Phosphorus sedimentation during stratification in two small lakes


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Arch.Hydrobiol.162 3 309–325 Stuttgart,March 2005
Phosphorus sedimentation during stratification in
two small lakes
and W.D.Taylor
University of Waterloo,Waterloo,Ontario,Canada
With 4 figures and 4 tables
Abstract:Sedimentation of phosphorus was measured with sediment traps during
spring through fall at 3 depths in 2 small lakes that had initially different fish and zoo-
plankton communities,but were subject to a manipulation of their fish communities.P
sedimentation (P area
) increased with depth in both lakes and all years,and
more than accounted for the decline in total P through the stratified season.Sedimenta-
tion measured at the base of the epilimnion was sufficient to remove the epilimnetic
total P only every 36 days on average,and sedimentation velocities were very low,
about 10 to 15 cm d
.P sedimentation did not vary significantly between lakes and
among years,although it did demonstrate temporal variability.Sedimentation velocity
also varied among depths,and was greater in the epilimnion than in the metalimnion.
Sedimentation rates were not related to particulate phosphorus concentrations,or to
particular size fractions,while sedimentation velocities were only weakly correlated to
particle-size distribution.Mass balance calculations suggest that there was substantial
input of P to the epilimnion of these small lakes during stratification.This and the re-
suspension and mineralization of P from the shallow sediments may account for the
differences between these results with those for larger lakes and for limnocorrals,re-
Key words:phosphorus,sedimentation rate,sedimentation velocity,plankton size-
Loss of phosphorus from the surface waters of lakes during the stratified sea-
son is sufficient to cause a decline of up to 60% of the total phosphorus (TP)
Authors’ addresses:Department of Biology,University of Waterloo,Waterloo On-
tario N2L 3G1 Canada.
Present address:Department of Biology,University of Saskatchewan,Saskatoon,
Saskatchewan S7N 5E2 Canada.
* Author for correspondence;
DOI:10.1127/0003-9136/2005/0162-0309 0003-9136/05/0162-0309 $ 4.25
2005 E.Schweizerbart’sche Verlagsbuchhandlung,D-70176 Stuttgart