Plates, Missing Ice and Manatees

17 May 2021

Plate Tectonics has been revised to some degree in a new study - using computer simulation of the process over millions of year, achingly slowly, one inch at a time - see ... the research came about after observation of rocks in the alpine region of Italy and the mountains of Turkey. It seemed to their surprise that rocks on their way to subduction already showed signs of breakup prior to the actual break up of the plates as they started to bend downwards. One might purse their lips and wonder if evidence of  rocks breaking up as plates collide might be more appropriate, or some other reason besides approaching subduction.

At ... the lowest portion of the atmosphere, dubbed the troposphere, contains mostly all of our weather. In the stratosphere, above, moisture levels drop very low - near to zero. The boundary between the two zones is known as the tropopause - the point at which water ceases to cool as altitude increases. In the  tropical zone of the tropopause it is extremely cold - and is situated higher in the atmosphere than in the temperate or polar regions. In a new study it was found more ice is falling out of the tropopause than ambient moisture can account for. Ice mass at the tropopause comes from two sources, it is thought - advection of cirrus clouds and deep convection. The latter = mosture rising upwards from the troposphere along a  thermal gradient. Warm air rises and warms moisture in the air. This may explain the missing ice.

At ... the formation of the Amazon Basin influenced the distribution of manatees. They split 6.5 million years ago, we are told, when a huge lake in Amazonia, with an outlet in the Caribbean [a sort of inland sea] was cut off [thereby leaving a lake]. Manatees occupy both the Amazon region and the Caribbean. The manatees in Amazonia became isolated from their kin by the falling levels of water in the lake, eventually dwindling to a wetland zone [open water and marsh] and later drying up altogether. They became stuck in a riverine environement whereas the Caribbean manatees flourished in a marine environment, although estuary locations were favoured. Manatees also live in Africa - in coastal waters between Senegal and northern Angola. They also live in rivers flowing into the sea. They live on aquatic plants growing on the bottom of the sea and estuaries and have adapted to fresh water locations as well as sea water, even the brackish waters of estuaries. They have also apparently adapted to changes in temperature over the passage of time.