| To help stem this decline, wetland areas are now being preserved and where
possible created. This study investigated water quality in a recreated reed bed in
south-west England designed specifically to provide habitat for birds. Since June 2000,
continuous measurements of temperature, pH, electrical conductivity and dissolved oxygen
have been logged. These data enable the partial pressure of CO2 to be calculated.
This paper looks at the data collected up to November 2001. Despite similar solar radiation
and water temperature conditions in both 2000 and 2001, peak summertime values of dissolved
oxygen dropped from >100% to <50% and pH values dropped from >7.7 to <7.2. Both also
show a reduction in diurnal variation. Over the same period, the average partial pressure
of CO2 increased from 19.7 to 56.1. Analysis of the diurnal dissolved oxygen
curves indicates a decrease in photosynthesis which, in the absence of a change in nutrient
concentrations in the water, may result from surface plant growth or from a reduction in
submerged plant cover. The implications of these changing hydro-chemical conditions are
that the site will be less able to support such a wide diversity of aquatic fauna, which
will reduce the effectiveness of the site as a habitat for some bird species.
Keywords: wetland, reed bed, hydrochemistry, dissolved oxygen, pH, continuous monitoring,
Hamwall, Somerset Levels |