Biomarker Records Associated with Mass Extinction Events

Abstract

The history of life on Earth is punctuated by a series of mass extinction episodes that vary widely in their magnitude, duration, and cause. Biomarkers are a powerful tool for the reconstruction of historical environmental conditions and can therefore provide insights into the cause and responses to ancient extinction events. In examining the five largest mass extinctions in the geological record, investigators have used biomarkers to elucidate key processes such as eutrophy, euxinia, ocean acidification, changes in hydrological balance, and changes in atmospheric CO 2 . By using these molecular fossils to understand how Earth and its ecosystems have responded to unusual environmental activity during these extinctions, models can be made to predict how Earth will respond to future changes in its climate.

A stable and productive marine microbial community was sustained through the end‐Devonian Hangenberg Crisis within the Cleveland Shale of the Appalachian Basin, United States

“…While the effects of the global HC on both marine and terrestrial macrofauna are well studied, little is known about the impact this biocrisis had on the phytoplankton and other microorganisms that provided the primary biomass that sustained food webs and controlled Paleozoic biogeochemical cycles (e.g., Marynowski & Filipiak, 2007;Cao et al, 2009;Marynowski et al, 2012;Rohrssen, Love, Fischer, Finnegan, & Fike, 2013;Tulipani, Grice, Greenwood, Haines et al, 2015;Whiteside & Grice, 2016). Lipid biomarkers, biomolecules that are recalcitrant on geologic timescales, can be used to distinguish sources of organic matter input and characterize fundamental aspects of the microbial ecology of an environment during sedimentary deposition, if the host strata have undergone a mild thermal history (Peters, Walters, & Moldowan, 2005).…”

A new method for the rapid analysis of 1H-Pyrrole-2,5-diones (maleimides) in environmental samples by two-dimensional gas chromatography time-of-flight mass spectrometry

“…Maleimides have also been detected in environmental samples, where they have been used as indicators of algal productivity, water column properties (i.e. redox conditions, stratification, chemocline depth) and depositional conditions [19,20,[26][27][28][29][30][31][32][33][34][35]. However, the precursors of many maleimides have still not been fully identified, the processes leading to their formation are incompletely understood and their environmental significance needs further investigation [29].…”

Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean

“…The occurrence of H 2 S in the PZ severely limits the zone of habitability for eukaryotic organisms, inhibiting the evolution of complex life, and later resulting in mass extinctions and delayed postextinction recovery (2). Multiple lines of evidence suggest that PZE accompanied at least four of the five major Phanerozoic mass extinctions (3). In the modern world, PZE also has important environmental implications because climate change and human activities are causing expansion of sulfidic zones on continental shelves (4), which may lead to enhanced PZE in the future and a consequent impact on marine ecosystems.…”