Flood Basalts and Mass Extinctions

2019 ◽  
Vol 47 (1) ◽  
pp. 275-303 ◽  
Author(s):  
Matthew E. Clapham ◽  
Paul R. Renne
Keyword(s):  
Environmental Changes ◽  
Flood Basalt ◽  
Respiratory Physiology ◽  
Mass Extinctions ◽  
Flood Basalts ◽  
Volatile Release ◽  
Ocean Carbon ◽  
Biological Extinction ◽  
Extinction Events ◽  
Environmental Disruption

Flood basalts were Earth's largest volcanic episodes that, along with related intrusions, were often emplaced rapidly and coincided with environmental disruption: oceanic anoxic events, hyperthermals, and mass extinction events. Volatile emissions, both from magmatic degassing and vaporized from surrounding rock, triggered short-term cooling and longer-term warming, ocean acidification, and deoxygenation. The magnitude of biological extinction varied considerably, from small events affecting only select groups to the largest extinction of the Phanerozoic, with less-active organisms and those with less-developed respiratory physiology faring especially poorly. The disparate environmental and biological outcomes of different flood basalt events may at first order be explained by variations in the rate of volatile release modulated by longer trends in ocean carbon cycle buffering and the composition of marine ecosystems. Assessing volatile release, environmental change, and biological extinction at finer temporal resolution should be a top priority to refine ancient hyperthermals as analogs for anthropogenic climate change. ▪ Flood basalts, the largest volcanic events in Earth history, triggered dramatic environmental changes on land and in the oceans. ▪ Rapid volcanic carbon emissions led to ocean warming, acidification, and deoxygenation that often caused widespread animal extinctions. ▪ Animal physiology played a key role in survival during flood basalt extinctions, with reef builders such as corals being especially vulnerable. ▪ The rate and duration of volcanic carbon emission controlled the type of environmental disruption and the severity of biological extinction.

Conservation biology of marine fishes: perceptions and caveats regarding assignment of extinction risk

2001 ◽  
Vol 58 (1) ◽  
pp. 108-121 ◽  
Author(s):  
Jeffrey A Hutchings
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Population Decline ◽  
Empirical Support ◽  
Marine Fishes ◽  
Marine Biodiversity ◽  
Population Declines ◽  
High Fecundity ◽  
Reproductive Rates ◽  
Biological Extinction

Quantitative criteria used to assign species to categories of extinction risk may seriously overestimate these risks for marine fishes. Contemporary perception is that marine fishes may be less vulnerable to extinction than other taxa, because of great natural variability in abundance, high fecundity, rapid population growth, and an intrinsically high capability of recovering from low population size. Contrary to perception, however, there appears to be generally little theoretical or empirical support for the hypotheses that marine fish are more likely to experience large reductions in population size, to produce unusually high levels of recruitment, to have higher reproductive rates, or to recover more rapidly from prolonged population declines than nonmarine fishes. Although existing population-decline criteria may not accurately reflect probabilities of biological extinction, they do appear to reflect the converse-population recovery. Insufficient support for contemporary perceptions of their susceptibility to extinction, coupled with caveats associated with the assignment of extinction risk, suggest that significant increases in the population-decline thresholds used to assign marine fishes to at-risk categories would be inconsistent with a precautionary approach to fisheries management and the conservation of marine biodiversity.

Atmospheric suspension settling characteristics of biological extinction material

2019 ◽  
Vol 48 (5) ◽  
pp. 521003
Author(s):  
陈 曦 Chen Xi ◽  
胡以华 Hu Yihua ◽  
顾有林 Gu Youlin ◽  
赵欣颖 Zhao Xinying ◽  
黄宝琨 Huang Baokun ◽  
...  
Keyword(s):  
Biological Extinction ◽  
Settling Characteristics

scholarly journals Assemblage turnovers in Mesozoic calcareous nannofossils: periodicity and distinction from the terminal Cretaceous event

1992 ◽  
Vol 6 ◽  
pp. 26-26
Author(s):  
James Bergen
Keyword(s):  
Geographic Area ◽  
Current Evidence ◽  
Calcareous Nannofossils ◽  
Low Latitude ◽  
Generic Level ◽  
The Family ◽  
The Common ◽  
Biological Extinction ◽  
Species Extinctions

Long-term cycles are evident in the stratigraphic distribution(appearances/extinctions) and dominance changes of Mesozoic calcareous nannofossils. These assemblage turnovers correspond to major episodes of biological extinction recognized in inverterbrate genera and families. The identified Mesozoic nannofossil assemblage turnovers are gradual, in contrast to the well-documented and geologically instantaneous terminal Cretaceous event. Such continuity indicates a non-catatrophic cause and suggests that these turnovers are unrelated to the terminal Cretaceous “accident”. Their timing instead corresponds to interpreted sea level trends and paleoceanographic changes in the sections studied.Current evidence is based on a limited number of sections spanning the Pliensbachian to Cenomanian, although published literature and a thorough analysis of the Cenomanian show that these turnovers can be recognized over a wide geographic area. These preliminary conclusions are based on detailed sample analyses of marine sections selected for their nannofossil content. This has eliminated any taxonomic or preservational bias and problems related to compiled literature ranges.Major dominance changes are recorded in the Pliensbachian, Bajocian, Tithonian, and Aptian. The Pliensbachian turnover is evident at the family and ordinal level, whereas the younger dominance changes occur at the generic level. A major diversification during the Pliensbachian resulted in the replacement of the Jurassic Family Crepidolithaceae by the important Jurassic placolith families. The Bajocian and Tithonian turnovers were initiated by dominance changes within the common imbricate placolith family, Ellipsagelosphaeraceae. The Tithonian turnover was most dramatic including: (1) a major diversification near the Jurassic/Cretaceous boundary; (2) the extinction of several genera; and (3) the establishment of a dominant low latitude assemblage (Nannoconus, Conusphaera, Micrantholithus). Species appearances and extinctions characterize the Cretaceous turnovers. There was an increase in species extinctions during the Hauterivian, Aptian, and Cenomanian. The Aptian also includes the extinction of the aforementioned low latitude assemblage and the subsequent diversification and radiation of more cosmopolitan floras, which continued until the end of the Albian. The highest number of nannofossil species extinctions within any Mesozoic stage (except for the terminal Cretaceous) are recorded in the Cenomanian. Although several of these species extinctions are associated with the Cenomanian/Turonian boundary anoxic event, most preceeded this event.

Diffusion characteristics of biological extinction material

2017 ◽  
Vol 46 (6) ◽  
pp. 621001
Author(s):  
李 乐 Li Le ◽  
胡以华 Hu Yihua ◽  
王 枭 Wang Xiao ◽  
顾有林 Gu Youlin ◽  
赵义正 Zhao Yizheng ◽  
...  
Keyword(s):  
Diffusion Characteristics ◽  
Biological Extinction

scholarly journals Spaceship Earth Revisited: The Co-Benefits of Overcoming Biological Extinction of Experience at the Level of Person, Place and Planet

2020 ◽  
Vol 17 (4) ◽  
pp. 1407 ◽  
Author(s):  
Susan L. Prescott ◽  
Jeffrey S. Bland
Keyword(s):  
Large Scale ◽  
Environmental Changes ◽  
Well Being ◽  
Natural World ◽  
Fine Grained ◽  
Resource Limitations ◽  
Biological Responses ◽  
Spaceship Earth ◽  
Biological Extinction ◽  
Extinction Of Experience

Extensive research underscores that we interpret the world through metaphors; moreover, common metaphors are a useful means to enhance the pursuit of personal and collective goals. In the context of planetary health—defined as the interdependent vitality of all natural and anthropogenic ecosystems (social, political and otherwise)—one enduring metaphor can be found in the concept of “Spaceship Earth”. Although not without criticism, the term “Spaceship Earth” has been useful to highlight both resource limitations and the beauty and fragility of delicate ecosystems that sustain life. Rene Dubos, who helped popularize the term, underscored the need for an exposome perspective, one that examines the total accumulated environmental exposures (both detrimental and beneficial) that predict the biological responses of the “total organism to the total environment” over time. In other words, how large-scale environmental changes affect us all personally, albeit in individualized ways. This commentary focuses the ways in which microbes, as an essential part of all ecosystems, provide a vital link between personal and planetary systems, and mediate the biopsychosocial aspects of our individualized experience—and thus health—over our life course journey. A more fine-grained understanding of these dynamics and our power to change them, personally and collectively, lies at the core of restoring “ecosystems balance” for person, place and planet. In particular, restoring human connectedness to the natural world, sense of community and shared purpose must occur in tandem with technological solutions, and will enhance individual empowerment for personal well-being, as well as our collective potential to overcome our grand challenges. Such knowledge can help shape the use of metaphor and re-imagine solutions and novel ways for restoration or rewilding of ecosystems, and the values, behaviors and attitudes to light the path toward exiting the Anthropocene.

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