Uv-B Radiation Was the Devonian-Carboniferous Boundary Terrestrial Extinction Kill Mechanism

Marshall, John C.; Lakin, Jon; Troth, Ian; Wallace-Johnson, Sarah

doi:10.1130/abs/2020am-356372

Cited by 11 publications

(27 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A prominent environmental stressor is UV radiation, which has been associated to some extinctions as in the Devonian–Carboniferous boundary period (Marshall et al., 2020). Nowadays, UV radiation has been intensified with human‐induced environmental changes due to, among other factors, the depletion of the ozone layer (Caldwell & Flint, 1994).…”

Section: Introductionmentioning

confidence: 99%

Interspecific hybrids show a reduced adaptive potential under DNA damaging conditions

Bautista

Marsit

Landry

2020

Evolutionary Applications

View full text Add to dashboard Cite

Hybridization may increase the probability of adaptation to extreme stresses. This advantage could be caused by an increased genome plasticity in hybrids, which could accelerate the search for adaptive mutations. High ultraviolet (UV) radiation is a particular challenge in terms of adaptation because it affects the viability of organisms by directly damaging DNA, while also challenging future generations by increasing mutation rate. Here we test if hybridization accelerates adaptive evolution in response to DNA damage, using yeast as a model. We exposed 180 populations of hybrids between species (Saccharomyces cerevisiae and Saccharomyces paradoxus) and their parental strains to UV mimetic and control conditions for approximately 100 generations. Although we found that adaptation occurs in both hybrids and parents, hybrids achieved a lower rate of adaptation, contrary to our expectations. Adaptation to DNA damage conditions comes with a large and similar cost for parents and hybrids, suggesting that this cost is not responsible for the lower adaptability of hybrids. We suggest that the lower Accepted Article This article is protected by copyright. All rights reserved adaptive potential of hybrids in this condition may result from the interaction between DNA damage and the inherent genetic instability of hybrids.

show abstract

Section: Introductionmentioning

confidence: 99%

Interspecific hybrids show a reduced adaptive potential under DNA damaging conditions

Bautista

Marsit

Landry

2020

Evolutionary Applications

View full text Add to dashboard Cite

show abstract

“…Recently, the volcanic "smoking gun" as a potential trigger of the Hangenberg Crisis has been questioned 8 . According to 8 , elevated UV-B radiation and a drastic drop in stratospheric ozone during global warming were responsible for this biotic overturn. Moreover, Fields et al 52 , postulated supernova explosions as a trigger for the event.…”

Section: Discussionmentioning

confidence: 99%

“…Marshall et al 8 described floral malformations in east Greenland and interpreted the observed floral mutagenesis to be a result of elevated UV-B radiation, reflecting ozone-layer reduction that was suggested to have been associated with global warming. Surprisingly, according to those authors, mercury data excluded planetary-scale volcanism as a potential trigger for the end-Devonian Hangenberg Crisis.…”

Section: Discussionmentioning

confidence: 99%

Mercury spikes as evidence of extended arc-volcanism around the Devonian–Carboniferous boundary in the South Tian Shan (southern Uzbekistan)

Rakociński

Pisarzowska

Corradini

et al. 2021

Sci Rep

View full text Add to dashboard Cite

Recently, the end-Devonian mass extinction (Hangenberg Crisis, 359 Ma) was identified as a first-order mass extinction, albeit not one of the “Big Five” events. Many marine and terrestrial organisms were affected by this crisis. The cause of this mass extinction is still conjectural and widely discussed. Here we report anomalously high mercury (Hg) concentrations from the South Tian Shan (Uzbekistan), together with correlation using conodont biostratigraphic data. Hg enrichment (to 5825 ppb) was detected in marine deposits encompassing the Hangenberg Crisis. In the Novchomok section, the Hangenberg Crisis interval does not contain typical Hangenberg Black Shales; however, by means of inorganic geochemistry (enrichment of redox-sensitive elements such as Mo, V, and U) we detected an equivalent level despite the lack of marked facies changes. This is the first record of Hg and Hg/total organic carbon anomalies in marly shales, marls and carbonates that are totally independent of facies changes, implying that volcanism was the most probable cause of the Hangenberg Crisis. This conclusion is confirmed by the presence of a negative δ13C excursion, which may reflect massive release of isotopically light carbon from volcanogenic and thermogenic devolatilization likely combined with increased arc-volcanism activity worldwide at the end of the Devonian.

show abstract

“…However, it is also possible that the field during the Devonian directly enabled biological crises through depletion of the ozone layer, which allowed more UV-B radiation to reach Earth's surface. Although it would be expected that malformed spores would be more widespread, and associated with other parts of the Devonian, instead of in distinctive intervals as the study of Marshall et al (2020) suggests.…”

Section: Did the Field Have An Impact On Life In The Devonian?mentioning

confidence: 98%

“…Recently, the study of Marshall et al (2020) has linked the terrestrial phase of the Hangenberg event at the Devonian-Carboniferous boundary to an increase in ultraviolet (specifically, UV-B) radiation, which they hypothesize to be caused by an increase in convective transport of ClO (chlorine monoxide) through global warming. Fields et al (2020) dispute this cause and have instead suggested that the increase in UV-B radiation during the Hangenberg event could have been caused by supernovae.…”

Section: Did the Field Have An Impact On Life In The Devonian?mentioning

confidence: 99%

A Persistent Non-uniformitarian Paleomagnetic Field in the Devonian?

Boon¹,

Biggin²,

Thallner³

et al. 2021

Preprint

View full text Add to dashboard Cite

The Devonian, like much of the Paleozoic, has long been a problematic period for paleomagnetism. Devonian paleomagnetic data are generally difficult to interpret and have complex partial or full overprints; problems that arise in data obtained from both sedimentary and igneous rocks. As a result, the reconstruction of tectonic plate motions, performed largely using apparent polar wander paths, has large uncertainty. Similarly, the Devonian geomagnetic polarity time scale is very poorly constrained. Paleointensity studies suggest that the field was much weaker than the modern field, and it has been hypothesised that this was accompanied by many polarity reversals (a hyperreversing field). We sampled middle to upper Devonian sections in Germany, Poland and Canada which show low conodont alteration indices, implying low thermal maturity. We show in this study that there are significant issues with these data, and they are not straightforward to interpret, even though no significant heating and remineralisation was likely to have caused overprinting. We compare our data to other magnetostratigraphic studies from the Devonian and review the polarity pattern as presented in the Geologic Time Scale. Combined with estimates for the strength of the magnetic field during the Devonian, we suggest that the field during the Devonian might have been so weak and in part non-dipolar that obtaining reliable primary paleomagnetic data from Devonian rocks is challenging. Careful examination of all data, no matter how unusual, is the best way to push forward our understanding of the Devonian magnetic field. Paleointensity studies show that the field during the Devonian had a similar low strength to that recently advocated during the Ediacaran. Independent evidence from malformed spores around the Devonian-Carboniferous boundary suggests that the terrestrial extinction connected to the Hangenberg event, was caused by increased UV-B radiation, supporting the weak field hypothesis. A fundamentally weak and possibly non-dipolar field during the Devonian could have been produced, in part, by true polar wander acting to maximise core-mantle heat flow in the equatorial region. It may also have influenced evolution and extinctions in this time period. There is a large-number of paleobiological crises in the Devonian, and we pose the question, did the Earth's magnetic field influence these crises?

show abstract

Uv-B Radiation Was the Devonian-Carboniferous Boundary Terrestrial Extinction Kill Mechanism

Cited by 11 publications

References 9 publications

Interspecific hybrids show a reduced adaptive potential under DNA damaging conditions

Interspecific hybrids show a reduced adaptive potential under DNA damaging conditions

Mercury spikes as evidence of extended arc-volcanism around the Devonian–Carboniferous boundary in the South Tian Shan (southern Uzbekistan)

A Persistent Non-uniformitarian Paleomagnetic Field in the Devonian?

Contact Info

Product

Resources

About