This video introduces Siberian and Beringia Vegetation
during the Last Glacial Maximum
And it explains why huge ice sheets existed in Europe and North America
but glaciers didn't form in Beringia.
In the last video, we looked at the topography of Europe during the LGM.
Following this story,
this video will look at Sibieria's climatic environment and vegetation,
including Beringia, during the same period.
This video uses the Topology base map to help you understand.
Doctor N. Ray and J.M. Adams' model developed the LGM Vegetation Map was used.
According to their model,
the steppe tundra known as the Mammoth steppe stretched from the southern coast of the United Kingdom in the west to the borders of the Russian state of Yakutia in the east.
In present-day China, the Mammoth steppe from the middle reaches of the Yellow River,
where there is an archaeological site of the Erlitou culture that opened the early Bronze Age to Manchuria.
In addition, the Mammoth Steppe continued to Chita, Amur, Primorsky Krai, and Sakhalin in Russia.
Northern Korea and even Japan's Hokkaido were stepp-tundra.
At that time, Sakhalin and Hokkaido were connected by land.
Mammoth Grassland was created during the Last Glacial Period,
which began 126,000 years ago.
And it flourished without significant change for 100,000 years,
but it gradually began to decrease after the ice age began to melt,
and it was reduced to a small area 12,000 years ago.
It was cold and dry there.
Palatable high-productivity grasses, herbs, and willow shrubs dominated vegetation.
Reindeer, bison, horses, and woolly mammoths dominated animal biomass.
More details about the biogeology of LGM are introduced in another video.
The polar and alpine desert extends to Alaska east of the steppe tundra.
This polar desert stretches to the Queen Elizabeth Islands in northern Canada.
Some of the vegetation in Beringia,
which was connected by the Russian and Alaska Landbridge, was Tundra.
In Europe, there was an ice sheet slightly above London.
London's latitude is 51.5.
But why didn't an ice sheet exist in eastern Siberia and Beringia?
Even if the latitude is the same, the further east you go, the colder the temperature.
he map you're looking at now will allow you to see the temperature difference between Europe and eastern Siberia.
This is the average temperature for 2016.
The average annual temperature in London is 11.3°C (52.3°F).
However, the average yearly temperature of east Siberia and Beiringia is much lower.
Nevertheless, the lack of glaciers in these areas during the LGM is for two reasons.
The first reason is that the LGM coastline was farther out than it is now,
so there was little water vapor inflow from the sea.
The Barents-Kara Ice sheet extended to the Taymyr Peninsula.
The LGM shoreline to its east is about 465 kilometers (289 miles) from the present shoreline.
To the east, the coastline was farther than it is now.
At the start of the Chukchi Autonomous Prefecture,
the LGM coastline was approximately 907 km (564 miles) from the present coast.
In the case of Beringia, the distance between the north and south coasts was up to about 2154km(1339mi).
The distance from the Canadian border in the north to the Mexican border in the south of the western United States
is approximately 1817km(1128mi).
Comparing this to the north-south distance of Landbrige at the time of the LGM gives you an idea of the size of Beringia.
There was little water vapor coming in from the sea,
and the temperature was freezing,
so it was an environment where glaciers could not grow,
unlike in western Europe or North America.
Snow fell, but not enough to create glaciers.
This is why the Polar desert was made.
Most Polar deserts are also called white deserts because icefields cover them.
Polar deserts are relatively common during ice ages because they are dry.
If the latitudinal region is Polar,
the potential evapotranspiration ratio is less than 1,
the annual precipitation is less than 500mm,
and the critical temperature is less than 1.5°C, it is called a polar desert.
A second reason why eastern Siberia and Beringia did not glacier is the Ocean Current's circulation system.
At the equator, warmed seawater flows into the Gulf of Mexico in the Equatorial Counter Current.
The warmed water meets the Gulf Stream and flows into the sea west of Ireland.
The north arctic drift cools warm water carried by the Gulf Stream into the Norwegian Sea.
Water vapor is produced in this process.
This water vapor enters North America, Greenland, and Europe.
And the cold temperatures make a lot of snow.
This snow accumulates on the land for a long time, becoming glacial.
However, the surface currents flow in the Pacific Ocean differs from that of the Atlantic Ocean.
Water warmed at the equator cools as it flows east along the Kuroshio Current.
Sea water flows across the North Pacific at the 40th parallel north, evaporates, and enters North America.
This cooled sea water flows into Alaska.
Little water flow joined Beringia and Siberia,
so there was no glacial during the LGM.
Then, from now on, I will introduce the topography of Beringia.
As the temperature gradually rose 20,000 years before the present,
Beringia, which was a Polar desert, slowly turned into Mammoth Tundra.
The average depth of the Bering Strait is 40-50 meters (130-160 ft).
During the last Ice Age,
water froze into the vast ice sheets that covered North America and Europe,
lowering sea levels.
As the temperature warms, the humidity here must have increased.
Until the Bering land bridge was closed 11,000 years ago,
this place was a refuge for people and animals.
There were high mountains on either side of the Beringia Landbridge, and it was dried and cold.
In particular, there was a vast ice sheet in the Americas.
Water, essential for human and animal survival, was hard to come by.
But Beringia was different.
It had lakes and rivers, making it an ideal place for Ice Age refuge.
It is believed that between 20,000 and 16,500 years ago,
a small population of several thousand arrived here from Siberia and East Asia
before spreading to settlements in the Americas.
About 50,000 years ago lived in East Asia,
people belonging to Y-DNA Haplogroup C2.
Also, from 40,000 years before the present,
ANE, Ancient North Eurasian ancestors belonging to Y-DNA haplogroup K2 lived in Siberia.
30,000 years ago, Y-DNA haplogroups Q and R split in Siberia.
20,000 years ago, R migrated to Europe, and part of the paternal lines Q and R and part C went to the Americas.
Y-DNA Q is so high in Native Americans and R1 and C in many tribes.
Some populations migrated south of the Americas along the coastline.
Massive population movement would have been more effortless,
once the ice-free corridor was fully opened.
As a result of the research,
it is known that the first opening of the IFC and Ice free corridor was 13800 years ago.
Some archaeological evidence suggests that human arrival in the Americas likely occurred before the last glacial maximum,
more than 20,000 years ago.
The possibility of that exists.
However, they are not the genetic ancestors of modern Native Americans.
Native American genetic ancestry is closely related to ANE ancestry.
You can check the Y DNA Haplogroup Q migration route to America,
and the migration route of the population of Haplogroup R, C through the linked video.
Various grasses and herbs mostly dominate LGM Beringia.
There were patches of shrub tundra with isolated refugia of larch and spruce forests with birch and alder trees.
Temperatures warm up 15,000 years before the present.
These temperature changes provide more forage for browsers.
Large species such as saiga antelopes,
woolly mammoths, and caballid horses have migrated here,
adapting to live in the driest steppe.
I made an imaginary scenery of Beringia through computer animation.
Finally, I will show the process of closing Beringia on a map.
Thank you for watching until the end.
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