Effects of chronic crude oil exposure on early developmental stages of the Northern krill (Meganyctiphanes norvegica)

ABSTRACT

Rising oil and gas activities in northern high latitudes have led to an increased risk of petroleum pollution in these ecosystems. Further, seasonal high UV radiation at high latitudes may elevate photo-enhanced toxicity of petroleum pollution to marine organisms. Zooplanktons are a key ecological component of northern ecosystems; therefore, it is important to assess their sensitivity to potential pollutants of oil and gas activity. As ontogenetic development may be particularly sensitive, the aim of this study was to examine the impact of chronic exposure to oil water dispersion (OWD) on development and feeding of early life stages of the Northern krill, Meganyctiphanes norvegica. In a range of experiments, embryonic, nonfeeding, and feeding larval stages were exposed to concentrations of between 0.01 and 0.1 mg/L of oil or photo-modified oil for 19 and 21 d. No significant effects on egg respiration, hatching success, development, length and larval survival were observed from these treatments. Similarly, evolution of fatty acid composition patterns during ontogenetic development was unaffected. The results indicates a high degree of resilience of these early developmental stages to such types and concentrations of pollutants. However, feeding and motility in later calyptopis-stage larvae were significantly impaired at exposure of 0.1 mg/L oil. Data indicate that feeding larval stage of krill was more sensitive to OWD than early nonfeeding life stages. This might be attributed to the narcotic effects of oil pollutants, their direct ingestion, or accumulated adverse effects over early development.

Acknowledgments

We wish to thank Mark Berry (for help and technical support) and Kjell Birger Øysæd (for analysis of oil in water using fluorescence) at IRIS (International Research Institute of Stavanger). Fatty acid analysis was carried out at the Royal Netherlands Institute of Sea Research, Yerseke, The Netherlands, with special thanks to Pieter van Rijswijk and Peter van Breugel. The authors would also like to thank Thierry Baussant for valuable comments on a final draft of the manuscript.

Funding

This study was funded by The Research Council of Norway (RCN) through two projects where the main objectives were to study seasonal variation in the sensitivity of Northern krill to oil (NRC SEASENS no#234291) and biological effects/risk and environmental indicators in integrated model system based management of pelagic Arctic ecosystems (NRC IMS no#204023/E40).

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Funding

This study was funded by The Research Council of Norway (RCN) through two projects where the main objectives were to study seasonal variation in the sensitivity of Northern krill to oil (NRC SEASENS no#234291) and biological effects/risk and environmental indicators in integrated model system based management of pelagic Arctic ecosystems (NRC IMS no#204023/E40).