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 l Climate change l Toxic chemicals l Oil development l Over-harvest

Ocean currents in the Arctic AMAP

Air currents

Distribution of polar bears

Study area

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 Ecological Monographs

Telemetry data Satellite collar on adult female

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

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

RIP Macrophage T-cell Virus Bacteria B-cell N K cell Infected cell Plasma cell with antibody production Antigen presentation Phagocytosis: T-lymphocyte proliferation Cytokin production 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 - immunise 35 bears RECAPTURE Blood sample Immune response? NORMAL RECAPTURE Blood sample Immune response? CAPTURE - immunise 35 bears Lie et al. 2004

Effects of age

PCB in plasma associated with nutritional index Nutritional condition index Ln [PCB 153 (ng/g wet weight)] (3) (77) (131) (27) (3)

Transfer of pollution to young

Concentration of POPs in polar bear milk Lost cubs Kept cubs

Contaminant metabolites Svalbard vs Canadian High Arctic Sandau et al. in prep. OH-PCB Sum PCBs OH-PCBSum 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