SciTech Briefs

Sweet potato beat humans to Polynesia by thousands of years

For years, it's been thought that determining how long ago the sweet potato took root in Polynesia would reveal when ancient South Americans and Pacific Islanders first encountered each other. Anthropologists are interested in this question because when Europeans arrived in Polynesia, they saw plenty of sweet potatoes — native to South America — growing on the Pacific islands. Many believe they were brought there by Polynesian sailors who made trips to South America.

But that may not necessarily be the case. A new genetic analysis, published April 12 in Current Biology, appears to indicate that sweet potatoes actually arrived in the Pacific about 100,000 years ago, without human help. Sweet potato seeds are able to sprout even after exposure to salt water, and could easily have been carried by birds.

However, anthropologists are not taking this to mean Polynesians and South Americans never met.

“This paper shows sweet potatoes were already in Polynesia when the islands were first colonized by humans thousands of years ago,” says Lars Fehren-Schmitz, a paleogeneticist at the University of California, Santa Cruz. “But it can’t prove there was no contact between Polynesians and South Americans before Europeans arrived.”

Source: Nature

Record numbers of scientists running for office in 2018

As cities across America prepare for the second March for Science, hundreds of scientists are running for office around the country at the local, state, and federal levels.

Scientist-candidates cite the country's current political climate as the main reason they are seeking election, pointing out that the current administration has a tendency to reject scientific evidence.

“The attacks on science certainly didn’t start with Trump,” says Ted Bordelon, spokesperson for advocacy group 314 Action. “But he has been a huge catalyst. That may be one of the bright spots of his presidency — more scientists saying they want to be in the ring when it comes to lawmaking.”

"After Trump was elected, I thought, ‘I have a nice job, I’m tenured, I’m safe,’ but I felt so pessimistic,” explains physicist Elaine DeMasi, running to represent New York's First Congressional District.

For many of these candidates, science is its own platform. “Evidence-based politics is what I care about. I don’t care if it comes from the right or the left or the other right or the other left. As scientists, we are trained to prove ourselves wrong,” she says. “Government should have the same open mind.”

Source: Science News

Cargo ships must cut their emissions in half by 2050

In a first for the shipping industry, a new United Nations deal will restrict the greenhouse gas emissions of cargo ships.

The tens of thousands of cargo ships that transport goods around the world each year have primarily been powered by heavy fuel oil since the 1960s. According to James Corbett, an expert in global shipping at the University of Delaware in Newark, heavy fuel oil contains 1,800 times as much sulfur as diesel fuel.

The fuel burned by cargo ships produces two to three percent of greenhouse gas emissions annually — roughly the same amount as the entire nation of Germany. The 2015 Paris climate accord did not address these emissions at all in its plan to mitigate global warming.

The U.N.'s International Maritime Organization (IMO) is working to rectify that, with a new deal ratified April 13 by 170 nations. The plan is to reduce cargo ship greenhouse gas emissions below 50 percent of 2008 levels.

The IMO plan encourages shipping companies to reduce emissions with more energy-efficient ship designs, cleaner fuels, and better business practices.

According to Veronica Frank, an adviser to Greenpeace, the restrictions are “far from perfect, but the direction is now clear — a phaseout of carbon emissions.”

“Clearly the IMO is moving into the 21st century,” says Corbett.

Source: Science News