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Eichenseer Et Al. (2019) Presentation NANJING UNIVERSITY Jurassic Shift From Abiotic to Biotic Control on Marine Ecological Success Reporter: Zhang Shuhan Content l Background Ø Mesozoic Marine Revolution Ø Calcite And Aragonite Sea Ø Skeleton Building l Main Study Ø Hypothesis Ø New Concept Ø Environment Drivers Ø Biotic Change Ø Model Ø Result l Discussion Ø Data Uncertainty Ø Different Explanation Of Linear Model lSummary Mesozoic Marine Revolution • The Mesozoic Marine Revolution (MMR) is the rapid adaption to shell- crushing (durophagous) and boring predation in benthic organisms throughout the Mesozoic era (251 Mya to 66 Mya). (Vermeij GJ ,1977) Calcite And Aragonite Sea • In the inorganic formation of calcium carbonate (CaCO3), high magnesium-to-calcium (Mg/Ca) ratios and high temperatures have been shown to favour the precipitation of aragonite over calcite, and vice versa. • Across the Phanerozoic, tectonically driven changes in sea- water chemistry and climate have caused aragoniteand calcite- favouring conditions to alternate, which gives rise to episodes of aragonite seas and calcite seas Skeleton Building • The skeletal mineralogy of calcifying organisms is strongly tied to the phylogenetic history, but the de novo acquisition of biominerals, skeletal composition, skeletal production and growth rates of many marine calcifiers are affected by the Mg/Ca ratio and temperature of the surrounding sea-water. Content l Background Ø Mesozoic Marine Revolution Ø Calcite And Aragonite Sea Ø Skeleton Building l Main Study Ø Hypothesis Ø New Concept Ø Environment Drivers Ø Biotic Change Ø Model Ø Result l Discussion Ø Data Uncertainty Ø Different Explanation Of Linear Model lSummary Hypothesis • The evolutionary importance of the abiotic environment, relative to intrinsic biotic factors, has • The ‘Red Queen vs. the declined through Court Jester’ (Barnosky 2000 JVP; Benton 2009 geological time. Science) New Concept • ASI • a model of past Mg/Ca ratios with δ18O temperature reconstructions to quantify the aragonite sea intensity (ASI) in 85 post-Cambrian stages. • SCORara • a measure of the environmental occupancy, or success, of aragonitic genera relative to all calcifying genera (SCORara), calculated with the summed common species occurrence rate (SCOR) Environment Drivers--Temperature • Mean stage-level tropical shallow water temperatures calculated from oxygen isotope measurements compiled in Veizer and Prokoph. Stages with only one measurement are drawn as solid dots, stages without observations are averaged from the neighbouring stages and are shown as circles. Shaded areas represent 2 s.e.m. (Veizer et al.,2015) (Wotte et al.,2019) Environment Drivers-- Other drivers • Periodic changes in the envelope of third-order δ13C variations • The box plots show the variability of I/Ca ratios from shallow water carbonates within sampling localities Biotic Change • Sampling- standardized marine genus- level diversity with the long- from PBDB,2017 term trend line (brown). LOESS regression with a smoothing span of 0.1. • The newest dataset • Totally different from what we know (Sepkoski,1981) before (Alroy et al.,2008) Model • linear models were generated using ordinary least squares (OLS) or GLS • The CCM skill shows a sustained drop when the Jurassic–Early Cretaceous stages are added, which implies a continuously weakening dynamic influence of ASI on SCORara Result A decreasing environmental influence on marine calcifiers success. a significant dynamic influence of ASI on SCORara in the Ordovician– Jurassic After a maximum in the early Jurassic (Sinemurian), the CCM prediction skill decreased gradually until the Early Cretaceous and remained low thereafter. the success of aragonitic calcifiers decreased chiefly in two episodes: around the Carboniferous–Permian boundary, and in a second episode centred in the Middle Jurassic Result • the proliferation of calcifying plankton • Enhance ocean buffering • extinctions in the Late Permian • the survival of active and physiologically buffered animals • iodine-to-calcium (I/C) ratios • Increasing oxygenation of shallow ocean water • This rise in the available metabolic energy • The cost of secreting a shell out of sync with aragonite-calcite sea conditions. Content l Background Ø Mesozoic Marine Revolution Ø Calcite And Aragonite Sea Ø Skeleton Building l Main Study Ø Hypothesis Ø New Concept Ø Environment Drivers Ø Biotic Change Ø Model Ø Result l Discussion Ø Data Uncertainty Ø Different Explanation Of Linear Model lSummary Data Uncertainty • With relatively limited data • Test for the completeness of record of aragonitic and calcitic genera • What can be done so far • The conclusion seems right despite all these uncertain data Different Explanation Of Linear Model Data bias (e.g. pull of recent) Relative small data set Content l Background Ø Mesozoic Marine Revolution Ø Calcite And Aragonite Sea Ø Skeleton Building l Main Study Ø Hypothesis Ø New Concept Ø Environment Drivers Ø Biotic Change Ø Model Ø Result l Discussion Ø Data Uncertainty Ø Different Explanation Of Linear Model lSummary Summary • Biotic evolution • Abiotic factors’ influence • A new evolutionary regime NANJING UNIVERSITY Thank You.
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