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Demographic and temporal variations in immunity and condition of polar bears (Ursus maritimus) from the southern Beaufort Sea.

https://arctichealth.org/en/permalink/ahliterature289228
Source
J Exp Zool A Ecol Integr Physiol. 2017 06; 327(5):333-346
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
06-2017
Author
Lorin A Neuman-Lee
Patricia A Terletzky
Todd C Atwood
Eric M Gese
Geoffrey D Smith
Sydney Greenfield
John Pettit
Susannah S French
Author Affiliation
Department of Biology, Arkansas State University, Jonesboro, Arkansas.
Source
J Exp Zool A Ecol Integr Physiol. 2017 06; 327(5):333-346
Date
06-2017
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Abstract
Assessing the health and condition of animals in their natural environment can be problematic. Many physiological metrics, including immunity, are highly influenced by specific context and recent events to which researchers may be unaware. Thus, using a multifaceted physiological approach and a context-specific analysis encompassing multiple time scales can be highly informative. Ecoimmunological tools in particular can provide important indications to the health of animals in the wild. We collected blood and hair samples from free-ranging polar bears (Ursus maritimus) in the southern Beaufort Sea and examined the influence of sex, age, and reproductive status on metrics of immunity, stress, and body condition during 2013-2015. We examined metrics of innate immunity (bactericidal ability and lysis) and stress (hair cortisol, reactive oxygen species, and oxidative barrier), in relation to indices of body condition considered to be short term (urea to creatinine ratio; UC ratio) and long term (storage energy and body mass index). We found the factors of sex, age, and reproductive status of the bear were critical for interpreting different physiological metrics. Additionally, the metrics of body condition were important predictors for stress indicators. Finally, many of these metrics differed between years, illustrating the need to examine populations on a longer time scale. Taken together, this study demonstrates the complex relationship between multiple facets of physiology and how interpretation requires us to examine individuals within a specific context.
PubMed ID
29356384 View in PubMed
Less detail

Demographic and temporal variations in immunity and condition of polar bears (Ursus maritimus) from the southern Beaufort Sea.

https://arctichealth.org/en/permalink/ahliterature294180
Source
J Exp Zool A Ecol Integr Physiol. 2017 06; 327(5):333-346
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
06-2017
Author
Lorin A Neuman-Lee
Patricia A Terletzky
Todd C Atwood
Eric M Gese
Geoffrey D Smith
Sydney Greenfield
John Pettit
Susannah S French
Author Affiliation
Department of Biology, Arkansas State University, Jonesboro, Arkansas.
Source
J Exp Zool A Ecol Integr Physiol. 2017 06; 327(5):333-346
Date
06-2017
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Age Factors
Animals
Arctic Regions
Body mass index
Female
Hair - chemistry
Hydrocortisone - analysis
Immunity, Innate - immunology
Male
Reactive Oxygen Species - blood
Serum Bactericidal Test - veterinary
Sex Factors
Stress, Physiological - immunology
Ursidae - immunology - physiology
Abstract
Assessing the health and condition of animals in their natural environment can be problematic. Many physiological metrics, including immunity, are highly influenced by specific context and recent events to which researchers may be unaware. Thus, using a multifaceted physiological approach and a context-specific analysis encompassing multiple time scales can be highly informative. Ecoimmunological tools in particular can provide important indications to the health of animals in the wild. We collected blood and hair samples from free-ranging polar bears (Ursus maritimus) in the southern Beaufort Sea and examined the influence of sex, age, and reproductive status on metrics of immunity, stress, and body condition during 2013-2015. We examined metrics of innate immunity (bactericidal ability and lysis) and stress (hair cortisol, reactive oxygen species, and oxidative barrier), in relation to indices of body condition considered to be short term (urea to creatinine ratio; UC ratio) and long term (storage energy and body mass index). We found the factors of sex, age, and reproductive status of the bear were critical for interpreting different physiological metrics. Additionally, the metrics of body condition were important predictors for stress indicators. Finally, many of these metrics differed between years, illustrating the need to examine populations on a longer time scale. Taken together, this study demonstrates the complex relationship between multiple facets of physiology and how interpretation requires us to examine individuals within a specific context.
PubMed ID
29356384 View in PubMed
Less detail

Environmental and behavioral changes may influence the exposure of an Arctic apex predator to pathogens and contaminants.

https://arctichealth.org/en/permalink/ahliterature301645
Source
Sci Rep. 2017 10 16; 7(1):13193
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
10-16-2017
Author
Todd C Atwood
Colleen Duncan
Kelly A Patyk
Pauline Nol
Jack Rhyan
Matthew McCollum
Melissa A McKinney
Andrew M Ramey
Camila K Cerqueira-Cézar
Oliver C H Kwok
Jitender P Dubey
Steven Hennager
Author Affiliation
US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK, 99508, USA. tatwood@usgs.gov.
Source
Sci Rep. 2017 10 16; 7(1):13193
Date
10-16-2017
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Animals
Arctic Regions
Brucella - immunology - isolation & purification
Coxiella burnetii - immunology - isolation & purification
Ecosystem
Environmental Pollutants - toxicity
Francisella tularensis - immunology - isolation & purification
Ice Cover
Neospora - immunology - isolation & purification
Toxoplasma - immunology - isolation & purification
Ursidae - microbiology
Abstract
Recent decline of sea ice habitat has coincided with increased use of land by polar bears (Ursus maritimus) from the southern Beaufort Sea (SB), which may alter the risks of exposure to pathogens and contaminants. We assayed blood samples from SB polar bears to assess prior exposure to the pathogens Brucella spp., Toxoplasma gondii, Coxiella burnetii, Francisella tularensis, and Neospora caninum, estimate concentrations of persistent organic pollutants (POPs), and evaluate risk factors associated with exposure to pathogens and POPs. We found that seroprevalence of Brucella spp. and T. gondii antibodies likely increased through time, and provide the first evidence of exposure of polar bears to C. burnetii, N. caninum, and F. tularensis. Additionally, the odds of exposure to T. gondii were greater for bears that used land than for bears that remained on the sea ice during summer and fall, while mean concentrations of the POP chlordane (SCHL) were lower for land-based bears. Changes in polar bear behavior brought about by climate-induced modifications to the Arctic marine ecosystem may increase exposure risk to certain pathogens and alter contaminant exposure pathways.
PubMed ID
29038498 View in PubMed
Less detail

Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity.

https://arctichealth.org/en/permalink/ahliterature295310
Source
Glob Chang Biol. 2018 01; 24(1):410-423
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
01-2018
Author
Karyn D Rode
Ryan R Wilson
David C Douglas
Vanessa Muhlenbruch
Todd C Atwood
Eric V Regehr
Evan S Richardson
Nicholas W Pilfold
Andrew E Derocher
George M Durner
Ian Stirling
Steven C Amstrup
Michelle St Martin
Anthony M Pagano
Kristin Simac
Author Affiliation
U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA.
Source
Glob Chang Biol. 2018 01; 24(1):410-423
Date
01-2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Animals
Arctic Regions
Caniformia
Climate change
Diet
Food chain
Ice Cover
Population Dynamics
Reproduction
Seasons
Ursidae - blood
Abstract
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (=7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.
PubMed ID
28994242 View in PubMed
Less detail