Research

Lipson Lab HOME	Current and Recent Research Projects
	Global Change Research at Biosphere 2 Research Center
The Biosphere 2 Research Center is located in Oracle, Arizona. It is owned by Edward Bass, and, until recently, was operated by Columbia University as a state-of-the-art research facility, including a large-scale elevated atmospheric carbon dioxide experiment for use in global change research. This facility is currently for sale. For more information, visit their web site: http://www.bio2.com/	(photo stolen from BS2 webpage)
	Publications resulting from this work:
Lipson DA, M Blair, G Barron-Gafford, K Grieve, R Murthy (2006) Relationships between microbial community structure and soil processes under elevated atmospheric carbon dioxide Microbial Ecology (in press)
ABSTRACT: There is little current understanding of the relationship between soil microbial community composition and soil processes rates, nor of the effect climate change and elevated CO₂ will have on microbial communities and their functioning. Using the eastern cottonwood plantation at the Biosphere 2 Laboratory, we studied the relationships between microbial community structure and process rates, and the the effects of elevated atmospheric CO₂ on microbial biomass, activity and community structure. Soils were sampled from three treatments (400, 800, and 1200 ppm CO₂), a variety of microbial biomass and activity parameters were measured, and the bacterial community was described by 16S rRNA libraries. Glucose substrate-induced respiration (SIR) was significantly higher in the 1200 ppm CO₂treatment. There were also a variety of complex, non-linear responses to elevated CO₂. There was no consistent effect of elevated CO₂ on bacterial diversity, however, there was extensive variation in microbial community structure within the plantation. The southern ends of the 800 ppm and 1200 ppm CO₂ bays were dominated by b-Proteobacteria, and had higher fungal biomass, whereas the other areas contained more a-Proteobacteria and Acidobacteria. A number of soil process rates, including salicylate, glutamate and glycine SIR and proteolysis, were significantly related to the abundance of the three most frequent bacterial taxa, and to fungal biomass. Overall, variation in microbial activity was better explained by microbial community composition than by CO₂ treatment. However, the altered diversity and activity in the southern bays of the two high CO₂ treatments could indicate an interaction between CO₂ and light.
Barron-Gafford G., Martens D., Grieve K., McLain J.E., Lipson D., Murthy R. (2005) Growth of Eastern Cottonwoods (Populus deltoides) in elevated CO2 stimulates stand-level respiration and rhizodeposition of carbohydrates, accelerates soil nutrient depletion, yet stimulates above and belowground biomass production. Global Change Biology 11:1220-1233.