Norwegian sea areas are becoming increasingly warmer and more acidic due to man-made CO₂ emissions.
– The heating and acidification is surprisingly fast – and is unusual in such deep water, says Ingunn Skjelvanresearching chemical oceanography at NORCE.
– Drilled and blasted in almost every hill and knoll
Longest in the world
She and several researchers are measuring the sea areas in the Barents Sea-Lofoten, the Norwegian Sea and the North Sea-Skagerak, on behalf of the Norwegian Environment Agency.
– The measurements in the Norwegian Sea are among the longest measurement series of the deep water in the world, and are from 1948 until today. Already in the 80s, we saw that the deep water started to get warmer. Now, 40 years later, it has warmed by more than 0.2. It may sound small, but it is an unusually large amount at such great depths, says Skjelvan, who is responsible for one of the measuring stations in the Norwegian Sea.
CONCERNED: Ingunn Skjelvan measures the amount of CO2 in the sea, in addition to monitoring temperature and acidification in the Norwegian Sea. Photo: Private Show more
In addition to measuring pH value and temperature, Skjelvan also began measuring carbon at 2000 meters from 2001.
– I was curious as to whether we could see changes in the amount of carbon in the sea at this station. Now I have been measuring for over two decades and we see that the carbon content in the surface water is rising a little faster than what we see in the air, says Skjelvan and continues:
– This happens because humans release large amounts of CO₂ into the air. But the carbon is not only at the sea surface, but also in the deepest layer, at 2000 metres. It is surprising.
IN DANGER: When the sea becomes more acidic, there is less lime in the water. Then organisms that make shells and skeletons from cold have problems growing and reproducing. Like this wing snail, which is important in the diet of many species of fish, seabirds and marine mammals. Photo: Erling Svensen Show more
Corals in danger
The functioning of the ocean is very important for the planet. Every year, the ocean takes up as much as 25 percent of the amount of CO₂ that humans release into the air, and thus helps to reduce global warming.
– The flip side of the coin is that the sea is gradually becoming more acidic because it absorbs extra carbon dioxide. In addition to ocean acidification, the amount of calcium ions is decreasing. It will affect organisms in the sea that have calcareous skeletons, says Skjelvan.
At the measuring station in the Norwegian Sea, you can now see that the amount of lime is decreasing, and at 2,000 meters it is starting to dissolve.
WILL STRUGGLE: If the ocean continues to become more acidic and warmer, the coral forest off the Norwegian coast will struggle. Among them is anthothela grandiflora, which is one of several horn corals that can help form coral forests. Photo: Mareano Show more
CRITICAL: The oxygen disappears, the plants die and the fish escape. The Oslofjord is in crisis, says Fredrik Myhre, head of the ocean team at the WWF World Wide Fund for Nature. Reporter: Line Fransson / Anton Lier. Video: Fredrik Myhre / Nina Hansen / Dagbladet TV. view more
Off the Norwegian coast, coral reefs grow at depths of 200 to 500 metres. In the long term, these will be in danger, because the more acidic water rises ever higher, according to Skjelvan.
– The coral reef consists of both dead and living coral. When the corrosive water comes up here, the dead corals will dissolve, which in turn means that the living corals will struggle to reproduce and grow because the water is low in calcium ions, says the researcher and adds:
– This will affect the ecosystem in the sea, which will ultimately also have an impact on what we can have on our dinner plate.
Inertia in the system
Fortunately, the acidification process does not go very quickly, according to Skjelvan.
– But if we stop emitting carbon dioxide tomorrow, there is so much CO₂ in the air that it will take a long time for the sea to stabilize. There is an inertia in the system and we know that the ocean will become more acidic for a long time to come.
MUST STOP: The oil industry accounts for a large proportion of the world’s CO2 emissions, and must stop if the planet and the oceans are to be saved. The picture is from the Åsgard oil and gas field, outside central Norway. Archive photo: NTB Show more
What worries the researchers is that “there is little will to do anything about the cause of the oceans becoming warmer and more acidic” among Norwegian politicians and decision-makers.
– The only thing that is effective in limiting ocean acidification is to reduce CO₂ emissions sharply. This means a sharp reduction or alternatively a stop in Norwegian oil production, says Skjelvan.
Buffer reduced
The sea basically has a great ability to regulate itself: A natural amount of CO₂ that has been taken up in the sea has been neutralized so that the acidity of the sea has not changed.
– The difference now is that the sea has to cope with colossally large amounts of CO₂, and then the buffering capacity of the sea is eroded. This means that the ocean has less ability to regulate and neutralize ph changes. We can already see that the buffer capacity has become weaker, says the researcher.
The researchers expect a worse situation further north of the Norwegian Sea.
– The sea areas in the north are more vulnerable because cold water can absorb more CO₂ than warm water. Therefore, the water in the Arctic will be more vulnerable, says Gunnar Skotte, chief engineer in the section for environmental monitoring and mapping in the Norwegian Environment Agency.
Less resilience
In addition, climate change and the melting of ice and snow in the northern regions will provide even fresher water – and thus less resistance to acidification, according to Skotte. For the time being, there is much uncertainty about how life in the sea will change.
– In the longer term, we fear that it will have consequences for a number of species, says Skotte.
MUST ACT: Gunnar Skotte in the Norwegian Environment Agency monitors the sea, and is concerned about developments in the north. Photo: Private Show more
Microalgae and calcareous algae may decrease in occurrence. Molluscs, shells, snails and squid also get a reduced amount of calcium ions in the sea. Sea urchins, sea sausages, starfish and corals will also be negatively affected. Which in turn means that the species that eat these, such as fish, will also struggle.
– A change of 0.1 and 0.2 percent does not sound like much, but the ph scale is a so-called logarithmic scale. So that 0.1 ph unit now actually means 26 percent more acidic. And since we expect the CO₂ concentration in the atmosphere to rise, the ocean will become significantly more acidic during the coming century, says Skotte.
2023-11-27 19:40:07
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