Cellular responses induced by environmental stress factors in Arctic Seabird chicks : Responses of the antioxidant defense system and autophagic lysosomal processes related to contaminant exposure and food restriction

Abstract

This PhD study has investigated how two commonly occurring environmental stress factors in the Arctic (periods with little food and exposure to halogenated organic contaminants) have had an impact on two important cellular defense mechanisms in Arctic seabirds.

The antioxidant defense system and autophagic lysosomal responses in liver cells of Arctic seabird chicks have been studied. Samples were collected from three seabird species at Svalbard and Tromsø area: Black-legged kittiwake (Rissa tridactyla), northern fulmar (Fulmarus glacialis) and herring gull (Larus argentatus ), as well as samples from a feeding experiment with herring gull chicks. The findings show that there are major species differences, and that the antioxidant defense system and autophagic lysosomal responses in the seabird chicks are affected by factors such as diet, species-specific physiology and fasting, as well as high-grade contaminant exposure. Some of the effects of contaminant exposure were dose-dependent. The contaminant concentrations found in the birds in this study were relatively low. Hence, more pronounced effects could therefore be present in wild-living birds that have higher contaminant concentrations than birds in this study. Some of the cellular effects observed in this study have been associated with adverse health effects in other animal species. Additional studies of these cellular systems in seabirds are recommended in order to implement such analysis in regularly monitoring of seabird health status in the future and may contribute to improved management of the important seabird populations in these areas.