title: Impact of lower atmospheric carbon dioxide on tropical mountain ecosystems
abstract: Carbon-isotope values of bulk organic matter from high-altitude lakes on Mount Kenya and Mount Elgon, East Africa, were 10 to 14 per mil higher during glacial times than they are today. Compound-specific isotope analyses of leaf waxes and algal biomarkers show that organisms possessing CO2-concentrating mechanisms, including C4 grasses and freshwater algae, were primarily responsible for this large increase. Carbon limitation due to lower ambient CO2 partial pressures had a significant impact on the distribution of forest on the tropical mountains, in addition to climate. Hence, tree line elevation should not be used to infer palaeotemperatures.
authors.affiliation: F. A. Street-Perrott and R. A. Perrott are in the Tropical Palaeoenvironments Research Group, Department of Geography, University of Wales Swansea, Swansea SA2 8PP, UK. Y. Huang and G. Eglinton are at the Biogeochemistry Research C.
authors.initials: FA
authors.lastname: Street-Perrott
authors.initials: Y
authors.lastname: Huang
authors.initials: RA
authors.lastname: Perrott
authors.initials: G
authors.lastname: Eglinton
authors.initials: P
authors.lastname: Barker
authors.initials: LB
authors.lastname: Khelifa
authors.initials: DD
authors.lastname: Harkness
authors.initials: DO
authors.lastname: Olago