Competition between Silicifiers and Non-silicifiers in the Past and Present Ocean and Its Evolutionary Impacts

Abstract

Competition is a central part of the evolutionary process, and silicification is no exception: between biomineralized and non-biomineralized organisms, between siliceous and non-siliceous biomineralizing organisms, and between different silicifying groups. Here we discuss evolutionary competition at various scales, and how this has affected biogeochemical cycles of silicon, carbon, and other nutrients. Across geological time we examine how fossils, sediments, and isotopic geochemistry can provide evidence for the emergence and expansion of silica biomineralization in the ocean, and competition between silicifying organisms for silicic acid. Metagenomic data from marine environments can be used to illustrate evolutionary competition between groups of silicifying and non-silicifying marine organisms. Modern ecosystems also provide examples of arms races between silicifiers as predators and prey, and how silicification can be used to provide a competitive advantage for obtaining resources. Through studying the molecular biology of silicifying and non-silicifying species we can relate how they have responded to the competitive interactions that are observed, and how solutions have evolved through convergent evolutionary dynamics.

A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements

“…Substantial advances have occurred in our understanding of the evolution of the geological Si cycle through the use of the fossil record, silica isotope geochemistry and the phylogenomics of biosilicification Hendry et al, 2018). The first biological impacts on the Si cycle are hypothesized to have occurred with the evolution of cyanobacteria in the Archean with further decreases in the mid-Proterozoic with evolution of eukaryotes capable of Si biomineralization.…”

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“…The keynote talks pointed out some recent findings, including the importance of recycled iron for biological productivity on seasonal-to-ice-age timescales (Rafter et al 2017), and complex biomineralization processes of silicifiers and their impact on the silicon isotopic ratio (Hendry et al 2018). Multi-tracer analysis of the same water sample is one of the strongest strategies of the GEOTRaCES program, and multi-proxy reconstruction provides the most reliable results.…”

Digging deeper: why we need more Proterozoic algal fossils and how to get them

“…, Hendry et al. ). This perspective also does not attempt to survey the many excellent paleolimnological studies of modern lakes that employ algal remains as diagnostic bioindicators of environmental change (e.g., Siver and Lott ), or involve cosampling structural and DNA remains from lake sediments (e.g., Stivrins et al.…”