. | . |
Researchers puncture explanation for largest increase of biodiversity in Earth's history by Staff Writers Copenhagen, Denmark (SPX) Nov 11, 2021
In a geological period 469 million years ago known as the Ordovicium Period, Earth's seas were inhabited by animals like trilobites (reminiscent of pillbugs), conodonts (eel-like vertebrates) and brachichipods (animals with two-part shells reminiscent of seashells). But suddenly, something happened that became crucial for life to develop towards the life we know from today's oceans. Marine biodiversity quadrupled in a few million years. In fact, it was the largest increase in biodiversity in the history of our planet. The reason for this sudden spike in species diversity has always been a subject of hot debate in research circles. One of the most spectacular explanations has been that the explosion of an asteroid between Mars and Jupiter caused a gigantic, sustained meteor bombardment of Earth, one that formed a mass of cosmic dust that shadowed the Sun and resulted in a period of colder temperatures. While there is broad consensus that colder temperatures are crucial for the increase in biodiversity, the cosmic dust explanation does not hold. This, according to a new study by researchers at the University of Copenhagen and Museum Mors. "Our results demonstrate that the period of colder weather and increased biodiversity occurred long before the asteroid explosion and subsequent meteor bombardment - 600,000 years earlier, to be precise. This proves that these two phenomena cannot be linked," explains Nicolas Thibault, an associate professor at the University of Copenhagen's Department of Geosciences and Natural Resource Management. In fact, the researchers' analysis of fossils in ancient sedimentary layers of seabed at Steinsodden in southern Norway reveals that, on the contrary, the asteroid explosion led to a stagnation in biodiversity on Earth. "Instead of triggering an increase in biodiversity, the cosmic dust from the asteroid's explosion probably acted as a temporary brake on species evolution. The dust blocked sunlight, which impaired most photosynthetic processes - and the living conditions of animals in general, as a result," explains Jan Audun Rasmussen, curator and researcher at Museum Mors and the study's lead author.
Colder weather led to a change in Earth's climate cycles "Our study shows that a shift towards a colder climate began exactly 469.2 million years ago. 200,000 years later, temperatures were even lower and caused ice to form at the then south pole," explains the study's co-author, Christian Mac Orum Rasmussen, an associate professor at the University of Copenhagen's GLOBE Institute. This change in climate, which the new study finds recorded in limestone layers from southern Norway, coincides with a change in relation to the planet's axis of rotation and orbit around the sun. According to the researchers, this is the change that triggered a permanent shift towards colder climates and the consequent blooming of marine biodiversity. "Our study has brought us a step closer to understanding what led to this large increase in biodiversity. At the same time, we have also discovered an important piece of the puzzle with regards to how climate affects biodiversity and life on Earth in general. This knowledge will allow us to better prevent the loss of animal and plant diversity in the future," concludes Nicolas Thibault.
Research Report: "Middle Ordovician astrochronology decouples asteroid breakup from glacially-induced biotic radiations"
Researchers discover first dinosaur species that lived on Greenland 214 million years ago Halle, Germany (SPX) Nov 09, 2021 The two-legged dinosaur Issi saaneq lived about 214 million years ago in what is now Greenland. It was a medium-sized, long-necked herbivore and a predecessor of the sauropods, the largest land animals ever to live. It was discovered by an international team of researchers from Portugal, Denmark and Germany, including the Martin Luther University Halle-Wittenberg (MLU). The name of the new dinosaur pays tribute to Greenland's Inuit language and means "cold bone". The team reports on its discovery in the ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |