Pigment-based chemotaxonomy--a quick alternative to determine algal assemblages in large shallow eutrophic lake?

• Published in: PloS one Vol. 10; no. 3; p. e0122526
• Main Authors: Tamm, Marju, Freiberg, René, Tõnno, Ilmar, Nõges, Peeter, Nõges, Tiina
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24-03-2015; Public Library of Science (PLoS)
• Subjects: Algae; Analysis; Annual variations; Aquatic ecosystems; Bacillariophyta; Biomass; Change detection; Chemotaxonomy; Chlorophyll; Chlorophyll - analysis; Chlorophyll A; Chromatography; Classification - methods; Communities; Community composition; Cyanobacteria; Dinoflagellates; Ecological monitoring; Ecosystems; Environmental assessment; Environmental changes; Environmental monitoring; Environmental science; Estonia; Eutrophic environments; Eutrophic lakes; Eutrophication; Fresh water; Freshwater; Freshwater ecosystems; Freshwater environments; Indicator organisms; Lakes; Lakes - microbiology; Life sciences; Limnology; Marine environment; Methods; Microbiota; Microscopy; Phytoplankton; Phytoplankton - chemistry; Phytoplankton - classification; Phytoplankton - cytology; Pigments; Pigments, Biological - analysis; Plankton; Ratios; Remote sensing; Seasonal variations; Software; Taxonomy; Water management; Water quality; Estonia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0122526

Pigment-based chemotaxonomy and CHEMTAX software have proven to be a valuable phytoplankton monitoring tool in marine environments, but are yet underdeveloped to determine algal assemblages in freshwater ecosystems. The main objectives of this study were (1) to compare the results of direct microscopy and CHEMTAX in describing phytoplankton community composition dynamics in a large, shallow and eutrophic lake; (2) to analyze the efficiency of the pigment-based method to detect changes in phytoplankton seasonal dynamics and during rapid bloom periods; (3) to assess the suitability of specific marker pigments and available marker pigment:chlorophyll a ratios to follow seasonal changes in eutrophic freshwater environment. A 5-year (2009-2013) parallel phytoplankton assessment by direct microscopy and by CHEMTAX was conducted using published marker pigment:chlorophyll a ratios. Despite displaying some differences from microscopy results, the pigment-based method successfully described the overall pattern of phytoplankton community dynamics during seasonal cycle in a eutrophic lake. Good agreement between the methods was achieved for most phytoplankton groups - cyanobacteria, chlorophytes, diatoms and cryptophytes. The agreement was poor in case of chrysophytes and dinoflagellates. Our study shows clearly that published marker pigment:chlorophyll a ratios can be used to describe algal class abundances, but they need to be calibrated for specific freshwater environment. Broader use of this method would enable to expand monitoring networks and increase measurement frequencies of freshwater ecosystems to meet the goals of the Water Framework Directive.