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The paleoecology of hard places to make a living - in particular, oxygen-deficient environments - is a common thread in Droser lab research. We want to know what, where, and how organisms lived and breathed in such environments, but also we aim to extend the use of fossil and trace preservation to glean even more paleoenvironmental information from this unique rock record. Droser lab alumni have worked extensively to describe Cambrian-aged Burgess Shale-type deposits by determining the role of low oxygen in exceptional fossil preservation, observing monospecific assemblages of trilobites opportunistically inhabiting the exarobic zone (where there is almost no oxygen), and utilizing the abundance of burrows (via the ichnofabric index) to semi-quantitatively infer short term changes in bottom water oxygenation.
The paleoecology of hard places to make a living - in particular, oxygen-deficient environments - is a common thread in Droser lab research. We want to know what, where, and how organisms lived and breathed in such environments, but also we aim to extend the use of fossil and trace preservation to glean even more paleoenvironmental information from this unique rock record. Droser lab alumni have worked extensively to describe Cambrian-aged Burgess Shale-type deposits by determining the role of low oxygen in exceptional fossil preservation, observing monospecific assemblages of trilobites opportunistically inhabiting the exarobic zone (where there is almost no oxygen), and utilizing the abundance of burrows (via the ichnofabric index) to semi-quantitatively infer short term changes in bottom water oxygenation.
We have expanded our interest in low-oxygen environments to include black shales from the Late Devonian Appalachian Basin. These organic-rich rocks offer a window into a time where prolonged oxygen stress in shallow epeiric seaways - combined with several major mass extinction events - built a unique ecosystem. We have found that groups of specialized taxa and distinct life habits are representative of different oxygen levels, and can thus be used to infer relative bottom water oxygen conditions as a paleoenvironmental proxy. Recently, lab members have joined forces with the Love and Lyons biogeochemistry groups at UCR to combine paleoecological insight and observations with quantitative geochemical analysis of these Devonian black shales. We have targeted several mass extinction events (including the Frasnian-Fammenian extinction and the Hangenberg Bioevent) with a paleontological perspective, aiming to use lipid biomarkers, which can be considered molecular fossils, to determine relative changes in primary producer communities with changing oxygen and extinction stress. So far, we’ve found that microbial communities are stable and thriving in these Devonian environments, regardless of the mass extinction occurring around them. Further, macrofaunal extinction magnitude appears to be decoupled from the level of oxygen stress.
We have expanded our interest in low-oxygen environments to include black shales from the Late Devonian Appalachian Basin. These organic-rich rocks offer a window into a time where prolonged oxygen stress in shallow epeiric seaways - combined with several major mass extinction events - built a unique ecosystem. We have found that groups of specialized taxa and distinct life habits are representative of different oxygen levels, and can thus be used to infer relative bottom water oxygen conditions as a paleoenvironmental proxy. Recently, lab members have joined forces with the Love and Lyons biogeochemistry groups at UCR to combine paleoecological insight and observations with quantitative geochemical analysis of these Devonian black shales. We have targeted several mass extinction events (including the Frasnian-Fammenian extinction and the Hangenberg Bioevent) with a paleontological perspective, aiming to use lipid biomarkers, which can be considered molecular fossils, to determine relative changes in primary producer communities with changing oxygen and extinction stress. So far, we’ve found that microbial communities are stable and thriving in these Devonian environments, regardless of the mass extinction occurring around them. Further, macrofaunal extinction magnitude appears to be decoupled from the level of oxygen stress.
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