Saturday 18 February 2023

Worries About the Earth's Carbon Cycle

 Worries About the Earth's Carbon Cycle

I have written before about Geology Bites. I listened to the LATEST ONE last week and was mightily impressed - and worried. In it Oliver Stimpel talks to Dan Rothman who is professor of Geophysics at MIT.

The professor studies the carbon cycle and has found about 30 disruptions. These occur when there are injections of carbon into the system. These are usually associated with very large volcanic eruptions. And five of these disruptions are associated with mass extinctions.

Here are the mass extinctions.

Extinction rates for marine animals during the Phanerozoic.  The “Big Five” extinctions are labeled: end-Ordovician (Ord), Frasnian-Famennian (FF), end-Permian (PT), end-Triassic (TJ), and end-Cretaceous (KT).

And here is the size of the carbon injection graphed against the duration of the disruption.

This is the key plot discussed by Dan Rothman in the podcast.  It shows the relative sizes (m = mass of carbon) versus the durations of 31 disruptions of the carbon cycle during the Phanerozoic.  The red dots mark the disruptions corresponding to the five major mass extinctions (see figure above), while the blue dots represent disruptions that were not associated with unusually high rates of extinction.  The straight line denotes a characteristic rate of change of the carbon in the Earth system.  Most of the events fall near the line (gray region), while four of the five events corresponding to the major mass extinctions fall above the line.  The fifth mass extinction, in the late Devonian at the Frasnian-Famennian boundary, is clearly different, lying in the slow region below the line.  Some researchers have suggested that the Frasnian-Famennian event is not an extinction event but instead represents a decrease in the rate at which new species originate.

Rothman, D.H. (2017), Science Advances, 3:e1700906

The podcast gets worrying when it looks at what is happening in the present day.

Listen to the podcast and read the associated WEB PAGE. The pod cast is near the top of the page

Saturday 11 February 2023

Volatile Elements Coming to Earth from Space

 Volatile Elements Coming to Earth from Space

I came across this on the internet - you might find it interesting.

Volatile elements refer to those elements that readily vaporize at relatively low temperatures. These elements, along with other building blocks of life such as carbon, nitrogen, and oxygen, are important for the formation and sustenance of life on Earth.

The Earth's volatile elements were not all present on the planet from its formation. A significant portion of them was brought to the Earth through a process called "accretion." This process involved the collision of smaller celestial bodies with the early Earth, which resulted in the transfer of volatile elements from these bodies to the Earth.

Over time, the Earth's volatile elements were also replenished through the process of bombardment by comets and asteroids. These objects, known as "volatile-rich bodies," contain large amounts of volatile elements such as water, carbon dioxide, and ammonia. When they collide with the Earth, they release these elements into the atmosphere and onto the surface, where they can contribute to the formation of the oceans and the development of life.

The continued delivery of volatile elements to the Earth is crucial for the sustenance of life. For example, the water brought to the Earth by comets and asteroids is essential for the survival of living organisms, as it provides a medium for the chemical reactions necessary for life. The carbon and nitrogen brought to the Earth by these objects also play a crucial role in the formation of organic molecules, the building blocks of life.

In conclusion, volatile elements play a significant role in the formation and sustenance of life on Earth. Their delivery to the Earth through processes such as accretion and bombardment by comets and asteroids has had a lasting impact on the planet and its ability to support life. The continued delivery of these elements is essential for the maintenance of a thriving biosphere.

You might think this is rather better written than most of the stuff on this blog. Because it was not written by me! It was written by a computer! 

I went to and asked it to "Write a short essay on "Volatile elements coming to Earth from space."" and the stuff in blue text appearred a few seconds later. It seems pretty good stuff - it would get a reasonable mark in a first year exam. It certainly came up with it in a shorter time than I would. 

Perhaps I can get it to write the blog in the future.

Tuesday 7 February 2023

Volcanic Activity Heats Up at Santorini?

 Volcanic Activity Heats Up at Santorini?

Another Correspondent found THIS ARTICLE in the Guardian. It is based on THIS academic paper. It concerns the Kolumbo submarine volcano which last erupted in 1650 CE when it killed 70 people.

There are rather more people around Santorini nowadays compared to 1650 but the likelihood of an unheralded eruption is low. Indeed the burden of the articles is that Kolumbo should be monitored closely so that any danger can be foreseen.

The Kolumbo volcano is not in the caldera of Santorini but some 15km to the north east along the Kolumbo Chain.

There are other scientific investigations of the area being carried out currently. In particular Joides Resolution is working in the area at present. You can read all about it HERE.

When Greenland was Green

When Greenland was Green 

A correspondent sent me THIS LINK to a very interesting article about finding the world's oldest DNA and the even more interesting fact that 2 million years ago Greenland was indeed green!

The DNA was recovered from sediment taken from northernmost point of Greenland. This is environmental DNA - stuff shed into the environment by living creatures and plants. The DNA fragments were compared with the "DNA Library" and found to have come from things not found in Northern Greenland today. (I don't think there is much to be found there nowadays!)

The most eye catching find was mastodon DNA. The thought of "elephants" at the North Pole is rather mind-blowing!

But everything else is equally surprising. The picture which emerges is of an environment 10 to 17 degrees Celcius warmer than todays Greenland.

As amazing as the lush ecosystem of 2 million years ago is the extraction of DNA from sediment. I wonder what other amazements will come from this.

An artist's reconstruction of what the Kap KĂžbenhavn Formation in northern Greenland might have looked like 2 million years ago. Beth Zaiken

Thursday 2 February 2023

Australia's Prehistoric Giant Eggs

Australia's Prehistoric Giant Eggs 

I didn't know it was a controversy, but it has now been settled!

In the 1980s people started finding large eggs, and fragments of eggs in eroding sand dunes in the centre of Australia. Some were identified as emu eggs but others were identified as being laid by Genyornis, an extinct member of the thunderbirds.(!)

The eggshells were age dated and ranged from 400,000 years old to 50,000 years. Some of the youngest eggs showed signs of having been cooked. Did Genyornis become extinct due to human predation?

Then the controversy started. One group said that the eggs came from Progura an extinct relative of brush turkeys. And until recently no agreement was to be had.

DNA was no help - the molecules were too degraded. So, as described in THIS ARTICLE, proteins were recruited to settle the matter. Proteins last longer than DNA and partial protein sequences were retrieved from some eggshells and these were used to get structures for the molecules using very sophisticated computer software. Proteins provide similar information as DNA.

These structures were then compared with a database of bird genomes. The birds position in the tree of bird genomes could not be determined but it could be proved that it was not related to brush turkeys. So the only candidate standing was Genyornis.

Isotope work on the shells showed that the diet of Genyornis had changed over the lifetime of the species. And by the time it died out summer grasses had disappeared from its diet. The reduction in monsoon rain was the cause of that. That, and the start of human predation, was enough to cause the extinction of the giant birds.

The giant bird Genyornis went extinct in Australia around 50,000 years ago. Gifford Miller