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