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- Title
An inter-basin comparison of nutrient limitation and the irradiance response of pulse-amplitude modulated (PAM) fluorescence in Lake Erie phytoplankton.
- Authors
Rattan, K.
- Abstract
This research examined the application of the maximum quantum efficiency ( F/ F) and relative electron transport rate versus irradiance curves (rETR) as a rapid, sensitive assessment of Lake Erie phytoplankton nutrient status. I evaluated the potential benefits of the variable fluorescence parameters by comparing these parameters with chemical and physiological nutrient status assays. I tested the hypothesis that F/ F and rETR curves could diagnose nutrient status in natural lake phytoplankton and be capable of discriminating which inorganic nutrient is limited temporally and spatially. F/ F was on average highest in the more eutrophic west basin (WB) and lowest in the more oligotrophic central basin (CB). According to the chemical and physiological indicators, P deficiency was most severe in the CB during summer stratification and N deficiency was strongest in the WB during isothermal conditions. Like F/ F, rETR at light saturation (rETR) and the initial slope of the rETR versus irradiance curve (α) decreased as the severity of N and P deficiency increased. Amendment with N or P stimulated increased F/ F, rETR, and α in N- and P-limited samples, respectively, and abolished the photoinhibition apparent in rETR curves of nutrient-limited samples. These results supported the view that the N and P deficiency assays, and corresponding variations of variable fluorescence parameters, were valid indicators of widely variable N and P deficiency in the phytoplankton, and could be used to provide a promising tool in determining phytoplankton nutrient status. Contrary to my hopes, it did not appear that rETR-irradiance curves could discriminate between N and P deficiency. Identification of the most limiting nutrient still demanded additional information beyond the variable fluorescence measurements.
- Subjects
LAKE Erie; PULSE amplitude modulation; PHYTOPLANKTON populations; QUANTUM efficiency; QUANTUM chemistry; PLANT nutrients; LAKE ecology; MARINE pollution research
- Publication
Aquatic Ecology, 2014, Vol 48, Issue 1, p107
- ISSN
1386-2588
- Publication type
Article
- DOI
10.1007/s10452-014-9470-7