|Quantifying the responses of calcareous periphyton crusts to rehydration: a microcosm study (Florida Everglades)|Thomas, S.; Gaiser, E.; Gantar, M.; Scinto, L.J. (2006). Quantifying the responses of calcareous periphyton crusts to rehydration: a microcosm study (Florida Everglades). Aquat. Bot. 84(4): 317-323. dx.doi.org/10.1016/j.aquabot.2005.12.003
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770, more
Drying; Periphyton; Phosphorus; Fresh water
|Authors|| || Top |
- Thomas, S.
- Gaiser, E.
- Gantar, M.
- Scinto, L.J.
We examined the high-resolution temporal dynamics of recovery of dried periphyton crusts following rapid rehydration in a phosphorus (P)-limited short hydroperiod Everglades wetland. Crusts were incubated in a greenhouse in tubs containing water with no P or exogenous algae to mimic the onset of the wet season in the natural marsh when heavy downpours containing very low P flood the dry wetland. Algal and bacterial productivity were tracked for 20 days and related to compositional changes and P dynamics in the water. A portion of original crusts was also used to determine how much TP could be released if no biotic recovery occurred. Composition was volumetrically dominated by cyanobacteria (90%) containing morphotypes typical of xeric environments. Algal and bacterial production recovered immediately upon rehydration but there was a net TP loss from the crusts to the water in the first 2 days. By day 5, however, cyanobacteria and other bacteria had re-absorbed 90% of the released P. Then, water TP concentration reached a steady-state level of 6.6 μg TP/L despite water TP concentration through evaporation. Phosphomonoesterase (PMEase) activity was very high during the first day after rehydration due to the release of a large pre-existing pool of extracellular PMEase. Thereafter, the activity dropped by 90% and increased gradually from this low level. The fast recovery of desiccated crusts upon rehydration required no exogenous P or allogenous algae/bacteria additions and periphyton largely controlled P concentration in the water.