Warning: The Norwegian Sea is warmer and more acidic

Norwegian marine areas are becoming increasingly warmer and more acidic due to human-caused carbon dioxide emissions.

“The heating and acidification are surprisingly rapid,” he says, “which is unusual in such deep waters.” Injun SkjelvanResearch in Chemical Oceanography at NORCE.

The longest in the world

She and several researchers measure marine areas in the Barents-Lofoten Sea, the Norwegian Sea, and the North Sea-Skagerrak, on behalf of the Norwegian Environment Agency.

The measurements in the Norwegian Sea are considered one of the longest series of deep-water measurements in the world, from 1948 until today. Already in the 1980s, we saw that deep waters were starting to get warmer. Now, 40 years later, its temperature has risen by more than 0.2 degrees. It may seem small, but it’s an unusually large amount at such great depths, says Skilvan, who is in charge of one of the measuring stations in the Norwegian Sea.

In addition to measuring pH and temperature, Skillvan has also begun measuring carbon at a depth of 2,000 meters since 2001.

– I was curious to see if we could see changes in the amount of carbon in the sea at this station. Now I’ve been measuring for more than two decades, and we see that the carbon content in surface waters is rising a little faster than what we see in the air, says Skjellvan, and continues:

-This happens because humans release large amounts of carbon dioxide into the air. But carbon is not only found on the surface of the sea, but also in the deepest layer, 2,000 meters deep. This is surprising.

Coral reefs are in danger

The functioning of the ocean is very important for the planet. Every year, the oceans consume up to 25% of the amount of carbon dioxide that humans release into the air, thus helping to limit global warming.

– The other side of the coin is that the sea becomes progressively more acidic as it absorbs more carbon dioxide. In addition to ocean acidification, the amount of calcium ions is decreasing. This will affect organisms in the sea that have calcareous skeletons, Skjelvan says.

At the measuring station in the Norwegian Sea, you can now see that the amount of lime is decreasing, and at an altitude of 2000 metres, it begins to dissolve.

Off the Norwegian coast, coral reefs grow at depths of 200 to 500 metres. In the long term, these will be in danger, as more acidic waters rise ever higher, according to Scjelvan.

Coral reefs consist of living and dead corals. When corrosive water comes here, the dead coral will dissolve, which in turn means that the living coral will struggle to reproduce and grow because the water is low in calcium ions, the researcher says.

– This will affect the ecosystem in the sea, which will ultimately also have an impact on what we can eat on our dinner plate.

Inertia in the system

Fortunately, the acidification process does not proceed very quickly, according to Skjelvan.

– But if we stop emitting carbon dioxide tomorrow, there is so much carbon dioxide in the air, it will take a long time for the sea to stabilize. There is inertia in the system and we know that the oceans will become more acidic for a long time to come.

What worries the researchers is that “there is little will to do anything about why the oceans are warmer and more acidic” among Norwegian politicians and decision-makers.

The only thing effective in reducing ocean acidification is to sharply reduce carbon dioxide emissions. Skilvan says this means a sharp decline or cessation of Norwegian oil production.

The buffer has been reduced

The sea basically has a great ability to regulate itself: the natural amount of carbon dioxide absorbed into the sea has been neutralized so that the acidity of the sea does not change.

The difference now is that the sea has to deal with huge amounts of carbon dioxide, and so the sea’s ability to temporarily store it is eroded. This means that the ocean has less ability to regulate and neutralize changes in pH. The researcher says: We can already see that the buffer capacity has become weaker.

Researchers expect a worse situation north of the Norwegian Sea.

Marine areas in the north are more vulnerable because cold water can absorb more carbon dioxide than warm water. Therefore, Arctic waters will be more vulnerable, says Gunnar Scott, senior engineer at the Environmental Monitoring and Mapping Department at the Norwegian Environment Agency.

Less flexibility

In addition, climate change and the melting of ice and snow in northern regions will provide purer water – and therefore less resistant to acidification, according to Scotti. Nowadays, there is a lot of uncertainty about how life at sea will change.

– In the long term, we fear this will have consequences for a number of species, says Scott.

Microalgae and calcareous algae may decrease in incidence. Molluscs, shells, snails and squid also get a low amount of calcium ions in the sea. Sea urchins, sea sausages, starfish and corals will also be negatively affected. This in turn means that species that eat these foods, such as fish, will also face difficulties.

– A change of 0.1 and 0.2 percent does not seem like much, but the pH scale is what is called the logarithmic scale. So a 0.1 pH unit now means a 26 percent increase in acidity. As we expect the concentration of carbon dioxide in the atmosphere to rise, the oceans will become dramatically more acidic over the next century, Scott says.