Pondering the Precambrian #28

Proterozoic:

NeoProterozoic:

Ediacaran:

A cyanobacteria normally associated with the Phanerozoic has been found in Ediacaran deposits in China.

There was a significant shift in what the limiting nutrients were across the Ediacaran/Cambrian boundary.

How did the black shales form across the Ediacaran/Cambrian boundary?

Was the Sao Francisco Basin a restricted basin during the Ediacaran?

A section in China appears to be a record of the late Ediacaran glaciations, showing a cold, dry climate.

The Cathayasian block was attached to Gondwana since 630 million years ago.

The fate of an inland sea from during the Neoproterozoic gets discussed.

Evidence of the Milkanovich cycles is preserved in Ediacaran deposits.

Tubular fossils from the Weng'an Biota are algae, not metazoans.

Weng'an Biota also provides examples of preserved encysting of eukaryotes.

Cryogenian:

Could the banded iron formations of the Cryogenian be related to ocean acidification?

There is evidence of a less than complete snowball earth from China during the Marinoan Glaciation.

Cryogenian Period deposits of Datangpo Formation of China from the interglacial period between the Sturtian and Marinoan glaciations show a very stratified ocean.

The majority of the time, the NeoProterozoic oceans were anoxic and were supersaturated with dolomite.

Tonian:

Fungus fossils appear to have been found in Tonian (neoproterozoic) or Stenian (mesoproterozoic) deposits in Canada.

There appears to have been a paleorifting event during the Tonian of the Sao Francisco-Congo continent.

The Sognefjel complex appears to have formed in the Asgardian Sea during the early Tonian.

Did the Paleo-South China Ocean close during the Tonian?

MesoProterozoic:

The Eastern European Craton has a Mesoproterozoic signal.

The southern Grenville formation dates from Mesoproterozoic and is from purely Laurentian sources.

Reported stromatolites from a Stenian lake cannot be proven to be biogenic.

Paleoproterozoic:

600 million years of sedimentation is examined from the Paleoproterozoic of Lapland.

Statherian Period evolution of the Oolongbuluke terraine is explained.

In Brazil, the Sobreiro Formation appears to be from the Orosirian/Statherian boundary.

Archean:

There is evidence of retreating oceanic slab subduction from the NeoArchean of China.

Evidence from India suggests there was significant local variation in Archean ocean conditions.

The Caozhuang basin appears to be a case of sagduction.

Fossils from paleoarchean South Africa show bacteria dividing and they appear to be very similar to cyanobacteria Pleurocapsales.

Eoarchean stromatolites get examined.

Hadean:

Was the Earth covered in a lava ocean before Theia impacted and created the moon?

META:

What are the implications of a hotter mantle, but colder subduction during the Precambrian?

Ants Domesticated Fungus for Farming 60 to 55 Million Years ago During the Paleogene

A group of South American ants has farmed fungi since shortly after the dinosaurs died out, according to an international research team including Smithsonian scientists. The genes of the ant farmers and their fungal crops reveal a surprisingly ancient history of mutual adaptations. This evolutionary give-and-take has led to some species--the leafcutter ants--developing industrial-scale farming that surpasses human agriculture in its efficiency.

The key chapters of the history of ant agriculture are written into the genes of both the insects and their crop fungi. A team including Jacobus Boomsma, research associate at the Smithsonian Tropical Research Institute and biology professor at the University of Copenhagen with his colleagues there, Sanne Nygaard and Guojie Zhang, looked at the genes of seven species of farming ants and their associated fungi to understand how the partnership developed. In a study published in Nature Communications, the scientists found that 55 to 60 million years ago ants belonging to the tribe Attini switched from a hunter-gatherer lifestyle to subsistence farming of fungi that grew on decomposing, woody plant matter. The slow-growing fungi sustained tiny colonies of ants, but it was the first step toward agriculture on a much larger scale.

"The ants lost many genes when they committed to farming fungi," said Boomsma. This tied the fate of the ants to their food--with the insects depending on the fungi for nutrients, and the fungi increasing their likelihood of survival if they produced more nutritious crop. "It led to an evolutionary cascade of changes, unmatched by any other animal lineage studied so far."

The researchers found that around 25 million years ago one lineage of fungus-farming ants began cultivating fungi that produced tiny, protein-rich bulbs that the ants preferentially harvested. More nutritious food supported larger colonies, spurring even more advances in ant-fungus co-evolution until, 15 million years ago, the leafcutter ants emerged. Leafcutter ant species cut and sow their underground farms daily with fresh, green plant matter, cultivating a fully domesticated species of fungus on an industrial scale that can sustain colonies with up to millions of ants.

Domestication changed both partners in the relationship. Unlike its ancestors and present-day wild relatives, the leafcutter ants' fungus can no longer produce enzymes that digest woody plant matter, making it reliant on leafy greens brought in by the ants. In turn, the fungus produces fruiting bodies swollen with proteins essential for the ants' growth. The ants have evolved special enzymes to easily digest this superfood and cannot eat anything else. Unable to survive without each other, the symbiotic leafcutters and their fungi nonetheless form the largest colonies of any of the fungus-farming ants. They work together as the dominant herbivores in Neotropical forests.

link.

CRISPR Cleared for Commericial Mushrooms

The US Department of Agriculture (USDA) will not regulate a mushroom genetically modified withthe gene-editing tool CRISPR–Cas9.

The long-awaited decision means that the mushroom can be cultivated and sold without passing through the agency's regulatory process—making it the first CRISPR-edited organism to receive a green light from the US government.

“The research community will be very happy with the news,” says Caixia Gao, a plant biologist at the Chinese Academy of Sciences’s Institute of Genetics and Developmental Biology in Beijing, who was not involved in developing the mushroom. “I am confident we'll see more gene-edited crops falling outside of regulatory authority.”

link.

Tortotubus: a Fossil Fungus From Aeronian Silurian Sweden

A fossil dating from 440 million years ago is not only the oldest example of a fossilised fungus, but is also the oldest fossil of any land-dwelling organism yet found. The organism, and others like it, played a key role in laying the groundwork for more complex plants, and later animals, to exist on land by kick-starting the process of rot and soil formation, which is vital to all life on land.

This early pioneer, known as Tortotubus, displays a structure similar to one found in some modern fungi, which likely enabled it to store and transport nutrients through the process of decomposition. Although it cannot be said to be the first organism to have lived on land, it is the oldest fossil of a terrestrial organism yet found. The results are published in the Botanical Journal of the Linnean Society.

"During the period when this organism existed, life was almost entirely restricted to the oceans: nothing more complex than simple mossy and lichen-like plants had yet evolved on the land," said the paper's author Dr Martin Smith, who conducted the work while at the University of Cambridge's Department of Earth Sciences, and is now based at Durham University. "But before there could be flowering plants or trees, or the animals that depend on them, the processes of rot and soil formation needed to be established."

Working with a range of tiny microfossils from Sweden and Scotland, each shorter than a human hair is wide, Smith attempted to reconstruct the method of growth for two different types of fossils that were first identified in the 1980s. These fossils had once been thought to represent parts of two different organisms, but by identifying other fossils with 'in-between' forms, Smith was able to show that the fossils actually represented parts of a single organism at different stages of growth. By reconstructing how the organism grew, he was able to show that the fossils represent mycelium - the root-like filaments that fungi use to extract nutrients from soil.

It's difficult to pinpoint exactly when life first migrated from the seas to the land, since useful features in the fossil record that could help identify the earliest land colonisers are rare, but it is generally agreed that the transition started early in the Palaeozoic era, between 500 and 450 million years ago. But before any complex forms of life could live on land, there needed to be nutrients there to support them. Fungi played a key role in the move to land, since by kick-starting the rotting process, a layer of fertile soil could eventually be built up, enabling plants with root systems to establish themselves, which in turn could support animal life.

link.

Black Fungi From Antarctica Survived in Simulated Martian Conditions for 18 Months on the ISS

Survival of Antarctic Cryptoendolithic Fungi in Simulated Martian Conditions On Board the International Space Station

Authors:

Silvano et al

Abstract:

Dehydrated Antarctic cryptoendolithic communities and colonies of the rock inhabitant black fungi Cryomyces antarcticus (CCFEE 515) and Cryomyces minteri (CCFEE 5187) were exposed as part of the Lichens and Fungi Experiment (LIFE) for 18 months in the European Space Agency's EXPOSE-E facility to simulated martian conditions aboard the International Space Station (ISS). Upon sample retrieval, survival was proved by testing colony-forming ability, and viability of cells (as integrity of cell membrane) was determined by the propidium monoazide (PMA) assay coupled with quantitative PCR tests. Although less than 10% of the samples exposed to simulated martian conditions were able to proliferate and form colonies, the PMA assay indicated that more than 60% of the cells and rock communities had remained intact after the “Mars exposure.” Furthermore, a high stability of the DNA in the cells was demonstrated. The results contribute to assessing the stability of resistant microorganisms and biosignatures on the surface of Mars, data that are valuable information for further search-for-life experiments on Mars.

Marine Fungi Discovered, Majority of Diversification/Evolution Seems to Have been Terrestrial

Researchers from the University of Exeter have discovered several new species of marine fungi inhabiting previously undescribed branches of the tree of life. Little is known about the fungi flourishing in the world's oceans and this study, which set out to investigate its diversity and abundance, revealed that many marine fungi are very different from those found on land.

The research, published in Proceedings of the Royal Society B, used large-scale DNA sequencing to describe the diversity of fungal microbes in a wide range of marine environments.

The study found a lower diversity and abundance of fungi in marine environments, suggesting that the majority of evolutionary diversification of fungi occurred on the land not in the sea.

link.

The Morel of the Story

ok.  just a mushroom.  dried and hard.

Great Trippin Titanosaurs! Grass, Ergot Fungus Found in Amber From Albian/Cenomanian Cretaceous Myanmar

A perfectly preserved amber fossil from Myanmar has been found that provides evidence of the earliest grass specimen ever discovered - about 100 million years old - and even then it was topped by a fungus similar to ergot, which for eons has been intertwined with animals and humans.

Ergot has played roles as a medicine, a toxin, and a hallucinogen; been implicated in everything from disease epidemics to the Salem witch trials; and more recently provided the hallucinogenic drug LSD.

Apparently both ergot and the grasses that now form most of the diet for the human race evolved together.

And if they already seemed a little scary, imagine a huge sauropod dinosaur that just ate a large portion of this psychotropic fungus, which in other animal species can cause anything from hallucinations to delirium, gangrene, convulsions or the staggers. The fungus, the grasses it lived on and dinosaurs that ate grass co-existed for millions of years.

The findings and analysis of this remarkable fossil were just published online in the journal Palaeodiversity, by researchers from Oregon State University, the USDA Agricultural Research Service and Germany.

"It seems like ergot has been involved with animals and humans almost forever, and now we know that this fungus literally dates back to the earliest evolution of grasses," said George Poinar, Jr., an internationally recognized expert on the life forms found in amber and a faculty member in the OSU College of Science.

"This is an important discovery that helps us understand the timeline of grass development, which now forms the basis of the human food supply in such crops as corn, rice or wheat," Poinar said. "But it also shows that this parasitic fungus may have been around almost as long as the grasses themselves, as both a toxin and natural hallucinogen.

"There's no doubt in my mind that it would have been eaten by sauropod dinosaurs, although we can't know what exact effect it had on them."

link.

Hypothesis: Lichen-Fungal Colonization of the Land Drove NeoProterozoic Oxidation Event?

Hypothesized link between Neoproterozoic greening of the land surface and the establishment of an oxygen-rich atmosphere

Author:

Kump

Abstract:

Considerable geological, geochemical, paleontological, and isotopic evidence exists to support the hypothesis that the atmospheric oxygen level rose from an Archean baseline of essentially zero to modern values in two steps roughly 2.3 billion and 0.8–0.6 billion years ago (Ga). The first step in oxygen content, the Great Oxidation Event, was likely a threshold response to diminishing reductant input from Earth’s interior. Here I provide an alternative to previous suggestions that the second step was the result of the establishment of the first terrestrial fungal–lichen ecosystems. The consumption of oxygen by aerobes respiring this new source of organic matter in soils would have necessitated an increase in the atmospheric oxygen content to compensate for the reduced delivery of oxygen to the weathering environment below the organic-rich upper soil layer. Support for this hypothesis comes from the observed spread toward more negative carbon isotope compositions in Neoproterozoic (1.0–0.542 Ga) and younger limestones altered under the influence of ground waters, and the positive correlation between the carbon isotope composition and oxygen content of modern ground waters in contact with limestones. Thus, the greening of the planet’s land surfaces forced the atmospheric oxygen level to a new, higher equilibrium state.

Pre Guadelupean Permian Extinction Lagerstätte Found in Antarctica

A high-latitude Gondwanan lagerstätte: The Permian permineralised peat biota of the Prince Charles Mountains, Antarctica

Authors:

Slater et al

Abstract:

The Toploje Member chert is a Roadian to Wordian autochthonous–parautochthonous silicified peat preserved within the Lambert Graben, East Antarctica. It preserves a remarkable sample of terrestrial life from high-latitude central Gondwana prior to the Capitanian mass extinction event from both mega- and microfossil evidence that includes cryptic components rarely seen in other fossil assemblages. The peat layer is dominated by glossopterid and cordaitalean gymnosperms and contains moderately common herbaceous lycophytes, together with a broad array of dispersed organs of ferns and other gymnosperms. Rare arthropod-plant and fungal-plant interactions are preserved in detail together with a plethora of fungal morphotypes, Peronosporomycetes, arthropod remains and a diverse coprolite assemblage. Comparisons to other Palaeozoic ecosystems show that the macroflora is of low diversity. The fungal and invertebrate-plant associations demonstrate that a multitude of ecological interactions were well developed by the Middle Permian in high-latitude forest mires that contributed to the dominant coal deposits of the Southern Hemisphere. Quantitative analysis of the constituents of the silicified peat and of macerals within adjacent coal seams reveals that whilst silicified peats provide an unparalleled sample of the organisms forming Permian coals, they do not necessarily reflect the volumetric proportions of constituents within the derived coal. The Toploje Member chert Lagerstätte provides a snapshot of a rapidly entombed mire climax ecosystem in the closing stages of the Palaeozoic, but prior to the onset of the protracted crisis that engulfed and overthrew these ecosystems at the close of the Permian.

ID the Mushroom Part II

ID the Mushroom

Found under Redwoods...

Anyone with an ID?

No, not likely to eat it.

Chrytid Fungus Reservoir Discovered...and its bad news

Scientists have found a new culprit in spreading the disease that's been driving the world's frogs to the brink of extinction: crayfish.

In the last few decades, the disease caused by the chytrid fungus has been a disaster for frogs and other amphibians. More than 300 species are nearly extinct because of it. Many probably have gone extinct, but it can be difficult to know for sure when a tiny, rare species disappears from the face of the Earth.

"This pathogen is bad news. It's worse news than any other pathogen in the history of life on Earth as far as we know it," says Vance Vredenburg, a conservation biologist at San Francisco State University who studies frogs but did not work on the new study.

The chytrid fungus was only discovered in the late 1990s. Since then, scientists have been scrambling to figure out how it spreads and how it works.

One of the biggest mysteries is how chytrid can persist in a frogless pond. Researchers saw it happen many times and were perplexed: If all of a pond's amphibians were wiped out, and a few frogs or salamanders came back and recolonized the pond, they would also die—even though there were no amphibians in the pond to harbor the disease.

One possible reason is that chytrid infects other animals. For a study published today in Proceedings of the National Academy of Sciences, Taegan McMahon, a graduate student in ecology at the University of South Florida in Tampa, looked at some possible suspects and focused on crayfish, those lobsterlike crustaceans living in freshwater. They seemed like a good possibility because they're widespread and because their bodies have a lot of keratin, a protein the fungus attacks.

In the lab, McMahon exposed crayfish to the disease and they got sick. More than a third died within seven weeks, and most of the survivors were carrying the fungus. She also put infected crayfish in the water with tadpoles—separated by mesh, so the crustaceans wouldn't eat the baby frogs—and the tadpoles got infected. When McMahon and her colleagues checked out wetlands in Louisiana and Colorado, they also found infected crayfish.

That means crayfish can probably act as a reservoir for the disease. The fungus seems to be able to dine on crayfish then leap back to amphibians when it gets a chance. No one knows for sure where the fungus originally came from or why it's been such a problem in recent decades, but this research suggests one way that it could have been spread. Crayfish are sometimes moved from pond to pond as fish bait and are sold around the world as food and aquarium pets.