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Degree Name

Doctor of Philosophy




In 1982, productivity and biomass of epiphyton and phytoplankton and ash free dry weight (AFDW) of filamentous algae were measured in marshes either unflooded or flooded continuously for one or two years in an experimental marsh complex in Delta Marsh, Manitoba, Canada. Productivity measurements were made at 19(DEGREES)C ('(+OR-))1 and 15 (mu)E/m('2)/sec. of PAR in the laboratory using a ('14)C method. In 1983, epiphyton and phytoplankton productivity and biomass were estimated in two marshes flooded for two years and in five unflooded marshes. Productivity estimates were made both in the field and in the laboratory (175 (mu)E/m('2)/sec. of PAR and 19(DEGREES)C ('(+OR-))1). Artificial substrata incubated in the marsh were used to estimate epiphyton productivity and biomass. Phytoplankton productivity was estimated using marsh water incubated in 60-ml bottles. Total chlorophyll, chlorophyll-a, carbon and nitrogen were used as estimates of biomass.;In 1982, marshes flooded two years had significantly higher filamentous algal biomass (annual mean of 66 g AFDW/m('2)) than marshes either flooded one year (20 g AFDW/m('2)) or unflooded (2.6 g AFDW/m('2)). Filamentous algal biomass in flooded marshes was not correlated with any chemical parameters measured.;In 1982, phytoplankton productivity and biomass in flooded marshes were significantly lower than unflooded marshes. Mean epiphyton productivity per unit area of artificial substrata was significantly higher in marshes flooded one year than unflooded marshes. Epiphyton productivity and biomass per unit marsh area were significantly higher in flooded than unflooded marshes because of the greater colonizable surface area available in flooded marshes.;In 1983, no significant difference was found between average productivity in the field and the laboratory. Mean phytoplankton productivity in unflooded marshes (2290 mg C/m('3)/day) was significantly higher than in flooded marshes (290 mg C/m('3)/day). Zooplankton grazing and lower nutrient levels in flooded marshes seem to be the two main reasons for these differences. Mean epiphyton productivity of marshes flooded for two years (1000 mg C/day/m('2) substrata) was not significantly different from productivity of unflooded marshes (670 mg C/day/m('2) substrata).



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Syed Mohammad Hosseini



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105 pages