Abstract Detail

The rise and fall of photosynthate: Evolution of plant/fungus interactions from paleobotanical and phylogenomic perspectives

Mills, Benjamin [1], Lenton, Timothy [2].

Geochemical cycles at the dawn of terrestrialization.

Photosynthetic life on the land surface must obtain nutrients, particularly phosphate, from local mineral sources. In doing do, they have a dramatic effect on the long term geochemical cycles of phosphorus, carbon and oxygen. Increased phosphate supply to the ocean drives greater primary productivity, which ultimately controls the burial rate of reduced organic carbon in sediments. This is the primary source of atmospheric oxygen over geological timescales, and thus the establishment of a complex land biosphere may be the critical step in the rise of atmospheric oxygen concentration to breathable levels during the Paleozoic. Moreover, biotic amplification of silicate rock weathering increases the supply of Ca and Mg cations to the ocean, which leads to the burial of inorganic carbonates in sediments. This process is a major long-term sink for CO₂, and therefore the rise of both vascular and earlier non-vascular land plants has also been linked to severe glacial episodes. Using a combination of Earth System modelling and laboratory studies of present day analogue species, we attempt to link the evolution of early plant types to their effects on global elemental cycles and climate (as preserved in geochemical tracers such as carbon isotopes, redox proxies and global surface temperature). We find that even before the rise of forests, land plants may have had a significant impact on global climate [Lenton et al. 2012], whilst theoretical studies show that the Proterozoic and early Phanerozoic Earth System may have had a high sensitivity to any potential biological activity on land [Mills et al. 2014]. Lenton, T. M. et al. Nature Geoscience 5, 86-89 (2012). Mills, B. et al. PNAS 111, 9073-9078 (2014).

1 - University of Bristol, School of Geographical Sciences, Clifton, Bristol, BS8 1SS, UK
2 - University of Exeter, Earth Systems Science, Laver Building, North Park Road, Exeter, EX4 4QE, UK

Keywords:
Earth system
Carbon cycle
terrestrialization of plants and fungi.

Presentation Type: Symposium Presentation
Session: SY12
Location: Hall A/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 2:45 PM
Number: SY12004
Abstract ID:812
Candidate for Awards:None