Earth Surface Processes and Landforms Earth1436 Surf. Process. Landforms 33, 1436 –1457 (2008) F. Alayne Street-Perrott and Philip A. Barker Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/esp.1712 Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon F. Alayne Street-Perrott1* and Philip A. Barker 2 1 Tropical Palaeoenvironments Research Group, School of the Environment and Society, Swansea University, Singleton Park, Swansea SA2 8PP, UK 2 Department of Geography, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YB, UK *Correspondence to: Abstract F. Alayne Street-Perrott, 6 Tropical Palaeoenvironments On geological time-scales (≥10 years), the global geochemical cycles of carbon and silicon Research Group, School are coupled by the drawdown of atmospheric CO2 through chemical weathering of Ca- and of the Environment and Mg-silicate minerals in continental rocks. Rivers transport the soluble products of weather- Society, Swansea University, ing (cations, alkalinity and silicic acid) to the oceans, where they are utilized by marine Singleton Park, Swansea ecosystems. On decadal to glacial–interglacial time-scales, however, large biotic fluxes and SA2 8PP, UK. E-mail: storages of Si within terrestrial and freshwater ecosystems need to be taken into account.
[email protected] Recent studies have emphasized the importance of Si-accumulating plants, which deposit significant amounts of amorphous hydrated silica in their tissues as opal phytoliths. These include grasses, sedges, palms, some temperate deciduous trees and conifers, and many tropical hardwoods. Landscapes dominated by accumulator plants, such as tropical rainfor- ests, grasslands, herbaceous wetlands and bamboo forests, act as ‘silica factories’.