polar bears and pollution: trouble at the top?
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Polar Bears and Pollution:Trouble at the top?
Biology 381
Andrew E. Derocher
Department of Biological Sciences
University of Alberta
Outline
• Research activities on polar bears and their ecosystem
• Background: ecology
• Geographic variation
• Hints on possible effects…
• Trends in persistent organic pollutants
– monitoring
Threats to Polar Bears
Climate change Toxic chemicals Oil development Over-harvest
Ocean currents in the Arctic
AMAP
Air currents
Distribution ofpolar bears
Study area
SvalbardFranz Josef Land
Barents Sea
G reenland
Norway
• long food chain
• high fat content
Arctic food web
FOOD WEB - INTERACTIONS
• Predation: – Trophic relationships
AMAP, 1998
• Social interactions– Parental care
MARGINAL ICE ZONE FOOD WEB
Scott et al., 1999
Diet composition
• Understanding diet is a key component for understanding movement of pollutants through an ecosystem
• 2 “new” methods being used– Carbon and nitrogen isotopes
• see papers by K.A. Hobson
– Fatty acid composition • see Iverson et al. 2004 Ecological Monographs
Telemetry data
Satellite collar on adult female
60°
65°
65°
70°
70°
75°
75°
80°
80°
85° 85°55° 45° 35° 25° 15° 5°
5°
5°
5°
15°
15°
25°
25°
35°
35°
45°
45°
55°
55°
65°
65°
75°
75°
85°
85°
95°
95°
Home ranges of 3 female polar bears
Same population but
dramatically different
strategies
Mean annual location and pollution level
• bigger circle indicates higher pollution load (PCB)
• larger home range means more energy in which in turn
results in higher pollution load Olsen et al. 2003
Effects of Pollution
Polychlorinated biphenyls• 209 congers (congener = type)
– Vary by placement and number of chlorine atoms– Vary in toxicity and persistence– Developed in 1929 used in transformers, lubricants,
hydraulics
Ge
omet
ric M
ean
(m
g/kg
lipi
d)
PC B
Norstrom et al. 1998, Archives of Environmental Contamination and Toxicology
Polar bear
PCB levels
Svalbard-
Alaska
Andersen et al. 2001, Polar Biology
DDT
Chlordane
PCB
1,500,000 tonnes of DDT used between 1948-93
RIP
MacrophageT-cell
VirusBacteria
B-cell
N K cell Infected cell
Plasma cellwithantibodyproduction
AntigenpresentationPhagocytosis:
T-lymphocyteproliferation
Cytokinproduction
Illustration adapted from Ane Reppe
Immune system - PCB relationships
Field experiment
• Immunisation trial
• Challenge immune system
• 2 study areas
Immunisation experiment
HIGH POLLUTION
SVALBARD
LOW POLLUTION
CANADA
5 Week interval
NORMAL? REDUCED?
CAPTURE - immunise35 bears
RECAPTUREBlood sample
Immune response?
NORMAL
RECAPTUREBlood sample
Immune response?
CAPTURE - immunise35 bears
Lie et al. 2004
Effects of age
PCB in plasma associated with nutritional index
Nutritional condition index
1 2 3 4 51
2
3
4
5
Ln [
PC
B 1
53 (
ng/g
wet
wei
ght)
]
(3)
(77)
(131)
(27)
(3)
Transfer of pollution to young
Concentration of POPs in polar
bear milk
Lost cubs
Kept cubs
225
167
91 2
5
2 2 1
214
147
131
37 3 1 1
155
122
220
46 5 2 1
105
70 95 18
3 3 1
51
39 7
9
67 8 5 1
59
39 40
12
3 4 1
112
87
32
28 3 3 2
157
122
69
39 5 4 1
0
50
100
150
200
250
Co
nc.
(ng
/g
w.w
.)
Resolute juveniles (N=5)
Resolute females (N=13)
Resolute males (N=12)
Resolute cubs (N=3)
Svalbard males (N=18)
Svalbard cubs (N=3)
Svalbard juveniles (N=2)
Svalbard females (N=15)
Contaminant metabolitesSvalbard vs Canadian High Arctic Sandau et al. in prep.
OH-PCB
Sum PCBs
OH-PCB Sum PCBs(Hydroxylated PCB)
Monitoring
repeated assessment of status of some quantity to detect change over time
Organochlorine changes between 1967 and 1994 for adult males and females sampled at Svalbard
Derocher et al. 2003
Trend of PCB-153 in blood for polar bears in the Norwegian Arctic
Pollution in polar bears may impact:
learning - behaviour endocrine function growth patterns immune system function survival litter size reproductive success
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