Spatial and historical variation in sediment phosphorus fractions and mobility in a shallow lake.
Temporal and spatial variation in sediment P composition and mobility were investigated in Loch Leven. Little change was observed in total sediment P (surface sediment at 4m depth), in comparison to a previous study (1990), despite significant reduction of external point sources of P. Labile P and residual P have both increased (0.007-0.039 mg PO(4)-P and 0.121-0.420 mg PO(4)-P per gram dry weight of sediment, respectively) since 1990. An analysis of P fractions, along a depth transect, indicated elevated labile P concentrations in shallow water sediment (<12 m overlying water depth). Regression analysis showed that spatial variability in reductant-adsorbed P was significantly related to sediment chlorophyll a concentration (R(2)=0.733, p<0.05). This may be linked to the production of oxygen, by benthic algae, resulting in the maintenance of an oxygenated layer at the sediment surface. Variation in labile P was best explained by overlying water temperature and equilibrium phosphate concentration (EPC0).
Spears
Bryan M
BM
Centre for Ecology and hydrology Edinburgh, Penicuik, Midlothian, Scotland EH26 OQB, UK. spear@ceh.ac.uk
Carvalho
Laurence
L
Perkins
Rupert
R
Kirika
Alex
A
Paterson
David M
DM
D004784:Environmental Monitoring; D049673:History, 20th Century; D010710:Phosphates / Q000032:analysis; D010758:Phosphorus / Q000032:analysis* / Q000266:history; D012044:Regression Analysis; D012606:Scotland; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry; D014873:Water Pollutants / Q000032:analysis* / Q000266:history; D014881:Water Supply
D010710:Phosphates; D014873:Water Pollutants; D014867:Water; D010758:Phosphorus