On the Oceanography of Makinson Inlet

Abstract

On completion of observations in Nares Strait from the CCGS Louis S. St. Laurent during August 1971, the opportunity arose to make a quick reconnaissance in Makinson Inlet. This inlet ... provides a sea-level passage from the North Water area through the coast range of eastern Ellesmere Island .... However, nothing was known of its bathymetry or oceanography except for a line of soundings run by CCGS Labrador in 1966. Since all of the oceanographic party with the exception of the author had already left the ship, the investigation could only be superficial, but ... a few preliminary observations were made. ... On the way up the inlet a line of soundings was maintained and a series of shoreline photographs was taken. ... On the way down the inlet, 4 oceanographic stations were occupied and Knudsen bottle samples were taken for temperature, salinity and dissolved oxygen content. Bathythermograph slides were also obtained. Since there is no sill in the main section of the inlet the classic fiord structure cannot develop and the results obtained indicate that the inlet, from the fork seaward, is from the oceanographic point of view merely a section of northern Baffin Bay. The T-S curves ... show that there are two main layers, one below 300 m and a second between 100 and 200 m These layers match those in northern Baffin Bay .... Above these in the upper 75 m or so the effects of melt water are apparent. Since the fresh water input is distributed down the full length of the inlet, the salinity at 10 m actually decreases to seaward by 0.98 per mil between Stations 1 and 4, but the gradient reverses when the salinity is integrated over the upper 75 m .... It must be stressed that the melt water effect is very short lived with the bulk of the run-off coming in a period-as short as 2 weeks. The dissolved oxygen content remains high (>6 ml/L) right to the bottom, another indication of identity with the water in Baffin Bay. A great deal of work is still needed to provide the comprehensive view of the oceanography of this inlet which is necessary before any regular use by shipping. The details of water exchange with Baffin Bay, the amount and duration of fresh water input from the numerous glaciers, the existence of a sill in the entrance to the North West Arm and the possibility of stagnant water behind it are some of the obvious lines of investigation in the future. ...