Stratification, Currents, and Upwelling in Lake Ontario, Summer 1982

Abstract

A description is presented of physical measurements carried out on Lake Ontario during the summer of 1982. Seasonal variations of stratification and circulation are illustrated by monthly averages of temperature and current distributions in a north–south cross section of the lake. Day-to-day variations of temperature and currents are presented for three periods coinciding with biochemical investigations along the same transect of the lake. A wind-induced upwelling event followed by alongshore propagation of a warmwater wave is described and the dynamics involved are discussed.

Physical–chemical measurements in the water column along a transect through a tilapia cage fish farm in Lake Malawi, Africa

“…Water currents are important in lakes and oceans because they influence the transport pathways of nutrients and suspended particles (Beletsky et al, 1999;Simons and Schertzer, 1987;Hamblin et al, 2003) and can result in nutrient distributions that are spatially variable (horizontally and vertically) and declining away from major nutrient sources in most large lakes (Simons and Schertzer, 1987) including Lake Malawi (Bootsma, 1993;Patterson and Kachinjika, 1995;Hamblin et al, 2003;Gondwe et al, 2008). In water bodies where cage culture is operated, adequate water currents are necessary to maintain oxygen concentrations and disperse organic wastes generated in fish cages.…”

Spatiotemporal patterns of water quality in Lake Ontario and their implications for nuisance growth of Cladophora

“…As a consequence of prevailing westerly and southwesterly winds (e.g., Boyce et al, 1989;Chow-Fraser, 1999;L. Léon, U. Waterloo, personal communication) and Lake Ontario's predominant east-west orientation, upwelling events occur frequently along the north coast (Csanady and Scott, 1980;Rao and Schwab, 2007;Simons and Schertzer, 1987). Because upwelling events have the potential to increase cross-shore water exchange (Austin and Lentz, 2002;Rao and Schwab, 2007), north shore stations may experience greater mixing with offshore waters.…”

Chinook salmon and rainbow trout catch and temperature distributions in Lake Ontario

“…Annual variation in temperature also can change the seasonal timing and amplitude of warming and stratification. This general pattern is modified by wind-induced upwellings, currents, and internal seiches and can result in persistent regional differences in thermal structure (Boyce et al, 1983;Simons and Schertzer, 1987;Stewart and Robertson,, 1991). We reasoned that seasonal changes in thermal structure would be related to distance from shore, vertical water depth, region, and annual variations in mean lake temperature.…”