ADVERTISEMENT

Rapid Recovery Of Reef-Building Organisms After The End-Permian Mass Extinction

In its whole history, the Earth has witnessed five big and several smaller mass extinctions. The greatest extinction, however, took place at the end of the Permian period, some 252 million years ago, marking the end of the Paleozoic Era. It has been estimated that during this extinction, 80% to even more than 90% of all marine species died out, including such iconic fossil groups like trilobites and all reef-building corals.

What was the cause of such a cataclysmic biotic crisis? There is a general agreement that the ultimate cause of this extinction was a massive volcanism in the area of the present-day Siberia (so-called Siberian Large Igneous Province). As evidenced from the sedimentary rock record in different parts of the world, the volcanism caused the large-scale atmospheric/oceanographic perturbations which led to several, not mutually exclusive proximate kill mechanisms such as warming, oxygen depletion, eutrophication, ocean acidification, toxic metal poisoning, or wholesale productivity decline. During such a cascade of events, life after the extinction needed much time to fully recover.

ADVERTISEMENT

One of the most characteristic signs of the end-Permian crisis is the absence of such ecologically important bioconstructions as reefs and other similar build-ups overwhelmingly formed by skeletal animals in the aftermath of the extinction. Instead, after the crisis, during the earliest Triassic times (the very beginning of the Mesozoic Era), such a bioconstructional role was dominantly played by microbes, which could have formed quite thick reef-like build-ups (so-called stromatolites) in both shallow and deeper seas across different parts of the post-extinction world.

It is generally considered that proliferation of microbe-dominating stromatolites resulted from specific conditions in the seas that were maybe even harsh for other benthic animals. If any skeletons of animals are detected in the post-extinction, early Triassic reef-like structures, these occur to be numerically subordinate component thriving within the stromatolite structures. The first organic build-ups in which animal skeletons played a significant role, appeared about 1 million years after the extinction in the area of the present –day Nevada, USA. There, the small ‘reefs’ were built by sponges and cementing bivalves.

A recent study (1) shows that, in fact, the true animal-forming (or metazoan) bioconstructions could have formed much earlier, even after about 300 thousand years after the Permian-Triassic boundary. These newly described bioconstructions were exclusively formed by an extinct group of small tubeworms called microconchids (“tiny shells”). Microconchids, which disappeared in the Jurassic Period, were known as “reef” builders in other periods in the Earth’s history; however, when they are found forming such bioconstructions just after the end-Permian mass extinction and well-before the other skeletal animals, like sponges and bivalves, is the first time they were able to do that.

Interestingly, these small-sized microconchid bioconstructions formed in a shallow sea in what is now East Greenland. Does it mean that such skeletal bioconstructions were able to form very quickly after the greatest of the mass extinctions only in higher latitudes? Or maybe microconchids coped much better in harsh environments than other animals and thus could have formed such structures much earlier? To fully answer these questions, more research in other areas must be conducted.

ADVERTISEMENT

These findings are described in the article entitled Earliest Triassic metazoan bioconstructions from East Greenland reveal a pioneering benthic community in the immediate aftermath of the end-Permian mass extinction, recently published in the journal Global and Planetary Change. This work was conducted by Michal Zaton and Michal Rakocinski from the Faculty of Earth Sciences, University of Silesia in Katowice, Poland, and Grzegorz Niedzwiedzki, Henning Blom, and Benjamin P. Kear from Department of Organismal Biology and Museum of Evolution, Uppsala University, Sweden.

Comments

READ THIS NEXT

What Is A Rhombus?

A rhombus (rhombi pl.) is the name for a special kind of quadrilateral, one in which all 4 sides are […]

Wood Spirit, An Alert Signal For Plants Under Attack

There is a plant-protecting spirit blowing through the air. If you breathe in carefully now you will smell… wood spirit! […]

Citizen Scientists Have Found A New Kind Of Aurora, Named “Steve”

The auroras have always been a sight of beauty and wonder that has captivated us throughout the ages. From myths and […]

Presence And Removal Of Perfluoroalkyl And Polyfluoroalkyl Substances In Potable Reuse

Many communities within the United States are experiencing a decline in both the quality and the quantity of water available […]

Nanotechnology For Sensitive Detection Of The Carcinoembryonic Antigen: A Cancer Biomarker

The carcinoembryonic antigen (CEA) is one of the most important clinical cancer biomarkers.  It is reported that an increase in […]

Functions Of The Golgi Body

The Golgi body, also sometimes referred to as the Golgi apparatus or Golgi complex, is an intracellular organelle that is responsible for […]

Plant Cell Diagram

A plant cell diagram, like the one above, shows each part of the plant cell including the chloroplast, cell wall, […]

Science Trends is a popular source of science news and education around the world. We cover everything from solar power cell technology to climate change to cancer research. We help hundreds of thousands of people every month learn about the world we live in and the latest scientific breakthroughs. Want to know more?