Bristol (UK): Burrowing animals were among the first to recover after the end-Permian mass extinction, according to researchers investigating ancient sea bed traces and burrows.The findings of the study were published in the journal Science Advances in which researchers from China, the United States, and the United Kingdom describe how life in the water rebounded from the event, which killed more than 90% of the species on Earth, from their observations of trace fossils.Life was devastated by the end-Permian mass extinction 252 million years ago, and recovery of life on Earth took millions of years for biodiversity to return to pre-extinction levels. But by examining trails and burrows on the South China sea bed, the international team were able to piece together sea life's revival by pinpointing what animal activity was happening when.Professor Michael Benton from the University of Bristol's School of Earth Sciences, a collaborator on the new paper, said: "The end-Permian mass extinction and the recovery of life in the Early Triassic are very well documented throughout South China."We were able to look at trace fossils from 26 sections through the entire series of events, representing seven million crucial years of time, and showing details at 400 sampling points, we finally reconstructed the recovery stages of all animals including benthos, nekton, as well as these soft-bodied burrowing animals in the ocean."Dr Xueqian Feng from the China University of Geosciences in Wuhan led the study, and his focus was on ancient burrows and trails. He explained: "Trace fossils such as trails and burrows document mostly soft-bodied animals in the sea. Most of these soft-bodied animals had no or poor skeletons."There are some amazing localities in South China where we find huge numbers of beautifully preserved trace fossils, and the details can show infaunal ecosystem engineering behaviours, as well as their feedback effects on biodiversity of skeletonized animals." Professor Zhong-Qiang Chen, director of the study, said: "The trace fossils show us when and where soft-bodied, burrowing animals flourished in this Early Triassic greenhouse world."For example, elevated temperatures and extended anoxia coincided with low values of behavioural and ecologic diversities across the Permian-Triassic boundary, and it took about 3 million years for ecological recovery of soft-bodied animals to match the pre-extinction levels."Professor David Bottjer, a collaborator in the study from the University of Southern California, added: "One of the most remarkable aspects of the South China data is the breadth of ancient environments we could sample. "Differential responses of infaunal ecosystems to variable environmental controls may have played a significant but heretofore little appreciated evolutionary and ecologic role in the recovery in the hot Early Triassic ocean."Dr Chunmei Su, another collaborator, said: "The mass extinction killed over 90 percent of species on Earth, and we see that in the catastrophic reduction in ecological function of the surviving animals in the ocean."At first, there were only a few survivors, and recovery began in deeper waters. The recovery of nekton occurred at the same time as the full rebound of infaunal ecosystem engineering activities."Alison Cribb, a collaborator in the study from the University of Southern California, added: "The first animals to recover were deposit feeders such as worms and shrimps. The recovery of suspension feeders such as brachiopods, bryozoans and many bivalves took much longer."Maybe the deposit feeders were making such a mess of the seafloor that the water was polluted with mud, the churned mud meant suspension feeders could not properly settle on the seafloor, or the muddy water produced by those deposit feeders just clogged the filtering structures of suspension feeders and prohibited them from feeding efficiently."Professor Chen added: "And some animals, such as corals, had disappeared completely. Coral reefs did not return until much later."Dr Feng concludes: "Why does it matter to understand these great mass extinctions of the geological past?"The answer is that the end-Permian crisis -- which was so devastating to life on Earth -- was caused by global warming and ocean acidification, but trace-making animals may be selected against by the environment in a way that skeletal organisms were not. "Our trace fossil data reveals soft-bodied animals' resilience to high CO2 and warming. These ecosystem engineers may have played a role in benthic ecosystem recovery after severe mass extinctions, potentially, for example, triggering the evolutionary innovations and radiations in the Early Triassic."&nbsp;—ANI

Burrowing animals were among the first to recover after the end-Permian mass extinction, according to researchers investigating ancient sea bed traces and burrows.

Study: Burrowing Animals To Recover After Largest Mass Extinction

Washington: Rapid changes in marine oxygen levels may have played a significant role in driving Earth's first mass extinction, according to a new study led by Florida State University researchers.
About 443 million years ago, life on Earth was undergoing the Late Ordovician mass extinction, or LOME, which eliminated about 85% of marine species. Scientists have long studied this mass extinction and continue to investigate its possible causes, such as reduced habitat loss in a rapidly cooling world or persistent low-oxygen conditions in the oceans.
By measuring isotopes of the element thallium, which shows special sensitivity to changes in oxygen in the ancient marine environment, the research team found that previously documented patterns of this mass extinction coincided with an initial rapid decrease in marine oxygen levels followed by a rapid increase in oxygen. Their work is published online in the journal Science Advances.
"Paleontologists have noted that there were several groups of organisms, such as graptolites and brachiopods that started to decline very early in this mass extinction interval, but we didn't really have any good evidence of an environmental or climate signature to tie that early decline of these groups to a particular mechanism," said co-author Seth Young, an associate professor in the Department of Earth, Ocean and Atmospheric Science.
"This paper can directly link that early phase of extinction to changes in oxygen. We see a marked change in thallium isotopes at the same time these organisms start their steady decline into the main phase of the mass extinction event," he said.
That decrease in oxygen was immediately followed by an increase. This rapid shift in oxygen coincided with the traditional first die-off of mass extinction and major ice sheet growth over the ancient South Pole.
"Turbulence in oxygen levels in oceanic waters is really what seems to have been pretty problematic for organisms that were living in the Late Ordovician at that time, which might have been adapted to cope with low oxygen conditions initially or vice versa," Young said.
"The fact that oxygen levels in the oceans next to the continents switching back and forth over short geologic time scales (a few hundred thousand years) really did seem to play havoc with these marine ecosystems," he added.
The Late Ordovician extinction was one of five major mass extinctions in Earth's history and the only one scientists are confident took place in what are called 'icehouse' conditions, in which widespread ice sheets are present on Earth's surface. Earth is currently experiencing icehouse conditions and loss of biodiversity, which makes this ancient mass extinction an important analog for present-day conditions, along with trying to understand Earth's future as our climate continues to warm and ice sheets recede.
Previous research into environmental conditions surrounding the LOME used evidence found in limestones from more oxygenated settings, but this study used shales that were deposited in deeper, oxygen-poor water, which record different geochemical signatures, allowing the researchers to make conclusions about global marine conditions, rather than for local conditions.
"The discovery of the initial expansion of low-oxygen conditions on a global level and the coincidence with the early phases of decline in marine animals helps paint a clearer picture of what was happening with this extinction event," said lead author Nevin Kozik, a visiting assistant professor at Occidental College and former FSU doctoral student. —ANI

 Rapid changes in marine oxygen levels may have played a significant role in driving Earth's first mass extinction, according to a new study led by Florida State University researchers.

Rapid Fluctuations In Oxygen Levels Coincided With Earth's First Mass Extinction

London: According to a recent study, bird species with unusual or severe combinations of features are most at risk of going extinct. The results are presented in the journal Functional Ecology by the British Ecological Society.
The most distinctive birds on the planet, according to a recent study done by scientists at Imperial College London, are also the most endangered. The loss of these species and their distinctive ecological functions, such as seed dispersal, pollination, and predation, could negatively impact ecosystem health.
The study, which is the most thorough to date, examined the extinction risk and physical characteristics (such as wing length and beak shape) of 99 per cent of all living bird species.
The scientists discovered that there would be a noticeably greater reduction in the physical (or morphological) diversity among birds in simulated scenarios were all threatened and near-threatened bird species went extinct than in scenarios where extinctions were random.
The Christmas Frigatebird (Fregata andrewsi), which only breeds on Christmas Island, and the Bristle-thighed Curlew (Numenius tahitiensis), which makes an annual migration from its breeding grounds in Alaska to South Pacific islands, are two bird species that are both morphologically distinctive and endangered.&nbsp;
Jarome Ali, a PhD candidate at Princeton University who completed the research at Imperial College London and was the lead author of the research, said: "Our study shows that extinctions will most likely prune a large proportion of unique species from the avian tree. Losing these unique species will mean a loss of the specialised roles that they play in ecosystems.
"If we do not take action to protect threatened species and avert extinctions, the functioning of ecosystems will be dramatically disrupted."
The authors of the study employed a dataset of measurements taken from 9943 different bird species, both living birds and museum specimens. Physical characteristics such as beak size and form as well as the lengths of wings, tails, and legs were measured.
Based on the IUCN Red List's current threat classifications for each species, the authors linked the morphological data with the risk of extinction. Then they performed simulations to see what would occur if the most endangered bird species became extinct.
The information utilised in the study was able to demonstrate that the most distinctive birds were also listed as threatened on the Red List, but it was unable to demonstrate the relationship between avian uniqueness and extinction risk.
Jarome Ali said: "One possibility is that highly specialised organisms are less able to adapt to a changing environment, in which case human impacts may directly threaten species with the most unusual ecological roles. More research is needed to delve deeper into the connection between unique traits and extinction risk." —ANI

According to a recent study, bird species with unusual or severe combinations of features are most at risk of going extinct. The results are presented in the journal Functional Ecology by the British Ecological Society.

Planet's Most Unique Birds At Higher Risk Of Extinction

'Rahul, Rahul': Desperate Rahul, Rahul akin to "immediate SOS" from dangerously dangling "beings" "out of all kinds of reliefs including very sustainence itself". Being totally devoid of any way to stick on to, to change their immense predicament, duress in to 180-degree turn, they are actually "begging" Rahul Gandhi mobilise his "magic wand all round and extract them frô their current near-extinction-cum-all round penury". According to them, only Rahul G, none else, is all round capable enough to provide "immediate and permanent" relief to them not only for now "but for all times to come". Thus, "Rahul, Rahul...".
—Soumitra Bose

Urgent calls for Rahul Gandhi to wield his 'magic wand' for immediate, permanent relief to those in dire straits, seen as the only beacon of hope for a better future.

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Study: Burrowing Animals To Recover After Largest Mass Extinction

Inam Ansari

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Study: Burrowing Animals To Recover After Largest Mass Extinction

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Rapid Fluctuations In Oxygen Levels Coincided With E ...

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