Related Experiment Video
Updated: Jun 21, 2026

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays
Published on: October 1, 2013
Spatial and historical variation in sediment phosphorus fractions and mobility in a shallow lake
Bryan M Spears1, Laurence Carvalho, Rupert Perkins
1Centre for Ecology and hydrology Edinburgh, Penicuik, Midlothian, Scotland EH26 OQB, UK. spear@ceh.ac.uk
Abstract:
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).
Related Concept Videos
The Phosphorus Cycle
Diversity of Protists III
Freshwater Microbial Ecology

