This volume is derived from a symposium on High Latitude Limnology held during the 23rd Congress of the Societas Internationalis Limnologiae in Hamilton, New Zealand. The symposium stemmed from our belief that an exchange of views between limnologists working in the north and south polar zones would be timely and productive. Over the last decade there has been a major increase in the limnological research effort in Antarctica with the expansion of science programmes there by many nations from both the northern and southern hemispheres. Freshwater research has also continued to develop in the Arctic, stimulated by the need for basic information to assess environmental impacts of the oil industry, mining, urbanisation and other human activities. By bringing together aquatic investigators from both poles we hope to draw attention to the distinctive features that high latitude systems hold in common, and to the marked contrasts between and within each zone. The dominant impression from the assemblage of papers presented here is one of great limnological diversity. The studies include clear, turbid and brown water rivers in the sub Arctic (LaPerriere, Van Nieuwenhuyse & Anderson); chlorophyte dominated streams in the maritime Antarctic (Hawes); streams on the antarctic continent lined with thick cyanobacterial mats (Howard-Williams & Vincent); meromictic waters in the Arctic (Ouellet, Dickman, Bisson & Page) and Antarctic (e. g.

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Rivers and streams.- Filamentous green algae in freshwater streams on Signy Island, Antarctica.- The effects of nutrient limitation and stream discharge on the epilithic microbial community in an oligotrophic Aretic stream.- Microbial communities in southern Victoria Land streams (Antarctica) I. Photosynthesis.- Microbial communities in southern Victoria Land streams (Antarctica) II. The effects of low temperature.- Nitrogen dynamics in two antaretic streams.- Benthic algal biomass and productivity in high subarctic streams, Alaska.- Broadscale patterns in the distribution of aquatic and terrestrial vegetation at three ice-free regions on Ross Island, Antarctica.- Community structure of benthic invertebrates in interior Alaskan (USA) streams and rivers.- Variability of macroinvertebrate community composition in an arctic and subarctic stream.- Geochemical processes in the Lake Fryxell Basin (Victoria Land, Antarctica).- Lakes and ponds.- Some aspects of iron cycling in maritime antarctic lakes.- Nitrogen cycling in Arctic lakes and ponds.- Photon dependence of inorganic nitrogen transport by phytoplankton in perennially ice-covered Antarctic lakes.- Patterns of energy storage in Pseudoboeckella poppei (Crustacea, Copepoda) from two contrasting lakes on Signy Island, Antarctica.- Tundra ponds of the Yukon Delta, Alaska, and their macroinvertebrate communities.- Vertical distributions of a planktonic harpacticoid and a calanoid (Copepoda) in a meromictic Antarctic lake.- Physico-chemical characteristics and origin of hypersaline meromictic Lake Garrow in the Canadian High Arctic.- Meromixis in an Antarctic fjord; a precursor to meromictic lakes on an isostatically rising coastline.- Chemical characteristics of pond waters in the Labyrinth of southern Victoria Land, Antarctica.- Biogeochemical study of organic substances in Antarctic lakes.- Vertical distribution of organic constituents in an Antarctic lake: Lake Fryxell.- Perennially ice-covered Lake Hoare, Antarctica: physical environment, biology, and sedimentation.- Geographical index.- Map index.