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Ancient burial site in Belize reveals when people started eating maize

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June 3 (UPI) — Maize is a staple crop across much of the Americas, and new research suggests it’s been that way for at least 4,700 years.

Reconstructing the diets of early human populations in tropical regions like Central America has proven quite difficult, but scientists recently discovered a burial site in present-day Belize that has been continuously used for over 10,000 years.

Given the shallow nature of most graves and burial sites, it’s rare for human remains to end up layered sequentially — let alone a burial site featuring well-preserved remains.

“Finding intact burials from any time period is rare in tropical environments as the high temperatures and humidity are favorable to bacteria and other decomposers,” archaeologist Mark Robinson, a postdoctoral research fellow at Exeter University in Britain, told UPI in an email. “The rock shelters we excavated just happen to have the perfect set of factors to protect from the elements, creating a very dry, loose sediment, with no tree roots disturbing the interred bones.”

To find out when humans that frequented the two rock shelters first started eating maize, scientists analyzed bones from 44 human skeletons.

“The food we consume is absorbed and builds our body’s tissues,” Robinson said. “The chemical signature of that food leaves its mark in our bodies, meaning we really are what we eat.”

Because maize photosynthesizes differently than other kinds of plants, it leaves a unique chemical signature in bones.

“Maize, in the grass family of plants, creates a different carbon signature than the fruit, nuts, and leafy greens we consume from trees and herbs,” Robinson said.

The oldest remains that researchers recovered from the burial site were dated to between 9,600 and 8,600 years ago. Humans continued to bury the dead at the rock shelters until just 1,000 years ago. The isotopic ratios measured in the ancient bones showed humans in Central America began eating maize nearly 5,000 years ago.

Prior to the introduction of maize, humans in the region relied on herbs, fruits and nuts from local trees and shrubs, as well as with meat from hunting native land animals. Isotopic analysis of the bones of two infants suggests their mothers were eating large amounts of maize by at least 4,700 years ago.

As early as 4,000 years ago, maize made up nearly 70 percent of the diets of some people in Central America.

By the time the first European explorers arrived in the Americas, corn was ubiquitous among native populations. The new study — published Wednesday in the journal Science Advances — can help researchers reconstruct the growing importance of maize among native populations.

“Decades of research has revealed the importance of the crop for cultural identity, cosmological beliefs, creation myths, landscape management, the economy, as well as dietary nutrition,” Robinson said.

“Although the impact and importance of maize has been extensively researched, how, why and when maize was domesticated and adopted by so many diverse groups is still little understood,” he said. “The data from these contexts enables us for the first time to chronologically explore these questions in a single location.”

As the new analysis revealed, what began as a supplemental food source slowly became more important over several generations.

“Farmers would have to learn how to cultivate the crop and make the decision to increase the labor investment into its cultivation, becoming more reliant on the grain at the expense of other sources of nutrition,” Robinson said.

“By the later periods, whole socioeconomic systems were built around maize agriculture, with landscapes transformed to maximize cultivation,” Robinson said. “These data provide the first lines of evidence for how that adoption process took place and how long it took.”

The latest isotopic analysis can provide context to the archaeological remains of early Central American settlements. The adoption of corn as a staple diet was closely intertwined with the development of farming tools and food processing technologies, as was the evolution of local economies and social and political structures.

By the time the Mayan civilization emerged some 2,000 years ago, maize wasn’t just a source of calories, it was a crop of tremendous importance — culturally, economically and politically.

“We are currently analyzing genomic data from the skeletal material, which will provide new insight into who these people were,” Robinson said. “This will help us unravel the process of adoption of the technology. Did a new population enter the area, bringing maize agriculture, or were the seeds and plants passed between communities.”



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Citizen scientists help improve space weather forecasts

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Sept. 18 (UPI) — Data collected by citizen scientists have helped space weather forecasters more accurately predict when Earth will get hit by solar storms, according to a study published Friday in the journal AGU Advances.

When researchers supplement computer models with citizen scientist-collected data on the size and shape of coronal mass ejections, or CMEs, forecasts were 20 more accurate.

The supplemental data, collected by volunteers through the Solar Stormwatch citizen science project, also reduced forecasting uncertainty by 15 percent.

“CMEs are sausage-shaped blobs made up of billions of tonnes of magnetized plasma that erupt from the sun’s atmosphere at a million miles an hour,” lead researcher Luke Barnard said in a news release.

“They are capable of damaging satellites, overloading power grids and exposing astronauts to harmful radiation,” said Barnard, space weather scientist at the University of Reading in Britain. “Predicting when they are on a collision course with Earth is therefore extremely important.”

Because the speed and trajectory of coronal mass ejections vary dramatically, scientists have struggled to accurately predict when and where solar storms will hit Earth.

“Solar storm forecasts are currently based on observations of CMEs as soon as they leave the Sun’s surface, meaning they come with a large degree of uncertainty,” Barnard said. “The volunteer data offered a second stage of observations at a point when the CME was more established, which gave a better idea of its shape and trajectory.”

Researchers say the study supports the deployment of wide-field CME imaging cameras on space weather monitoring missions.

Real-time analysis of the images provided by the spacecraft cameras could help forecasters pinpoint solar storm threats days in advance, they said.



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Ancient footprints in Saudi Arabia help researchers track human migrations out of Africa

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Sept. 18 (UPI) — Paleontologists have discovered a diverse assemblage of 120,000-year-old human and animal footprints in an ancient lake deposit in Saudi Arabia’s Nefud Desert, offering new insights into the trajectories of human migrations out of Africa, according to a study published Friday in the journal Science Advances.

A mounting body of evidence, compiled and published over the last two decades, has upended early theories that humans migrated out of Africa in one or two giant waves.

“As more and more fossils are discovered, it seems that humans repeatedly dispersed out of Africa and did so much earlier than previously thought,” study co-author Mathew John Stewart told UPI in an email.

“Precisely when, how often and under what conditions remain open questions,” said Stewart, a researcher at the Max Planck Institute for Chemical Ecology in Germany.

For answers to these questions, researchers have mostly looked to Africa and Eurasia, ignoring the Arabian Peninsula. Though it neighbors both Africa and Asia, evidence of human occupation in the region is scant.

“The area today is a hyper-arid desert, characterized by very little rainfall and large, expansive sand dunes,” Stewart said. “The conditions are not very amenable to the preservation of material and sediments. Significant erosion of sediments and the subsequent destruction of material, such as fossil remains, is unfortunately common.”

Paleoclimate data suggests that Arabia wasn’t always as dry as it was today, and a scattering of fossil discoveries has confirmed that humans were able to make forays into the Arabian interior when shifts in climate turned the peninsula’s deserts into grassland.

The ancient footprints found in the Nefud Desert, fossilized in an ancient lake deposit known as ‘Alathar’ — Arabic for “the trace” — suggests humans made one of those forays roughly 120,000 years ago.

“The age of the footprints are consistent with Homo sapiens fossils in the Levant, and suggests that there were multiple routes that humans took upon expanding beyond Africa,” study co-author Richard Clark-Wilson told UPI in an email.

“There is earlier evidence for our species moving into the Mediterranean environment of the Levant and southern Greece, but this is the earliest evidence of our species moving into a semi-arid grassland as Arabia would have been,” said Clark-Wilson, a postgraduate research student at Royal Holloway in Britain.

In addition to human footprints, researchers uncovered footprints left by elephants, horses and hippos, suggesting Homo sapiens weren’t the only species drawn to the open grasslands and water resources of northern Arabia. Research suggests it’s possible humans were following animals when they first moved into the region.

“Whats exciting about the animal footprints is that it closely ties human and animal movements around lakes in northern Arabia,” Stewart said. “Unlike most other records, footprints provide very high-resolution information, on the order of hours or days. Also, the animal footprints provide information on what the environment and ecology was like when these people were moving through the landscape.”

While the discovery of ancient footprints in Arabia suggests human movements out of Africa extended eastward into northern Arabia, Stewart said plenty of questions remain unanswered.

“Precisely what happened to these people during the more arid periods? How long did they occupy the Arabian interior? Where did they go?”



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Study: Commercial fisheries regularly catch threatened, endangered fish species

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Sept. 21 (UPI) — Despite Australia’s international reputation for high quality marine conservation programming, new research out of the University of Queensland suggests Australia’s seafood eaters are regularly consuming engendered species.

The findings, published Monday in the journal Nature Communications, suggest the consumption of endangered fish species isn’t just a problem Down Under — it is a global crisis.

When researchers surveyed commercial catch and seafood import data, they found 92 endangered and 11 critically endangered species of seafood are being caught elsewhere before being imported and sold at grocery stores, fish markets and restaurants in Australia, Europe and elsewhere.

That’s because it’s perfectly legal for commercial fishers to catch species threatened with extinction. Additionally, seafood is not required to be labeled according to its species.

“This means that the ‘fish’, ‘flake’ or ‘cod’ that Australians typically order at the fish and chip shop could be critically endangered,” lead researcher Leslie Roberson said in a news release.

“Australian seafood is not as sustainable as consumers would like to think, and it’s definitely not in line with many of the large international conservation agreements that Australia has signed to protect threatened species and ecosystems,” said Roberson, a doctoral candidate at the University of Queensland.

Home to the Great Barrier Reef and tremendous marine biodiversity, Australia has earned a reputation for progressive marine conservation programming.

But according to the latest study, unsustainable seafood importation and consumption patterns can undermine conservation efforts at home.

“Australia imports around 75 per cent of the seafood we consume and is internationally regarded as having effective conservation and fisheries management policies,” said study co-author Carissa Klein.

“When importing seafood from other places, we are displacing any social or environmental problems associated with fishing to that place, which is likely to have less capacity to sustainably manage its ocean,” Klein, senior research fellow at the University of Queensland.

According to Roberson, Klein and their colleagues, the estimates for the number of threatened species currently being caught by commercial fisheries are quite conservative.

The study authors suggest that part of the problem is that the international seafood trade is highly complex, making it difficult to track and regulate. One part of a fish may be processed in China, but the rest may go to Europe, they said.

“A typical situation might look something like — a fishing boat operating in Australian waters, owned by a Chinese company, with a crew of fishermen from the Philippines,” Roberson said. “We don’t know what we’re eating — it’s really hard to trace seafood back to its origin and species because the industry is such a mess.”

Researchers suggest trade and importation rules can be put in place to encourage Australians to eat more local seafood, which can be more easily regulated for sustainability. Australian-farmed abalone and wild-caught sardines are two seafood sources that could ease pressures on threatened fish species.

“Improving the sustainability of Australia’s seafood trade policies could significantly benefit the ocean worldwide, as well as the billions of people that depend on a healthy ocean for their health and livelihoods,” Klein said.

“It should be illegal to eat something that is threatened by extinction, especially species that are critically endangered — if we can better coordinate fisheries and conservation policies, we can prevent it from happening,” she said.



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