Nicholls, K. H.
Limnol. Oceangr. 43:715-719
Phosphorus concentrations in a 19-year record of the Lake Huron outflow (Laurentian Great Lakes of North America) were negatively correlated with the extent of Great Lakes winter ice cover. The highest phosphorus concentrations (2-3 times higher than normal) occurred during 1983, 1987, and 1992 in response to strong El Mmo-related moderation of winter temperatures. The 1983 winter air temperature anomaly of +2.5°C (the mildest winter in the record) is well within the output of predicted temperature increases by general circulation models for the Great Lakes basin under a 2X CO2 climate warming scenario. Lake data from strong El Niño years, when contrasted with other years having near-normal winter temperatures and ice cover, can thus serve to identify some previously unanticipated air impacts of global warming on lake water quality. 1 suggest that global warming may have important implications for eutrophication control in the Great Lakes.