Phosphorus uptake by plankton and periphyton in relation to irradiance and phosphate availability in a subtropical lake (Lake Okeechobee, Florida, USA)
Havens, K. E.; Steinman, A. D.; Hwang, S.-J.
published: Apr 27, 2001
ArtNo. ESP141015102007, Price: 29.00 €
Phosphorus (P) uptake by plankton and periphyton was studied at the whole-community level, and a conceptual model was developed relating community P dynamics to irradiance and phosphate (PO4) availability. Studies were done in the littoral wetland and pelagic-littoral ecotone regions of a shallow subtropical lake using 32P-labelled inorganic (DIP) and organic (DOP) phosphorus as tracers, under laboratory conditions simulating ambient temperature. In the pelagic-littoral ecotone, where light attenuation and P availability are highly variable, P dynamics displayed a strong temporal pattern. During a "turbid" period when underwater irradiance was low, water column PO4 was high, and community P uptake was very low. During a "clear water" period when underwater irradiance was higher, water column PO4 was lower, and there was rapid uptake of both PO4 and DOP by plankton. In the littoral region underwater irradiance always was high, PO4 always was low, and there was active year-round uptake of PO4 and DOP both by plankton and periphyton. We also observed adaptations to P deficiency at the community level, in terms of greater use of DOP as a P source when PO4 availability declined.