APPLICATIONS: CARBON ISOTOPES IN SOILS

REQUIRED READING

von Fischer JC, Tieszen LL, Schimel DS (2008) Climate controls on C3 vs. C4 productivity in North American grasslands from carbon isotope composition of soil organic matter. Global Change Biology 14: 1141-1155

A recent examination of the climatology of C3 vs. C4 plants on the Great Plains, as seen through soil organic carbon. We’ll be comparing these results to those of several other papers from the supplemental reading (Koch et al. 2004, Nordt et al. 2009)

Quade J, Cerling TE, Bowman JR (1989) Development of Asian monsoon revealed by marked ecological shift during the latest Miocene in Northern Pakistan. Nature 342: 163-166

Another classic paper by this group. Here they show the classic C3-C4 transition in southern Asia and attribute it to a change in rainfall. Not long after, Cerling would switch to a drop in pCO2 as the cause. Quade vacillates on this issue, while the actual record of change in pCO2 becomes increasingly more uncooperative.

Fox DL, Koch PL (2003) Tertiary history of C4 biomass in the Great Plains, USA. Geology 31: 809-812

We show that the C4 “expansion” in North America C4 is massively out of phase with that in Asia (rendering pCO2 an unlikely cause). We argue that maybe we’re seeing a C3 “retraction” rather than a C4 “expansion”.

SUPPLEMENTAL READING

Krull ES, Skjemstad JO, (2005) d13C and d15N profiles in 14C-dated Oxisol and Vertisols as a function of soil chemistry and mineralogy. Geoderma, 112: 1-29.

We may read this one when we do soil N.

Koch PL, Diffenbaugh NS, Hoppe KA (2004) The effects of Late Quaternary climate and pCO2 change on C4 plant abundance in the south-central Unites States. Palaeogeography, Palaeoclimatology, Palaeoecology 207: 331– 357

We reconstruct %C4 in the diets of bison and other critters, and compare our results to different climate-vegetation models.

Nordt L, von Fischer J, Tieszen L, Tubbs J (2008) Coherent changes in relative C4 plant productivity and climate change during the late Quaternary in the North American Great Plains. Quaternary Science Reviews 27: 1600-1611

A careful examination of the history of C3 vs. C4 plants on the Great Plains, as seen through soil organic carbon, interpreted in light of the results on modern soil organic carbon from von Fischer et al. (2008).