Preliminary evaluation of an in vivo fluorometer to quantify algal periphyton biomass and community composition

Lake and Reservoir Management
By:  and 



The bbe-Moldaenke BenthoTorch (BT) is an in vivo fluorometer designed to quantify algal biomass and community composition in benthic environments. The BT quantifies total algal biomass via chlorophyll a (Chl-a) concentration and may differentiate among cyanobacteria, green algae, and diatoms based on pigment fluorescence. To evaluate how BT measurements of periphytic algal biomass (as Chl-a) compared with an ethanol extraction laboratory analysis, we collected BT- and laboratory-measured Chl-a data from 6 stream sites in the Indian Creek basin, Johnson County, Kansas, during August and September 2012. BT-measured Chl-a concentrations were positively related to laboratory-measured concentrations (R2 = 0.47); sites with abundant filamentous algae had weaker relations (R2 = 0.27). Additionally, on a single sample date, we used the BT to determine periphyton biomass and community composition upstream and downstream from 2 wastewater treatment facilities (WWTF) that discharge into Indian Creek. We found that algal biomass increased immediately downstream from the WWTF discharge then slowly decreased as distance from the WWTF increased. Changes in periphyton community structure also occurred; however, there were discrepancies between BT- and laboratory-measured community composition data. Most notably, cyanobacteria were present at all sites based on BT measurements but were present at only one site based on laboratory-analyzed samples. Overall, we found that the BT compared reasonably well with laboratory methods for relative patterns in Chl-a but not as well with absolute Chl-aconcentrations. Future studies need to test the BT over a wider range of Chl-aconcentrations, in colored waters, and across various periphyton assemblages.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Preliminary evaluation of an in vivo fluorometer to quantify algal periphyton biomass and community composition
Series title Lake and Reservoir Management
DOI 10.1080/10402381.2015.1025153
Volume 31
Issue 2
Year Published 2015
Language English
Publisher Taylor & Francis
Contributing office(s) Kansas Water Science Center
Description 7 p.
First page 127
Last page 133
Country United States
State Kansas
County Johnson County
Other Geospatial Indian Creek basin
Online Only (Y/N) N
Additional Online Files (Y/N) N
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