суббота, 8 февраля 2020 г.

Past climate safe havens now most vulnerable

The profound threat of future climate change to biodiversity demands that scientists seek ever more effective ways to identify the most vulnerable species, communities, and ecosystems.

Past climate safe havens now most vulnerable
Forecast warming threatens species in biodiversity rich regions, including the Indo–Pacific
[Credit: University of Adelaide]
In a new study, published in Nature Climate Change, an international team of scientists has shown that the most biodiverse regions on Earth are among the most vulnerable to future climate change.

By establishing global patterns of unusually extreme climate change events during Earth's history, and comparing these to 21st century patterns, the researchers were able to show that human-driven climate change will quickly erode important mechanisms that are likely to have sustained biodiversity across time.

"Our results show that the magnitude and accelerated rate of future climate change will disproportionately affect plants and animals in tropical regions and biodiversity hotspots. Worryingly, these are regions on Earth with the highest concentrations of biodiversity," says lead author Associate Professor Damien Fordham from the University Adelaide's Environment Institute.

Historically these regions have been safe havens from climate change during glacial-interglacial cycles. By providing refuge for species during periods of unfavourable global warming, these climate safe havens have shaped biodiversity by allowing older species to survive and new lineages to generate.

"Disturbingly, our research shows that more than 75% of the area of these climate safe havens will be lost in the near future due to 21st century warming," said Dr Stuart Brown from the University of Adelaide, who led the analysis.

"The future is most ominous for species in tropical oceans. Severe negative impacts on the richness of coral species and marine life they support are expected in regions such as the Indo-Pacific. This is likely to cause human hardship for communities that depend on these resources for food, employment and income."

For areas where climate safe havens are forecast to persist until the end of this century, the researchers show that temperatures are likely to exceed the acclimation capacity of many species, making them short-term hospices for biodiversity at best.

More generally the research shows that future climate change not only threaten species in polar environments, but also tropical regions, which contain particularly high biodiversity.

Author: Crispin Savage | Source: University of Adelaide [February 04, 3030]

* This article was originally published here

Save the giants, save the planet

Habitat loss, hunting, logging and climate change have put many of the world's most charismatic species at risk. A new study, led by the University of Arizona, has found that not only are larger plants and animals at higher risk of extinction, but their loss would fundamentally degrade life on earth.

Save the giants, save the planet
Protecting large plants and animals has a disproportionate positive impact on the health
of the planet and resilience to climate change [Credit: University of Arizona]
The study, published in Nature Communications, is based on computer simulations that compared the state of the natural world during the Pleistocene (a past epoch long before human-caused extinctions began), the present day, and a future world in which all large plants and animals had gone extinct.

Results showed that the continued loss of large animals alone would lead to a 44% reduction in the total amount of wild animal biomass on the planet. It would also lead to a 92% reduction in soil fertility, which underpins the ability of the earth to grow plants and sustain life.

"This research shows there are fundamental scientific principles that explain why large animals and trees matter for the health and integrity of all life on Earth," said lead author Brian Enquist, professor of ecology and evolutionary biology at the University of Arizona. "Protecting big, charismatic species does have an umbrella effect to protect the wider ecosystem."

A key reason for these results lies with the transport of nutrients. When large animals eat in one location and defecate or urinate in another, they transport nutrients, often moving them from nutrient-rich areas to other, less fertile parts of the land and oceans. Similarly, the largest trees are the most productive, and contain and stir more nutrients and carbon.

"Ecosystems with larger trees and animals are also more productive and provide more vital ecological services," Enquist said. "I use this analogy: The largest banks and corporations in the economy are the most productive and have the most impact on the economy, so when those large banks failed during the great recession in 2009, we had to prop them up economically, or they would have had a disproportionate negative impact on economy. It's a similar principle with large plants and animals across ecosystems."

Unfortunately, these large organisms are more susceptible to human pressures and climate change and take longer to recover from shocks, making them more prone to extinction.

"For hundreds of millions of years, Earth has been a planet of giants. In the last few thousand years, these large animals and plants have been whittled away, and this process continues today. Our paper shows why this loss of these giants matters for the very fabric of life on Earth, and why we must do everything possible to protect and restore them," said Yadvinder Malhi, leader of the ecosystems group at the Environmental Change Institute at the University of Oxford.

The findings help to answer an ongoing debate about where to channel limited conservation resources. While charismatic species such as the tiger or redwood tree have historically been most appealing and therefore effective at pulling in donations, some scientists worried that the focus on a certain subset of plants and animals could be coming at the cost of protecting other, less well-loved species.

"Our findings instead point to the importance of policies that emphasize the promotion of large trees and animals, as such policies will have a more disproportionate impact on biodiversity, ecosystem processes and climate mitigation," Enquist said. "We can use this model to focus our conservation concerns. For example, we can identify the forest that still contains some of the largest tress on the planet, or forests that have healthy size structure and prioritise them because they're more productive and resilient."

Author: Mikayla MacE | Source: University of Arizona [February 04, 2020]

* This article was originally published here

'Oldest bamboo' fossil from Eocene Patagonia turns out to be a conifer

A fossilised leafy branch from the early Eocene in Patagonia described in 1941 is still often cited as the oldest bamboo fossil and the main fossil evidence for a Gondwanan origin of bamboos. However, a recent examination by Dr. Peter Wilf from Pennsylvania State University revealed the real nature of Chusquea oxyphylla. The recent findings, published in the paper in the open-access journal Phytokeys, show that it is actually a conifer.

'Oldest bamboo' fossil from Eocene Patagonia turns out to be a conifer
The holotype of the species Retrophyllum oxyphyllum (comb. nov.),
previously thought to be the oldest known bamboo
[Credit: Peter Wilf]
The corrected identification is significant because the fossil in question was the only bamboo macrofossil still considered from the ancient southern supercontinent of Gondwana. The oldest microfossil evidence for bamboo in the Northern Hemisphere belongs to the Middle Eocene, while other South American fossils are not older than Pliocene.

Over the last decades, some authors have doubted whether the Patagonian fossil was really a bamboo or even a grass species at all. But despite its general significance, modern-day re-examinations of the original specimen were never published. Most scientists referring to it had a chance to study only a photograph found in the original publication from 1941 by the famous Argentine botanists Joaquin Frenguelli and Lorenzo Parodi.

In his recent study of the holotype specimen at Museo de La Plata, Argentina, Dr. Peter Wilf revealed that the fossil does not resemble members of the Chusquea genus or any other bamboo.

"There is no evidence of bamboo-type nodes, sheaths or ligules. Areas that may resemble any bamboo features consist only of the broken departure points of leaf bases diverging from the twig. The decurrent, extensively clasping leaves are quite unlike the characteristically pseudopetiolate leaves of bamboos, and the heterofacially twisted free-leaf bases do not occur in any bamboo or grass," wrote Dr. Wilf.

Instead, Wilf linked the holotype to the recently described fossils of the conifer genus Retrophyllum from the same fossil site, the prolific Laguna del Hunco fossil lake-beds in Chubut Province, Argentina. It matches precisely the distichous fossil foliage form of Retrophyllum spiralifolium, which was described based on a large set of data - a suite of 82 specimens collected from both Laguna del Hunco and the early middle Eocene Rio Pichileufu site in Rio Negro Province.

Retrophyllum is a genus of six living species of rainforest conifers. Its habitat lies in both the Neotropics and the tropical West Pacific.

The gathered evidence firmly confirms that Chusquea oxyphylla has nothing in common with bamboos. Thus, it requires renaming. Preserving the priority of the older name, Wilf combined Chusquea oxyphylla and Retrophyllum spiralifolium into Retrophyllum oxyphyllum.

The exclusion of a living New World bamboo genus from the overall floral list for Eocene Patagonia weakens the New World biogeographic signal of the late-Gondwanan vegetation of South America, which already showed much stronger links to living floras of the tropical West Pacific.

The strongest New World signal remaining in Eocene Patagonia based on well-described macrofossils comes from fossil fruits of Physalis (a genus of flowering plants including tomatillos and ground cherries), which is an entirely American genus, concludes Dr. Wilf.

Source: Pensoft Publishers [February 04, 2020]

* This article was originally published here

Mosaic X-rays reveal Peruvian mummy mysteries

Western researchers, including two undergraduate students, have become pivotal players in developing a mobile X-ray protocol that could transform how mummies are examined in the field.

Mosaic X-rays reveal Peruvian mummy mysteries
A CT scan of the skull of the same Peruvian mummy shows greater detail, including the textiles
that were placed around him in death [Credit: University of Western Ontario]
Anthropology professor Andrew Nelson and his team have pioneered a process to digitize and stitch together X-ray images so that they can non-destructively 'view' Peruvian mummy bundles in their entirety. The process will enable other anthropologists to conduct valuable work without damaging the objects.

"Lots of people have X-rayed mummies. But, as far as I know, we're the first to do the mosaic X-ray technique and do that digitally," Nelson explained.

Mummy bundles—called fardos—sometimes have been examined by unwrapping the textiles encasing the mummy. That process destroys the mummy and its context at least as much as it informs researchers about the past.

A less destructive but more time-consuming examination entails X-raying the bundles using film, which is then developed by hand, then transporting the heavy images home and analyzing them from afar.

But this new process is faster, portable and produces a far more complete picture. Here's how it works:

Researchers bring a suitcase-sized machine—Nelson's was funded by the Social Sciences and Humanities Research Council of Canada (SSHRC) – originally designed for use by veterinarians. The X-rays then go straight to the computer in digital form. No need to process into film or transport anything off-site. Those two-dimensional images are then electronically stitched together into composite, full-body images for immediate analyses.

Mosaic X-rays reveal Peruvian mummy mysteries
Researchers do a preliminary examination of a mummy bundle, one of hundreds discovered in Pachacamec, Peru, during
 a 2015 excavation to build a new museum. Pictured are, from left, Western student Lauren Poeta, Anthropology
 professor Andrew Nelson, Arizona researcher Suellen Gauld and archaeologist Sarita Fuentes Villalobos
of the Site Museum at Pachacamac [Credit: University of Western Ontario]
That scan can stand on its own as a more-than-basic record of the mummy's condition, position and setting. It can also offer rich enough detail for researchers to decide whether the mummy warrants further study through more detailed computer tomography (CT) scanning.

Last summer, Nelson's team conducted 880 X-rays and 31 CT scans in six days at the archaeological site of Pachacamac, Peru, where almost 200 fardos were discovered during excavation for a new museum in 2015.

This is the first time these mummy bundles—which date from about AD 1100 to AD1470—have been examined.

While the X-rays showed many mummies inside the bundles were no longer intact, the scans also indicated many were worthy of further non-destructive investigation.

"The great thing about doing the X-rays digitally and on site was the instant feedback we had," said David Seston, in his final year of undergraduate Anthropology studies and a key member of the team in data management and tech troubleshooting during the six-week study.

Anthropology Ph.D. student Joanna Motley pioneered the composite work in X-ray imaging.

Mosaic X-rays reveal Peruvian mummy mysteries
Undergraduate Anthropology student Lauren Poeta prepares a mummy bundle – called
  a fardo – of a Peruvian child for X-rays. The Western team has developed scanning
 processes that better assesses the mummy without damaging the fardo
[Credit: Andrew Nelson/Special to Western News]
Lauren Poeta, now in her fourth year of Anthropology, said the fieldwork in Peru—which included both teaching and learning from Peruvian researchers—offered an unparalleled opportunity in experiential learning.

"It was incredible because you don't expect to see that or have the opportunity to do that after just your third year. You get to do the experiential stuff. Instead of seeing pictures in two dimensions or in a textbook, this is totally different. You start to learn what to look for and what's important to see."

Poeta developed a standardized checklist of what researchers should be looking for as they try to discover how the fardos represent a microcosm of their society, including identifying the:

- Wrapping textile;

- Position of the mummy whether extended or with legs flexed towards their chest;

- Person's age, sex and any suspected health issues before death; and

- Type and location of any other artifacts buried with them.

Some fardos that have been CT-scanned and further analyzed show unusual objects wrapped with them.

Mosaic X-rays reveal Peruvian mummy mysteries
Credit: University of Western Ontario
Decorative shells. Stones. A mysterious folded disc they've nicknamed a 'taco." One person has a sharp object pierced through an eye socket. Another has a tattoo on one hand. One is surrounded by a 'cloud' of cotton seeds, be it to provide filler for the fardo or as a symbol for something else, no one yet knows.

Another question as-yet-unanswered is whether mummification—the preservation of tissue and clothing—was the main intent for wrapping and encasing the bodies, or whether mummification was an unintended result of the process, coupled with the dry climate and their burial in sand.

Together, all these details form clues into who these people were as individuals, how they lived, how they interacted with their community and how they were respected in death. They are, Nelson said, individually and collectively important to the study of pre-Columbian life in Peru.

Further study of the fardos and their images continues here year-round and by Peruvian researchers, with further work expected by a Western-Peruvian team this coming summer. "It's the awesome part of having a multi-year project," Nelson said.

A CT scan of the skull of the same Peruvian mummy shows greater detail, including the textiles that were placed around him in death. Credit: University of Western Ontario

Mosaic X-rays reveal Peruvian mummy mysteries
A CT scan of the skull of the same Peruvian mummy shows greater detail, including the textiles
 that were placed around him in death [Credit: University of Western Ontario]
Meanwhile, they have co-authored six collaborative papers about their work during and since last summer's research in Peru, and have presented research at archaeological and anthropological proceedings.

For Poeta, the experiential learning offered critical-thinking skills and a greater passion for anthropological fieldwork.

Seston said the experiential learning was both a personal and professional stretch.

"As an undergraduate, the chances of getting this kind of opportunity are incredibly rare. I knew when we went down there that this would change my perspective—but I never expected how much.

"A lot of work I do takes place on a computer. But being actually in the field and examining them changes my perspective 100 percent. It's not just an image on a screen. These are people and you have to respect them as people. You honour them by bringing them out and bringing back their stories."

Author: Debora Van Brenk | Source: University of Western Ontario [February 04, 2020]

* This article was originally published here

Wasp nests used to date ancient Australian rock art

Mud wasp nests have helped establish a date for one of the ancient styles of Aboriginal rock art in the Kimberley, Western Australia. University of Melbourne and ANSTO scientists put the Gwion Gwion art period around 12,000 years old.

Wasp nests used to date ancient Australian rock art
Wasp nests near the paintings have given scientists a major breakthrough
on Kimberley rock art [Credit: Damien Finch]
"This is the first time we have been able to confidently say Gwion style paintings were created around 12,000 years ago," said PhD student Damien Finch, from the School of Earth Sciences at the University of Melbourne. "No one has been able present the scientific evidence to say that before."

One wasp nest date suggested one Gwion painting was older than 16,000 years, but the pattern of the other 23 dates is consistent with the Gwion Gwion period being 12,000 years old.

The rock paintings, more than twice as old as the Giza Pyramids, depict graceful human figures with a wide range of decorations including headdresses, arm bands, and anklets. Some of the paintings are as small as 15cm, others are more than two metres high.

The details of the breakthrough are detailed in the paper 12,000-year-old Aboriginal rock art from the Kimberley region, Western Australia, now published in Science Advances.

Wasp nests used to date ancient Australian rock art
Two classic Gwion human figures with headdresses and arm
and waist decorations [Credit: Mark Jones]
More than 100 mud wasp nests collected from Kimberley sites, with the permission of the Traditional Owners, were crucial in identifying the age of the unique rock art.

"A painting beneath a wasp nest must be older than the nest, and a painting on top of a nest must be younger than the nest," Mr Finch said. "If you date enough of the nests, you build up a pattern and can narrow down an age range for paintings in a particular style."

Lack of organic matter in the pigment used to create the art had previously ruled out radiocarbon dating. But the University of Melbourne and ANSTO scientists were able to use dates on 24 mud wasp nests under and over the art to determine both maximum and minimum age constraints for paintings in the Gwion style.

The project was initiated by Professor Andy Gleadow and Professor Janet Hergt, from the School of Earth Sciences, and started in 2014 with funding from the Australian Research Council and the Kimberley Foundation. It is the first time in 20 years scientists have been able to date a range of these ancient artworks.

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Cortington Coffin (from a single oak tree with carved headrest, 4300 yrs old), Great North Museum,...

Cortington Coffin (from a single oak tree with carved headrest, 4300 yrs old), Great North Museum, Hancock, Newcastle upon Tyne, January 2020.

* This article was originally published here

NASA's Webb Will Seek Atmospheres around Potentially Habitable Exoplanets

This artist’s concept portrays the seven rocky exoplanets within the Trappist-1 system, located 40 light-years from Earth. Astronomers will observe these worlds with Webb in an effort to detect the first atmosphere of an Earth-sized planet beyond our solar system. Credits: NASA and JPL/Caltec. Release Images

This month marks the third anniversary of the discovery of a remarkable system of seven planets known as TRAPPIST-1. These seven rocky, Earth-size worlds orbit an ultra-cool star 39 light-years from Earth. Three of those planets are in the habitable zone, meaning they are at the right orbital distance to be warm enough for liquid water to exist on their surfaces. After its 2021 launch, NASA’s James Webb Space Telescope will observe those worlds with the goal of making the first detailed near-infrared study of the atmosphere of a habitable-zone planet.

To find signs of an atmosphere, astronomers will use a technique called transmission spectroscopy. They observe the host star while the planet is crossing the face of the star, known as a transit. The light of the star filters through the planet’s atmosphere, which absorbs some of the starlight and leaves telltale fingerprints in the star’s spectrum.

Finding an atmosphere around a rocky exoplanet — the word scientists use for planets beyond our solar system — won’t be easy. Their atmospheres are more compact than those of gas giants, while their smaller size means they intercept less of the star’s light. TRAPPIST-1 is one of the best available targets for Webb since the star itself is also quite small, meaning the planets’ size relative to the star is larger.

“The atmospheres are harder to detect but the reward is higher. It would be very exciting to make the first detection of an atmosphere on an Earth-sized planet,” said David Lafrenière of the University of Montreal, principal investigator on one of the teams examining TRAPPIST-1.

Red dwarf stars like TRAPPIST-1 tend to have violent outbursts that could make the TRAPPIST-1 planets inhospitable. But determining whether they have atmospheres, and if so, what they're made of, is the next step to finding out whether life as we know it could survive on these distant worlds.

A coordinated effort

More than one team of astronomers will study the TRAPPIST-1 system with Webb. They plan to use a variety of instruments and observing modes to tease out as many details as they can for each planet in the system.

“It’s a coordinated effort because no one team could do everything we wanted to do with the TRAPPIST-1 system. The level of cooperation has been really spectacular,” explained Nikole Lewis of Cornell University, the principal investigator on one of the teams.

“With seven planets to choose from, we can each have a piece of the cake,” added Lafrenière.

Lafrenière’s program will target TRAPPIST-1d and -1f in an effort to not only detect an atmosphere but determine its basic composition. They expect to be able to distinguish between an atmosphere dominated by water vapor, or one composed mainly of nitrogen (like Earth) or carbon dioxide (like Mars and Venus).

Lewis’s program will observe TRAPPIST-1e with similar goals. TRAPPIST-1e is one of the planets beyond our solar system that has the most in common with Earth in terms of its density and the amount of radiation that it receives from its star. That makes it a great candidate for habitability — but scientists need to know more to find out.

A broad variety of planets

While the TRAPPIST-1 planets hold particular appeal from a standpoint of potential habitability, Lafrenière’s program will target a variety of planets — from rocky to mini-Neptunes to Jupiter-sized gas giants — at a variety of distances from their stars. The goal is to learn more about how, and where, these planets form.

In particular, astronomers continue to debate how gaseous planets can be found very close to their stars. Most believe that such a planet must have formed farther out in the protoplanetary disk — the disk around a star where planets are born — since more material is available far from the star, and then migrated inward. However, other scientists theorize that even large gas giants can form relatively close to their star.

“Also, maybe they formed farther out, but how much farther out?” asked Lewis.

To help inform the debate, astronomers will look at the ratio of carbon to oxygen in an assortment of exoplanets. This ratio can serve as a tracer of where a planet formed, because it varies with the distance from the star.

Weather maps

In addition to examining planets using transmission spectroscopy, the teams will also employ a technique known as a phase curve. This involves observing a planet over the course of an entire orbit, which is only practical for the hottest worlds with the shortest orbital periods.

A planet circling its star very close becomes tidally locked, meaning that it always shows the same face to the star, as the Moon does to Earth. As a result, distant observers watching the planet will see it go through various phases, since different sides of the planet are visible at different points in its orbit.

By measuring the planet at various times, astronomers can build up a map of the atmospheric temperature as a function of longitude. This technique was pioneered by NASA’s Spitzer Space Telescope, which made the first “weather map” of an exoplanet in 2007.

In addition, by observing the planet’s own heat emission, astronomers can model the atmosphere’s vertical structure.

“With a phase curve, we can build a complete 3D model of a planet’s atmosphere,” explained Lafrenière.

This work is being conducted as part of a Webb Guaranteed Time Observations (GTO) program. This program is designed to reward scientists who helped develop the key hardware and software components or technical and interdisciplinary knowledge for the observatory.

The James Webb Space Telescope will be the world’s premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

* This article was originally published here

Researchers revise timing of Easter island's societal collapse

The prehistoric collapse of Easter Island's monument-building society did not occur as long thought, according to a fresh look at evidence by researchers at four institutions.

Researchers revise timing of Easter island's societal collapse
Ahu Nau Nau, a cultural and religious site built by Rapa Nui society on Easter Island's Anakena beach, was among
11 sites where previously gathered data were examined as part of the new study led by University of Oregon
doctoral candidate Robert DiNapoli. The site is located on the north shore of the Easter Island
[Credit: Robert DiNapoli]
"The general thinking has been that the society that Europeans saw when they first showed up was one that had collapsed," said Robert J. DiNapoli, a doctoral candidate in the University of Oregon's Department of Anthropology who led the analysis. "Our conclusion is that monument-building and investment were still important parts of their lives when these visitors arrived."

Easter Island, a Chilean territory also known as Rapa Nui, is located about 3,000 kilometers (1,864 miles) from South America and 2,000 kilometers (1,242 miles) from any other inhabited island.

Rapa Nui is believed to have been settled in the 13th century by Polynesian seafarers. They soon began building massive stone platforms stacked with megalithic statues and large, cylindrical stone hats that were used for cultural and religious rituals, including burial and cremation. A widely-held narrative is that monument construction stopped around 1600 after a major societal collapse.

In the new research, detailed online ahead of print in the Journal of Archaeological Science, DiNapoli's team presents a chronology for the statue platform construction by integrating existing radiocarbon dates with the order of assembly required to build the monuments and the written records of Dutch, Spanish and English seafarers who began arriving in 1722.

Taken together, DiNapoli said, the integration of data, using Bayesian statistics, brings clarity to radiocarbon-dating at various sites. Rapa Nui islanders, the researchers concluded, continued to build, maintain and use the monuments for at least 150 years beyond 1600.

The project began as part of DiNapoli's dissertation, which is focused on the process of building the monuments' architecture. Looking at 11 sites, the researchers examined the necessary sequence of construction, beginning with building a central platform and then adding different structures and statues.

That helped make sense of differing radiocarbon dates found at various excavation sites. Monument construction, according to the team, began soon after initial Polynesian settlement and increased rapidly, sometime between the early 14th and mid-15th centuries, with a steady rate of construction events that continued well beyond the hypothesized collapse and the European arrival.

When the Dutch arrived in 1722, their written observations reported that the monuments were in use for rituals and showed no evidence for societal decay. The same was reported in 1770, when Spanish seafarers landed on the island.

"Their stays were short and their descriptions brief and limited," DiNapoli said. "But they provide useful information to help us think about the timing of building and using these structures as part of their cultural and religious lives."

However, when British explorer James Cook arrived four years later, in 1774, he and his crew described an island in crisis, with overturned monuments.

"The way we interpret our results and this sequence of historical accounts is that the notion of a pre-European collapse of monument construction is no longer supported," DiNapoli said.

"Once Europeans arrive on the island, there are many documented tragic events due to disease, murder, slave raiding and other conflicts," said co-author Carl Lipo, an anthropologist at Binghamton University in New York.

"These events are entirely extrinsic to the islanders and have, undoubtedly, devastating effects. Yet, the Rapa Nui people - following practices that provided them great stability and success over hundreds of years - continue their traditions in the face of tremendous odds," he said. "The degree to which their cultural heritage was passed on - and is still present today through language, arts and cultural practices - is quite notable and impressive. I think this degree of resilience has been overlooked due to the collapse narrative and deserves recognition."

The approach developed for the research, which was funded by the National Science Foundation, may be useful for testing hypotheses of societal collapse at other complex sites around the world where similar debates on timing exist, the researchers noted.

Source: University of Oregon [February 06, 2020]

* This article was originally published here

The Bronze Age ‘Collette Hoard’, (1000 to 840BCE), Great North Museum, Hancock,...

The Bronze Age ‘Collette Hoard’, (1000 to 840BCE), Great North Museum, Hancock, Newcastle upon Tyne, January 2020.

* This article was originally published here

Massive centuries-old shipwreck found on bottom of Poland's River Vistula

A huge shipwreck measuring 37-metres-long and dating back centuries has been discovered by archaeologists in the Vistula River north of Warsaw.

Massive centuries-old shipwreck found on bottom of Poland's River Vistula
Sonar image of the boat discovered near Łomianki Dolne
[Credit: A. Szerszeń]
The 6-metre-wide vessel which was probably used to carry up to 100 tonnes of goods, was found by scientists carrying out research on the bottom of the Vistula in an area covering a dozen or so kilometres.

Underwater archaeologist and head of the project, Artur Brzóska from the Association of Archaeologists Jutra, said: “This is most likely a large transport vessel that was used from the 14th to the 18th century.”

Because of poor visibility and rapid currents the researchers failed to find any items related to the boat, for example, but as Brzóska pointed out: “We probably can’t count on much anyway. I believe that the boat probably transported grain to Gdańsk. Such goods could not be preserved.”

Boat wrecks are very rare. The best-preserved vessel of this type in Poland was recovered in 2018 in Czersk, from where it was transported to the Rybno Storage and Studio Centre of the State Archaeological Museum in Warsaw.

Massive centuries-old shipwreck found on bottom of Poland's River Vistula
A diver in the place where the wreck is located [Credit: A. Szerszeń]
The second previously unknown wreck was located near Buraków. Brzóska believes that because of its guides, probably for ropes, on its sides, this is most likely a ferry from the end of the 19th or from the first half 20th century.

Only two wrecks were previously known in this section of the river: one from the 16th century (the type of vessel is difficult to determine due to its condition) and another from the 19th century. This is a so-called berlinka, or longitudinal barge for canal and river sailing.

Researchers also came across the remains of a World War II bridge, located near Łomianki Dolne. These are five piles driven into the bottom of the river. Remains of steel structure are also preserved. “Our analyses and historical information show that the bridge was built by German sappers,” Brzóska said.

Sonar mounted on a motorboat was used during the research. After selecting promising sites, the scientists dived to verify the findings. Before starting the actual tests, they tested the sonar on the Vistula near Warsaw`s Old Town.

Massive centuries-old shipwreck found on bottom of Poland's River Vistula
Remnants of the bridge from World War II [Credit: P. Prejs]

During the experiments, researchers also found a fragment of the ship driven into the bottom of the river. According to Brzóska, it could also be a cargo boat, as evidenced by a fragment of the vessel pulled to the surface. It is a wooden bottom frame weighing about 250 kg, which was part of the bow or stern of the boat.

Last year, archaeologists sailed around 400 kilometres in a motorboat along parallel lines, to survey a 13-km-long section of the river with an area covering nearly 500 hectares.

Now scientists want to take research samples from the newly-discovered boats to determine the precise age of the sunken vessels. The project was financed from the funds of the Ministry of Culture and Scientific Heritage, with the substantive support of the Institute of Archaeology of the University of Warsaw.

Author: Szymon Zdziebłowski | Source: PAP - Science in Poland [February 01, 2020]

* This article was originally published here

Prehistoric Pottery, Great North Museum, Hancock, Newcastle upon Tyne, January 2020.

Prehistoric Pottery, Great North Museum, Hancock, Newcastle upon Tyne, January 2020.

* This article was originally published here

Underwater research at ancient Oloundas and the harbour of Ierapetra in Crete

The Ministry of Culture and Sports announced that submerged archaeological evidence in the area and urban center of ancient Oloundas, today’s Elounda on Crete, has been investigated by an underwater research team from the Ephorate of Underwater Antiquities and a team of geophysicists from the Laboratory of Satellite Remote Sensing of the Institute of Mediterreanean Studies. The research, conducted last October in much of Elounda Bay, involved volunteer divers and scientists of other specialties. This is the third research season in the five year project of the two bodies launched in 2017 and supported by the Municipality of Agios Nikolaos.

Underwater research at ancient Oloundas and the harbour of Ierapetra in Crete
View of the submerged structures in the Vathi Bay of the Kolokytha peninsula
[Credit: Greek Ministry of Culture]
The city of Oloundas is quite clearly mentioned in ancient sources, mainly in inscriptions. Sporadic rescue excavations in the greater gulf region and especially in the area of Alykes and Poros, where the Kolokytha peninsula is joined to Crete, indicate the use of the site since prehistoric times. The city was particularly prosperous in historical years until the first Byzantine period, when it was abandoned and probably started to sink underwater.

The research is twofold: the underwater overview of the coasts of Elounda Bay and the Kolokytha Peninsula and the documentation and mapping of the submerged structures on both sides of Poros, where the urban center of the ancient city is situated.

Underwater research at ancient Oloundas and the harbour of Ierapetra in Crete
Documentation of remains of a later shipwreck to the west of the Poros Bay
[Credit: Greek Ministry of Culture]
So far, submerged building complexes in Vathi and Melissos gulfs on Kolokytha as well as ancient quarries in three different parts of the peninsula have been located and mapped by methods of remote sensing and photogrammetry.

In one of these, the research identified chiselled bollards and the loading platform. Also found were ships’ ballast, anchors, accidental rejects, signs of a Byzantine shipwreck, as well as remnants of a more recent 20th century shipwreck.

Underwater research at ancient Oloundas and the harbour of Ierapetra in Crete
Remains of submerged buildings on the seabed of the Poros Bay in Elounda
[Credit: Greek Ministry of Culture]

Underwater research at ancient Oloundas and the harbour of Ierapetra in Crete
Cleaning ancient structures in the Poros Bay to achieve satisfactory mapping
 [Credit: Greek Ministry of Culture]
After surface clearing, remnants of the ancient city’s buildings, as well as parts of its fortification were located and are being gradually mapped in the Poros region, both on the two sides of the isthmus and in the adjacent bay to its southwest, at “Hava ton Lakko”,as it is known locally..

Evidence on the sea bed surface and the coast is completed by an investigation below the region’s sea bed by geophysical surveys (magnetic and electrical tomography), which show the existence of structures at depths of up to -1.5 m below seabed level.

Underwater research at ancient Oloundas and the harbour of Ierapetra in Crete
Cleaning part of the wall of ancient Oloundas in the Bay of 'Hava Lakkos'
[Credit: Greek Ministry of Culture]
All information is included in a digital geographic database (GIS), compatible with the one developed at the Crete Office of the Ephorate of Underwater Antiquities for the whole of the island’s marine cultural reserve.

During the same period, the two bodies conducted a three-day reconnaissance of the port of Ierapetra to comprehend the remains of the harbour works and natural formations found in the area. The brief survey assisted by “Ierapetra”, the local cultural association, gathered necessary data to get a clearer understanding of the site.

Underwater research at ancient Oloundas and the harbour of Ierapetra in Crete
View of a 3D depiction of part of the wall of ancient Oloundas, submerged today in the Bay of Poros
[Credit: Greek Ministry of Culture]
This data, along with information from ancient, medieval and modern literature referring to the harbour, helps clarify relevant references to three harbour basins and the similarity of the ancient port with that of Alexandria, Egypt. The data will be used to study this important harbour of Roman Crete and the planning of more extensive underwater geo-archaeological research in the future.

Source: Greek Ministry of Culture [trsl. Archaeology & Arts, February 01, 2020]

* This article was originally published here


Соединение Юпитера  ♃  и  Сатурна  ♄   21 декабря 2020   16 : 30 по Гринвичу, 21 декабря 2020 года, состоится условное соединение Юпитера ♃ ...