HR: 10:35h
AN: B21G-02    [PDF]
TI: Relative Impact of Biologically versus Physiochemically Dominated Modes of Mineralization on the Earth's Environment
AU: * Constantz, B R
EM: brentc@stanford.edu
AF: Stanford University, Biomechanical Engineering Division, 217 Durand, Stanford, CA 94305 United States
AB: Taxonomic groups forming biominerals that have had the largest impact on the earth's environment may have common styles of mineralization processes. Lowenstam recognized that organisms utilize two principal modes in biomineralization: "biologically-dominated" and "physiochemically-dominated" mineralization. The most prolific mineralizing taxa are: (1) reef framework builders, (2) reef sediment formers, (3) pelagic carbonate formers, and (4) planktonic mineralizers associated with upwelling. Taxa that have had the least impact on the earth's environment are mobile organisms with non-massive, often exceptionally strong skeletons. The prolifically mineralizing taxa (1 -4) have modes of mineralization dominated by physiochemical mineralization processes. The least prolific mineralizers have modes of mineralization dominated by biologically-controlled processes. Examples of biologically-dominated modes of mineralization are the skeletons of mobile echinoderms, mollusks, and arthropods. There are less common sessile examples of these three phyla (echinoderms, mollusks, arthropods) that have physiochemically-dominated modes of mineralization that have had important impacts on the earth's environment. Taxa that are (1) reef framework builders such as scleractinian corals and rudistid bivalves show a physiochemically-dominated mode of mineralization. Green algae, the most important (2) reef sediment formers in modern reef systems, show a physiochemically-dominated mode of mineralization. Modern coocolithophoridae, the most abundant modern contributors to (3) pelagic realm deep sea carbonates above the calcium carbonate compensation depth, have a mode of mineralization dominated by physiochemical processes. Modern diatoms dominate the biological production of minerals in upwelling environments (4), and demonstrate a physiochemically-dominated mode of mineralization. Changes in the taxonomic assemblages of mineralizing organisms in these ecological settings over the course of evolutionary time have altered the impact of biominerlization processes in each respective ecological setting. Stochastic changes in global carbon cycling and climatic fluctuations may play a role in the relative impact of physiochemically-dominated mineralizers on the earth's environment and their evolutionary success.
DE: 0400 Biogeosciences
DE: 1223 Ocean/Earth/atmosphere interactions (3339)
DE: 3675 Sedimentary petrology
DE: 4805 Biogeochemical cycles (1615)
DE: 4815 Ecosystems, structure and dynamics
SC: Biogeosciences [B]
MN: 2003 Fall Meeting