Telomere length in relation to persistent organic pollutant exposure in white-tailed eagle (Haliaeetus albicilla) nestlings from Sweden sampled in 1995–2013

Elisabeth Hansen,Tove Skotnes,Jan Ove Bustnes,Björn Helander,Igor Eulaers,Jiachen Sun,Adrian Covaci,Bård-Jørgen Bårdsen,Sandrine Zahn,Francois Criscuolo,Sophie Bourgeon

doi:10.1016/j.envres.2022.112712

Abstract

Telomeres are used as biomarkers of vertebrate health because of the link between their length, lifespan, and survival. Exposure to environmental stressors appears to alter telomere dynamics, but little is known about telomere length and persistent organic pollutant (POP) exposure in wildlife. The white-tailed eagle (WTE; Haliaeetus albicilla) is an avian top predator that accumulates high levels of POPs and may subsequently suffer adverse health effects. Here we study the Baltic WTE population that is well documented to have been exposed to large contaminant burdens, thereby making it a promising candidate species for analyzing pollutant-mediated effects on telomeres. We investigated telomere lengths in WTE nestlings (n = 168) over 19 years and examined legacy POP concentrations (organochlorines and polybrominated diphenyl ethers) in whole blood and serum as potential drivers of differences in telomere length. Although we detected significant year-to-year variations in telomere lengths among the WTE nestlings, telomere lengths did not correlate with any of the investigated POP concentrations of several classes. Given that telomere lengths did not associate with POP contamination in the Baltic WTE nestlings, we propose that other environmental and biological factors, which likely fluctuate on a year-to-year basis, could be more important drivers of telomere lengths in this population.

Highlights

Telomeres are repeated sequences of non-coding DNA that cap the ends of chromosomes and play an important role in stabilizing and protecting the coding sequences in eukaryote genomes (Blackburn, 1991)
The white-tailed eagle is an avian top predator associated with aquatic habitats in many Eurasian countries (Cramp and Simmons, 1983)
Poor breeding success has been reported for other white-tailed eagle (WTE) populations in the Baltic Sea region (Koivusaari et al, 1980; Scharen berg and Struwe-Juhl, 2006)

Summary

Introduction

Telomeres are repeated sequences of non-coding DNA that cap the ends of chromosomes and play an important role in stabilizing and protecting the coding sequences in eukaryote genomes (Blackburn, 1991). There are relationships between increased rates of telomere shortening and sub-optimal environmental conditions such as dramatic changes in climate (Mizutani et al, 2013), warmer and wetter springs (van Lieshout et al, 2021), unfavorable natal or wintering conditions (Angelier et al, 2013; Watson et al, 2015), and low adult habitat quality (Apfelbeck et al, 2019; Wilbourn et al, 2017), possibly mediated through increased oxidative stress (the imbalance within an organism between free radi cals’ production and antioxidants availability or activity) (Haussmann and Marchetto, 2010; von Zglinicki, 2002). The Swedish WTE population on the Baltic coastline has suffered reproductive failure and population decline during the 1950s until the 1980s as a consequence of contamination by legacy POPs (Helander, 1985; Helander et al, 1982, 2002). The WTE represents a species that is useful for examination of possible detrimental impacts of exposure to environmental POPs (Helander et al, 2008)

Methods

Results

Conclusion