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2.5 billion-year-old Fossils in the Northern Cape Province of South Africa Show Life Existed without Oxygen

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December 1, 2016: Researchers have discovered fossils of 2.5 billion-year-old sulfur-oxidising bacteria that existed just fine without any oxygen.

The ancient life forms were found fossilised in two separate locations in the Northern Cape Province of South Africa.

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“These are the oldest reported fossil sulfur bacteria to date,” said Andrew Czaja, Assistant Professor of Geology at University of Cincinnati in the US.

“And this discovery is helping us reveal a diversity of life and ecosystems that existed just prior to the Great Oxidation Event, a time of major atmospheric evolution,” Czaja noted.

These bacteria were thriving just before the era when other shallow water bacteria began creating more and more oxygen as a by-product of photosynthesis.

“We refer to this period as the Great Oxidation Event that took place 2.4 to 2.2 billion years ago,” Czaja said.

The 2.52 billion-year-old sulfur-oxidising bacteria are described by Czaja as exceptionally large, spherical-shaped, smooth-walled microscopic structures much larger than most modern bacteria.

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In the study published in journal Geology, Czaja and his colleagues revealed samples of bacteria that were abundant in deep water areas of the ocean in a geologic time known as the Neoarchean Eon (2.8 to 2.5 billion years ago).

“These fossils represent the oldest known organisms that lived in a very dark, deep water environment,” Czaja said.

“We discovered these microfossils preserved in a layer of hard silica-rich rock called chert located within the Kaapvaal craton of South Africa,” Czaja noted.

With an atmosphere of much less than one percent oxygen, scientists have presumed that there were things living in deep water in the mud that did not need sunlight or oxygen, but experts did not have any direct evidence for them until now, Czaja said.

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“These early bacteria likely consumed the molecules dissolved from sulfur-rich minerals that came from land rocks that had eroded and washed out to sea, or from the volcanic remains on the ocean’s floor,” he added.(IANS)

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Chocolate Ingredient Cacao Dates Back To 5,400 yrs Ago

A growing interest in cacao flavors, indicates a return to a time when chocolate wasn't just an ingredient buried in a candy bar.

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A worker holds dried cacao seeds at a plantation in Cano Rico, Venezuela. VOA

New research strengthens the case that people used the chocolate ingredient cacao in South America 5,400 years ago, underscoring the seed’s radical transformation into today’s Twix bars and M&M candies.

Tests indicate traces of cacao on artifacts from an archaeological site in Ecuador, according to a study published Monday. That’s about 1,500 years older than cacao’s known domestication in Central America.

“It’s the earliest site now with domesticated cacao,” said Cameron McNeil of Lehman College in New York, who was not involved in the research.

The ancient South American civilization likely didn’t use cacao to make chocolate since there’s no established history of indigenous populations in the region using it that way, researchers led by the University of British Columbia in Canada said.

Cacao,chocolate
-A cacao pod hangs from a tree at the Agropampatar chocolate farm co-op in El Clavo, Venezuela. VOA

But the tests indicate the civilization used the cacao seed, not just the fruity pulp. The seeds are the part of the cacao pod used to make chocolate.

Indigenous populations in the upper Amazon region today use cacao for fermented drinks and juices, and it’s probably how it was used thousands of years ago as well, researchers said.

Scientists mostly agree that cacao was first domesticated in South America instead of Central America as previously believed. The study in Nature Ecology & Evolution provides fresh evidence.

Three types of tests were conducted using artifacts from the Santa Ana-La Florida site in Ecuador. One tested for the presence of theobromine, a key compound in cacao; another tested for preserved particles that help archeologists identify ancient plant use; a third used DNA testing to identify cacao.

Chocolate
A light almond cream candy carries the initials for Russell Stover Candies in Kansas City, Kansas. VOA

Residue from one ceramic artifact estimated to be 5,310 to 5,440 years old tested positive for cacao by all three methods. Others tested positive for cacao traces as well, but were not as old.

How cacao’s use spread between South America and Central America is not clear. But by the time Spanish explorers arrived in Central America in the late 1400s, they found people were using it to make hot and cold chocolate drinks with spices, often with a foamy top.

“For most of the modern period, it was a beverage,” said Marcy Norton, a historian at the University of Pennsylvania and author of “Sacred Gifts, Profane Pleasures: A History of Tobacco and Chocolate in the Atlantic World.”

The chocolate drinks in Central America often contained maize and differ from the hot chocolate sold in the U.S. They did not contain milk, Norton said, and when they were sweetened, it was with honey.

 

cocoa, chocolate
A worker holds cocoa beans at SAF CACAO, a export firm in San-Pedro, Ivory Coast, Jan. 29, 2016. VOA

By the 1580s, cacao was being regularly imported into Spain and spread to other European countries with milk being added along the way. It wasn’t until the 1800s that manufacturing advances in the Netherlands transformed chocolate into a solid product, Norton said.

Michael Laiskonis, who teaches chocolate classes the Institute of Culinary Education, said he’s seeing a growing interest in cacao flavors, indicating a return to a time when chocolate wasn’t just an ingredient buried in a candy bar.

Also Read: Consuming Cacao May Improve Vitamin D Intake, Says Study

He said he tries to incorporate chocolate’s past into his classes, including a 1644 recipe that combines Mayan and Aztec versions of drinks with European influences.

“It’s something that’s always been transforming,” he said. (VOA)