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By Marlene Cimons
Much of the deep sea has never been explored close-up by humans. Some submarines have plumbed its depths, but reaching the ocean bottom is a complicated and expensive journey, challenging because the seabed lies under more than three miles of water, which exerts huge amounts of pressure. "We know more about space than about the bottom of the oceans in our own planet, even though more than two-thirds of the surface of the Earth is covered by marine sediments," said Olivier Sulpis, a researcher and doctoral student at McGill University's department of earth and planetary sciences.
Thus, "we hear less about the effects of human activity at the seafloor than on corals, for instance, simply because coral bleaching sounds more appealing than mud dissolving at the bottom of the sea," he added. "When you think that before Google maps arrived, it took humans several centuries to map the continents, it's easy to understand why exploring the deep sea is so hard."
Nevertheless, he and his colleagues found a way to study it without actually going there. They recreated its environment in the lab, building little boxes filled with sediments overlain by sea water, keeping them in the dark. They duplicated sea water temperature and chemistry, as well as the composition of the sediment. By mimicking seabed conditions, "we don't need to go to the bottom of the sea to do measurements, and we save some time and energy." Sulpis said.
Sulpis and his team studied ocean floor sediment from the middle of the North Atlantic. Olivier Sulpis
What they found was worrisome. It has already been established that climate change—specifically atmospheric carbon dioxide emitted by fossil fuel burning—has been acidifying the oceans, damaging fragile coral reefs and disturbing vulnerable marine ecosystems. But the McGill scientists discovered that carbon dioxide also has begun to drift to the ocean bottom, dissolving the very materials that help put the brakes on acidification.
"Humans have become a geological force, and there is not a single part of the surface of our planet where we cannot find a trace of human activity," Sulpis said. "Paleoclimate scientists and Earth sciences students have heard and described many times past abrupt climate change and ocean acidification episodes, millions of years ago, that caused mass extinctions all around the world. These events were caused by meteoritic impacts, global wildfires, volcanic eruptions, etc. Today, it seems that we are at the dawn of one of these catastrophic events, and we don't need to look far to find the cause of it. Each one of us is the cause of it."
A diver surveys coral bleaching.The Ocean Agency
Normally, the seafloor is chalky white, largely made up of calcite formed from the skeletons and shells of planktonic organisms and corals. Calcite neutralizes carbon dioxide acidity, keeping seawater from becoming too acidic. But these days, at least in certain hotspots such as the North Atlantic and the southern oceans, the ocean's chalky bed is turning murky brown, the result of human activities that are causing carbon dioxide levels in the water to become too high and the water too acidic, according to new research published in Proceedings of the National Academy of Sciences. Eventually, the researchers predicted, the calcite won't be able to keep pace with acidification, dissolving before it can do its job.
"The calcite at the bottom of the ocean is like a big anti-acid pill," Sulpis said. "It dissolves when there is too much CO2 and this neutralizes excess CO2 in the process. If the seafloor runs out of calcite, the ocean loses its anti-acid pill, and we could go towards a scary state of runaway ocean acidification."
The researchers measured how fast sediments dissolved when placed in boxes covered by seawater. "We did this for a few years, and eventually we realized that we understand this dissolution reaction well enough to describe it using simple mathematical equations," Sulpis explained. "If we know the chemical conditions and the sediment properties down there, we can compute the dissolution rate of calcite in these sediments. "
They used state-of-the-art ocean models, computing calcite dissolution rates across the seafloor. The experiments produced insights as to what controls calcite dissolution in marine sediments. By comparing pre-industrial and modern seafloor dissolution rates, they could determine how much of the total dissolution was caused by humans.
Scientists know that calcite has historically helped de-acidify the ocean. "What is surprising and concerning, however, is that it is already happening now," Sulpis said. "Scientists thought it would take much longer before we start seeing some calcite dissolution at the seafloor that is caused by our CO2. We know how our climate works. We know how our oceans works, but what we are incapable of predicting is our society and how we will adapt our behavior to this changing world."
The findings have far-reaching implications. "Just as climate change isn't just about polar bears, ocean acidification isn't just about coral reefs," said David Trossman, now a research associate at the University of Texas-Austin and co-author of the study. "Our study shows that the effects of human activities have become evident all the way down to the seafloor in many regions, and the resulting increased acidification in these regions may impact our ability to understand Earth's climate history."
In future work, the researchers plan to study how dissolution likely will progress in the coming centuries. Since much of the carbon dioxide from burning fossil fuels still remains on the ocean surface, it could take decades, possibly even centuries, for CO2 to drop down to the bottom of the ocean, the scientists said. So all isn't lost—at least not yet, he said.
"Luckily for us, there is a lot of calcite out there, and only so much fossil fuel we can burn," Sulpis said. "That doesn't mean we have the green light to pollute more—it simply means that the oceans will be there to clean our mess, should it take thousands of years…" Hopefully, he added, "by then we will likely have stopped burning some fossil fuel, either because we ran out or—a smarter option—because we would have developed alternative, renewable energies."
Reposted with permission from our media associate Nexus Media.
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By Patti Lynn
2018 was a groundbreaking year in the public conversation about climate change. Last February, The New York Times reported that a record percentage of Americans now believe that climate change is caused by humans, and there was a 20 percentage point rise in "the number of Americans who say they worry 'a great deal' about climate change."
England faces an "existential threat" if it does not change how it manages its water, the head of the country's Environment Agency warned Tuesday.
By Jessica Corbett
A new analysis revealed Tuesday that over the past two decades heat records across the U.S. have been broken twice as often as cold ones—underscoring experts' warnings about the increasingly dangerous consequences of failing to dramatically curb planet-warming emissions.
By Madison Dapcevich
Ask any resident of San Francisco about the waterfront parrots, and they will surely tell you a story of red-faced conures squawking or dive-bombing between building peaks. Ask a team of researchers from the University of Georgia, however, and they will tell you of a mysterious string of neurological poisonings impacting the naturalized flock for decades.
The initial cause of the fire was not yet known, but it has been driven by the strong wind and jumped the North Santiam River, The Salem Statesman Journal reported. As of Tuesday night, it threatened around 35 homes and 30 buildings, and was 20 percent contained.
The unanimous verdict was announced Tuesday in San Francisco in the first federal case to be brought against Monsanto, now owned by Bayer, alleging that repeated use of the company's glyphosate-containing weedkiller caused the plaintiff's cancer. Seventy-year-old Edwin Hardeman of Santa Rosa, California said he used Roundup for almost 30 years on his properties before developing non-Hodgkin's lymphoma.
"Today's verdict reinforces what another jury found last year, and what scientists with the state of California and the World Health Organization have concluded: Glyphosate causes cancer in people," Environmental Working Group President Ken Cook said in a statement. "As similar lawsuits mount, the evidence will grow that Roundup is not safe, and that the company has tried to cover it up."
Judge Vince Chhabria has split Hardeman's trial into two phases. The first, decided Tuesday, focused exclusively on whether or not Roundup use caused the plaintiff's cancer. The second, to begin Wednesday, will assess if Bayer is liable for damages.
"We are disappointed with the jury's initial decision, but we continue to believe firmly that the science confirms glyphosate-based herbicides do not cause cancer," Bayer spokesman Dan Childs said in a statement reported by The Guardian. "We are confident the evidence in phase two will show that Monsanto's conduct has been appropriate and the company should not be liable for Mr. Hardeman's cancer."
Some legal experts said that Chhabria's decision to split the trial was beneficial to Bayer, Reuters reported. The company had complained that the jury in Johnson's case had been distracted by the lawyers' claims that Monsanto had sought to mislead scientists and the public about Roundup's safety.
However, a remark made by Chhabria during the trial and reported by The Guardian was blatantly critical of the company.
"Although the evidence that Roundup causes cancer is quite equivocal, there is strong evidence from which a jury could conclude that Monsanto does not particularly care whether its product is in fact giving people cancer, focusing instead on manipulating public opinion and undermining anyone who raises genuine and legitimate concerns about the issue," he said.
Many regulatory bodies, including the U.S. Environmental Protection Agency, have ruled that glyphosate is safe for humans, but the World Health Organization's International Agency for Research on Cancer found it was "probably carcinogenic to humans" in 2015. A university study earlier this year found that glyphosate use increased cancer risk by as much as 41 percent.
Hardeman's lawyers Jennifer Moore and Aimee Wagstaff said they would now reveal Monsanto's efforts to mislead the public about the safety of its product.
"Now we can focus on the evidence that Monsanto has not taken a responsible, objective approach to the safety of Roundup," they wrote in a statement reported by The Guardian.
Hardeman's case is considered a "bellwether" trial for the more than 760 glyphosate cases Chhabria is hearing. In total, there are around 11,200 such lawsuits pending in the U.S., according to Reuters.
University of Richmond law professor Carl Tobias told Reuters that Tuesday's decision showed that the verdict in Johnson's case was not "an aberration," and could possibly predict how future juries in the thousands of pending cases would respond.