Northern Research Reports

Aerobiological Investigations in the Arctic and Subarctic In view of the considerable development of the subject in civilized regions, and of its possible economic as well as academic significance, it is surprising how little work has been done in the North on the presence and identity of botanical and other ‘particles’ in the atmosphere. T o be sure, it has long been known that fungal spores and other disseminules may be present in the air in boreal regions north of the limits of extensive cultivation-as for example over Norway House, Manitoba-but so far as the Arctic and Subarctic are concerned the undersigned know of only two attempts at aerobiological investigations prior to 1947. These were by one of us (N.P.) in Lapland and Spitsbergen in 1933, and by Lindbergh over Greenland etc. in the-same year. The former work was abortive in that the “observations” were deemed insufficiently reliable for publication although they gave some suggestion of the presence of rather plentiful viable disseminules in the air a t low altitudes; the latter work appeared to confirm these suggestions for higher altitudes but was unfortunately never described in any detail. It remained for one of us (fi.P.), while flying with the Royal Canadian Air Force during August and September, 1947, on operations concerned primarily with ground survey work and locating the North Magnetic Pole, to expose from his aircraft nutrient Petri plates and vaselined microscopical slides especially prepared and packed under the direction of another of us (S.M.P.). Details of preparation, exposure, and packaging have already been published (Nature, vol. 160, pp. 876-7, 1947); a total of 5 I plates and 5 2 slides were exposed, the former for two minutes each and the latter for five minutes each. Not a single contamination developed on any of the 7 unexposed plates that were brought back. as controls, so that full confidence is felt in the apparatus and methods employed although these were quite simple, Most of the 1947 exposures were made at or around an altitude of 5,000 feet and airspeed IOO knots ( I 1 5 m.p.h.), well outside the fuselage of Norseman and Canso aircraft. Except for inevitable gaps due to liquid or ice precipitation or preoccupation with landing, etc., a nutrient plate and a sticky slide were exposed either every twenty or every thirty miles, approximately, throughout the flights concerned. The first of these flights was on August 12th, and extended in a northerly direction from a base-camp situated on an unnamed lake north-west of Great Bear Lake to Langton Bay on the Arctic Ocean coast, and thence to the mouth of the Horton River. The later exposures extended over about 1,500 miles from Somerset Island southwards to Edmonton, Alberta. The vaselined slides have been sent to specialists to examine for the spores of pathogenic Fungi which do not culture. Already the Dominion Rust Research Laboratory, Winnipeg, have reported that on some of the slides exposed near the Arctic Ocean coast there are represented spores of three of the most important I i airborne pathogens of cereal crops of Canada, viz. Wheat Stem-rust (Puccinia I graminis tritici), Wheat Leaf-rust (P . rubigo-vera=€’. triticina) , and Foot-rot of Barley and Rye (Helminthosporium sativum). This is the better part of 1000 miles north of the Peace River region, which is the nearest likely source of supply of any real extent, and would seem to extend remarkably the much-cited “at