Retention and Resuspension of Phosphorus, Nitrogen, and Iron in a Central Ontario Lake

Publisher Website
Google Scholar
Abstract
Sediment traps were used to estimate the downward flux of total phosphorus, total Kjeldahl nitrogen, and iron in a small Precambrian shield lake for 4 yr. The flux as determined by the sediment trap method was much higher than the retention of the same elements as measured by mass balance methods (input-outflow). Total phosphorus (TP) sedimentation was about 17 times higher than retention while N was about three times higher and Fe was about 31 times higher. Very high N/P ratios in epilimnetic waters (36/1 by weight) and low N/P ratios in trap material (8/1) and surficial sediments (mean 8/1, range 4-11/1), in conjunction with high sedimentation to retention ratios, strongly suggest that resuspended sediment is a major component of trap material. Fe/TP ratios suggest that surficial sediment from shallow waters (< 13 m) was the largest contributor to resuspended sediment. Large amounts of biologically available phosphorus originating with resuspended sediment may enter upper waters. The differences between N/P ratios in surficial sediments (4-11/1) and retained from mass balance calculations (50/1) is attributed to denitrification.

This publication has 22 references indexed in Scilit: