Montane forest root growth and soil organic layer depth as potential factors stabilizing Cenozoic global change

Tree roots and their symbiotic fungal partners are believed to play a major role in regulating long‐term global climate, but feedbacks between global temperature and biotic weathering have not yet been explored in detail. In situ field data from a 3000 m altitudinal transect in Peru show fine root growth decreases and organic layer depth increases with the cooler temperatures that prevail at increased altitude. We hypothesize that this observation suggests a negative feedback: as global temperatures rise, the soil organic layer will shrink, and more roots will grow in the mineral layer, thereby accelerating weathering and reducing atmospheric CO2. We examine this mechanism with a process‐based biological weathering model and demonstrate that this negative feedback could have contributed to moderating long‐term global Cenozoic climate during major Cenozoic CO2 changes linked to volcanic degassing and tectonic uplift events.

[1]  D. Beerling,et al.  Evolution of trees and mycorrhizal fungi intensifies silicate mineral weathering , 2012, Biology Letters.

[2]  P. Valdes,et al.  Evaluating the effects of terrestrial ecosystems, climate and carbon dioxide on weathering over geological time: a global-scale process-based approach , 2012, Philosophical Transactions of the Royal Society B: Biological Sciences.

[3]  D. Beerling,et al.  Convergent Cenozoic CO 2 history , 2011 .

[4]  D. Beerling,et al.  Convergent Cenozoic CO2 history , 2011 .

[5]  D. Beerling,et al.  Modeling the evolutionary rise of ectomycorrhiza on sub-surface weathering environments and the geochemical carbon cycle , 2011, American Journal of Science.

[6]  Y. Malhi,et al.  The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. , 2011, The New phytologist.

[7]  Luiz E. O. C. Aragão,et al.  Net primary productivity allocation and cycling of carbon along a tropical forest elevational transect in the Peruvian Andes , 2010 .

[8]  Sassan Saatchi,et al.  Introduction: Elevation gradients in the tropics: laboratories for ecosystem ecology and global change research , 2010 .

[9]  Lingli Liu,et al.  A global perspective on belowground carbon dynamics under nitrogen enrichment. , 2010, Ecology letters.

[10]  D. Beerling,et al.  Process‐based modeling of silicate mineral weathering responses to increasing atmospheric CO2 and climate change , 2009 .

[11]  K. Caldeira,et al.  The role of terrestrial plants in limiting atmospheric CO2 decline over the past 24 million years , 2009, Nature.

[12]  D. Beerling,et al.  Mycorrhizal evolution, biological weathering and the long-term carbon cycle , 2009 .

[13]  D. Soltis,et al.  Rosid radiation and the rapid rise of angiosperm-dominated forests , 2009, Proceedings of the National Academy of Sciences.

[14]  D. Beerling,et al.  Biological weathering and the long‐term carbon cycle: integrating mycorrhizal evolution and function into the current paradigm , 2009, Geobiology.

[15]  L. Aragão,et al.  The effects of water availability on root growth and morphology in an Amazon rainforest , 2008, Plant and Soil.

[16]  B. Currie,et al.  Palaeo-altimetry of the late Eocene to Miocene Lunpola basin, central Tibet , 2006, Nature.

[17]  J. Libarkin,et al.  Rapid late Miocene rise of the Bolivian Altiplano: Evidence for removal of mantle lithosphere , 2006 .

[18]  A. Kerkhoff,et al.  Plant allometry, stoichiometry and the temperature-dependence of primary productivity , 2005 .

[19]  Campbell O. Webb,et al.  Explosive Radiation of Malpighiales Supports a Mid‐Cretaceous Origin of Modern Tropical Rain Forests , 2005, The American Naturalist.

[20]  B. Lindahl,et al.  Carbon allocation to ectomycorrhizal roots and mycelium colonising different mineral substrates. , 2004, The New phytologist.

[21]  Timothy M. Lenton,et al.  COPSE: a new model of biogeochemical cycling over Phanerozoic time , 2004 .

[22]  R. Berner,et al.  5.06 – Plants and Mineral Weathering: Present and Past , 2003 .

[23]  Celine Dessert,et al.  Erosion of Deccan Traps determined by river geochemistry: impact on the global climate and the , 2001 .

[24]  Mark R. Lomas,et al.  Testing the Responses of a Dynamic Global Vegetation Model to Environmental Change: A Comparison of Observations and Predictions , 1997 .

[25]  T. Fahey,et al.  Controls on Soil Solution Chemistry in a Subalpine Forest in North-Central Colorado , 1993 .

[26]  Jennifer M. Robinson,et al.  Lignin, land plants, and fungi: Biological evolution affecting Phanerozoic oxygen balance , 1990 .

[27]  J. Shukla,et al.  Influence of Land-Surface Evapotranspiration on the Earth's Climate , 1982, Science.

[28]  V. Pope,et al.  The impact of new physical parametrizations in the Hadley Centre climate model: HadAM3 , 2000 .

[29]  R. Berner.  Geocarb III: A Revised Model of Atmospheric CO2 over Phanerozoic Time , 1994 .