Extremely significant image beside a river that was pronounced dead 70 years ago

The River Thames, the river is dubbed the most poetic of Europe, and is the most important river in southern England.

But that river is not always romantic. In the 1950s, the Thames was so heavily polluted that biologists were forced to confirm that it was "biologically dead". The amount of oxygen in the water then is not enough for any organism to survive.

And so, the photo below has become really meaningful to science and the British in particular.

The black spot in the picture is a seal - specifically a harbor seal.

The black spots in the picture are seals - specifically , harbor seals , totaling 138. They were seals born in the River Thames during the past 12 months, according to the London Zoological Society (ZSL - UK).

Specifically, ZSL since 2013 has started a program to recalculate seals on the River Thames. In 2017, there were 1104 harbor seals, and more than 2400 gray seals appeared at the mouth of the river. This shows that the river is gradually becoming a livable place, allowing seals to have more abundant food.

The Thames River is polluted in the days.

The river revived

Of course, a river is so polluted that it cannot die suddenly, but because people around it are aware of environmental problems. In the 1970s and 1980s, dangerous sources of waste into the river decreased significantly. People also no longer use pesticides, herbicides . to avoid the rain washed away into the river.

The number of seals in the Thames is increasing year by year.

It is known that the number of seals in the River Thames is increasing year by year, but it is not clear whether this is due to the availability of new generation seals, or the seals from other regions enter the herd after their herd. disintegrated. Therefore, ZSL decided to conduct a survey of the number of seals from the air, based on a small aircraft. This is an easier way to count the actual number of seals in an area, as the animals often travel quite a lot.

"138 seals were born in just one season," said Thea Cox, a conservation expert.

"The seals will not be able to breed here without a good source of food, so it can be said that the ecosystem in the River Thames is reviving, especially compared to the time when they are considered dead." 1950s ".

Anna Cucknel, director of the ZSL River Thames Conservation Project, said: "The restoration of the River Thames - the way we call the river - is vitally important to the ecosystem and the animals. "is home to over 100 species of fish - including two species of sharks, many species of seahorses and even the endangered European eel."

"Notably, young seal seals can swim only a few hours after birth, meaning they really adapt well to the habitat in this area."

"At high tide they can swim to the sea."

"Gray seals need more time to adapt. So they will breed elsewhere, then return to the Thames to feed."