Abstract

Over the last several decades, biogeochemical studies on terrestrial carbon cycle have converged on a consensus that tight association of organic matter (OM) with minerals through physical occlusion or surface complexation is critical in lengthening the turnover time of carbon (C).

The primary goal of the Christian River Basin Critical Zone Observatory (CRB-CZO) is to scale up C-mineral interactions that occur at molecular and mineral grain scales to soil profiles to hillslopes and finally to basin scales. While small (nano to mineral grain) scale characterizations of C mineral interactions are being made, physical movement of OM and minerals –such as soil mixing at soil profile scale, physical erosion and deposition in watershed scales, and stream turbulence in streams – is investigated as responsible for their contacts. Chemical weathering of minerals and minerals’ interaction with water are considered as processes that generate the surface area and reactivity of minerals where OM could be complexed. Additionally, biological cycling of OM prepares OM’s chemical affinity to minerals.

Preliminary analyses suggest that the extents of physical contacts between OM and minerals – which are required for C-mineral complexation – are indeed limited by their physical movements and that these movements are highly sensitive to land use types. Furthermore, eroded minerals from agricultural fields appear to complex C during their fluvial transit. The preliminary data support the core assumptions of our hypothesis that accelerated erosion and deposition in agricultural and constructional watershed may generate greater amount of mineral-complexed C.

In the end, we expect that our intensive field sampling and installation of wireless sensor network and data management toward testing our hypothesis should build our CRB-CZO as an excellent resource for entire scientific community.

Citation

Yoo, K., Aufdenkampe, A., Chen, C. and Sparks, D.L.. (2011): Christina River Basin Critical Zone Observatory: Carbon-mineral interactions from molecular to basin scales in the Anthropocene. Invited Talk, Goldschmidt 2011 conference, Prague, Czech Republic, August 14-19. p. 1224..