Soil carbon dynamics along gradients of climate and land use

Author:

Townsend, Alan Ronald

Title:

Soil carbon dynamics along gradients of climate and land use

Year:

1994

Volume:

Ph.D.

Subject:

Soils Mauna Kea Soils analysis Carbon isotopes

Summary:

This dissertation presents a combination of field, laboratory, and modeling work on the role of soil organic matter (SOM) in the global carbon cycle. Chapter 1 describes a simple model of the terrestrial carbon cycle, which showed that the high rates of carbon turnover in tropical ecosystems may cause the equatorial regions of earth to dominate the short-term carbon cycle feedbacks to a warmer climate. Chapter 2 and 3 present a series of studies which took advantage of a naturally occurring temperature gradient in parallel C3 forests and C4 pastures on the northeast flank of Mauna Kea Volcano, island of Hawaii. Measurements of soil carbon and respiration, along with isotopes 13C and 14C, to partition SOM estimate turnover times for the large intermediate pool were used. This work suggested that estimates of the responsiveness of soil carbon to environmental changes must account for its multi-pool structure; turnover times calculated by three different multi-pool models were three times slower than those from a single pool model.

Collection:

Monographs