Improvement of field fluorometry estimates of chlorophyll a concentration in a cyanobacteria‐rich eutrophic lake

Autor: Amir M. Chegoonian, Kiana Zolfaghari, Peter R. Leavitt, Helen M. Baulch, Claude R. Duguay
Rok vydání: 2022
Předmět:
Zdroj: Limnology and Oceanography: Methods. 20:193-209
ISSN: 1541-5856
DOI: 10.1002/lom3.10480
Popis: © 2022 The Authors. Limnology and Oceanography: Methods published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Instrumented buoys are used to monitor water quality, yet there remains a need to evaluate whether in vivo fluorometric measures of chlorophyll a (Chl a) produce accurate estimates of phytoplankton abundance. Here, 6 years (2014–2019) of in vitro measurements of Chl a by spectrophotometry were compared with coeval estimates from buoy-based fluorescence measurements in eutrophic Buffalo Pound Lake, Saskatchewan, Canada. Analysis revealed that fluorometric and in vitro estimates of Chl a differed both in terms of absolute concentration and patterns of relative change through time. Three models were developed to improve agreement between metrics of Chl a concentration, including two based on Chl a and phycocyanin (PC) fluorescence and one based on multiple linear regressions with measured environmental conditions. All models were examined in terms of two performance metrics; accuracy (lowest error) and reliability (% fit within confidence intervals). The model based on PC fluorescence was most accurate (error = 35%), whereas that using environmental factors was most reliable (89% within 3σ of mean). Models were also evaluated on their ability to produce spatial maps of Chl a using remotely sensed imagery. Here, newly developed models significantly improved system performance with a 30% decrease in Chl a errors and a twofold increase in the range of reconstructed Chl a values. Superiority of the PC model likely reflected high cyanobacterial abundance, as well as the excitation–emission wavelength configuration of fluorometers. Our findings suggest that a PC fluorometer, used alone or in combination with environmental measurements, performs better than a single-excitation-band Chl a fluorometer in estimating Chl a content in highly eutrophic waters. Support of buoy operations and research was obtained from NSERC Canada, Global Water Futures (FORMBLOOM funded via the Canada First Research Excellence Fund), Global Institute for Water Security and support of the Buffalo Pound Water Treatment Plant. The buoy and operations were also supported by the Canada Foundation for Innovation. Regina research was funded by grants to P.R.L. from NSERC Canada, Canada Foundation for Innovation, Canada Research Chairs, the Province of Saskatchewan, and University of Regina. Faculty yes
Databáze: OpenAIRE