Archives par mot-clé : Organisms

Permian–Triassic mass extinction pulses driven by major marine carbon cycle perturbations

by Jurikova, H. et al., Oct 19, 2020 in NatureGeoscience


The Permian/Triassic boundary approximately 251.9 million years ago marked the most severe environmental crisis identified in the geological record, which dictated the onwards course for the evolution of life. Magmatism from Siberian Traps is thought to have played an important role, but the causational trigger and its feedbacks are yet to be fully understood. Here we present a new boron-isotope-derived seawater pH record from fossil brachiopod shells deposited on the Tethys shelf that demonstrates a substantial decline in seawater pH coeval with the onset of the mass extinction in the latest Permian. Combined with carbon isotope data, our results are integrated in a geochemical model that resolves the carbon cycle dynamics as well as the ocean redox conditions and nitrogen isotope turnover. We find that the initial ocean acidification was intimately linked to a large pulse of carbon degassing from the Siberian sill intrusions. We unravel the consequences of the greenhouse effect on the marine environment, and show how elevated sea surface temperatures, export production and nutrient input driven by increased rates of chemical weathering gave rise to widespread deoxygenation and sporadic sulfide poisoning of the oceans in the earliest Triassic. Our findings enable us to assemble a consistent biogeochemical reconstruction of the mechanisms that resulted in the largest Phanerozoic mass extinction.


by Cap Allon, Sep 26, 2020 in Electroverse

Since 1850 Earth’s magnetic field has been weakening. At the turn of the millennium it then began reducing exponentially, at more than 10% per decade — this drop off is extreme and concerning, and here’s why.

Earth’s magnetic field protects us from space radiation. Our shields going down is very bad news for all life on our planet, and could possibly even lead to the next mass extinction.

“As the magnetic field weakens, the poles shift,” says David Mauriello of the ORP and MRN. For the past 100-or-so years, both north and south poles have been rapidly headed towards the equator (shown below), and their pace is increasing, warns Mauriello. The south pole is now off the Antarctic continent and making a beeline for Indonesia, and the north pole is shifting across the Arctic circle towards Siberia, it too headed for Indonesia–where the pair are likely to meet within the next few decades, perhaps around 2050.

This “meeting” will lead to one of two eventualities: 1) a full flip will take place (aka a “reversal” where the magnetic poles switch places), or 2) a “snap-back” will occur where the poles quickly return to their original starting points (aka an “excursion”).

Evolution after Chicxulub asteroid impact: Rapid response of life to end-cretaceous mass

by Geological Society of America, July 14, 2020 in ScienceDaily

The impact event that formed the Chicxulub crater (Yucatán Peninsula, México) caused the extinction of 75% of species on Earth 66 million years ago, including non-avian dinosaurs. One place that did not experience much extinction was the deep, as organisms living in the abyss made it through the mass extinction event with just some changes to community structure.

New evidence from International Ocean Discovery Program (IODP) Expedition 364 of trace fossils of burrowing organisms that lived in the seafloor of the Chicxulub Crater beginning a few years after the impact shows just how quick the recovery of the seafloor ecosystem was, with the establishment of a well-developed tiered community within  approximately 700,000 years after the event.

Acid Oceans? & Oyster Shells

by Jim Steele, July 14, 2020 in WUWT

(I wrote a white paper for the CO2  Coalition, providing more details and references to peer reviewed science regards how marine life counteracts ocean acidification. That paper can be downloaded here )

Search the internet for “acid oceans” and you’ll find millions of articles suggesting the oceans are becoming more corrosive due the burning of fossil fuels, and “acid oceans” are threatening marine life. Although climate modelers constantly claim the oceans’ surface pH has dropped since the 1800s, that change was never measured, as the concept of pH was not created until the early 1900s by beer-makers.

In 2003 Stanford’s Dr. Ken Caldeira coined the term “ocean acidification” to generate public concern about increasing CO2  . As New Yorker journalist Elizabeth Kolbert reported, “Caldeira told me that he had chosen the term ‘ocean acidification’ quite deliberately for its shock value. Seawater is naturally alkaline, with a pH ranging from 7.8 to 8.5—a pH of 7 is neutral—which means that, for now, at least, the oceans are still a long way from actually turning acidic.” Nonetheless Caldeira’s term “ocean acidification” evoked such undue fears and misunderstandings, we are constantly bombarded with catastrophic media hype and misdiagnosed causes of natural change.

For example, for nearly a decade the media has hyped the 2006-2008 die-off of larval oysters in hatcheries along Washington and Oregon. They called it a crisis caused by rising atmospheric CO2  and the only solution was to stop burning fossil fuels. But it was an understanding of natural pH changes that provided the correct solutions. Subsurface waters at a few hundred meters depth naturally contain greater concentrations CO2  and nutrients and a lower pH than surface waters. Changes in the winds and currents periodically bring those waters to the surface in a process called upwelling. Upwelling promotes a burst of life but also lowers the surface water pH.  Not fully aware of all the CO2  dynamics, the hatcheries had made 3 mistakes.

When Exposed To Natural, Long-Term Extreme ‘Ocean Acidification’, Coral And Urchin ‘Persist’ And Even ‘Thrive’

by K. Richard, June 29, 2020 in NoTricksZone

Marine species subjected to high CO2 extremes – 8,891 to 95,000 ppm – in their natural environments may not be adversely affected. They may even “thrive”.

Earlier this year we highlighted a study that says coral reefs “thrive” near seafloor volcanic vents where CO2 concentrations reach 60,000 to 95,000 ppm.

Urchins basking in volcanic vent streams of 8,891 ppm CO2 and daily CO2 variations of more than 2,000 ppm as well as day-to-day pH fluctuations ranging from 6.9 (“acidification”) to 8.1…grow more than two times faster than nearby control (stable 394 ppm CO2, 8.1 pH) urchins (Uthicke et al., 2016).

Actualité Débats Kervasdoué – Quelques vérités sur la biodiversité

by Jean de Kersvasdoué, 6 janvier 2020 in LePoint

Derrière une bataille de chiffres alarmistes se cachent des biais statistiques et des questions de fond sur ce que l’on entend par « biodiversité ».


À l’occasion des vœux à la nation, le président de la République, Emmanuel Macron, a déclaré vouloir « œuvrer en faveur de la biodiversité ». Cet objectif est noble pour de multiples raisons et, notamment, parce que certaines espèces de grands mammifères sont menacées mais aussi quelques plantes et animaux de la métropole. Les grands singes, le rhinocéros noir sont en voie d’extinction. En ce qui concerne ce dernier, selon l’UICN, il n’en restait que 5 055 têtes en 2012. Or ces animaux continuent d’être chassés pour les prétendues valeurs aphrodisiaques de leur corne revendue 40 000 dollars le kilo à Shanghai. On comprend pourquoi les braconniers les recherchent et trouvent des complicités chez des gardes mal payés qui, en outre, risquent leur vie en s’opposant aux auteurs de ces regrettables massacres. A contrario, certaines espèces que l’on croyait disparues à l’état sauvage renaissent, comme la perruche de l’île Maurice ou l’oryx d’Arabie. Toutefois, en la matière, les bonnes nouvelles sont rares et la liste des espèces menacées à l’état sauvage s’allonge dans le monde du fait de la croissance de la population de la planète et de la mise en culture d’espaces jusque-là occupés par la forêt. Des écosystèmes disparaissent et avec eux végétaux et animaux qui y vivaient. Si donc préserver ces espèces est un objectif louable, il concerne rarement la France à l’exception des forêts de Guyane, mais il la touche cependant.

En France métropolitaine, le nombre de plantes supérieures, à fleurs, dites « phanérogames », donc hors champignons, mousses, fougères, lichens, algues, etc., du territoire métropolitain est d’environ 5 000 espèces sauvages ou cultivées. Pour les vertébrés, on y trouve de l’ordre de 40 poissons d’eau douce, 40 amphibiens (ou batraciens), 40 reptiles (serpents, lézards, tortues), 400 oiseaux en comptant des migrateurs qui ne nichent pas sur le territoire national, et 80 mammifères. Au total : environ 600 vertébrés. Donc, en additionnant les végétaux supérieurs et les animaux supérieurs, au sens de l’évolution darwinienne, 5 600 espèces en France. La très grande majorité n’est pas menacée et les espèces qui sont prétendues l’être (1) ne le sont pas toujours.

L’exagération est la règle

Sur les six espèces décrites comme pouvant disparaître, il y a une plante (l’orchis couleur de lait) et cinq animaux (la sterne de l’Arctique, le lynx boréal, la grenouille des champs, la tortue d’Hermann et l’anguille). On trouve l’orchis couleur de lait dans le sud de la France et en Corse, il est difficile de mesurer la réalité de la menace qui pèse sur elle (2), faute de méthode de recensement. En ce qui concerne les espèces animales, deux ne sont en rien menacées (la sterne et le lynx boréal). Si la grenouille des champs l’est dans notre pays, elle ne l’est pas ailleurs en Europe à l’exception de la grenouille des Pyrénées. Restent la tortue d’Hermann et l’anguille européenne.

La tortue d’Hermann est la seule espèce de tortue terrestre de France. Elle est présente dans le Var et en Corse. Son habitat est détruit par les feux de forêt, le débroussaillage, le morcellement des parcelles, les routes et l’habitat pavillonnaire. Quant à l’anguille européenne (Anguilla anguilla), autrefois abondante dans tous les cours d’eau et les zones humides (lacs, étangs, marais, mares, fossés), son déclin se constate depuis 40 ans. Cette régression provient de plusieurs facteurs : divers contaminants toxiques (pesticides organochlorés bio-accumulés par l’anguille), la surpêche des civelles et des adultes de plus en plus appréciés, le braconnage, les obstacles sur la route des alevins et une augmentation du taux de parasitisme (par le nématode Anguillicola crassus) qui perturbe la migration marine des adultes. Un règlement européen (R(CE) no 1100/2007) impose des mesures de connaissance et de protection et de gestion de l’anguille et semble porter des fruits.

Continuer la lecture de Actualité Débats Kervasdoué – Quelques vérités sur la biodiversité

The Corals That Don’t Exist

by Donna Laframboise, November 18, 2019 in BigPictureNews

In December 2015 Peter Ridd, then a physics professor at Australia’s James Cook University, contacted a journalist. Researchers affiliated with his own institution, he said, were misleading the public about the Great Barrier Reef.

As an example, Ridd cited photos taken approximately 100 years apart near Bowen, a community of 10,000 on the Australian coast in the vicinity of the Reef. These photos tell a stark story: previously vibrant coral expanses are now desolate wastelands.

Ridd complained that this pair of photos was spreading across the Internet. They were appearing in official reports and news stories. Even though the 1995 paper in which they’d first been published had cautioned against viewing them as evidence the Reef was in “broad scale decline,” that’s exactly how they were being used.

Ridd supplied the journalist with recent photos from the same area. These showed healthy, abundant coral.

Patrick Moore auditionné par la Chambre des représentant des Etats Unis à propos du rapport de l’IPBES

by Usbek, 29 mai 2019 in ClimatEnvironnementEnergie

Le  22 mai 2019 la Chambre des représentants des Etats Unis a organisé une audition sur le récent rapport d’évaluationglobale de l’IPBES (Plateforme intergouvernementale scientifique et politique sur la biodiversité et les services éco systémiques ).

Patrick Moore a été invité a donner son témoignage; nous en donnons ci-dessous une traduction (les liens et renvois en bas de page sont du traducteur).

Je vous remercie de m’avoir donné l’occasion de témoigner à l’audience d’aujourd’hui.

En 1971, alors que j’étais doctorant en écologie, je me suis joint à un groupe d’activistes dans un sous-sol d’église à Vancouver, au Canada, et j’ai traversé le Pacifique à bord d’un petit bateau pour protester contre les essais américains de bombes à hydrogène en Alaska. Nous sommes devenus Greenpeace. Après 15 ans au sein du comité directeur, j’ai dû quitter Greenpeace, qui commençait à adopter des politiques que je ne pouvais accepter d’un point de vue scientifique.

Je me suis donné comme mission de toujours appliquer de sains principes scientifiques lors de l’examen des problèmes environnementaux critiques auxquels nous sommes confrontés aujourd’hui.

Ce n’est qu’au début des années 1900, marquées par la disparition définitive de la tourte voyageuse en 1914, que le grand public a commencé à s’intéresser de près à la question de l’extinction des espèces. Cette prise de conscience a été inspirée par l’activisme précoce de Théodore Roosevelt, John Muir et Gifford Pinchot.

UN Biodiversity Officials Fail Transparency Test

by Donna Laframboise, May 13, 2019 in BigPictureNews

The United Nations Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is a clone of the IPCC, the UN’s climate body. But there are some notable differences.

We’re told that a great deal of power resides with the Multidisciplinary Expert Panel (MEP), which currently consists of 28 individuals. These are the people who, for example, decide which international scholars will be assigned to discuss which topics within the pages of official IPBES reports.

To its credit, that entity’s website has been designed to provide the CV of everyone who sits on this panel. Rather than taking the UN’s word for it that these are world class experts, the public is given the opportunity to examine their credentials firsthand.

But saying you believe in transparency is different from acting like it. If organizations aren’t living up to the standards they’ve set for themselves, that’s worth noticing.

Last week was hugely important for the IPBES – it sought and received massive international media coverage. Despite this, it utterly failed its own transparency test. The CVs of most MEP members aren’t actually available online.

Methane-consuming bacteria could be the future of fuel

by Northwestern University, May 9, 2019 in ScienceDaily

Discovery illuminates how bacteria turn methane gas into liquid methanol.
Researchers have found that the enzyme responsible for the methane-methanol conversion in methanotrophic bacteria catalyzes the reaction at a site that contains just one copper ion. This finding could lead to newly designed, human-made catalysts that can convert methane — a highly potent greenhouse gas — to readily usable methanol with the same effortless mechanism.
The study will publish on Friday, May 10 in the journal Science. Rosenzweig is the Weinberg Family Distinguished Professor of Life Sciences in Northwestern’s Weinberg College of Arts and Sciences. Hoffman is the Charles E. and Emma H. Morrison Professor of Chemistry at Weinberg.

By oxidizing methane and converting it to methanol, methanotrophic bacteria (or “methanotrophs”) can pack a one-two punch. Not only are they removing a harmful greenhouse gas from the environment, they are also generating a readily usable, sustainable fuel for automobiles, electricity and more.

Current industrial processes to catalyze a methane-to-methanol reaction require tremendous pressure and extreme temperatures, reaching higher than 1,300 degrees Celsius. Methanotrophs, however, perform the reaction at room temperature and “for free”.

IPCC Clone Predicts Doom

by Donna Laframboise, May 6, 2019 in BigPictureNews

Here we ago again. For some time, I’ve warned that the Intergovernmental Panel on Climate Change (IPCC) is a template, that the United Nations is up to the same tricks elsewhere.

Today, in Paris, an IPCC clone known as the IPBES – the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services – will announce the completion of an 1,800-page report.

Jonathan Watts, the UK Guardian‘s global environment editor, has already told us everything we need to know about this ‘IPCC for Nature‘.

Under the headline Biodiversity crisis is about to put humanity at risk, UN scientists to warn, he insists this report was written by “The world’s leading scientists.” Funny, that’s how compliant, gullible journalists described IPCC personnel. For years and years. Until I began to notice that some of those involved were graduate students in their 20s.


by Andrew Montford, April 23, 2019 in GWPF

Extinction Rebellion seem to be everywhere at the moment. And everywhere their story is the same. We are in the middle of a climate catastrophe. As the Huffington Post put it,

Human-caused climate change is driving sea-level rise, drought, extreme weather and a biodiversity crisis that scientists have declared Earth’s sixth mass extinction event. As many as 150 species die off each day.

Scary eh? Surely that’s enough to justify the odd street protest?

It was therefore interesting to see read some remarks from Richard Betts today. Professor Betts is the head of climate impacts at the Met Office, so his views in this area carry a certain amount of weight. Asked what he thought were the top three negative impacts of climate change that have “absolutely started”, he replied:

  • Sea level rise
  • Increasing risk of high temperatures
  • Changes in phenology and distribution for numerous species

This left me agog. There was nothing about drought or hurricanes or any of the other manifestations of extreme weather that are said to be afflicting us; nothing about floods, or typhoons, or desertification or crashing crop yields or climate refugees, mass extinctions, skydiving walruses and any of the thousand and one tall tales that climate activists spin and the media faithfully repeat every day. The contrast between this take on currently observed negative impacts and David Attenborough’s risible Climate Change: the Facts programme last week is startling. The take home message is that most of what the “national treasure” told viewers about climate change was grubby insinuation rather than fact: less to do with science than with the BBC’s ongoing eco-campaign.

New evidence suggests volcanoes caused biggest mass extinction ever

by University of Cincinnati, April 15, 2019 in ScienceDaily from Nature

Mercury found in ancient rock around the world supports theory that eruptions caused ‘Great Dying’ 252 million years ago.

Researchers say mercury buried in ancient rock provides the strongest evidence yet that volcanoes caused the biggest mass extinction in the history of the Earth.

The extinction 252 million years ago was so dramatic and widespread that scientists call it “the Great Dying.” The catastrophe killed off more than 95 percent of life on Earth over the course of hundreds of thousands of years.

Paleontologists with the University of Cincinnati and the China University of Geosciences said they found a spike in mercury in the geologic record at nearly a dozen sites around the world, which provides persuasive evidence that volcanic eruptions were to blame for this global cataclysm.

The study was published this month in the journal Nature Communications.

The eruptions ignited vast deposits of coal, releasing mercury vapor high into the atmosphere. Eventually, it rained down into the marine sediment around the planet, creating an elemental signature of a catastrophe that would herald the age of dinosaurs.

“Volcanic activities, including emissions of volcanic gases and combustion of organic matter, released abundant mercury to the surface of the Earth,” said lead author Jun Shen, an associate professor at the China University of Geosciences.

“Global climate change” does not cause species extinctions

by Paul Berth, March 22, 2019 in ScienceClimatEnergie

Contrary to what the media tries to make you believe, global climate change is not a major cause of species extinction. A recent study published in March 2019 in Frontiers in Ecology and the Environment shows that the major cause of extinction is the introduction of invasive alien species (IAS) into ecosystems. This phenomenon, well known to biologists and confirmed by the IUCN (International Union for the Conservation of Nature), is unfortunately little known to the general public.

Figure 1. Number of recent animal extinctions (IUCN categories “extinct” [EX] and “extinct in the wild” [EW]) for different groups of animals (figures from IUCN Table 3a). The colors provide information on the causes of the extinctions (“Driver”); for example dark purple is used for IAS (“Alien”), extinctions caused by local species (“Native”) are light purple. The category “Neither” includes other causes of extinction or unknown causes (source, Blackburn et al., 2019).



Le “Changement climatique global’ ne cause pas de disparitions d’espèces

by Prof. Paul Berth, 22 mars 2019 in ScienceClimateEnergie

Contrairement à ce que les médias tentent de vous faire croire, le changement climatique global n’est pas une cause majeure de disparition d’espèces. Une récente étude publiée en mars 2019 dans le journal Frontiers in Ecology and the Environment vous le démontre : la cause majeure d’extinction est l’introduction d’espèces exotiques envahissantes (EEE) dans les écosystèmes. Ce phénomène, bien connu des biologistes et confirmé par l’IUCN(Union Internationale pour la Conservation de la Nature), est malheureusement peu connu du grand public.

1. Introduction

En se déplaçant d’un continent à l’autre, l’être humain a toujours emmené avec lui toute une série de plantes et d’animaux qui se retrouvaient ainsi en dehors de leurs limites biogéographiques habituelles. Avec le développement du commerce international ce phénomène ne fait que s’amplifier. Par exemple, à l’intérieur de l’Union Européenne, le nombre d’EEE aurait augmenté de 76% entre 1970 et 2007. Bien que l’impact écologique de la plupart des espèces introduites est inconnu ou semble négligeable, il est démontré que certaines introductions d’espèces ont provoqué des changements substantiels dans des écosystèmes[1]. Ces changements incluent souvent la disparition d’espèces locales[2]. On a d’abord pensé que ces phénomènes d’extinction étaient exagérés et que des espèces locales pouvaient également être à la base d’extinctions[3], et certains auteurs pensent même que les efforts déployés pour contrôler ou éradiquer les espèces étrangères introduites ne seraient pas nécessaires[4]. Cependant, personne n’a jamais vraiment testé si les espèces introduites provoquaient plus ou moins d’extinctions par rapport aux espèces locales ou aux autres causes d’extinctions. Cette question a donc été étudiée par l’équipe de Tim Blackburn (University College London, UK) dans une récente publication de mars 2019[5]. Ils ont pour cela utilisé la base de données des extinctions globales fournie par l’IUCN.

Figure 1. Nombre d’extinctions animales récentes (catégories IUCN “extinct” [EX] et “extinct in the wild” [EW]) pour différents groupes d’animaux (chiffres issus de la Table 3a de l’IUCN). Les couleurs renseignent sur les causes des extinctions (“Driver”); par exemple le mauve foncé est employé pour les EEE (“Alien”), les extinctions causées par des espèces locales (“Native”) sont en mauve clair. La catégorie “Neither” comporte les autres causes d’extinction ou alors des causes inconnues (source, Blackburn et al. 2019).


Uranium in mine dust could dissolve in human lungs

by American Chemical Society, December 5, 2018 in ScienceDaily

New Mexico contains hundreds of historic uranium mines. Although active uranium mining in the state has ceased, rates of cardiovascular and metabolic disease remain high in the population residing close to mines within the Navajo Nation. According to a new study in ACS’ journal Environmental Science & Technology Letters, inhaled uranium in dusts from the mines could be a factor.

Pulses of sinking carbon reaching the deep sea are not captured in global climate models

by Monterey Bay Aquarium Research Institute, December 3, 2018 in ScienceDaily

More than two miles below the ocean’s surface, microbes, worms, fishes, and other creatures great and small thrive. They rely on the transport of dead and decaying matter from the surface (marine snow) for food at these dark depths.

Up near the sea surface, carbon dioxide from the atmosphere is incorporated in the bodies of microscopic algae and the animals that eat them. When they die, these organisms sink to the depths, carrying carbon with them.

This supply of carbon to the deep sea isn’t steady. At times, months’ to years’ worth of marine snow falls to the abyss during very short “pulse” events.

In a new study published in the Proceedings of the National Academy of Sciences (PNAS), MBARI scientists and their collaborators show that there has been an increase in pulse events off the coast of California. They also show that, although such episodes are very important to the carbon cycle, they are not well represented in global climate models.

Another failure of peer review, due to corrupt temperature data from a single station

by Anthony Watts, November 7, 2018 in WUWT

A new study, based on 27 years of data from Mana Pools National Park in Zimbabwe, suggests that temperature increases over the last three decades have already caused major declines in local populations of tsetse flies.

This analysis, published in the journal PLOS Medicine this week, provides a first step in linking temperature to the risk of sleeping sickness in Africa.

My analysis

A model for fly population mortality is only as good as the temperature data used to run the model. It appears they only used one source of temperature data, the only one available to them, the Rekomitjie Research Station.

Interestingly, this helpful photo was also included in the press release from Eurekalert. It is the weather station used to monitor climate at the Rekomitjie Research Station, Zimbabwe. I provide it below, click for full-size. At the scale displayed above, you might not notice some important details about the weather station itself, but I did. Here it is, magnified: …

Integrated genomic and fossil evidence illuminates life’s early evolution and eukaryote origin

by Holly C. Betts et al., August 20, 2018 in NatureEcology&Evolution

We derive a timescale of life, combining a reappraisal of the fossil material with new molecular clock analyses. We find the last universal common ancestor of cellular life to have predated the end of late heavy bombardment (>3.9 billion years ago (Ga)). The crown clades of the two primary divisions of life, Eubacteria and Archaebacteria, emerged much later (<3.4 Ga), relegating the oldest fossil evidence for life to their stem lineages. The Great Oxidation Event significantly predates the origin of modern Cyanobacteria, indicating that oxygenic photosynthesis evolved within the cyanobacterial stem lineage. Modern eukaryotes do not constitute a primary lineage of life and emerged late in Earth’s history (<1.84 Ga), falsifying the hypothesis that the Great Oxidation Event facilitated their radiation…

Billion-year-old lake deposit yields clues to Earth’s ancient biosphere

by McGill University, July 18, 2018 in ScienceDaily

The findings, published in the journal Nature, represent the oldest measurement of atmospheric oxygen isotopes by nearly a billion years. The results support previous research suggesting that oxygen levels in the air during this time in Earth history were a tiny fraction of what they are today due to a much less productive biosphere.

“It has been suggested for many decades now that the composition of the atmosphere has significantly varied through time,” says Peter Crockford, who led the study as a PhD student at McGill University. “We provide unambiguous evidence that it was indeed much different 1.4 billion years ago.”

The study provides the oldest gauge yet of what earth scientists refer to as “primary production,” in which micro-organisms at the base of the food chain — algae, cyanobacteria, and the like — produce organic matter from carbon dioxide and pour oxygen into the air.

In the ocean’s twilight zone, tiny organisms may have giant effect on Earth’s carbon cycle

by Florida State University, July 18, 2018 in ScienceDaily

Deep in the ocean’s twilight zone, swarms of ravenous single-celled organisms may be altering Earth’s carbon cycle in ways scientists never expected, according to a new study from Florida State University researchers.

In the area 100 to 1,000 meters below the ocean’s surface — dubbed the twilight zone because of its largely impenetrable darkness — scientists found that tiny organisms called phaeodarians are consuming sinking, carbon-rich particles before they settle on the seabed, where they would otherwise be stored and sequestered from the atmosphere for millennia.

This discovery, researchers suggest, could indicate the need for a re-evaluation of how carbon circulates throughout the ocean, and a new appraisal of the role these microorganisms might play in Earth’s shifting climate.

The findings were published in the journal Limnology and Oceanography.

Scientists discover Earth’s youngest banded iron formation in western China

by University of Alberta, July 11, 2018 in ScienceDaily

Discovery provides evidence of iron-rich seawater much later than previously thought.

The banded iron formation, located in western China, has been conclusively dated as Cambrian in age. Approximately 527 million years old, this formation is young by comparison to the majority of discoveries to date. The deposition of banded iron formations, which began approximately 3.8 billion years ago, had long been thought to terminate before the beginning of the Cambrian Period at 540 million years ago.

The Early Cambrian is known for the rise of animals, so the level of oxygen in seawater should have been closer to near modern levels. “This is important as the availability of oxygen has long been thought to be a handbrake on the evolution of complex life, and one that should have been alleviated by the Early Cambrian,” says Leslie Robbins, a PhD candidate in Konhauser’s lab and a co-author on the paper.

Why life on Earth first got big

by University of Cambridge, June 25, 2018 in ScienceDaily

Some of the earliest complex organisms on Earth — possibly some of the earliest animals to exist — got big not to compete for food, but to spread their offspring as far as possible.

The research, led by the University of Cambridge, found that the most successful organisms living in the oceans more than half a billion years ago were the ones that were able to ‘throw’ their offspring the farthest, thereby colonising their surroundings. The results are reported in the journal Nature Ecology and Evolution.

Prior to the Ediacaran period, between 635 and 541 million years ago, life forms were microscopic in size, but during the Ediacaran, large, complex organisms first appeared, some of which — such as a type of organism known as rangeomorphs — grew as tall as two metres.


See also here

Ancient Greenland was much warmer than previously thought

by Amanda Morris, June 4, 2018 inNorthwesternUniversity

A tiny clue found in ancient sediment has unlocked big secrets about Greenland’s past and future climate.

Just beyond the northwest edge of the vast Greenland Ice Sheet, Northwestern University researchers have discovered lake mud that beat tough odds by surviving the last ice age. The mud, and remains of common flies nestled within it, record two interglacial periods in northwest Greenland. Although researchers have long known these two periods — the early Holocene and Last Interglacial — experienced warming in the Arctic due to changes in the Earth’s orbit, the mix of fly species preserved from these times shows that Greenland was even warmer than previously thought.

Giant clams tell the story of past typhoons

by Hokkaido University, May 24, 2018 in ScienceDaily

A highly precise method to determine past typhoon occurrences from giant clam shells has been developed, with the hope of using this method to predict future cyclone activity.

A team of researchers led by Tsuyoshi Watanabe of Hokkaido University has discovered that giant clams record short-term environmental changes, such as those caused by typhoons, in their shells. Analyzing the shell’s microstructure and chemical composition could reveal data about typhoons that occurred before written records were available… (…)

The whole Tridacna maxima valve. The shell was cut in two sections along the maximum growth axis.
Credit: Komagoe T. et al., Journal of Geophysical Research: Biogeosciences, April 19, 2018