH50) or tissue color (EC50 = 926 mu g/L tPAH50). Tissue regeneration proved to be a particularly sensitive measurement for toxicity effects (EC50 = 10 mu g/L tPAH50). Short duration (6 - 24 h) exposures using 503 mu g/L tPAH50 (average concentration) resulted in negative impacts to P. damicornis and its symbionts. Recovery of chlorophyll a fluorescence levels for 6 - 24 h oil exposures was observed in a few hours (Fv/Fm) to several days (EQY) following recovery in fresh seawater. The coral health assessments for tissue integrity and tissue color were not affected following short-term oil exposure durations, but the 96 h treatment duration resulted in significant decreases for both. A reduction in polyp behavior (extension) was observed for all treatment durations, with recovery observed for the short-term (6 - 24 h) exposures within 1-2 days following placement in fresh seawater. Wounded and intact fragments exposed to oil treatments were particularly sensitive, with significant delays observed in tissue regeneration. Estimating ecotoxicological values for P. damicornis exposed to crude oil HEWAFs provides a basis for natural resource damage assessments for oil spills in reef ecosystems. These data, when combined with ecotoxicological values for other coral reef species, will contribute to the development of species sensitivity models.
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