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Online monitoring of phytoplankton light response curves using a novel delayed fluorescence device
Author(s) -
Honti Mark,
Istvanovics Vera
Publication year - 2011
Publication title -
lakes and reservoirs: research and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.296
H-Index - 39
eISSN - 1440-1770
pISSN - 1320-5331
DOI - 10.1111/j.1440-1770.2011.00458.x
Subject(s) - photosynthetically active radiation , phytoplankton , environmental science , irradiance , photosynthesis , biomass (ecology) , productivity , oceanography , saturation (graph theory) , light intensity , attenuation , atmospheric sciences , ecology , geology , biology , nutrient , physics , botany , mathematics , optics , macroeconomics , combinatorics , economics
This study describes a novel delayed fluorescence (DF) device developed to automatically record photosynthetically active biomass and photosynthesis–irradiance (PI) curves of phytoplankton. The device was tested in shallow Lake Balaton, Hungary, and in moderately deep, dimictic Lake Erken, Sweden. We estimated the following: (i) saturation light intensity and maximum rate of photosynthesis from hourly PI curves; (ii) hourly vertical light profile using global radiation and vertical light attenuation data recorded simultaneously with the DF measurements; and (iii) daily integral of primary production. Estimated primary production was compared with gross community production derived from high‐frequency measurements of dissolved oxygen concentrations. Preliminary analysis indicated that online recording of PI curves might significantly reduce the uncertainty of primary production estimates. This suggestion is particularly obvious for shallow, turbid lakes, where underwater light climate changes rapidly as a function of wind‐induced sediment resuspension, and phytoplankton adapt to these changes at time scales ranging from minutes to season. The new method has a high potential for both facilitating understanding of the regulation of primary production and long‐term, high‐frequency monitoring of aquatic productivity.