пятница, 7 июня 2019 г.

Patagonia ice sheets thicker than previously thought, study finds

After conducting a comprehensive, seven-year survey of Patagonia, glaciologists from the University of California, Irvine and partner institutions in Argentina and Chile have concluded that the ice sheets in this vast region of South America are considerably more massive than expected.

Patagonia ice sheets thicker than previously thought, study finds
Glaciers in South America’s Patagonia region, including Argentina’s Viedma Glacier (pictured), are much thicker
than expected, according to a seven-year survey conducted by scientists from UCI, Chile and Argentina that
will enable researchers and planners to more accurately model the effects of global warming
and plan for potential disruptions in freshwater resources [Credit: Jeremie Mouginot/UCI]

Through a combination of ground observations and airborne gravity and radar sounding methods, the scientists created the most complete ice density map of the area to date and found that some glaciers are as much as a mile (1,600 meters) thick. Their findings were published today in the American Geophysical Union journal Geophysical Research Letters.

«We did not think the ice fields on the Patagonian plateau could be quite that substantial,» said co-author Eric Rignot, Donald Bren Professor and chair of Earth system science at UCI. «As a result of this multinational research project, we found that — added together — the northern and southern portions of Patagonia clearly hold more ice than anticipated, roughly 40 times the ice volume of the European Alps.»

Patagonia is home to the largest ice fields in the Southern Hemisphere outside Antarctica, and its glaciers are among the fastest-moving in the world. Surface elevation observations from satellite radar altimetry and optical imagery have shown that most of the ice slabs in the region have been thinning rapidly over the past four decades. The contribution to global sea level rise from their melting has increased at an accelerating pace during that time.

Study co-author M. Gabriela Lenzano, a researcher with Argentina’s National Scientific and Technical Research Council, said the results will «help the scientific community better explain the interactions and consequences of ice sheet dynamics and climate on this cold environment — and the impact on communities and ecosystems downstream.»

With more precise knowledge of the size and shape of the glaciers in this highly protected region — much of which is contained in one of the world’s largest national park systems — researchers and planners will be able to more accurately model the effects of global warming and plan for potential disruptions in freshwater resources that serve its inhabitants.

«This is why having accurate maps of the ice thickness is a priority,» said lead author Romain Millan, who was a UCI graduate student in Earth system science for the bulk of this research project and is now a postdoctoral scholar at the Institute of Environmental Geosciences in Grenoble, France. «It is fundamental to get the right contours and depth of the glacial valleys; otherwise, simulations of glacier retreat will always be wrong.»

The difficulty in quantifying bed elevation and thickness has limited scientists’ ability to predict the region’s potential contribution to sea level rise; model glacier dynamics in response to climate change; study the impacts on freshwater resources; or prepare against such hazards as lake outburst flooding, which occurs when a dam containing a glacial lake fails.

Past attempts to gauge the total heft of the ice have fallen short, because traditional sounding techniques were limited to the shallowest sections of the ice field. Another obstacle has been the temperate nature of Patagonian ice. The frozen water in the glaciers is near its melting point from the top to the bottom; the higher water content makes this kind of ice more difficult to measure with radar.

To overcome these challenges, the scientists took to the skies, flying over broad stretches of terrain in helicopters and fixed-wing aircraft equipped with gravimeters, devices that can determine the ice volume by reading changes in Earth’s gravitational field. The addition of data collected by glaciologists from Chile’s Center for Scientific Studies, who had mapped ice thickness with low-frequency airborne radar sounding since 2002, was instrumental in creating a more comprehensive description of the area’s conditions.

«This research has been enhanced and successfully completed thanks to our collaboration with the Rignot group at UCI and our Argentinean colleagues, with whom we have worked at both sides of the southern Patagonia ice field — disregarding the political border that divides the region,» said co-author Andrés Rivera of the Chilean center.

Source: University of California — Irvine [June 03, 2019]



Researchers find slowdown in Earth’s temps stabilized nature’s calendar

Sometimes referred to as nature’s calendar, phenology looks at the seasonal life cycle of plants and animals and is one of the leading indicators of climate change. It’s the observance of natural occurrences like the first formation of buds and flowers in the spring and the changing colors of leaves in the fall. According to researchers at the University of New Hampshire, when the rate of the Earth’s air temperature slows down for a significant amount of time, so can phenology.

Researchers find slowdown in Earth's temps stabilized nature's calendar
Credit: University of New Hampshire

In a study, recently published in the journal Nature Communications, researchers focused on a 15-year period in the early part of this century, when there was a temporary slowdown in the rise of the Earth’s air temperatures. It continued to rise, but more slowly than in the years before and after. Scientists found that during that period, phenology remained relatively constant from year to year, with no appreciable increase in the length of the growing seasons.

«This finding was a big surprise to us because the Earth’s climate is changing and affecting the length of the seasons,» says Jingfeng Xiao, a research associate professor at the UNH Earth Systems Research Center. «Over the past decades we have experienced longer growing seasons, with spring coming earlier and fall coming later, but this wasn’t the situation from 1998 to 2012 in the northern hemisphere.»

Phenology plays a major role in helping to regulate plant photosynthesis, transpiration, and energy exchange. When phenology stabilizes, it’s easier to estimate when to start a garden, when fall foliage will peak and helps life cycles like pollination, migration and mating.

Researchers examined the carbon dioxide exchange between plants and the atmosphere from 56 sites located in forests, croplands, savannas, shrublands and grasslands in the northern hemisphere. They were the first to compare those findings with satellite imagery that indicated the dates of leaf-out (when leaves emerge in the spring) and senescence (when leaves fall and plants die off or enter dormancy in autumn) to estimate the length and timing of the growing season, which stayed about the same for that time period.

Earlier leaf-out and/or later senescence can mean a longer growing season, increase in agriculture production and crop yield, as well as an increase in the amount of carbon dioxide absorbed by plants from the atmosphere. However, it can also mean the need for more water use and could affect stream flow and aggravate water crisis issues.

«It’s not just about plants, many people are also physically affected by phenological trends,» said Xiao. «Anyone suffering from seasonal allergies knows, an earlier spring, or growing season, can mean an earlier allergy season.»

Phenological variations also make it more difficult for scientists to estimate the Earth’s carbon, water and energy exchange between the atmosphere and the Earth’s surface, which can then affect climate change projections.

The scientists admit that the time period they studied, where the Earth’s air temperature rate slowed down, may seem to contrast with other research on global warming but they emphasize that even during this period the Earth’s temperatures continued to rise. They point out that temporary trends like this one require very long datasets—at least a decade or longer—to properly assess big-picture phenological trends.

Source: University of New Hampshire [June 03, 2019]



An island haven for frogs in a sea of extinctions

New Guinea is one of the only places in the world where frogs are safe from the species-destroying chytrid fungus. An international team of scientists has published a new paper that shows how to keep it that way, but they need help to carry out their plan.

An island haven for frogs in a sea of extinctions
The New Guinean frog Sphenophryne cornuta carrying its young on its back
[Credit: Stephen J Richards]

The chytrid fungus has wiped out more than 90 frog species around the world, and it’s driving hundreds more towards extinction. New Guinea—the world’s largest tropical island, and home to 6% of all known frog species—is one of the last remaining refuges from the deadly infection.

A team of scientists led by researchers from Macquarie University and the University of New England in Australia think they know how to keep the island’s frogs safe, but they need support to establish a long-term program of monitoring and conservation.

Writing in the journal Frontiers in Ecology and the Environment, the group of 30 experts from Australia, the USA, China, Indonesia and Papua New Guinea calls for urgent action.

«You don’t often spot a conservation disaster before it happens and get the chance to stop it,» says Deborah Bower of the University of New England in Armidale, Australia, who is the first author of the article. «We know what needs to be done.»

The infectious chytrid fungus has been described as the most destructive pathogen known to science. It has destroyed more than 90 species of frog entirely and caused declines in almost 500 more.

An island haven for frogs in a sea of extinctions
The New Guinean frog Lechriodus aganoposis is one of up to a hundred species that would be
at risk if the chytrid fungus reaches the tropical island [Credit: Stephen J. Richards]

The international pet trade helped the chytrid fungus spread rapidly from its origins in East Asia over recent decades, and it now infects frogs on every continent. It is one of the key reasons why 40% of the world’s frog species now face the threat of extinction.

New Guinea’s tropical climate and hundreds of native frog species make it an ideal environment for chytrid. But field tests have so far found no traces of the killer fungus.

«A lot of New Guinea’s frogs are closely related to Australian species that have been devastated by chytrid, so we expect they would be just as vulnerable,» says Simon Clulow at Macquarie University in Sydney, Australia, who leads the research team.

«Other New Guinea frog species are unusual because they hatch from eggs as fully formed frogs, rather than going through a tadpole stage, and we don’t know how chytrid will affect them.»

The team estimates that around 100 species of frog would be in danger if chytrid reaches New Guinea, and their decline could have huge impacts across the ecosystem as they are predators of insects and other small creatures but also prey for larger animals.

An island haven for frogs in a sea of extinctions
The frog Oreophryne oviprotector is one of around a hundred species that could be at risk if chytrid
fungus reaches the tropical island of New Guinea [Credit: Stephen J. Richards]

The research team includes international experts in frog conservation—including Lee Berger, the Australian who first discovered the chytrid fungus and showed it was responsible for frog species declines and extinctions—alongside local researchers with deep knowledge of the environment of New Guinea.

They have been studying frogs in New Guinea since 2015, and have already started working with zoos, universities and the Papua New Guinea government to build a program to keep captive frogs and store their sperm and eggs to preserve genetic diversity.

The team has developed a 5-step program of preparation, prevention, detection, response and recovery to keep the deadly fungus off New Guinea and to minimise the impact if it does arrive.

As well as preserving New Guinea’s frogs, the program would build local capacity in science, and disease surveillance and diagnosis that will have applications for animal and public health.

Source: Macquarie University [June 03, 2019]



Animals’ cultural lifestyles can influence evolution

Evolutionary adaptations resulting from cultural change, such as humans being able to consume dairy products, are more widespread in nature than previously thought.

Animals' cultural lifestyles can influence evolution
Some populations of killer whales have a specialised culture of hunting seals and have evolved genes that support
digestion of these mammals. Young killers like this one in the Antarctic learn the hunting technique
from their mothers. Other populations hunt different prey, like fish [Credit: Robert Pitman]

A new review, published in Nature Communications, suggests that such effects, already well established in humans, can be seen far more widely.

Many animal species show evolutionary changes which have been promoted by the introduction, and cultural spread, of new behaviors, with perhaps the most famous example being that the rise of dairy farming in humans.  Dairy farming brought about a genetic change which allowed some human beings to digest milk, a change not seen in non-dairy cultures.

Similarly, drinking alcohol or eating starchy agricultural foods led to natural selection favoring gene variations that help humans to metabolize these novel dietary elements.

Such «gene-culture co-evolution» had been thought to be unique to our species because of the exceptional role of culture in shaping human behavior.

However, the same effect can be seen in many other animal species such as the killer whale. Different clans of killer whale have adapted jaws and digestive systems to cope with very different prey species.

Animals' cultural lifestyles can influence evolution
A wild juvenile orangutan carefully watches how its mother uses a simple tool to extract nutritious seeds from a fruit.
The importance of acquiring a large array of skills critical to the ways of life of apes may be one explanation
for the evolution of their expanded brain size [Credit: Christiian Conradie and Caroline Schuppli]

Each group has preferred different prey with individuals learning these dietary preferences from older group members. This means killer whales may currently be evolving into multiple separate species because of their cultural differences.

Other changes may result in the evolution of a larger brain to permit deeper forms of learning from others. For example, orangutans from Sumatra, where cultural variations are greater, are cleverer and have bigger brains than those on Borneo.

Professor Andrew Whiten, of the School of Psychology and Neuroscience at the University of St Andrews, said: «There is even evidence that the cultural traditions of one species can drive the evolution of another.

«Reed warblers, for instance, learn to recognize cuckoos as brood parasites by attending to the alarm calls of other birds, a knock-on consequence of which is that natural selection favors cuckoos with unusual plumage patterns.»

After reviewing the evidence for a wide range of evolutionary effects across a broad array of species, especially birds, cetaceans (whales and dolphins) and primates, the authors of the new study conclude that the study of gene-culture coevolution may be in its infancy, but sufficient evidence now exists for it to shed new light on evolution.

Source: University of St Andrews [June 03, 2019]



Plant lineage points to different evolutionary playbook for temperate species

An ancient, cosmopolitan lineage of plants is shaking up scientists’ understanding of how quickly species evolve in temperate ecosystems and why.

Plant lineage points to different evolutionary playbook for temperate species
Micranthes atrata lives in the alpine tundra of the Tibetan Plateau in Central and East China. Tens of millions
of years ago, plants in the Saxifragales lineage were extreme specialists, inhabiting the few cold regions
on a more tropical Earth until a cooling climate opened up new habitats
[Credit: Rebecca Stubbs/Florida Museum]

Many researchers have thought new species evolve in tandem with the development of different physical characteristics and the appearance of new kinds of habitats. In this scenario, these three factors feed into one another, potentially leading to a dramatic increase in the number of new species. This burst of diversification eventually tapers off as species compete with one another in an increasingly crowded environment, much like a saturated market.
This hypothesis has held true in several studies of tropical organisms, but a new study by Florida Museum of Natural History researchers uncovered a very different pattern in temperate species, organisms that live in areas with warm summers and cold winters.

Plant lineage points to different evolutionary playbook for temperate species
Tellima grandiflora, bigflower tellima, is a Saxifragales species that lives in the forests of western
orth America from Alaska to Northern California [Credit: Rebecca Stubbs/Florida Museum]

When researchers examined the evolution of a large lineage of flowering plants known as Saxifragales, they found that species diversified first, driven by the Earth’s cooling climate 15 million years ago. These plants invaded new habitats and evolved new physical traits, too, but not until about 5 million years later.

«What we’re seeing is an evolutionary pattern that has never been observed before — and in areas of the world that are generally considered well studied,» said Ryan Folk, the study’s lead author and Florida Museum research associate. «Different rules are at play here than in tropical groups. Rates of diversification, habitats and traits matched up eventually, but there was a noteworthy lag before the latter two took off.»

Plant lineage points to different evolutionary playbook for temperate species
Saxifraga flagellaris, whiplash saxifrage, is native to the high Arctic, the Rocky Mountains and Norway
[Credit: Rebecca Stubbs/Florida Museum]

Today, Saxifragales is a group of nearly 2,500 species that encompasses trees such as sweet gum and katsura, shrubs such as gooseberry, succulents such as stonecrops, herbs, vines, parasitic plants and ornamentals such as coralbells and peonies. This plant lineage thrives in temperate regions: While all rainforests on Earth house fewer than two dozen species of Saxifragales combined, the Himalayas and Tibet can have 150 Saxifragales species in 50 square miles. Its global distribution and robust fossil record dating back 90 million years made the lineage a good candidate for testing models of evolutionary processes, Folk said.
Folk and his co-authors combined genetic data with datasets on plant traits and habitats and plugged these data into models to study the patterns of evolution in Saxifragales over time. The models showed that for tens of millions of years, Saxifragales remained wallflowers, eking out a living in colder regions at the poles and at high elevations — scarce habitats in the predominantly tropical Earth of the past. As the planet’s climate began to cool 15 million years ago, however, Saxifragales flourished and the lineage quickly diversified.

Plant lineage points to different evolutionary playbook for temperate species
Micranthes melanocentra thrives at high altitudes in China, Nepal and the Himalayas
[Credit: Rebecca Stubbs/Florida Museum]

The cooling trend continued, transforming once-tropical habitats into temperate ones for which the cold-loving plants were well suited, and creating more extreme niche habitats that certain Saxifragales species could inhabit after developing new traits that outfitted them for rugged growing conditions.

«This is the start of the landscape that we see today — ice-covered poles, temperate forests across the Northern Hemisphere, widespread grasslands, deserts, tundra and taiga,» Folk said. «As temperate habitats rapidly expanded, Saxifragales diversified to take advantage of habitats they already were adapted to.»

Plant lineage points to different evolutionary playbook for temperate species
Heuchera abramsii, San Gabriel alumroot, is a rare perennial herb found only
on the rocky slopes of the San Gabriel Mountains in Southern California
[Credit: Rebecca Stubbs/Florida Museum]

But significantly, the initial burst of Saxifragales diversification was not a result of shifts in habitats or trait adaptations and predated those changes by millions of years. Instead, diversification was primarily tied to climate change.
«If you look at the drop in global temperature and the increase in Saxifragales diversification, it’s amazing how closely those correspond,» Folk said. «Those curves are almost the perfect inverse of one another.»

Plant lineage points to different evolutionary playbook for temperate species
Saxifraga eschscholtzii, ciliate saxifrage, grows in Alaska and Northern Canada
[Credit: Rebecca Stubbs/Florida Museum]

Understanding how species responded to climate change in the past offers a template for how they are likely to react under future climate scenarios, Folk said.

«These plants have been in temperate habitats since their origin,» he said. «If temperatures warm, they’re not going to just adapt. My take is that most plant species are going to have little capacity to adapt to dramatic climate changes.»

Plant lineage points to different evolutionary playbook for temperate species
This phylogeny, or ancestral family tree, of Saxifragales depicts the relationships between the nearly 2,500 plant
species in this order. Plants that live in colder, drier habitats are represented by blue and green branches,
and plants that live in warmer, and often wetter, habitats are shown in yellow and red. The photos
showcase the diversity of environments that Saxifragales plants inhabit, from deserts to
wetlands to arid, rocky mountainsides [Credit: Folk et al. 2019]

Classical conceptions of major drivers of species diversification often hinge on geological events — the formation of a land bridge between North and South America, for example, or the splitting of the Indian subcontinent from Africa. But climate is not a singular event, Folk said: «It’s a dynamic curve.»
One reason evolutionary processes may vary between temperate and tropical systems is their difference in age. Many of the temperate landscapes that are familiar today are recent developments produced through environmental upheaval and destruction, Folk said. Although tropical landscapes also experienced change, they have been more stable.

Plant lineage points to different evolutionary playbook for temperate species
As the Earth cooled about 15 million years ago, Saxifragales diversification skyrocketed, followed
about 5 million years later by an uptick in new habitats [Credit: Folk et al. 2019]

«There has probably been rainforest at the equator since the beginning of the Cretaceous (about 145 million years ago),» he said. «That stability simply doesn’t exist for temperate habitats.»

So far, Saxifragales diversification has shown no signs of slowing, contradicting the hypothesis that an explosion of new species eventually sputters out as they fill up new habitats to the point of saturation.

Folk hopes the study will spur researchers to look for this pattern in the evolution of other temperate lineages, both plant and animal.

«If we’re looking for the signal of truly recent bursts, a lot of the action is in temperate ecosystems.»

The researchers published their findings in the Proceedings of the National Academy of Sciences.

Author: Natalie van Hoose | Source: Florida Museum of Natural History [June 03, 2019]



Human ancestors invented stone tools several times

The excavation site, known as Bokol Dora 1 or BD 1, is close to the 2013 discovery of the oldest fossil attributed to our genus Homo discovered at Ledi-Geraru in the Afar region of northeastern Ethiopia. The fossil, a jaw bone, dates to about 2.78 million years ago, some 200,000 years before the then oldest flaked stone tools. The Ledi-Geraru team has been working for the last five years to find out if there is a connection between the origins of our genus and the origins of systematic stone tool manufacture.

Human ancestors invented stone tools several times
A large green artefact found in situ at the Bokol Dora site. Right: Image of the same artefact
and a three dimensional model of the same artefact [Credit: David R. Braun]

A significant step forward in this search was uncovered when Arizona State University geologist Christopher Campisano saw sharp-edged stone tools sticking out of the sediments on a steep, eroded slope. «At first we found several artifacts lying on the surface, but we didn’t know what sediments they were coming from,» says Campisano. «But when I peered over the edge of a small cliff, I saw rocks sticking out from the mudstone face. I scaled up from the bottom using my rock hammer and found two nice stone tools starting to weather out.»
Sediment layer with animal bones and stone chips

It took several years to excavate through meters of sediments by hand before exposing an archaeological layer of animal bones and hundreds of small pieces of chipped stone representing the earliest evidence of our direct ancestors making and using stone knives. The site records a wealth of information about how and when humans began to use stone tools.

Human ancestors invented stone tools several times
Blade Engda of the University of Poitiers lifts an artefact from 2.6 million year old
sediment exposing an imprint of the artefact on the ancient surface below
[Credit: David R. Braun]

Preservation of the artifacts comes from originally being buried close to a water source. «Looking at the sediments under a microscope, we could see that the site was exposed only for a very short time. These tools were dropped by early humans at the edge of a water source and then quickly buried. The site then stayed that way for millions of years,» noted geoarchaeologist Vera Aldeias of the Interdisciplinary Center for Archaeology and Behavioral Evolution at the University of Algarve, Portugal.

Habitat change

Kaye Reed, who studies the site’s ecology, is director of the Ledi-Geraru Research Project and a research associate with Arizona State University’s Institute of Human Origins along with Campisano, notes that the animals found with these tools were similar to those found only a few kilometers away with the earliest Homo fossils.

«The early humans that made these stone tools lived in a totally different habitat than ‘Lucy’ did,» says Reed. Lucy is the nickname for an older species of hominin known as Australopithecus afarensis, which was discovered at the site of Hadar, Ethiopia, about 45 kilometers southwest of the new BD 1 site. «The habitat changed from one of shrubland with occasional trees and riverine forests to open grasslands with few trees. Even the fossil giraffes were eating grass!»

Human ancestors invented stone tools several times
Archaeologists from the Max Planck Institute, and the Ethiopian Authority for
Research and the Conservation of Cultural Heritage as well as geologists from
University of Algarve study the sediments at the Bokol Dora site. Stones were
placed on the contact surface during the excavation to preserve the fragile
stratigraphic contacts [Credit: Erin DiMaggio]

In addition to dating a volcanic ash several meters below the site, project geologists analyzed the magnetic signature of the site’s sediments. Over the Earth’s history, its magnetic polarity has reversed at intervals that can be identified. Other earlier archaeological sites near the age of BD 1 are in «reversed» polarity sediments. The BD 1 site is in «normal» polarity sediments. Because the reversal from «normal» to «reversed» happened at about 2.58 million years ago, the geologists knew that BD 1 was older than all the previously known sites.

The recent discovery of older hammering or «percussive» stone tools in Kenya dated to 3.3 million years ago, described as «Lomekwian», and butchered bones in Ethiopia shows the deep history of our ancestors making and using tools. However, recent discoveries of tools made by chimpanzees and monkeys have challenged «technological ape» ideas of human origins.

Archaeologists working at the BD 1 site wondered how their new stone tool discovery fit into this increasingly complex picture of hominin behavioural evolution. What they found was that not only were these new tools the oldest artifacts yet ascribed to the «Oldowan», a technology originally named after finds from Olduvai Gorge in Tanzania, but also were distinct from tools made by chimpanzees, monkeys or even earlier human ancestors.

Little in common with other tools

«We expected to see some indication of an evolution from the Lomekwian to these earliest Oldowan tools. Yet when we looked closely at the statistical patterns in the stone artefacts, there was very little connection to what has been described from older archaeological sites or to the stone tools modern primates are making,» said Will Archer of the Max Planck Institute for Evolutionary Anthropology in Leipzig and the University of Cape Town, South Africa.

Human ancestors invented stone tools several times
An image of the Bokol Dora excavation during the 2015 excavation. Stones were placed on
 the contact surface during the excavation to preserve the fragile stratigraphic contacts
[Credit: David Feary]

The major differences appear to be the ability for our ancestors to systematically chip off smaller sharp-edged tools from larger nodules of stone. Chimpanzees and monkeys generally use tools for percussive activities, to hammer and bash food items like nuts and shellfish, which seems to have been the case with the 3.3 million year old Lomekwian tools as well.
Something changed by 2.6 million years ago, and our ancestors became more accurate and skilled at striking the edge of stones to make tools. The BD 1 artifacts captures this shift. It appears that this shift in tool making occurred around the same time that our ancestor’s teeth began to change. This can be seen in the Homo jaw from Ledi-Geraru. As our ancestors began to process food prior to eating using stone tools, we start to see a reduction in the size of their teeth. Our technology and biology were intimately intertwined even as early as 2.6 million years ago.

New ways of manufacturing tools

The lack of clear connections with earlier stone tool technology suggests that tool use was invented multiple times in the past. David Braun, an archaeologist with George Washington University and the lead author on the paper, noted, «Given that primate species throughout the world routinely use stone hammers to forage for new resources, it seems very possible that throughout Africa many different human ancestors found new ways of using stone artifacts to extract resources from their environment. If our hypothesis is correct then we would expect to find some type of continuity in artifact form after 2.6 million years ago, but not prior to this time period. We need to find more sites.»

Aerial photography around the Bokol Dora site [Credit: David Feary]

By 2.6 million years ago, there appears to be a long-term investment in tool use as part of the human condition. Continued field investigations at the Ledi-Geraru project area are already producing more insights into the patterns of behavior in our earliest ancestors. New sites have already been found, and the Ledi-Geraru team will begin excavating them this year.

The findings are published in the Proceedings of the National Academy of Sciences.

Source: Max-Planck-Gesellschaft [June 03, 2019]



Antarctic glaciers named after satellites

ESA — European Space Agency patch.

7 June 2019

 Ice streams named

Dramatic changes in the shape of the Antarctic ice sheet have become emblematic of the climate crisis. And, in deference to the critical role that satellites play in measuring and monitoring Antarctic glaciology, seven areas of fast-flowing ice on the Antarctic Peninsula have been named after Earth observation satellites.

Reports of iceberg calving, changes in ice-sheet speed, thickness and mass have informed the climate change debate. These reports are thanks largely to routine monitoring by an international fleet of Earth observation satellites.

Recognising the importance of observations from space, the UK Antarctic Place-names Committee has approved seven new names for international use.

The decision follows a request by Anna Hogg from the Centre for Polar Observation and Modelling at the University of Leeds, UK, who identified that the major glaciers flowing westwards from the Dyer Plateau are thinning and flowing at rates of more than 1.5 metres a day.

To describe them in scientific papers, Dr Hogg requested that seven outlet glaciers be named.

“Naming the glaciers after the Earth observation satellites we use to measure them is a great way to celebrate the international collaboration in space, and on big science questions.

“It’s fantastic news that the UK Foreign Office have formally approved these new place names, which will be on the record forever more,” said Dr Hogg.

Antarctic Peninsula

The Ers Ice Stream that flows west between Jensen Nunataks and Gunn Peaks was named after the two ESA satellites – ERS-1 and ERS-2 – that operated between 1991 and 2011. They provided the first high-resolution, wide-swath and day-and-night images that were used to calculate the speed and direction of the flow of glacier ice.

The Envisat Ice Stream lies further to the west and commemorates ESA’s largest Earth observation satellite, which was launched in 2002 and operated until 2012. It carried 10 instruments that extended the datasets generated by ERS-1 and ERS-2.

The Cryosat Ice Stream flows further west and is named after the ESA Earth Explorer satellite launched in 2010. CryoSat was designed specifically to detect changes in the height of polar ice using a sophisticated instrument that provides high-accuracy elevation measurements over the rugged ice-sheet margins and for sea ice in polar waters.

Still further west lies the Grace Ice Stream, which commemorates the joint Gravity Recovery and Climate Change Experiment (GRACE) mission run by NASA and the German Aerospace Center. Between 2002 and 2017, the mission mapped, for the first time, Earth’s time-varying gravitational field, detecting Antarctic ice-sheet mass changes with unprecedented accuracy.

Sentinel Ice Stream

The Sentinel Ice Steam is named after the more recent series of satellites that ESA develops for the EU’s Copernicus programme to the environment and climate change. This programme provides open access to images, allowing the public to easily view and witness ongoing, year-round changes in Antarctica and the rest of the world.

The ALOS Ice Rumples are named after a Japan Aerospace Exploration Agency mission. Its optical and radar image data acquired between 2006 and 2011 have been used to map ice in the polar regions, with dedicated imaging campaigns to capture Antarctic ice-sheet surface changes during the International Polar Year campaign that ran between 2007 and 2009.

Finally, the Landsat ice stream is the most westerly of the newly named glaciers. It is named after the joint NASA/US Geological Survey series of Landsat Earth observation satellites that have been operating since 1972. Landsat has been one of the primary systems used in Antarctic studies, providing over 40 years of uninterrupted mapping of the continent for climate and environment studies.

Fifteen space agencies currently collaborate on coordinating Antarctic data collection from a wide range of satellites, and on the planning of data acquisition and products to address the needs of the scientific community, under the banner of the World Meteorological Organization’s Polar Space Task Group.

George VI Ice Shelf from the air

Mark Drinkwater, ESA chair of the task group, said, “Interagency planning is paying dividends for polar science, with more comprehensive multi-satellite, multi-instrument datasets and better coverage than previously possible, which enables the science community to address today’s key climate research challenges.”

This gesture of naming Antarctic glaciers after these ground-breaking satellites is a mark of recognition of the importance of Earth observation data in addressing the climate crisis.

Related links:

British Antarctic Survey: https://www.bas.ac.uk/

Antarctic Place-names Committee: https://apc.antarctica.ac.uk/

Scientific Committee on Antarctic Research: http://www.scar.org/

Composite Gazetteer of Antarctica: https://data.aad.gov.au/aadc/gaz/scar/

Centre for Polar Observation and Modelling: https://cpom.org.uk/

World Meteorological Organization’s Polar Space Task Group: http://www.wmo.int/pages/prog/sat/pstg_en.php

ESA’s Climate Change Initiative (CCI): http://cci.esa.int/

Geophysical Research Letters:

Increased ice flow in Western Palmer linked to ocean melting: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL072110

Related missions:

ERS: http://www.esa.int/Our_Activities/Observing_the_Earth/ERS_overview

Envisat: http://www.esa.int/Our_Activities/Observing_the_Earth/Envisat

CryoSat: http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat

GRACE: https://grace.jpl.nasa.gov/mission/grace/

Sentinel-1: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-1

Sentinel-2: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-2

Sentinel-3: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-3

ALOS: https://global.jaxa.jp/projects/sat/alos/index.html

Landsat: https://www.usgs.gov/land-resources/nli/landsat

Images, Text, Credits: ESA/CPOM/A. Hogg/Contains modified Copernicus Sentinel data (2017-2019), processed by ESA.

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2019 June 7 The Planet and the Pipe Image Credit &…

2019 June 7

The Planet and the Pipe
Image Credit & Copyright: Alain Maury, Jean-Marc Mari

Explanation: Now posing against our galaxy’s rich starfields and nebulae, brilliant planet Jupiter shines in the night sky. Its almost overwhelming glow is near the top of the frame in this colorful telephoto portrait of the central Milky Way. Spanning about 20 degrees on the sky, the scene includes the silhouette of LDN 1773 against the starlight, also know by the popular moniker the Pipe Nebula for its apparent outline of stem and bowl. The Pipe Nebula is part of the galaxy’s Ophiuchus dark cloud complex. Located at a distance of about 450 light-years, dense cores of gas and dust within are collapsing to form stars. Approaching its opposition, opposite the Sun in the sky on June 12, Jupiter is only about 36 light-minutes from planet Earth. Fans of dark markings on the sky can probably spot the Snake Nebula below and left of Jupiter’s glare.

∞ Source: apod.nasa.gov/apod/ap190607.html

Forecasting D-Day From Above


Image Credit: Department of Transportation. U.S. Coast Guard. Office of Public and International Affairs

It was the raw courage of the more than 160,000 Allied troops who stormed an 80-kilometer (50-mile) stretch of heavily fortified beaches in Normandy, France, that made victory on D-Day possible. But without the sound advice of meteorologists and geologists working behind the scenes, one of the most consequential battles in human history could have gone quite differently.

As D-Day neared, the American meteorologists predicted fair weather on June 5 and pushed for invasion, based on a forecasting method that gave great weight to historical weather conditions for a given date and location. The British forecasters took a different approach, focusing instead on analyzing measurements of temperature, pressure, and humidity to try to map out weather fronts. Unlike the Americans, the British teams predicted low clouds and stormy weather on June 5. At the last minute, Captain James Martin Stagg, the highest ranking of the meteorologists, convinced Eisenhower to postpone the invasion.


NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey

Meanwhile, on the other side of the English Channel, German meteorologists had come to the same conclusion—and then some. Their forecasters had predicted that gale-force winds would arrive on June 5 and persist until mid-June. The Germans were so confident that the Allies would not dare attack that they allowed many soldiers to leave their posts on the beaches and take part in war games in Rennes, France. Field Marshal Erwin Rommel felt comfortable enough to return to Germany to deliver a pair of shoes to his wife as a birthday present.


Image Credit: Department of Defense. Department of the Army. Office of the Deputy Chief of Staff for Operations. U.S. Army Audiovisual Center. ca. 1974-5/15/1984  

When the first paratroopers were dropped behind enemy lines around midnight and the first wave of Allied boats began to swarm the beaches at dawn on June 6, the weather was still far from ideal. Cloud cover meant many paratroopers ended up in the wrong locations, and rough seas and high winds made the task of landing boats and unloading tanks a terrible challenge. But by noon the skies cleared, just as the Allied meteorologists had predicted. The Germans, meanwhile, had been caught off guard. That day the Allies endured thousands of causalities, but they established a toehold in France that they would never give up.


NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey

An enormous amount of scientific expertise went into even the most unscientific of tasks, like rolling a tank up the Normandy beaches. Prior to the invasion, Allied military planners studied nearly one million aerial photographs of the shores of Normandy to find the best landing sites. The aerial photographs would have looked something like the Landsat 8 images shown above. Acquired by the Operational Land Imager (OLI) on July 15, 2018, these image offer a top-down view of the sandy Normandy beaches that were center stage on D-Day.

Read the full story: https://earthobservatory.nasa.gov/images/145143/forecasting-d-day

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Cool, Nebulous Ring around Milky Way’s Supermassive Black Hole

Artist impression of ring of cool, interstellar gas surrounding the supermassive black hole at the center of the Milky Way. New ALMA observations reveal this structure for the first time. Credit: NRAO/AUI/NSF; S. Dagnello. Hi-res image

ALMA image of the disk of cool hydrogen gas flowing around the supermassive black hole at the center of our galaxy. The colors represent the motion of the gas relative to Earth: the red portion is moving away, so the radio waves detected by ALMA are slightly stretched, or shifted, to the «redder» portion of the spectrum; the blue color represents gas moving toward Earth, so the radio waves are slightly scrunched, or shifted, to the «bluer» portion of the spectrum. Crosshairs indicate location of black hole. Credit: ALMA (ESO/NAOJ/NRAO), E.M. Murchikova; NRAO/AUI/NSF, S. Dagnello. Hi-res image 

Through decades of study, astronomers have developed a clearer picture of the chaotic and crowded neighborhood surrounding the supermassive black hole at the center of the Milky Way. Our galactic center is approximately 26,000 light-years from Earth and the supermassive black hole there, known as Sagittarius A* (A “star”), is 4 million times the mass of our Sun.

We now know that this region is brimming with roving stars, interstellar dust clouds, and a large reservoir of both phenomenally hot and comparatively colder gases. These gases are expected to orbit the black hole in a vast accretion disk that extends a few tenths of a light-year from the black hole’s event horizon. 

Until now, however, astronomers have been able to image only the tenuous, hot portion of this flow of accreting gas, which forms a roughly spherical flow and showed no obvious rotation. Its temperature is estimated to be a blistering 10 million degrees Celsius (18 million degrees Fahrenheit), or about two-thirds the temperature found at the core of our Sun. At this temperature, the gas glows fiercely in X-ray light, allowing it to be studied by space-based X-ray telescopes, down to scale of about a tenth of a light-year from the black hole.

In addition to this hot, glowing gas, previous observations with millimeter-wavelength telescopes have detected a vast store of comparatively cooler hydrogen gas (about 10 thousand degrees Celsius, or 18,000 degrees Fahrenheit) within a few light-years of the black hole. The contribution of this cooler gas to the accretion flow onto the black hole was previously unknown.

Although our galactic center black hole is relatively quiet, the radiation around it is strong enough to cause hydrogen atoms to continually lose and recombine with their electrons. This recombination produces a distinctive millimeter-wavelength signal, which is capable of reaching Earth with very little losses along the way.

With its remarkable sensitivity and powerful ability to see fine details, the Atacama Large Millimeter/submillimeter Array (ALMA) was able to detect this faint radio signal and produce the first-ever image of the cooler gas disk at only about a hundredth of a light-year away (or about 1000 times the distance from the Earth to the Sun) from the supermassive black hole. These observations enabled the astronomers both to map the location and trace the motion of this gas. The researchers estimate that the amount of hydrogen in this cool disk is about one tenth the mass of Jupiter, or one ten-thousandth of the mass of the Sun.

By mapping the shifts in wavelengths of this radio light due to the Doppler effect (light from objects moving toward the Earth is slightly shifted to the “bluer” portion of the spectrum while light from objects moving away is slightly shifted to the “redder” portion), the astronomers could clearly see that the gas is rotating around the black hole. This information will provide new insights into the ways that black holes devour matter and the complex interplay between a black hole and its galactic neighborhood.

“We were the first to image this elusive disk and study its rotation,” said Elena Murchikova, a member in astrophysics at the Institute for Advanced Study in Princeton, New Jersey, and lead author on the paper. “We are also probing accretion onto the black hole. This is important because this is our closest supermassive black hole. Even so, we still have no good understanding of how its accretion works. We hope these new ALMA observations will help the black hole give up some of its secrets.”

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.


Charles E. Blue
Public Information Officer
cblue@nrao.edu; 434-296-0314


E.M. Murchikova, et al., “A cool accretion disk around the Galactic Center black hole,” Nature, 06 June 2019

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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Planck finds no new evidence for cosmic anomalies

ESA — Planck Mission patch.

6 June 2019

ESA’s Planck satellite has found no new evidence for the puzzling cosmic anomalies that appeared in its temperature map of the Universe. The latest study does not rule out the potential relevance of the anomalies but they do mean astronomers must work even harder to understand the origin of these puzzling features.

Planck’s latest results come from an analysis of the polarisation of the Cosmic Microwave Background (CMB) radiation – the most ancient light in cosmic history, released when the Universe was just 380 000 years old.

Temperature and polarisation maps

The satellite’s initial analysis, which was made public in 2013, concentrated on the temperature of this radiation across the sky. This allows astronomers to investigate the origin and evolution of the cosmos. While it mostly confirmed the standard picture of how our Universe evolves, Planck’s first map also revealed a number of anomalies that are difficult to explain within the standard model of cosmology.

The anomalies are faint features on the sky that appear at large angular scales. They are definitely not artefacts produced by the behaviour of the satellite or the data processing, but they are faint enough that they could be statistical flukes – fluctuations which are extremely rare but not entirely ruled out by the standard model.

Alternatively, the anomalies might be a sign of ‘new physics’, the term used for as-yet unrecognised natural processes that would extend the known laws of physics.

To further probe the nature of the anomalies, the Planck team looked at the polarisation of the CMB, which was revealed after a painstaking analysis of the multi-frequency data designed to eliminate foreground sources of microwave emission, including gas and dust in our own Milky Way galaxy.

The history of the Universe

This signal is the best measurement to date of the so-called CMB polarisation E-modes, and dates back to the time when the first atoms formed in the Universe and the CMB was released. It is produced by the way light scattered off electron particles just before the electrons were gathered into hydrogen atoms.

Polarisation provides an almost independent view of the CMB, so if the anomalies were also to show up there, this would increase astronomers’ confidence that they could be caused by new physics rather than being statistical flukes.

While Planck was not originally designed to focus on polarisation, its observations have been used to create the most accurate all-sky maps of the CMB polarisation to date. These were published in 2018, greatly improving the quality of Planck’s first polarisation maps, released in 2015.

When the Planck team looked at this data, they saw no obvious sign of the anomalies. At best, the analysis, published today in Astronomy and Astrophysics, revealed some weak hints that some of the anomalies may be present.

“Planck’s polarisation measurements are fantastic,” says Jan Tauber, ESA Planck project scientist.

“Yet in spite of the great data we have, we don’t see any significant traces of anomalies.”

On the face of it, this would seem to make the anomalies more likely to be statistical flukes, but actually it does not rule out new physics because nature might be trickier than we imagine.

The CMB polarisation on large angular scales

As yet, there is no convincing hypothesis for what kind of new physics could be causing the anomalies. So, it could be that the phenomenon responsible only affects the temperature of the CMB, but not the polarisation.

From this point of view, while the new analysis does not confirm that new physics is taking place, it does place important constraints on it.

The most serious anomaly that showed up in the CMB temperature map is a deficit in the signal observed at large angular scales on the sky, around five degrees – as a comparison, the full Moon spans about half a degree. At these large scales, Planck’s measurements are about ten per cent weaker than the standard model of cosmology would predict.


Planck also confirmed, with high statistical confidence, other anomalous traits that had been hinted at in previous observations of the CMB temperature, such as a significant discrepancy of the signal as observed in the two opposite hemispheres of the sky, and a so-called ‘cold spot’ – a large, low-temperature spot with an unusually steep temperature profile.

“We said at the time of the first release that Planck would be testing the anomalies using its polarisation data. The first set of polarisation maps which are clean enough for this purpose were released in 2018, now we have the results,” says Krzysztof M. Górski, one of the authors of the new paper, from the Jet Propulsion Laboratory (JPL), Caltech, USA.

Unfortunately, the new data did not take the debate any further, as the latest results neither confirm nor deny the nature of the anomalies.

The CMB temperature on large angular scales

“We have some hints that, in the polarisation maps, there could be a power asymmetry similar to the one that is observed in the temperature maps, although it remains statistically unconvincing,” adds Enrique Martínez González, also a co-author of the paper, from Instituto de Física de Cantabria in Santander, Spain.

While there will be further analysis of the Planck results taking place, it is unlikely that they will yield significantly new results on this subject. The obvious route to make progress is for a dedicated mission specially designed and optimised to study the CMB polarisation, but this is at least 10 to 15 years into the future.

“Planck has given us the best data we will have for at least a decade,” says co-author Anthony Banday from Institut de Recherche en Astrophysique et Planétologie in Toulouse, France.

In the meantime, the mystery of the anomalies continues.

Notes for editors:

“Planck 2018 results. VII. Isotropy and Statistics of the CMB” by the Planck Collaboration is published in Astronomy & Astrophysics. The results are based on the Planck legacy data release, which was made public on 17 July 2018.

The Planck Legacy Archive: http://pla.esac.esa.int/pla/

More about Planck: http://sci.esa.int/planck/

Images, Animation, Text, Credits: ESA/Markus Bauer/Jan Tauber/JPL/Calla Cofield/Institut de Recherche en Astrophysique et Planétologie, Toulouse/Anthony Banday/Instituto de Física de Cantabria/Enrique Martínez González/Planck Collaboration.

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BEAM Opens for Tests; Crew Studies Biotech and Fluid Physics

ISS — Expedition 59 Mission patch.

June 6, 2019

The International Space Station’s BEAM opened up today for environmental sampling and cargo stowage activities as NASA continues to test the commercial module.  The Expedition 59 crew also explored biotechnology and fluid physics to improve Earth applications and space habitability.

Astronauts Anne McClain, Christina Koch and David Saint-Jacques checked out BEAM, the Bigelow Expandable Activity Module, today to sample the air for microbes and stow spare hardware inside. BEAM had its stay at the station’s Tranquility module extended in November 2017 after a successful installation and expansion in the spring of 2016. The soft material module is providing extra storage space at the orbiting lab and additional technology demonstrations that may inform future missions.

Image above: NASA astronaut Nick Hague assembles and installs the Water Storage System inside the U.S. Destiny laboratory module. Image Credit: NASA.

After the BEAM work, McClain sampled algae grown inside the Photobioreactor to explore the viability of closed, hybrid life-support systems in space. Koch wrapped up a study observing how fluids slosh and wave in space to improve satellite fuel systems and increase knowledge of Earth’s oceans and climate.

Bigelow Expandable Activity Module (BEAM). Image Credits: NASA/BEAM

Flight Engineer Nick Hague spent the majority of Thursday installing Water Storage System components in the U.S. Destiny laboratory module. The space plumbing work consisted of installing a variety of hoses including power and data cables to the main Potable Tank Assembly.

Commander Oleg Kononenko and Alexey Ovchinin started the morning taking breath and blood pressure measurements for a cardiopulmonary study. Next, they tested communication systems in the Soyuz MS-11 crew ship and spent the rest of the afternoon on a variety of Russian science and maintenance activities.

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

Bigelow Expandable Activity Module (BEAM): https://www.nasa.gov/mission_pages/station/structure/elements/bigelow-expandable-activity-module.html

Tranquility module: https://www.nasa.gov/mission_pages/station/structure/elements/tranquility/

Photobioreactor: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7426

Fluids slosh and wave in space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7426

U.S. Destiny laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/us-destiny-laboratory

cardiopulmonary study: https://www.energia.ru/iss/researches/human/19.html

Soyuz MS-11 crew ship: https://www.nasa.gov/feature/visiting-vehicle-launches-arrivals-and-departures

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.chArchive link

Jewellery and decorated pieces from Vindolanda Roman Fort and Vicus, Hadrian’s...

Jewellery and decorated pieces from Vindolanda Roman Fort and Vicus, Hadrian’s Wall, Northumberland, 31.5.19.

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https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...