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Photosynthetic response of two submersed macrophytes to dissolved inorganic carbon concentration and pH 1
Author(s) -
Titus John E.,
Stone Walter H.
Publication year - 1982
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.1982.27.1.0151
Subject(s) - myriophyllum , photosynthesis , macrophyte , total inorganic carbon , saturation (graph theory) , dissolved organic carbon , chemistry , botany , environmental chemistry , carbon fibers , aquatic plant , ecology , carbon dioxide , biology , materials science , mathematics , combinatorics , composite number , composite material , organic chemistry
The photosynthetic responses of Myriophyllum spicatum and Vallisneria americana to total dissolved inorganic carbon (DIC) concentration (pH 8.0; 25°C; saturating light) indicate that both species are sensitive to changes in DIC concentrations at natural lake levels, and that M. spicatum has a somewhat lower half‐saturation constant than V . americana for that relationship. This difference is probably not ecologically significant. Carbon uptake rates of V . americana decline by 61% from pH 7 to 8, but change little from pH 8 to 9, whereas those of M . spicatum decline by 35% from pH 7 to 8 and by a further 58% from pH 8 to 9. These decreases do not parallel the corresponding decline in free CO 2 availability over this pH range. Carbon compensation points expressed as total DIC, free CO 2 , or the atmospheric CO 2 concentration in equilibrium with the corresponding free CO 2 level are strongly pH‐dependent and do not differ substantially between M. spicatum and V . americana.