Premium
RNA / DNA ratio as a growth indicator of stream periphyton
Author(s) -
Mewes Daniela,
Spielvogel Sandra,
Winkelmann Carola
Publication year - 2017
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/fwb.12903
Subject(s) - periphyton , rna , biology , biomass (ecology) , chlorophyll a , ecology , nucleic acid , botany , gene , biochemistry
Summary The quantification of periphyton growth in situ poses numerous difficulties. The RNA / DNA ratio is widely used as a growth indicator in marine ecology. We tested its applicability as a growth indicator of periphyton in streams of different sizes. Periphyton‐covered stones sampled from two different watercourses during two seasons were exposed in laboratory flumes to different light levels to induce different growth rates. The relationship between rate of biomass accrual and RNA / DNA ratio was analysed by measuring the chlorophyll‐ a content and the RNA and DNA content of total nucleic acid extract of the periphyton respectively. The RNA / DNA ratios showed a linear relationship with the biomass accrual at all sampling times. The slopes of these relationships varied significantly between the two watercourses, but not between seasons within the same watercourse. These results indicate that the RNA / DNA ratio can be used as a growth indicator for the periphyton studied here. We recommend that it be used to detect differences in growth rate of the same periphyton community either over time or between different treatments in ecological or ecotoxicological experiments. However, for long‐term monitoring studies, we recommend taxonomic analyses of the assemblages because the observed differences in the relationship between the RNA / DNA ratio and growth rate might be attributed to community structure differences in the assemblages.