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Factors Influencing Decomposition of Surface Litter from the Cerrado in Central Brazil
Citation:
ZEPP, R. G., M. MOLINA, M. J. CYTERSKI, K. Kisselle, A. R. Kozovits, M. R. Silva, D. A. da Silva, AND M. M. Bustamante. Factors Influencing Decomposition of Surface Litter from the Cerrado in Central Brazil. Presented at Amazon in Perspective: International Science Conference, Manaus, BRAZIL, November 17 - 20, 2008.
Impact/Purpose:
The overall objective of the proposed study is to evaluate the loadings, fate and transport of bacterial contaminants from agricultural non-point sources in surface waters through the use of DNA-based technology that can quantify and track fecal contamination back to its source.
Description:
It is well-established that light-induced decomposition can accelerate the decomposition of the organic matter in aquatic environments. In this study, using the production of carbon monoxide as an indicator of decomposition, we investigated the wavelength dependence of the photodegradation of the litter derived from several plant species of the Cerrado. Using polychromatic UV and visible radiation with a series of cutoff filters, as originally described by Rundel (Physiol. Plant. 1986, 58, 360-366), we determined action spectra for the photodegradation. The action spectra indicated that the UV component of sunlight is primarily responsible for litter photodegradation. We also used the action spectra to model relationships between litter photodegradation rates and measurements of solar irradiance such as PAR or total irradiance that are commonly used to model terrestrial carbon dynamics based on satellite data. In addition to the litter photodecomposition studies, we conducted laboratory incubation studies on the effects of added fertilizers on bacterial consumption of carbon monoxide in soil samples obtained from native Cerrado areas (20-50% canopy cover). The studies were conducted in gas-tight jars maintaining the same soil moisture level throughout treatments. CO was taken up by the soil cores in all cases and the uptake was quantified as deposition velocities.
URLs/Downloads:
ZEPP 08 099.PDF (PDF, NA pp, 10 KB, about PDF)ZEPP 08 099A SLIDES BRAZIL.PDF (PDF, NA pp, 306 KB, about PDF)