Viruses are the most diverse and abundant type of biological entity on Earth,infecting species from all of life’s domains and being found in almost all types of environments.They are gaining increasing attention from...Viruses are the most diverse and abundant type of biological entity on Earth,infecting species from all of life’s domains and being found in almost all types of environments.They are gaining increasing attention from scientists,officials and the public due to recent major outbreaks with human health consequences(e.g.,AIDS,SARS,COVID-19)and a growing appreciation of the impact viruses have had on the long-term development of both the biosphere and geosphere.The ability to identify viruses in ancient times is of importance in promoting our understanding of viral evolution and the relationships of viruses to their hosts and to paleoclimate conditions,enabling predictions of present and future impacts of the virosphere on life and the climate system.展开更多
Ocean anoxia has been widely implicated in the Permian-Triassic extinction. However, the duration and distribution of the ocean anoxia remains controversial. In this study, the detailed redox changes across the Permia...Ocean anoxia has been widely implicated in the Permian-Triassic extinction. However, the duration and distribution of the ocean anoxia remains controversial. In this study, the detailed redox changes across the Permian-Triassic boundary （PTB） in the shallow platform interior at Great Bank of Guizhou （GBG） has been reconstructed based on the high-resolution microfossil composition and multiple paleo-redox proxies. The shallow platform is characterized by low sulfur （total sulfur （TS） and pyrite sulfur （Spy）） concentrations, low Spy/TOC ratios, and low DOP values before the mass extinction, representing oxic conditions well. Following the mass extinction, the shift of multiple geochemical proxies, including high Spy/TOC ratios and DOP values, indicates dysoxic-anoxic conditions in shallow ocean. Furthermore, we reconstruct the transition of the redox conditions of Nanpanjiang Basin： the intense volcanic eruptions, which release huge COz and SO2 before the mass extinction, provoke the temperature rising and the collapse of terrestrial ecosystem. As a result, the increased weathering influx causes the carbon iso- topic negative excursion and the expansion of the ocean oxygen minimum zone （OMZ）. When the OMZ expanded into the photic zone, the episodic H2S release events enhance the pyrite burial at Dajiang section. Thus, intense volcanic eruptions, temperature increase, and oceanic hypoxia together lead to the PTB extinction. Recent studies show high temperature might be the key mechanism of the PTB extinction. In addition, this study confirms that the microbialites were formed in the dysoxic- anoxic shallow water.展开更多
基金supported by the National Natural Science Foundation of China(41821001,41830319,42072336,and 42293294)the Program of Introducing Talents of Discipline to Universities(111 Program)(BP0820004)。
文摘Viruses are the most diverse and abundant type of biological entity on Earth,infecting species from all of life’s domains and being found in almost all types of environments.They are gaining increasing attention from scientists,officials and the public due to recent major outbreaks with human health consequences(e.g.,AIDS,SARS,COVID-19)and a growing appreciation of the impact viruses have had on the long-term development of both the biosphere and geosphere.The ability to identify viruses in ancient times is of importance in promoting our understanding of viral evolution and the relationships of viruses to their hosts and to paleoclimate conditions,enabling predictions of present and future impacts of the virosphere on life and the climate system.
基金supported by National Basic Research Program of China (Grant No. 2011CB808800)National Natural Science Foundation of China (Grant Nos. 41172312, 41272372, 41172036, 41240016, 41302271)+1 种基金Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan)Fund of State Key Laboratory of Biogeology and Environmental Geology (Grant No. BGEG1016)
文摘Ocean anoxia has been widely implicated in the Permian-Triassic extinction. However, the duration and distribution of the ocean anoxia remains controversial. In this study, the detailed redox changes across the Permian-Triassic boundary （PTB） in the shallow platform interior at Great Bank of Guizhou （GBG） has been reconstructed based on the high-resolution microfossil composition and multiple paleo-redox proxies. The shallow platform is characterized by low sulfur （total sulfur （TS） and pyrite sulfur （Spy）） concentrations, low Spy/TOC ratios, and low DOP values before the mass extinction, representing oxic conditions well. Following the mass extinction, the shift of multiple geochemical proxies, including high Spy/TOC ratios and DOP values, indicates dysoxic-anoxic conditions in shallow ocean. Furthermore, we reconstruct the transition of the redox conditions of Nanpanjiang Basin： the intense volcanic eruptions, which release huge COz and SO2 before the mass extinction, provoke the temperature rising and the collapse of terrestrial ecosystem. As a result, the increased weathering influx causes the carbon iso- topic negative excursion and the expansion of the ocean oxygen minimum zone （OMZ）. When the OMZ expanded into the photic zone, the episodic H2S release events enhance the pyrite burial at Dajiang section. Thus, intense volcanic eruptions, temperature increase, and oceanic hypoxia together lead to the PTB extinction. Recent studies show high temperature might be the key mechanism of the PTB extinction. In addition, this study confirms that the microbialites were formed in the dysoxic- anoxic shallow water.
