As scientists shrink to find out how warming ocean temperatures will affect marine ecosystems across the globe – from bleaching coral reefs to changing migration routes – is one of the ocean's most ubiquitous organisms to help scientists measure the changes that has already taken place. Centuries of fossil archives and live capture data show that some marine plankton populations reflect a clear change due to human industrialization and the heated oceans brought about.
Scientists found differences in the differences between communities of planktonic foraminifera small single cell creatures floating in marine waters ̵
While the notion that climate change is affecting marine life is not new, the plankton study incorporates an exceptionally complete dataset that spans the globe and intersects deeply in the last centuries to confirm human impact on the oceans.
Planktonic foraminifera provides a comprehensive fossil record, because their hard calcite shells are well preserved in sediment layers at the bottom of the sea, says lead author Lukas Jonkers, a paleontological oceanographer at the University of Bremen in Germany. The organisms also populate waters all over the world. Although it is rare in the surface sea, planktonic foraminifera are abundant at greater depths, and in some places they cover the entire slope of the seabed, Jonkers says.
"We can really compare the distribution of the species in the modern [era] with the past," says Jonkers. "There are not so many zooplankton groups where the fossil archives are so well preserved. In fact, I do not think there are any."
To understand the state of these societies before the era of industry began, Jonkers and his team analyzed more than 3,700 previously collected samples from sediment layers on the seabed. Based on how quickly the sediment accumulates and mixes on the seabed, the researchers estimated that the top layer of sediment cores – basically "mud bottles" that were pulled up from the bottom of the sea – would contain fossils that are a few centuries old, says Jonkers , The preliminary study of the industrial revolution.
The team then compared these pre-industrial specimens with newer data collected by sediment traps moored to the seabed, which grips something from the ocean surface (including the plankton that slides through the water). Using information collected from 1978 to 2013, the researchers discovered that the planktonic foraminifera communities changed significantly during the period between the deposition of the seabed fossils and the organisms trapped in sediment traps.
The shift, measured by comparing the relative amounts of dozens of plankton species within the samples, does not seem to be random. The amount of change in the plankton community correlated with the degree of documented temperature change in the surrounding waters. The direction of changing societies is also greatly favored by patterns of ocean temperature change found by the authors as they matched seabed philosophers with their closest analogues in modern society.
With the data showing a battle in both the degree and direction of Jonkers says he is confident that the temperature is the driving force for the shifts in planktonic foraminifera populations.
"I expected to see a difference and an effect of global change," says Jonkers. "But I didn't expect the signal to be so clear."
The new study globally replicates which other researchers have found in specific areas, says David Field, a marine researcher at Hawaii Pacific University who has researched planktonic foraminifera, but was not involved in this study. While scientists have not yet fully discovered why precise plankton environments are changing, evidence from this study and others clearly demonstrates to ocean warming as the probable cause, either as a direct influence or as an indirect impetus for other aspects of the subsea environment, Field says.
Comparison of sediment trap samples to seabed phosphors may not be a perfect analogy difference in conservation could be a potential impact on the data, but Field says the author's evidence convincingly supports the huge impact of marine warming on marine species.
"This indicates that warming began to have an impact on marine ecosystems long ago, even before we kept good records on it," Field says. "We can expect far more effect of ocean heating on ecosystems in the future. The oceans will continue to change in ways we have not seen before." Planktonic foraminifera may not be as majestic as whales or sea stars, but their fossil width is A useful basis for confirming a broader tendency to marine life is changing in response to human activity. Shifts in the plankton community are a significant indicator of the "bigger picture" of marine ecosystems, as sea temperatures continue to rise to rising speeds, Jonkers says.
"The question is, what happens to climate change?" Siger Jonkers. "Even to a degree [of temperature change]we already see major changes in planktonic foraminifera, and probably also in other marine biota. This means that all these species need to be adapted, and at present we do not know if they can or if they can Do it so fast enough. "
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