New analyzes of deep sea fossils have revealed that changes in ocean circulation may have caused a shift within the Atlantic ecosystems, not seen 10 thousand years ago, and this is the surprising result of a new study led by a research group at University College London (UCL), funded by the ATLAS project and published In the journal Geophysical Research Letters.
For 12,000 years, the climate has been completely stable since the end of the last Ice Age, a period known as the Holocene, and it is believed that this stability is what allowed human civilization to truly continue, according to Russia today.
In the ocean, it is also believed that the main currents were relatively stable during the Holocene period. These currents are characterized by natural cycles that affect the location of marine organisms, including plankton, fish, seabirds and whales.
However, climate change in the ocean has become evident, as tropical coral reefs bleach, the oceans become more acidic as they absorb carbon from the atmosphere, and species such as herring and mackerel move towards the poles.
The team looked for places in which the fossils of the sea floor not only covered the industrial age in detail, but also spanned several thousand years. They found the right patch of the sea floor just south of Iceland, where a large current in the deep sea causes sediments to accumulate in huge quantities.
To obtain fossil samples, they took nuclei from the sediments, which included sending long plastic tubes to the ocean floor and pushing them into the mud. When pulled again, it appears full of sediments that can be sifted through to find fossils.
The deepest sediments contain the most ancient fossils, while the surface sediments contain fossils deposited during the past few years.
One of the simplest ways to find out what the ocean was like in the past is to calculate the different types of fossil planktons that can be found in such sediments.
The researchers analyzed a species called foraminifera, which contains shells of calcium carbonate, that is easy to identify with a microscope and a small paint brush, which is used when dealing with fossils.
A new global study showed that modern foraminifera distributions differ from the beginning of the industrial age. Climate change is clearly affecting that.
Likewise, research conducted in 2018 objected to the view that modern ocean currents are similar to those that occurred in the past two thousand years, as it showed that the rotation of the "conveyor belt" was at its weakest level in 1500 years.
The new work builds on this image, and it is suggested that the turnover of the modern North Atlantic surface is different from any event seen in the past 10,000 years, roughly the entire Holocene period.
In southern Iceland directly, the decrease in the number of species of plankton in cold water and the increase in the numbers of warm water species show that warm water has replaced cold, nutrient-rich water.
Experts believe that these changes have also led to a movement of major fish species such as mackerel, northward, which are already causing a political crisis as different countries compete for fishing rights.
Further north, other fossil evidence shows that more warm water reached the Arctic from the Atlantic Ocean, likely contributing to melting sea ice. To the west, the slowdown in the rotation of the Atlantic carrier indicates that the waters do not rise as much as we expect, while the warmer Gulf Stream farthest west near the United States and Canada appears to be shifting to the north which will have profound consequences for important fisheries.
One way in which these rotating systems can be affected is the North Atlantic shift to less salinity. Climate change can cause this by increasing precipitation, increasing thaw, and increasing amount of dissolved water from the Arctic Ocean.
Perhaps the melting after the peak of the Little Ice Age in the mid-eighteenth century led to the introduction of fresh water, which caused some of the oldest changes that researchers found, with the recent climate change that helped push these changes beyond the natural volatility of the Holocene.
For 12,000 years, the climate has been completely stable since the end of the last Ice Age, a period known as the Holocene, and it is believed that this stability is what allowed human civilization to truly continue, according to Russia today.
In the ocean, it is also believed that the main currents were relatively stable during the Holocene period. These currents are characterized by natural cycles that affect the location of marine organisms, including plankton, fish, seabirds and whales.
However, climate change in the ocean has become evident, as tropical coral reefs bleach, the oceans become more acidic as they absorb carbon from the atmosphere, and species such as herring and mackerel move towards the poles.
The team looked for places in which the fossils of the sea floor not only covered the industrial age in detail, but also spanned several thousand years. They found the right patch of the sea floor just south of Iceland, where a large current in the deep sea causes sediments to accumulate in huge quantities.
To obtain fossil samples, they took nuclei from the sediments, which included sending long plastic tubes to the ocean floor and pushing them into the mud. When pulled again, it appears full of sediments that can be sifted through to find fossils.
The deepest sediments contain the most ancient fossils, while the surface sediments contain fossils deposited during the past few years.
One of the simplest ways to find out what the ocean was like in the past is to calculate the different types of fossil planktons that can be found in such sediments.
The researchers analyzed a species called foraminifera, which contains shells of calcium carbonate, that is easy to identify with a microscope and a small paint brush, which is used when dealing with fossils.
A new global study showed that modern foraminifera distributions differ from the beginning of the industrial age. Climate change is clearly affecting that.
Likewise, research conducted in 2018 objected to the view that modern ocean currents are similar to those that occurred in the past two thousand years, as it showed that the rotation of the "conveyor belt" was at its weakest level in 1500 years.
The new work builds on this image, and it is suggested that the turnover of the modern North Atlantic surface is different from any event seen in the past 10,000 years, roughly the entire Holocene period.
In southern Iceland directly, the decrease in the number of species of plankton in cold water and the increase in the numbers of warm water species show that warm water has replaced cold, nutrient-rich water.
Experts believe that these changes have also led to a movement of major fish species such as mackerel, northward, which are already causing a political crisis as different countries compete for fishing rights.
Further north, other fossil evidence shows that more warm water reached the Arctic from the Atlantic Ocean, likely contributing to melting sea ice. To the west, the slowdown in the rotation of the Atlantic carrier indicates that the waters do not rise as much as we expect, while the warmer Gulf Stream farthest west near the United States and Canada appears to be shifting to the north which will have profound consequences for important fisheries.
One way in which these rotating systems can be affected is the North Atlantic shift to less salinity. Climate change can cause this by increasing precipitation, increasing thaw, and increasing amount of dissolved water from the Arctic Ocean.
Perhaps the melting after the peak of the Little Ice Age in the mid-eighteenth century led to the introduction of fresh water, which caused some of the oldest changes that researchers found, with the recent climate change that helped push these changes beyond the natural volatility of the Holocene.
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