PTARMIGAN; 15, SPIDERS; 16, DUCKS ANDDIVERS; 17, ARCTIC FOX; 18, S...

14, ptarmigan; 15, spiders; 16, ducks and

divers; 17, Arctic fox; 18, skua and glaucous

1 4b

4a

24 22

gull; 19, planktonic algae; 20a, benthic

algae; 20b, decaying matter; 21, protozoa a;