Thorsten Dittmar and his group at the Max Planck Institute for Marine Microbiology analysed the samples in their laboratories at the University of Oldenburg which are an outpost station of the Bremen based Max Planck Institute. Their main research topic is the carbon cycle and the fate of the dissolved organic matter (DOM) in aquatic, mainly marine, systems. For the sample analysis of the present study they also used their ultrahigh resolution mass spectrometer.
Dittmar explains how they started their rain forest project: "A couple of years ago we detected telltale carbon compounds typical for burnt plant material and charcoal dissolved in ocean water. We speculated that the pre-harvest burning of sugar cane plantations and forest fires in Brazil was a major source. So, we as marine scientists, contacted our colleagues in Brazil, who had taken soil and water samples for years around the Paraiba do Sul river."
The results were surprising. Substantially more carbon compounds where discharged by the river than the annual procedure of pre-harvest burning of sugar cane plantations could produce. "When we plotted the results from the samples against time and compared this pattern with the amount of precipitation and the occurrence of fires, the relation became obvious. The charred carbon must have originated from the slash and burn period from much earlier times."
This assumption was confirmed by further experiments and data. The large scale slash and burn practice ended in 1973. The still practiced pre-harvest burning of the sugar cane plantations produces only 190-740 tons charred carbon annually, but the amount found in the river was three to sixteen times higher. The scientists extrapolated 50,000 to 70,000 tons for the annual load carried by rivers from the total area of the relict rain forest into the Atlantic Ocean. In the laboratory th
|Contact: Dr. Thorsten Dittmar|