Climate change that has warmed the world's oceans has caused a "worrying" northern migration among some of the smallest organisms in the ocean: plankton.
It is the end of the new research published Thursday in the journal Nature which examines the composition of plankton communities across the northern hemisphere.
The unpleasant creatures are sometimes referred to as the "building blocks" of the sea because of their importance in the food chain, and their apparent migration is another indicator of the profound effect of climate change on the planet.
"This is not good news for marine ecosystems," said Lukas Jonkers, the study's lead author and a postdoctoral researcher at the University of Bremen's center for marine environmental science.
"We see that we have pushed marine ecosystems or at least this group of zooplankton away from their natural state. It's very worrying," he told AFP.
"That means that while we manage to keep the global temperature rise below 1
Research is the organism known as planktonic foraminifera, a kind of plankton with a distinctive hard shell.
When these ubiquitous beings die, they fall to the seabed as snow, and their hard shells are able to withstand the ravages of times.
This means that they create an indispensable and incomparable overview of what plankton society in different parts of the world has resembled going back centuries.
And that record solves a long-standing problem for scientists trying to investigate how marine life has been affected by climate change – a clear baseline.
Jonkers decided to utilize the plate and compare samples collected in the present between 1978 and 2013, with seabed-based sediment dating back centuries.  What he found was that modern plankton communities often have little resemblance to the communities that are included in the sediment below.
Instead, the modern societies saw the sediment in the water further south, suggesting that plankton species have migrated northwards, as the water temperature became more like their original habitats.
Clear pattern for change  "Everything moved north," Jonkers said.
"In one place you will always find many different species, but we now see that this species of society is composed of different species that resemble warmer water better."
For example, the modern species seen near Greenland are the same as those in the pre-industrial sediment found further south.
The study looked at nearly 4,000 samples from a number of zones across the northern hemisphere, so it is not yet clear how modern plankton communities in southern waters compare to their predecessors in these tropical locations.
But Jonkers said that the pattern of change in the investigated places was clear.
"Where the temperament ature has changed more, the species has changed more."
It was not possible to determine a precise timeline for the change, but Jonkers said it seemed to be gradual.
And so far he said that there was no evidence of extinction of species, only the movement of communities from one place to another.
But migration can pose a problem for plankton and the animals that rely on them for food if the new arrivals do not adapt quickly enough to survive among the other inhabitants in their warmer environments.
The research is linked to a growing evidence of how climate change affects the sea.
In March, a team studying seals and whales in the Arctic, the animals were forced to shift their feeding habits like the warm, melting ice of the sea, and the encouragement of fish stocks to move.
Global warming hits hardest marine animals
Lukas Jonkers et al. Global change drives modern plankton communities away from the pre-industrial state, Nature (2019). DOI: 10,1038 / s41586-019-1230-3
© 2019 AFP
Migration to the North: Climate change puts plankton on the move (2019, May 22)
May 24, 2019
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