| Autor: |
Ullmann CV; University of Exeter, Camborne School of Mines & Environment and Sustainability Institute, Penryn Campus, Treliever Road, Penryn, TR10 9FE, United Kingdom. c.v.ullmann@gmx.net.; University of Oxford, Department of Earth Sciences, South Parks Road, Oxford, OX1 3AN, United Kingdom. c.v.ullmann@gmx.net., Boyle R; University of Exeter, Global Systems Institute, College of Life and Environmental Sciences, Exeter, EX4 4QE, United Kingdom., Duarte LV; University of Coimbra, MARE, 3030-790, Coimbra, Portugal., Hesselbo SP; University of Exeter, Camborne School of Mines & Environment and Sustainability Institute, Penryn Campus, Treliever Road, Penryn, TR10 9FE, United Kingdom., Kasemann SA; University of Bremen, Faculty of Geosciences and MARUM-Center for Marine Environmental Sciences, 28359, Bremen, Germany., Klein T; University of Bremen, Faculty of Geosciences and MARUM-Center for Marine Environmental Sciences, 28359, Bremen, Germany., Lenton TM; University of Exeter, Global Systems Institute, College of Life and Environmental Sciences, Exeter, EX4 4QE, United Kingdom., Piazza V; Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, 10115, Berlin, Germany., Aberhan M; Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, 10115, Berlin, Germany. |
| Abstrakt: |
Many aspects of the supposed hyperthermal Toarcian Oceanic Anoxic Event (T-OAE, Early Jurassic, c. 182 Ma) are well understood but a lack of robust palaeotemperature data severely limits reconstruction of the processes that drove the T-OAE and associated environmental and biotic changes. New oxygen isotope data from calcite shells of the benthic fauna suggest that bottom water temperatures in the western Tethys were elevated by c. 3.5 °C through the entire T-OAE. Modelling supports the idea that widespread marine anoxia was induced by a greenhouse-driven weathering pulse, and is compatible with the OAE duration being extended by limitation of the global silicate weathering flux. In the western Tethys Ocean, the later part of the T-OAE is characterized by abundant occurrences of the brachiopod Soaresirhynchia, which exhibits characteristics of slow-growing, deep sea brachiopods. The unlikely success of Soaresirhynchia in a hyperthermal event is attributed here to low metabolic rate, which put it at an advantage over other species from shallow epicontinental environments with higher metabolic demand. |
