The first underwater Aboriginal archaeological sites have been discovered off northwest Australia dating back thousands of years ago when the current seabed was dry land.
The discoveries were made through a series of archaeological and geophysical surveys in the Dampier Archipelago, as part of the Deep History of Sea Country Project, funded through the Australian Research Council's Discovery Project Scheme.
The Aboriginal artefacts discovered off the Plibara coast in Western Australia represent Australia's oldest known underwater archaeology.
An international team of archaeologists from Flinders University, The University of Western Australia, James Cook University, ARA - Airborne Research Australia and the University of York (United Kingdom) partnered with the Murujuga Aboriginal Corporation to locate and investigate ancient artefacts at two underwater sites which have yielded hundreds of stone tools made by Aboriginal peoples, including grinding stones.
In a study published today in PLOS ONE, the ancient underwater sites, at Cape Bruguieres and Flying Foam Passage, provide new evidence of Aboriginal ways of life from when the seabed was dry land, due to lower sea levels, thousands of years ago.
The submerged cultural landscapes represent what is known today as Sea Country to many Indigenous Australians, who have a deep cultural, spiritual and historical connection to these underwater environments.
"Today we announce the discovery of two underwater archaeological sites that were once on dry land. This is an exciting step for Australian archaeology as we integrate maritime and Indigenous archaeology and draw connections between land and sea," says Associate Professor Jonathan Benjamin who is the Maritime Archaeology Program Coordinator at Flinders University's College of Humanities, Arts and Social Sciences.
"Australia is a massive continent but few people realise that more than 30% of its land mass was drowned by sea-level rise after the last ice age. This means that a huge amount of the archaeological evidence documenting the lives of Aboriginal people is now underwater."
"Now we finally have the first proof that at least some of this archaeological evidence survived the process of sea level rise. The ancient coastal archaeology is not lost for good; we just haven't found it yet. These new discoveries are a first step toward exploring the last real frontier of Australian archaeology.
The dive team mapped 269 artefacts at Cape Bruguieres in shallow water at depths down to 2.4 metres below modern sea level. Radiocarbon dating and analysis of sea-level changes show the site is at least 7000 years old.
The second site at Flying Foam Passage includes an underwater freshwater spring 14 metres below sea level. This site is estimated to be at least 8500 years old. Both sites may be much older as the dates represent minimum ages only; they may be even more ancient.
The team of archaeologists and geoscientists employed predictive modelling and various underwater and remote sensing techniques, including scientific diving methods, to confirm the location of sites and presence of artefacts.
"At one point there would have been dry land stretching out 160 km from the current shoreline. That land would have been owned and lived on by generations of Aboriginal people. Our discovery demonstrates that underwater archaeological material has survived sea-level rise, and although these sites are located in relatively shallow water, there will likely be more in deeper water offshore" says Chelsea Wiseman from Flinders University who has been working on the DHSC project as part of PhD research.
"These territories that are now underwater harboured favourable environments for Indigenous settlements including freshwater, ecological diversity and opportunities to exploit marine resources which would have supported relatively high population densities" says Dr Michael O'Leary, a marine geomorphologist at The University of Western Australia.
The discovery of these sites emphasises the need for stronger federal legislation to protect and manage underwater heritage across 2 million square kilometres of landscapes that were once above sea level in Australia, and hold major insights into human history.
"Managing, investigating and understanding the archaelogy of the Australian continental shelf in partnership with Aboriginal and Torres Strait Islander traditional owners and custodians is one of the last frontiers in Australian archaeology" said Associate Professor Benjamin.
"Our results represent the first step in a journey of discovery to explore the potential of archaeology on the continental shelves which can fill a major gap in the human history of the continent" he said.
In Murujuga this adds substantial additional evidence to support the deep time history of human activities accompanying rock art production in this important National Heritage Listed Place.
Deep History of Sea Country Project with Murujuga Aboriginal Corporation
People in what is now Washington State were smoking Rhus glabra, a plant commonly known as smooth sumac, more than 1,400 years ago.
The discovery, made by a team of Washington State University researchers, marks the first-time scientists have identified residue from a non-tobacco plant in an archeological pipe.
Unearthed in central Washington, the Native American pipe also contained residue from N. quadrivalvis, a species of tobacco not currently grown in the region but that is thought to have been widely cultivated in the past. Until now, the use of specific smoking plant mixtures by ancient people in the American Northwest had only been speculated about.
"Smoking often played a religious or ceremonial role for Native American tribes and our research shows these specific plants were important to these communities in the past," said Korey Brownstein, a former WSU Ph.D. student now at the University of Chicago and lead author of a study on the research in the journal Frontiers in Molecular Biosciences. "We think the Rhus glabra may have been mixed with tobacco for its medicinal qualities and to improve the flavor of smoke."
The discovery was made possible by a new metabolomics-based analysis method that can detect thousands of plant compounds or metabolites in residue collected from pipes, bowls and other archeological artifacts. The compounds can then be used to identify which plants were smoked or consumed.
"Not only does it tell you, yes, you found the plant you're interested in, but it also can tell you what else was being smoked," said David Gang, a professor in WSU's Institute of Biological Chemistry and a co-author of the study. "It wouldn't be hyperbole to say that this technology represents a new frontier in archaeo-chemistry."
Previously, the identification of ancient plant residues relied on the detection of a limited number of biomarkers, such as nicotine, anabasine, cotinine and caffeine. Gang said the issue with this approach is while the presence of a biomarker like nicotine shows tobacco was smoked it doesn't distinguish which species it was.
"Also, if you are only looking for a few specific biomarkers, you aren't going to be able to tell what else was consumed in the artifact," Gang said.
In addition to identifying the first non-tobacco plant smoked in an archaeological pipe, the WSU researchers' work also helps elucidate the complex evolution of tobacco trade in the American Northwest.
Analysis of a second pipe that was used by people living in Central Washington after Euro-American contact revealed the presence of a different tobacco species, N. rustica, which was grown by native peoples on the east coast of what is now the United States.
"Our findings show Native American communities interacted widely with one another within and between ecological regions, including the trade of tobacco seeds and materials," said Shannon Tushingham, an assistant professor of anthropology at WSU and co-author of the study. "The research also casts doubt on the commonly held view that trade tobacco grown by Europeans overtook the use of natively-grown smoke plants after Euro-American contact."
Moving forward, the WSU researchers' work could ultimately help scientists studying ancient societies in the Americas and elsewhere around the globe identify which plant species ancient people were consuming, providing important information about the evolution of drug use and similar plant-human dynamics.
Closer to home, the WSU team is also putting their work to use helping confirm connections between ancient plant management practices from before the arrival of Western settlers with cultural traditions of modern indigenous communities such as the Nez Perce.. The researchers shared their work with members of the tribe who also used some of the seeds from the study to grow some of the pre-contact tobacco. The smoking of tobacco is a sacred tradition for Native American groups including the Nez Perce, Colville and other northwest Tribes and before now it was impossible to tell which kind of tobacco their ancestors smoked.
"We took over an entire greenhouse to grow these plants and collected millions of seeds so that the Nez Perce people could reintroduce these native plants back onto their land," Brownstein said. "I think these kinds of projects are so important because they help build trust between us and tribal communities and show that we can work together to make discoveries."
More than ten years ago, large geometric earthworks found in the southwestern parts of the Amazon, called geoglyphs, were reported in the global scientific news. A pre-colonial civilization unknown to scholars that built geometric ceremonial centers and sophisticated road systems. This civilization flourished in the rainforest area 2,000 years ago. The discovery radically altered the prevailing notion of the pristine Amazon rainforest. The research of an interdisciplinary Finnish-Brazilian team continues in the region with the support of the Academy of Finland. Recent findings show that large ancient construction projects not only shaped the landscape, but civilization has also impacted the diverse construction of rainforest.
The research team's latest article "Domestication in Motion" has been published in the journal Environmental Archeology last week. The article shows that in addition to the cultivation of manioc, maize and squash, the protection, care and planting of several trees were important for the food supply of the region's Indigenous peoples, says research director Professor Martti Pärssinen. In particular, Brazilian nut and palm trees with protein-rich fruits are common in samples from geoglyphic sites. They show the pre-colonial diet of the geoglyphic ceremonial sites.
The article also describes how tree domestication was not a linear process in Amazon conditions, as wild forms of plants could also be protected. During the archaeological excavations wild and domesticated forms of peach palm fruit were found, among other plants. On the other hand, especially Brazilian nut trees as well as many palm trees, which are vital for both their fruits and palm kernels, were domesticated in the rainforest area for human consumption. Their fruits are clearly larger than they were 2,000 years ago.
A unlinear process of domestication is evident, as both wild and domesticated peach palm trees are still well known by Indigenous peoples in the state of Acre, and the latter have spread to a very large area across the Amazon, says Pirjo Kristiina Virtanen, assistant professor involved in the project.
Human impact on the Amazon rainforest stand has been significant, and therefore there is no such thing as virgin rainforest. On the other hand, the study shows that Indigenous peoples of the Amazon have been able to use their environment in a sustainable way by domesticating certain plants while protecting and respecting it. There is no indication that large areas of forest would have been deforested.
These new findings argue against the idealistic notion of the pristine Amazon rainforest. At the same time, however, it highlights how Indigenous peoples utilize wild plants while domesticating certain plants for humans' use. The relationship between the peoples of the Amazon and forest has been proved sustainable. It should be explored further and lessons could be learned from this.
Reservoirs in the heart of an ancient Maya city were so polluted with mercury and algae that the water likely was undrinkable.
Researchers from the University of Cincinnati found toxic levels of pollution in two central reservoirs in Tikal, an ancient Maya city that dates back to the third century B.C. in what is now northern Guatemala.
UC's findings suggest droughts in the ninth century likely contributed to the depopulation and eventual abandonment of the city.
"The conversion of Tikal's central reservoirs from life-sustaining to sickness-inducing places would have both practically and symbolically helped to bring about the abandonment of this magnificent city," the study concluded.
A geochemical analysis found that two reservoirs nearest the city palace and temple contained toxic levels of mercury that UC researchers traced back to a pigment the Maya used to adorn buildings, clayware and other goods. During rainstorms, mercury in the pigment leached into the reservoirs where it settled in layers of sediment over the years.
But the former inhabitants of this city, made famous by its towering stone temples and architecture, had ample potable water from nearby reservoirs that remained uncontaminated, UC researchers found.
The study was published in the Nature journal Scientific Reports.
UC's diverse team was composed of anthropologists, geographers, botanists, biologists and chemists. They examined layers of sediment dating back to the ninth century when Tikal was a flourishing city.
Previously, UC researchers found that the soils around Tikal during the ninth century were extremely fertile and traced the source to frequent volcanic eruptions that enriched the soil of the Yucatan Peninsula.
"Archaeologists and anthropologists have been trying to figure out what happened to the Maya for 100 years," said David Lentz, a UC professor of biological sciences and lead author of the study.
For the latest study, UC researchers sampled sediment at 10 reservoirs within the city and conducted an analysis on ancient DNA found in the stratified clay of four of them.
Sediment from the reservoirs nearest Tikal's central temple and palace showed evidence of toxic algae called cyanobacteria. Consuming this water, particularly during droughts, would have made people sick even if the water were boiled, Lentz said.
"We found two types of blue-green algae that produce toxic chemicals. The bad thing about these is they're resistant to boiling. It made water in these reservoirs toxic to drink," Lentz said.
UC researchers said it is possible but unlikely the Maya used these reservoirs for drinking, cooking or irrigation.
"The water would have looked nasty. It would have tasted nasty," said Kenneth Tankersley, an associate professor of anthropology in UC's College of Arts and Sciences. "There would have been these big algae blooms. Nobody would have wanted to drink that water."
But researchers found no evidence of the same pollutants in sediments from more distant reservoirs called Perdido and Corriental, which likely provided drinking water for city residents during the ninth century.
Today, Tikal is a national park and a UNESCO World Heritage site. Researchers believe a combination of economic, political and social factors prompted people to leave the city and its adjacent farms. But the climate no doubt played a role, too, Lentz said.
"They have a prolonged dry season. For part of the year, it's rainy and wet. The rest of the year, it's really dry with almost no rainfall. So they had a problem finding water," Lentz said.
Co-author Trinity Hamilton, now an assistant professor of biology at the University of Minnesota, worked on the analysis of ancient DNA from algae that sank to the reservoir bottom and was buried by centuries of accumulated sediment.
"Typically, when we see a lot of cyanobacteria in freshwater, we think of harmful algal blooms that impact water quality," Hamilton said.
Finding some reservoirs that were polluted and others that were not suggests the ancient Maya used them for different purposes, she said.
Reservoirs near the temple and palace likely would have been impressive landmarks, much like the reflecting pool at the National Mall is today.
"It would have been a magnificent sight to see these brightly painted buildings reflected off the surface of these reservoirs," said co-author Nicholas Dunning, head of geography in UC's College of Arts and Sciences.
"The Maya rulers conferred to themselves, among other things, the attribute of being able to control water. They had a special relationship to the rain gods," Dunning said. "So the reservoir would have been a pretty potent symbol."
UC's Tankersley said one popular pigment used on plaster walls and in ceremonial burials was derived from cinnabar, a red-colored mineral composed of mercury sulfide that the Maya mined from a nearby volcanic feature known as the Todos Santos Formation.
A close examination of the reservoir sediment using a technique called energy dispersive X-ray fluorescence spectrometry found that mercury did not leach into the water from the underlying bedrock. Likewise, Tankersley said, UC ruled out another potential source of mercury -- volcanic ash that fell across Central America during the frequent eruptions. The absence of mercury in other nearby reservoirs where ash would have fallen ruled out volcanoes as the culprit.
Instead, Tankersley said, people were to blame.
"That means the mercury has to be anthropogenic," Tankersley said.
With its bright red color, cinnabar was commonly used as a paint or pigment across Central America at the time.
"Color was important in the ancient Maya world. They used it in their murals. They painted the plaster red. They used it in burials and combined it with iron oxide to get different shades," Tankersley said.
"We were able to find a mineral fingerprint that showed beyond a reasonable doubt that the mercury in the water originated from cinnabar," he said.
Tankersley said ancient Maya cities such as Tikal continue to captivate researchers because of the ingenuity, cooperation and sophistication required to thrive in this tropical land of extremes.
"When I look at the ancient Maya, I see a very sophisticated people with a very rich culture," Tankersley said.
UC's team is planning to return to the Yucatan Peninsula to pursue more answers about this remarkable period of human civilization.
A new report published in Science Advances on the emergence of agriculture in highland Papua New Guinea shows advancements often associated with a later Neolithic period occurred about 1000 years' earlier than previously thought.
University of Otago Archaeology Programme Professor and report co-author Glenn Summerhayes says findings in Emergence of a Neolithic in highland New Guinea by 5000 to 4000 years ago, provide insights into when and how the highlands were first occupied; the role of economic plants in this process; the development of trade routes which led to the translocation of plants and technologies; and an associated record of landscape, environment and climate change through time.
The report details the earliest figurative stone carving and formally manufactured pestles in Oceania, dating to 5050 to 4200 years ago, which were found at a dig site in Waim. Also found were the earliest planilateral axe-adzes uncovered in New Guinea to date, and the first evidence for fibrecraft and interisland obsidian transfer from neighbouring islands over distances of at least 800km.
"The new evidence from Waim fills a critical gap in our understanding of the social changes and technological innovations that have contributed to the developing cultural diversity in New Guinea," Professor Summerhayes says.
The combination of symbolic social systems, complex technologies, and highland agricultural intensification supports an independent emergence of a Neolithic around 1000 years before the arrival of Neolithic migrants, the Lapita, from Southeast Asia. When considered together with a growing corpus of studies indicating expansion and intensification of agricultural practices, these combined cultural elements represent the development of a regionally distinct Neolithic.
The research establishes dating for other finds at the site, including a fire lighting tool, postholes, and a fibrecraft tool with ochre, possibly used for colouring string fibre.
The report suggests increased population pressure on the uneven distribution of natural resources likely drove this process, which is further inferred by language and genetic divergence.
The project arose out of an Australian Research Council Grant awarded to Dr Judith Field (University of New South Wales) and Professor Summerhayes.
"Former Otago postgraduate student Dr Ben Shaw was employed as postdoctoral fellow to do the "leg work in the field" and Dr Anne Ford (Otago Archaeology Programme) contributed to understandings of the stone tool technologies. As it worked out many of these rich discoveries were made by Dr Shaw. It was one of the best appointments Dr Field and I have ever made. I am proud of our Otago graduates who are some of the best in the world."
Professor Summerhayes and his team had previously completed a Marsden funded project in the Ivane Valley of Papua, establishing the beginning of human occupation at 50,000 years ago. The results of this work were published inSciencein 2010.
"This project is a follow-on where we wanted to construct a chronology of human presence in the Simbai/Kaironk Valley of Papua New Guinea by systematic archaeological survey with subsequent excavation and analysis of a select number of sites.
"This work tracks long-term patterns of settlement history, resource use and trade, and establishes an environmental context for these developments by compiling vegetation histories, with particular attention paid to fire histories, indicators of landscape disturbance and markers of climate variability. This will add to understandings of peoples' impact on the environment."
Professor Summerhayes received a Marsden grant in late 2019 for his project "Crossing the divide from Asia to the Pacific: Understanding Austronesian colonisation gateways into the Pacific." This will involve work in the Ramu Valley, which was once part of an inland sea, and will tie in the developments of Highland New Guinea, with the movements of Austronesian speakers into the Pacific.
The assassination of Julius Caesar on the Ides of March in 44 B.C.E. triggered a 17-year power struggle that ultimately ended the Roman Republic leading to the rise of the Roman Empire. To the south, Egypt, which Cleopatra was attempting to restore as a major power in the Eastern Mediterranean, was shook by Nile flood failures, famine, and disease. These events are among the best known and important political transitions in the history of western civilization. A new study reveals the role climate change played in these ancient events.
An international team of researchers, including Yale's Joe Manning, used historical accounts and climate proxy records -- natural preservers of an environment's history (such as ice cores) -- to uncover evidence that the eruption of Alaska's Okmok volcano in 43 B.C.E. caused global climatic changes that sparked the period's political and social unrest and ultimately changed the course of ancient history. The research was published June 22 in the journal Proceedings of the National Academy of Sciences.
The interdisciplinary team analyzed volcanic fallout records in six Arctic ice cores, and found that the largest volcanic eruption in the northern Hemisphere of the past 2,500 years occurred in early 43 B.C.E. The researchers found that the geochemistry of tephra -- rock fragments and particles ejected by a volcanic eruption -- originated from the Okmok volcano in Alaska. Climate proxy records show that 43 and 42 B.C.E. were among the coldest years of the recent millennia in the Northern Hemisphere at the start of one of the coldest decades. Further research suggested that this high-latitude eruption led to pronounced changes in hydroclimate, including colder seasonal temperatures in specific Mediterranean regions during the two-year period following the eruption.
The team synchronized these scientific findings with written and archaeological sources from the period, which described unusual climate, crop failures, famine, disease, and unrest in the Mediterranean immediately following the eruption -- suggesting, Manning said, that the otherwise sophisticated and powerful ancient states were significantly vulnerable to these climatic shocks from a volcanic eruption located on the opposite side of the earth.
The decade of the 40's BCE was a period of food insecurity and famine in Egypt during the reign of Cleopatra, both of which took place during a time when the Nile River failed to flood. While there is some rain in the region, there is not enough to sustain agriculture, and Egyptians relied heavily on annual Nile River flood to water their crops, said Manning, the William K. and Marilyn Milton Simpson Professor of Classics and a scholar of ancient Egyptian history. "We know that the Nile River did not flood in 43 B.C.E.and 42 B.C.E. -- and now we know why. This volcanic eruption greatly affected the Nile watershed."
One of the texts that corroborated these findings is dated about 39 B.C.E. -- year 13 of Cleopatra's reign -- but refers to large-scale famine and social distress of the previous decade. The inscription describes a local governor who saves the population from widespread famine by finding food when there hadn't been a Nile River flood for several years. He is recognized as a savior by priesthoods, said Manning. "This inscription does not describe collapse or resilience," he said. "It is a more complicated story of trying to survive and to figure out how to distribute grain during a very chaotic time."
Today, Okmok Island, located in the mid-Aleutian Islands, has a population of about 40 people and 7,500 head of cattle. Manning finds irony in the fact that one of the most significant places in world history is in an extremely remote part of the world: "This large volcanic eruption that happened in the winter of 43 B.C.E. had cascading impacts on the climate system and on human societies in the Mediterranean during a vulnerable period of time."
Yet, he added, "Neither Roman scientists nor ancient priests had any notion of Okmok Island."
The new research "allows us to rethink ancient history, especially with regard to environment and climate, and to create a vision of a dynamic, three-dimensional society," Manning said.
An international team of scientists and historians has found evidence connecting an unexplained period of extreme cold in ancient Rome with an unlikely source: a massive eruption of Alaska's Okmok volcano, located on the opposite side of the Earth.
Around the time of Julius Caesar's death in 44 BCE, written sources describe a period of unusually cold climate, crop failures, famine, disease, and unrest in the Mediterranean Region -impacts that ultimately contributed to the downfall of the Roman Republic and Ptolemaic Kingdom of Egypt. Historians have long suspected a volcano to be the cause, but have been unable to pinpoint where or when such an eruption had occurred, or how severe it was.
In a new study published this week in Proceedings of the National Academy of Sciences (PNAS), a research team led by Joe McConnell, Ph.D. of the Desert Research Institute in Reno, Nev. uses an analysis of tephra (volcanic ash) found in Arctic ice cores to link the period of unexplained extreme climate in the Mediterranean with the caldera-forming eruption of Alaska's Okmok volcano in 43 BCE.
"To find evidence that a volcano on other side of the earth erupted and effectively contributed to the demise of the Romans and the Egyptians and the rise of the Roman Empire is fascinating," McConnell said. "It certainly shows how interconnected the world was even 2,000 years ago."
The discovery was initially made last year in DRI's Ice Core Laboratory, when McConnell and Swiss researcher Michael Sigl, Ph.D. from the Oeschger Centre for Climate Change Research at the University of Bern happened upon an unusually well preserved layer of tephra in an ice core sample and decided to investigate.
New measurements were made on ice cores from Greenland and Russia, some of which were drilled in the 1990s and archived in the U.S., Denmark, and Germany. Using these and earlier measurements, they were able to clearly delineate two distinct eruptions - a powerful but short-lived, relatively localized event in early 45 BCE, and a much larger and more widespread event in early 43 BCE with volcanic fallout that lasted more than two years in all the ice core records.
The researchers then conducted a geochemical analysis of the tephra samples from the second eruption found in the ice, matching the tiny shards with those of the Okmok II eruption in Alaska - one of the largest eruptions of the past 2,500 years.
"The tephra match doesn't get any better," said tephra specialist Gill Plunkett, Ph.D. from Queen's University Belfast. "We compared the chemical fingerprint of the tephra found in the ice with tephra from volcanoes thought to have erupted about that time and it was very clear that the source of the 43 BCE fallout in the ice was the Okmok II eruption."
Working with colleagues from the U.K., Switzerland, Ireland, Germany, Denmark, Alaska, and Yale University in Connecticut, the team of historians and scientists gathered supporting evidence from around the globe, including tree-ring-based climate records from Scandinavia, Austria and California's White Mountains, and climate records from a speleothem (cave formations) from Shihua Cave in northeast China. They then used Earth system modeling to develop a more complete understanding of the timing and magnitude of volcanism during this period and its effects on climate and history.
According to their findings, the two years following the Okmok II eruption were some of the coldest in the Northern Hemisphere in the past 2,500 years, and the decade that followed was the fourth coldest. Climate models suggest that seasonally averaged temperatures may have been as much as 7oC (13oF) below normal during the summer and autumn that followed the 43 BCE eruption of Okmok, with summer precipitation of 50 to 120 percent above normal throughout Southern Europe, and autumn precipitation reaching as high as 400 percent of normal.
"In the Mediterranean region, these wet and extremely cold conditions during the agriculturally important spring through autumn seasons probably reduced crop yields and compounded supply problems during the ongoing political upheavals of the period," said classical archaeologist Andrew Wilson, D.Phil. of the University of Oxford. "These findings lend credibility to reports of cold, famine, food shortage and disease described by ancient sources."
"Particularly striking was the severity of the Nile flood failure at the time of the Okmok eruption, and the famine and disease that was reported in Egyptian sources," added Yale University historian Joe Manning, Ph.D. "The climate effects were a severe shock to an already stressed society at a pivotal moment in history."
Volcanic activity also helps to explain certain unusual atmospheric phenomena that were described by ancient Mediterranean sources around the time of Caesar's assassination and interpreted as signs or omens - things like solar halos, the sun darkening in the sky, or three suns appearing in the sky (a phenomenon now known as a parahelia, or 'sun dog'). However, many of these observations took place prior to the eruption of Okmok II in 43 BCE, and are likely related to a smaller eruption of Mt. Etna in 44 BCE.
Although the study authors acknowledge that many different factors contributed to the fall of the Roman Republic and Ptolemaic Kingdom, they believe that the climate effects of the Okmok II eruption played an undeniably large role - and that their discovery helps to fill a knowledge gap about this period of history that has long puzzled archaeologists and ancient historians.
"People have been speculating about this for many years, so it's exciting to be able to provide some answers," McConnell said.
Innovation by ancient farmers to improve soil fertility continues to have an impact on the biodiversity of the Amazon, a major new study shows.
Early inhabitants fertilized the soil with charcoal from fire remains and food waste. Areas with this "dark earth" have a different set of species than the surrounding landscape, contributing to a more diverse ecosystem with a richer collection of plant species, researchers from the State University of Mato Grosso in Brazil and the University of Exeter have found.
The legacy of this land management thousands of years ago means there are thousands of these patches of dark earth dotted around the region, most around the size of a small field. This is the first study to measure the difference in vegetation in dark and non-dark earth areas in mature forests across a region spanning a thousand kilometers.
The team of ecologists and archaeologists studied abandoned areas along the main stem of the Amazon River near Tapajós and in the headwaters of the Xingu River Basin in southern Amazonia.
Lead author Dr Edmar Almeida de Oliveira said: "This is an area where dark earth lush forests grow, with colossal trees of different species from the surrounding forest, with more edible fruit trees, such as taperebá and jatobá."
The number of indigenous communities living in the Amazon collapsed following European colonization of the region, meaning many dark earth areas were abandoned.
The study, published in the journal Global Ecology and Biogeography, reveals for the first time the extent to which pre-Columbian Amerindians influenced the current structure and diversity of the Amazon forest of the areas they once farmed.
Researchers sampled around 4,000 trees in southern and eastern Amazonia. Areas with dark earth had a significantly higher pH and more nutrients that improved soil fertility. Pottery shards and other artefacts were also found in the rich dark soils.
Professor Ben Hur Marimon Junior, from the State University of Mato Grosso, said: "Pre-Columbian indigenous people, who fertilized the poor soils of the Amazon for at least 5,000 years, have left an impressive legacy, creating the dark earth, or Terras Pretas de Índio"
Professor José Iriarte, an archaeologist from the University of Exeter, said: "By creating dark earth early inhabitants of the Amazon were able to successfully cultivate the soil for thousands of years in an agroforestry system
"We think ancient communities used dark earth areas to grow crops to eat, and adjacent forests without dark earth for agroforestry."
Dr Ted Feldpausch, from the University of Exeter, who co-authored the study with Dr Luiz Aragão from the National Institute for Space Research (INPE) in Brazil, said: "After being abandoned for hundreds of years, we still find a fingerprint of the ancient land-use in the forests today as a legacy of the pre-Colombian Amazonian population estimated in millions of inhabitants.
"We are currently expanding this research across the whole Amazon Basin under a project funded by the UK Natural Environment Research Council (NERC) to evaluate whether historical fire also affected the forest areas distant from the anthropogenic dark earths".
Many areas with dark earth are currently cultivated by local and indigenous populations, who have had great success with their food crops. But most are still hidden in the native forest, contributing to increased tree size, carbon stock and regional biodiversity. For this reason, the lush forests of the "Terra Preta de Índio" and their biological and cultural wealth in the Amazon must be preserved as a legacy for future generations, the researchers have said. Areas with dark earth are under threat due to illegal deforestation and fire.
"Dark earth increases the richness of species, an important consideration for regional biodiversity conservation. These findings highlight the small?scale long?term legacy of pre?Columbian inhabitants on the soils and vegetation of Amazonia," said co-author Prof Beatriz Marimon, from the State University of Mato Grosso.
> The genome of an adult male from the heart of the world famous Newgrange passage tomb points to first-degree incest, implying dynasty and echoing local place-name folklore first recorded in Medieval times
> Far-flung kinship ties between Newgrange and passage tomb cemeteries in the west (Carrowkeel and Carrowmore, Co. Sligo) indicate an elite social stratum was widespread
> Before megalith builders arrived en masse, Ireland was home to a small hunter-gatherer population, whose genomes speak of long-term isolation from Britain and Europe
> The earliest case of Down Syndrome was discovered in a male infant from the famous Poulnabrone portal tomb
Archaeologists and geneticists, led by those from Trinity College Dublin, have shed new light on the earliest periods of Ireland's human history.
Among their incredible findings is the discovery that the genome of an adult male buried in the heart of the Newgrange passage tomb points to first-degree incest, implying he was among a ruling social elite akin to the similarly inbred Inca god-kings and Egyptian pharaohs.
Older than the pyramids, Newgrange passage tomb in Ireland is world famous for its annual solar alignment where the winter solstice sunrise illuminates its sacred inner chamber in a golden blast of light. However, little is known about who was interred in the heart of this imposing 200,000 tonne monument or of the Neolithic society which built it over 5,000 years ago.
The survey of ancient Irish genomes, published today in leading international journal, Nature, suggests a man who had been buried in this chamber belonged to a dynastic elite. The research, led by the research team from Trinity, was carried out in collaboration with colleagues from University College London, National University of Ireland Galway, University College Cork, University of Cambridge, Queen's University Belfast, and Institute of Technology Sligo.
"I'd never seen anything like it," said Dr Lara Cassidy, Trinity, first author of the paper. "We all inherit two copies of the genome, one from our mother and one from our father; well, this individual's copies were extremely similar, a tell-tale sign of close inbreeding. In fact, our analyses allowed us to confirm that his parents were first-degree relatives."
Matings of this type (e.g. brother-sister unions) are a near universal taboo for entwined cultural and biological reasons. The only confirmed social acceptances of first-degree incest are found among the elites - typically within a deified royal family. By breaking the rules, the elite separates itself from the general population, intensifying hierarchy and legitimizing power. Public ritual and extravagant monumental architecture often co-occur with dynastic incest, to achieve the same ends.
"Here the auspicious location of the male skeletal remains is matched by the unprecedented nature of his ancient genome," said Professor of Population Genetics at Trinity, Dan Bradley. "The prestige of the burial makes this very likely a socially sanctioned union and speaks of a hierarchy so extreme that the only partners worthy of the elite were family members."
The team also unearthed a web of distant familial relations between this man and other individuals from sites of the passage tomb tradition across the country, including the mega-cemeteries of Carrowmore and Carrowkeel in Co. Sligo.
"It seems what we have here is a powerful extended kin-group, who had access to elite burial sites in many regions of the island for at least half a millennium," added Dr Cassidy.
Remarkably, a local myth resonates with these results and the Newgrange solar phenomenon. First recorded in the 11th century AD, four millennia after construction, the story tells of a builder-king who restarted the daily solar cycle by sleeping with his sister. The Middle Irish place name for the neighbouring Dowth passage tomb, Fertae Chuile, is based on this lore and can be translated as 'Hill of Sin'.
"Given the world-famous solstice alignments of Brú na Bóinne, the magical solar manipulations in this myth already had scholars questioning how long an oral tradition could survive," said Dr Ros Ó Maoldúin, an archaeologist on the study. "To now discover a potential prehistoric precedent for the incestuous aspect is extraordinary."
The genome survey stretched over two millennia and unearthed other unexpected results. Within the oldest known burial structure on the island, Poulnabrone portal tomb, the earliest yet diagnosed case of Down Syndrome was discovered in a male infant who was buried there five and a half thousand years ago. Isotope analyses of this infant showed a dietary signature of breastfeeding. In combination, this provides an indication that visible difference was not a barrier to prestige burial in the deep past.
Additionally, the analyses showed that the monument builders were early farmers who migrated to Ireland and replaced the hunter-gatherers who preceded them. However, this replacement was not absolute; a single western Irish individual was found to have an Irish hunter-gatherer in his recent family tree, pointing toward a swamping of the earlier population rather than an extermination.
Genomes from the rare remains of Irish hunter-gatherers themselves showed they were most closely related to the hunter-gatherer populations from Britain (e.g. Cheddar Man) and mainland Europe. However, unlike British samples, these earliest Irelanders had the genetic imprint of a prolonged island isolation. This fits with what we know about prehistoric sea levels after the Ice Age: Britain maintained a land bridge to the continent long after the retreat of the glaciers, while Ireland was separated by sea and its small early populations must have arrived in primitive boats.