Premium
Effect of altitude on the carbon‐isotope composition of forest and grassland soils from Papua New Guinea
Author(s) -
Bird M. I.,
Haberle S. G.,
Chivas A. R.
Publication year - 1994
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/93gb03487
Subject(s) - altitude (triangle) , soil water , grassland , environmental science , litter , vegetation (pathology) , δ13c , carbon fibers , isotopes of carbon , plant litter , effects of high altitude on humans , soil carbon , total organic carbon , soil science , agronomy , ecology , environmental chemistry , stable isotope ratio , chemistry , ecosystem , biology , mathematics , pathology , composite number , geometry , quantum mechanics , medicine , physics , anatomy , materials science , composite material
The carbon‐isotope composition of both forest and grassland soils from Papua New Guinea exhibit predictable trends with increasing altitude. Soils under pure C 3 vegetation (forests and alpine grasslands above 4000 m) show an increase in δ 13 C value with altitude paralleling the increase in δ 13 C value observed in plant leaves by Körner et al. [1988]. Grassland soils show a decrease in δ 13 C value above about 1000 m, from maximum values which are close to pure C 4 values (−12 to −13‰ vs. PDB) to minimum values which are indistinguishable from pure C 3 values at 3500–4000 m (∼−26‰). Within this general framework, several factors can influence the soil δ 13 C value at individual locations. In local forest settings, soil δ 13 C values will be influenced by the degree to which respired CO 2 is re‐utilized during photosynthesis, the proportions of leaf and wood litter, and the degree of decomposition. In grassland settings the primary factor controlling the observed δ 13 C variability at any specific altitude is the amount of nongrass C 3 carbon present in the sample. It is also possible that other factors, such as moisture availability, may play some role in determining the proportions of C 3 and C 4 grasses at any given altitude, although further work would be required to substantiate such a link. The results provide a framework within which to more accurately constrain the carbon‐isotope composition of terrestrial carbon pools and to interpret variations in the isotopic composition of riverine particulate organic carbon.