A scientist warns that the "dead zone" without oxygen in the sea spreads four times compared to 1950 and it affects the ecosystem
Living creatures can not live due to less oxygen contained in the seawaterDead zone"Is increasing worldwide and research has revealed that there is a possibility that it will make a big shadow on the global ecosystem in the future.
Declining oxygen in the global ocean and coastal waters | Science
Oceans suffocating as huge dead zones quadruple since 1950, scientists warn | Environment | The Guardian
This research was conducted by Dennis Brightberg and others of the Smithsonian Environment Research Center in the USA and others. Oxygen is dissolved in seawaterDissolved oxygen amountHas risen to the level of zero has increased to four times the data of 1950 data and the sea area where oxygen concentration is very low in the coastal area has been expanded tenfold.
Although some powerful theories have been advocated for the cause of the decrease in the amount of dissolved oxygen, one of them is "seawater temperature rises". The amount of oxygen dissolved in water tends to decrease as the water temperature becomes higher, so the amount of oxygen contained in the seawater heated especially near the equator tends to decrease. Other causes of the decrease in the amount of dissolved oxygen at the coastal area are fertilizer and sewage of soil and agricultural land containing a lot of nutrients flowing into the sea through soil and river.
A research paper published in science journal "Science" is the first comprehensive analysis of this problem, "The major extinction events in the history of the earth are related to climate warming and oceanic oxygen deficiency "I write down. Mr. Brightberg said, "We will aim for the direction we are facing now, but the fact that we are waiting for humanity in the future is a terrible thing so that we do not want to proceed as it is," It is ringing.
However, Mr. Brightberg also talks about the prospect that "This is a problem that can be solved." Mr. Brightberg, the AmericanChesapeake BayAnd the example that the amount of oxygen was restored in the Thames river in the UK, "Global efforts are necessary to halt climate change, but by promoting efforts gradually in various parts of the world, oxygen of oxygen by eutrophication It is possible to halt the decline. "
However, the influence of the amount of oxygen in the ocean has a big influence on the world. The area that is particularly greatly affected by fishery is the area of fishery, the amount of landing of fishes has decreased due to the fact that fish can not be lived as the amount of dissolved oxygen decreases, and the life of fishermen who are said to be 350 million worldwide It will be affected, people's food cycle and even the natural ecosystem will be affected.
The dead zone of the ocean revealed in this survey reached more than 500 places, which greatly exceeded the data of "50 places" in 1950. Although it is necessary to keep in mind what area coverage was covered in the survey of the time in 1950, it is said that the current study does not cover all the sea areas yet, the increase trend of the dead zone It is said that it is considered to be almost certain.
It is said that a drop in sea brain oxygen concentration causes another "negative feedback". Microorganisms growing at very low oxygen levels emit a lot of "nitrous oxide", which is 300 times more potent greenhouse gas than carbon dioxide. This will further accelerate the global warming of the earth and the sea water temperature can rise more and more.