Convenors:
Edwin Cotard

In the last decade, the use of isotopes measured in biogenic silica has been widely used in global biogeochemical cycle research. Multiple new techniques have been introduced or refined and are now being applied to solving broad questions in biogeochemistry, marine or terrestrial ecology, abiotic processes and paleoceanography.

This session welcomes contributions dedicated to emerging isotopes, analytical methods, instrumentation, modeling, or other applied approaches used for the development and application of new or existing technologies to geochemical problems. Submissions which develop novel approaches, tracers, or proxies and those which aim to better understand the methodological biases and constraints of existing techniques are all relevant. Moreover, in the context of current climate and environmental crises, this session also invites contributions that showcase results and develop best practices in climate mitigation and innovative biotechnologies.

Convenors: Lisa Friberg

Siliceous marine organisms, such as diatoms, silicoflagellates, radiolarians, and  sponges, play a pivotal role in shaping intricate and climate-sensitive interconnections among the biogeochemical cycles of silicon, carbon, and various nutrients within the oceans. In this session, we invite contributions that use elemental and isotope data derived from seawater, biogenic silica, and sediments to investigate nutrient cycles in the modern ocean. We eagerly welcome a diverse range of studies, encompassing both observational fieldwork and advanced modeling approaches.

Convenors: Franziska M. Stamm, Sonja Geilert, Tzu-Hao Huang

Abiogenic silica-bearing precipitates range from amorphous silica (i.e., opals) and  short-range order phases (e.g., hydroxyaluminosilicates) , to the neoformation of minerals with different orders of crystallinity (e.g., allophane, zeolites, clay minerals such as kaolinite, glauconite etc). The formation, dissolution and re-organisation of these abiogenic silica phases, either coupled to biogenic silica or independently, has gained more and more interest in recent years due to its significant contribution to the marine and terrestrial silicon, cation and carbon cycles. In this session, we welcome experimental and theoretical (modelling) approaches as well as field studies, investigating and tracing abiogenic silica reactions using major and trace element variations, Ge/Si ratios and stable isotopes such as Si, O, B, Li, Mg, Fe, etc.

Convenors: Yan Ye, Sophie Westacott

The Silica Cycle through time is influenced by abiotic and biotic (biomineralization) precipitation, weathering, hydrothermal activity and changes in oceanography. Especially, the biomineralization and evolution of silicifiers are thought to have had a great influence on the past Silica Cycle.

This session invites contributions of paleo-application studying the Silica Cycle in all environments (marine, lacustrine, terrestrial) as well as biotic (biomineralization) or abiotic processes. Applications can include isotope analyses (Si, O, N, B, Li etc.), modeling and taxonomic approaches.

Convenors: Phillippe Roux, Jotis Baronas

From its status as a pivotal beneficial element for plants in ecology to its use to decipher critical zone biogeochemical processes, the role of silicon (Si) in terrestrial ecosystems has attracted increasing attention, particularly in the context of climate change. The terrestrial Si balance has been shown to be largely driven by soil plant feedback interactions with strong implications for the global carbon (C) balance through 3 main processes: soil organic matter (SOM) decomposition, silicate weathering and plant productivity. Consequently, understanding how future climatic scenarios affect silica dynamics in terrestrial ecosystems is paramount to enhance our comprehension of ecosystem responses in the context of climate change.

In this session, we welcome studies utilizing elemental and/or isotopic data, with the aim of enriching our understanding of the ecosystem processes involving silica occurring in terrestrial environments.