Thursday, 9 September 2021

Underwater Glacial Geomorphology

Underwater Glacial Geomorphology 

A correspondent spotted THIS on the BBC website and passed it on to me.

It concerns sub-glacial landforms which were made under ancient ice sheets. These were where the North Sea is now and have only recently been discovered using seismic survey techniques. Deep seismic techniques are used to find possible oil bearing structures, these shallow ones were originally developed to find suitable foundations for oil industry infrastructure,

The structures may give us a picture of what is happening beneath Greenland's ice cap as it melts under today's conditions of global warming.



How the Moon Made Life on Earth Possible

How the Moon Made Life on Earth Possible

A  correspondent brought two links to my notice. THE FIRST is the scientific paper on which THE SECOND (a YouTube Video) is based. If you are anything like me you will find the video much more approachable.

The thesis is multi staged. 
  • The moon slows down the rotation of the Earth.
  • Oxygen producing cyanobacteria rise to the sea surface during daylight.
  • Anaerobic bacteria rise to the sea surface at night.
  • Cyanobacteria rise slowly.
  • When day length is short cyanobacteria are not in daylight for long.
  • Longer days mean more oxygen produced.
  • Oxygen in the atmosphere allows multicellular life to develop.
You can read all about it in the Nature paper, or you can watch the video. Also in the video you have the chance to buy a T shirt!!!

You can read about the sinkholes which feature in the previous links HERE.




A term used in both paper and video is "diel". It is one I had not come across before. It is usually phrased as diel vertical migration, and Wikipedia defines it as:- 

Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The migration occurs when organisms move up to the uppermost layer of the sea at night and return to the bottom of the daylight zone of the oceans or to the dense, bottom layer of lakes during the day. The word diel comes from the Latin dies day, and means a 24-hour period. In terms of biomass, it is the greatest migration in the world. It is not restricted to any one taxon as examples are known from crustaceans (copepods), molluscs (squid), and ray-finned fishes (trout). Various stimuli are responsible for this phenomenon, the most prominent being response to changes in light intensity, though evidence suggests that biological clocks are an underlying stimulus as well. The phenomenon may arise for a number of reasons, though it is most typically to access food and avoid predators. While this mass migration is generally nocturnal, with the animals ascending from the depths at nightfall and descending at sunrise, the timing can be altered in response to the different cues and stimuli that trigger it. Some unusual events impact vertical migration: DVM is absent during the midnight sun in Arctic regions and vertical migration can occur suddenly during a solar eclipse.

Saturday, 4 September 2021

Dave Green's Programme for 2021 - 22

Dave Green's Programme for 2021 - 22 

Dave Green has produced a programme for the next year which is bursting with geological goodness!. I have put down my name for the trip to the Eastern Pyrenees next February already!

You can download the programme HERE.

Or read it below. 


Friday, 3 September 2021

Down to Earth Extra - September 2021

  Down to Earth Extra - September 2021 
 
The latest edition of Down to Earth Extra is HERE.

And you can read it below.