Premium
Changes in carbon stable isotope ratios during periphyton development
Author(s) -
Hill Walter R.,
Middleton R. Gerry
Publication year - 2006
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2006.51.5.2360
Subject(s) - periphyton , δ13c , trophic level , environmental science , biomass (ecology) , stable isotope ratio , isotopes of carbon , chlorophyll a , hydrology (agriculture) , ecology , environmental chemistry , chemistry , total organic carbon , biology , geology , botany , physics , geotechnical engineering , quantum mechanics
Stable isotopes are widely used to infer trophic relationships with little attention paid to temporal variability at the base of the food web. We examined changes in the carbon‐stable isotope composition during periphyton development, sampling periphyton that accumulated on ceramic tiles at four stream sites over a 2‐month period. Periphyton 13 C rose and fell in general concordance with rising and falling biomass at all four sites, resulting in significant correlations between periphyton Δ 13 C and chlorophyll a (Chl a ). Mean Δ 13 C values at one site rose from ‐26‰ to ‐20‰ in 2 weeks, falling back to ‐24‰ the next week after a large scouring spate. Periphyton 13 C also underwent a smaller, longer‐term increase that correlated with a gradual rise in stream temperature. Multiple regression analysis with both Chl a and temperature as independent variables accounted for up to 88% of the temporal variability in Δ 13 C, with Chl a the largest source of variability. Water velocity, measured on each sampling occasion, was unrelated to temporal changes in 13 C. Depletion of inorganic carbon within the periphyton matrix is the probable cause of increasing 13 C in periphyton as biomass develops. Rising Δ 13 C values during periphyton biomass development suggest the possibility of carbon‐limited periphyton growth, even in alkaline waters. The strong link between biomass and periphyton 13 C helps explain the large range of Δ 13 C reported for periphyton in streams, where temporal and spatial variability in periphyton biomass are notorious.