Rune Dietz

Age and seasonal variation in testis and baculum morphology in East Greenland polar bears (Ursus maritimus) in relation to high concentrations of persistent organic pollutants

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Age and seasonal variation in testis and baculum morphology in East Greenland polar bears (Ursus maritimus) in relation to high concentrations of persistent organic pollutants. / Spörndly-Nees, Ellinor; Holm, Lena; van Beest, Floris M.; Fakhrzadeh, Azadeh; Ekstedt, Elisabeth; Letcher, Robert; Magnusson, Ulf; Desforges, Jean Pierre; Dietz, Rune; Sonne, Christian.

I: Environmental Research, Bind 173, 06.2019, s. 246-254.

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

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Spörndly-Nees, Ellinor ; Holm, Lena ; van Beest, Floris M. ; Fakhrzadeh, Azadeh ; Ekstedt, Elisabeth ; Letcher, Robert ; Magnusson, Ulf ; Desforges, Jean Pierre ; Dietz, Rune ; Sonne, Christian. / Age and seasonal variation in testis and baculum morphology in East Greenland polar bears (Ursus maritimus) in relation to high concentrations of persistent organic pollutants. I: Environmental Research. 2019 ; Bind 173. s. 246-254.

Bibtex

@article{849c334a0d4443d9ad7804a37fa2342d,
title = "Age and seasonal variation in testis and baculum morphology in East Greenland polar bears (Ursus maritimus) in relation to high concentrations of persistent organic pollutants",
abstract = "Persistent organic pollutants (POPs) are found in high concentrations in the Artic. Polar bears (Ursus maritimus) are one of the most exposed mammals in the Arctic and are thereby vulnerable to reproductive disruption. The aim of this study was to investigate male polar bear reproduction based on a detailed evaluation of testis histology and to assess possible effects of environmental chemicals on male polar bear reproduction. Reproductive groups that were identified based on histology were as follows: actively reproductive (REP), non-reproductive either with degenerated testes (DEG), undeveloped seminiferous tubules (UND), or morphology in-transition (INT). Categorization into these groups was supported by significant differences in testis and baculum measurements among REP, DEG, and UND, as well as differences in the area and diameter of seminiferous tubules among REP, DEG, and UND. These results show that it is possible to identify the reproductive stage in polar bears even if capture date and or age is lacking. Based on testis morphology we suggest that adult male polar bears from East Greenland have active spermatogenesis in February to June, and inactive degenerated testes in August to January. January to February was the main period of reproductive transition, characterised by a shift between inactive and active spermatogenesis. Baculum and testis size measurements decreased significantly with increasing concentrations of the chlordane metabolite oxychlordane, suggesting a potential impact on male reproductive success. Half of the investigated polar bears in REP group displayed signs of disorganization of the spermatogenesis which might be a sign of disrupted reproduction. However, no correlations with levels of the investigated POPs were detected. Reproductive organ measurements in polar bears differed significantly between REP and DEG groups, which cannot be explained by age, and therefore should be considered when investigating the effect of POPs on male reproduction.",
keywords = "Bioaccumulative toxicants, Ecotoxicology, Reproduction, Spermatogenesis, Top predators",
author = "Ellinor Sp{\"o}rndly-Nees and Lena Holm and {van Beest}, {Floris M.} and Azadeh Fakhrzadeh and Elisabeth Ekstedt and Robert Letcher and Ulf Magnusson and Desforges, {Jean Pierre} and Rune Dietz and Christian Sonne",
year = "2019",
month = jun,
doi = "10.1016/j.envres.2019.03.036",
language = "English",
volume = "173",
pages = "246--254",
journal = "Environmental Research",
issn = "0013-9351",
publisher = "Academic Press",

}

RIS

TY - JOUR

T1 - Age and seasonal variation in testis and baculum morphology in East Greenland polar bears (Ursus maritimus) in relation to high concentrations of persistent organic pollutants

AU - Spörndly-Nees, Ellinor

AU - Holm, Lena

AU - van Beest, Floris M.

AU - Fakhrzadeh, Azadeh

AU - Ekstedt, Elisabeth

AU - Letcher, Robert

AU - Magnusson, Ulf

AU - Desforges, Jean Pierre

AU - Dietz, Rune

AU - Sonne, Christian

PY - 2019/6

Y1 - 2019/6

N2 - Persistent organic pollutants (POPs) are found in high concentrations in the Artic. Polar bears (Ursus maritimus) are one of the most exposed mammals in the Arctic and are thereby vulnerable to reproductive disruption. The aim of this study was to investigate male polar bear reproduction based on a detailed evaluation of testis histology and to assess possible effects of environmental chemicals on male polar bear reproduction. Reproductive groups that were identified based on histology were as follows: actively reproductive (REP), non-reproductive either with degenerated testes (DEG), undeveloped seminiferous tubules (UND), or morphology in-transition (INT). Categorization into these groups was supported by significant differences in testis and baculum measurements among REP, DEG, and UND, as well as differences in the area and diameter of seminiferous tubules among REP, DEG, and UND. These results show that it is possible to identify the reproductive stage in polar bears even if capture date and or age is lacking. Based on testis morphology we suggest that adult male polar bears from East Greenland have active spermatogenesis in February to June, and inactive degenerated testes in August to January. January to February was the main period of reproductive transition, characterised by a shift between inactive and active spermatogenesis. Baculum and testis size measurements decreased significantly with increasing concentrations of the chlordane metabolite oxychlordane, suggesting a potential impact on male reproductive success. Half of the investigated polar bears in REP group displayed signs of disorganization of the spermatogenesis which might be a sign of disrupted reproduction. However, no correlations with levels of the investigated POPs were detected. Reproductive organ measurements in polar bears differed significantly between REP and DEG groups, which cannot be explained by age, and therefore should be considered when investigating the effect of POPs on male reproduction.

AB - Persistent organic pollutants (POPs) are found in high concentrations in the Artic. Polar bears (Ursus maritimus) are one of the most exposed mammals in the Arctic and are thereby vulnerable to reproductive disruption. The aim of this study was to investigate male polar bear reproduction based on a detailed evaluation of testis histology and to assess possible effects of environmental chemicals on male polar bear reproduction. Reproductive groups that were identified based on histology were as follows: actively reproductive (REP), non-reproductive either with degenerated testes (DEG), undeveloped seminiferous tubules (UND), or morphology in-transition (INT). Categorization into these groups was supported by significant differences in testis and baculum measurements among REP, DEG, and UND, as well as differences in the area and diameter of seminiferous tubules among REP, DEG, and UND. These results show that it is possible to identify the reproductive stage in polar bears even if capture date and or age is lacking. Based on testis morphology we suggest that adult male polar bears from East Greenland have active spermatogenesis in February to June, and inactive degenerated testes in August to January. January to February was the main period of reproductive transition, characterised by a shift between inactive and active spermatogenesis. Baculum and testis size measurements decreased significantly with increasing concentrations of the chlordane metabolite oxychlordane, suggesting a potential impact on male reproductive success. Half of the investigated polar bears in REP group displayed signs of disorganization of the spermatogenesis which might be a sign of disrupted reproduction. However, no correlations with levels of the investigated POPs were detected. Reproductive organ measurements in polar bears differed significantly between REP and DEG groups, which cannot be explained by age, and therefore should be considered when investigating the effect of POPs on male reproduction.

KW - Bioaccumulative toxicants

KW - Ecotoxicology

KW - Reproduction

KW - Spermatogenesis

KW - Top predators

UR - http://www.scopus.com/inward/record.url?scp=85063467644&partnerID=8YFLogxK

U2 - 10.1016/j.envres.2019.03.036

DO - 10.1016/j.envres.2019.03.036

M3 - Journal article

C2 - 30928855

AN - SCOPUS:85063467644

VL - 173

SP - 246

EP - 254

JO - Environmental Research

JF - Environmental Research

SN - 0013-9351

ER -