Trace Element Concentrations in Relation to the Trophic Behaviour of Endangered Ivory Gulls (Pagophila eburnea) During Their Stay at a Breeding Site in Svalbard.

Magali Lucia,Geir W. Gabrielsen,Hallvard Strøm,Paco Bustamante

doi:10.1007/s00244-016-0320-6

Abstract

The ivory gull is a high-Arctic species considered endangered in most parts of its breeding range. Ivory gulls must cope with both the reduction of sea ice cover triggered by climate change and increasing contaminant loads due to changes in global contaminant pathways. The objective of this study was to assess the concentration of 14 essential and nonessential trace elements at four colonies of ivory gulls breeding on Barentsøya, Svalbard, and the relationship between contaminant exposure and the diet of individuals. Contaminants and stable isotopes (δ15N, δ13C) were determined in blood (red blood cells and whole blood), and feathers of ivory gulls collected over several years. The most quantitatively abundant nonessential trace element found in the ivory gull was mercury (Hg). Selenium (Se) was present in substantial surplus compared with Hg, which would imply relative protection against Hg toxic effects but raises concern about Se potential toxicity. Moreover, other elements were detected, such as silver, arsenic, cadmium, and lead, which would warrant monitoring because of the potential additive/synergetic effects of these compounds. This study demonstrated individual differences in trophic behaviour that triggered discrepancies in Hg concentrations, highlighting the potential biomagnifying ability of this metal in the ivory gull's food web. Results highlighted the mixing of birds coming from different geographical areas on Barentsøya.

Highlights

Among trace elements, some are categorized as non-essential, such as silver (Ag), cadmium (Cd), lead (Pb), and mercury (Hg), whereas others are considered nutritionally essential, such as arsenic (As), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), selenium (Se), vanadium (V), and zinc (Zn)
Mean concentrations and ranges of the 14 trace elements in feathers, whole blood and red blood cells of the ivory gull are presented in Tables 1 and 2 for non-essential and essential elements, respectively
Mercury reached high mean concentrations, ranging between 0.81 ± 0.05 μg g-1 dw in the whole blood and 3.39 ± 0.30 μg g-1 dw in feathers

Summary

Introduction

Some are categorized as non-essential, such as silver (Ag), cadmium (Cd), lead (Pb), and mercury (Hg), whereas others are considered nutritionally essential, such as arsenic (As), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), selenium (Se), vanadium (V), and zinc (Zn). One of the main goals in ecotoxicology is to examine more precisely the trophic ecology of species to better understand exposure pathways and explain contaminant concentrations in animal populations In this context, carbon and nitrogen stable isotopes have become a powerful tool to investigate trophic relationships and/or origins of prey to elucidate broad-scale, inter-, and intraspecific dietary patterns. Arsenic may act as an endocrine disruptor, impair reproduction, trigger sublethal effects or even induce individuals’ death in acute cases of As poisoning (Eisler 1994; Kunito et al 2008) This element is considered mainly toxic under its inorganic form. It appears evident that the cumulative and synergetic effects of trace elements, associated with already high organic contaminant levels previously recorded, could be detrimental to this endangered species (Braune et al 2006; Lucia et al 2015)

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