Unique sled dogs helped the inuit thrive in the North American Arctic

By: Thomas Schmitt Attorney on November 27, 2019 / comment : 0 Archaeology, Arctic, Genetics, Indigenous Cultures, North America, Ticker

A unique group of dogs helped the Inuit conquer the tough terrain of the North American Arctic, major new analysis of the remains of hundreds of animals shows.

A team of Greenland sled dogs working in Greenland’s Disko Bay  [Credit: Tatiana Feuerborn]

The study shows that the Inuit brought specialised dogs with them when they migrated from Alaska and Siberia instead of adopting local dogs they would have come across during their migration. They instead maintained their own dogs, suggesting they were keen to enhance or keep the special features they had. By analysing the shape of elements from 391 dogs, the study shows that the Inuit had larger dogs with a proportionally narrower cranium to these earlier dogs. The Inuit dogs are the direct ancestors of modern Arctic sledge dogs, although their appearance has continued to change over time.

Experts had thought the Inuit used dogs to pull sledges, and this is the first study which shows they introduced a new dog population to the region to do this. These dogs then spread across the North American Arctic alongside Inuit migrants.

Dr Carly Ameen, an archaeologist from the University of Exeter who led the study, said: "Dogs have lived in North America for as long as humans, but we show here that the Inuit brought new dogs to the region which were genetically distinct and physically different from earlier dogs.

"Thousands of years ago there was not the huge number of dog breeds as we know them today. Through analysing the DNA and morphology of the remains of hundreds of dogs we've found that the dogs used by the Inuit had distinctive skull and teeth shapes, and would have likely looked different in life to dogs already in the Arctic."

The ancestors of these dogs arrived with the Inuit to the North American Arctic [Credit: Tatiana Feuerborn]

Experts also examined the DNA from 921 dogs and wolves who lived during the last 4,500 years. This analysis of the DNA, and the locations and time periods in which they were found, shows dogs from Inuit sites occupied from around 2,000 years ago were genetically different from the dogs already in the region.

Study co-lead author Tatiana Feuerborn, from the Globe Institute in Denmark and the Centre for Palaeogenetics in Sweden, said: "Archaeological evidence has shown us that before the Inuit arrived in North America dog sledging was a rarity. Our analysis of the DNA suggests dogs brought by the Inuit were distinct from the earlier dogs of the North American Arctic to fill specialist role in helping communities thrive in this hostile environment by aiding with transportation and hunting. The genetic legacy of these Inuit dogs can still be seen today in Arctic sledge dogs."

The Inuit were specialised sea mammal hunters, and were more mobile than other groups living in the Arctic, migrating huge distances across the region over 1,000 years ago, with the help of dog sledges and water craft. Today, sledge dogs whose origins can be traced back to the Inuit period continue to be an important part of Arctic communities.

The article is published in the journal Proceedings of the Royal Society B.

Source: University of Exeter [November 27, 2019]

Last Arctic ice refuge is disappearing

By: Thomas Schmitt Attorney on November 12, 2019 / comment : 0 Arctic, Climate Change, Earth Science, Ecosystems, Environment, Natural Heritage

The oldest and thickest Arctic sea ice is disappearing twice as fast as ice in the rest of the Arctic Ocean, according to new research.

New research finds the Arctic’s oldest and thickest ice is more mobile and is vanishing twice as fast as ice in the rest of the Arctic [Credit: NOAA]

A new study in AGU's journal Geophysical Research Letters finds ice in the Arctic Ocean north of Greenland is more mobile than previously thought, as ocean currents and atmospheric winds are likely transporting the old, thick ice found there to other parts of the Arctic. As a result, ice mass in the area - the last place researchers think will lose its year-round ice cover - is declining twice as fast as ice in the rest of the Arctic, according to the new findings.

Climate models predict Arctic summers will soon be ice-free - perhaps as early as 2030 - meaning less than 1 million square kilometers (386,000 square miles) of summer sea ice will blanket the Arctic Ocean. Arctic warming has already created an environment which leads to younger sea ice. Watch a visualization of the age of Arctic sea ice over time here.

Most ice covering the Arctic is only one to four years old, according to the National Snow and Ice Data Center. As thin, young ice melts in future summers, only a 2,000-kilometer (1,240-mile) arc of ice will remain, stretching from the western Canadian Arctic Archipelago to Greenland's northern coast. In this slice of the Arctic, which experts call the Last Ice Area, sea ice is more than five years old and can measure more than four meters (13 feet) thick.

The new research suggests the Last Ice Area is a dynamic place encompassing two sub-regions where ice thickness fluctuates by 1.2 meters (4 feet) from year to year. Ice is becoming thinner in two distinct subregions, which are losing 0.4 meters (1.3 feet) of ice thickness per decade, amounting to a 1.5-meter (5 foot) loss of ice since the late 1970s, according to the new study.

Annual mean sea ice thickness (m) over the Arctic Ocean from 1979 – 2018. The black line  surrounds the area where the ice thickness exceeds 3 m and can be considered as the  region known as the Last Ice Area. The white lines surround the two areas where the ice thickness exceeds 4m [Credit: Kent Moore/University of Toronto]

"We can't treat the Last Ice Area as a monolithic area of ice which is going to last a long time," said Kent Moore, an atmospheric physicist at the University of Toronto in Canada and lead author of the new study. "There's actually lots of regional variability."

For wildlife who rely on sea ice for survival, the Last Ice Area offers a sanctuary, and is the final place they can retreat to in a warming world. Understanding how the Last Ice Area changes throughout the year could help pinpoint which spots are best suited to provide a refuge for wildlife who are dependent on sea ice, according to the study's authors.

Places with less ice movement, for example, may provide more suitable conditions for a wildlife sanctuary, as the ice will remain longer. The new study presents context for policymakers to consider when they establish protected areas in the Arctic, Moore said.

"Eventually the Last Ice Area will be the region that will repopulate the Arctic with wildlife," Moore said. "If we lose all the ice, we lose those species. This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning."

A dynamic zone

The Last Ice Area is home to the Arctic's oldest and thickest ice because ocean currents and atmospheric winds carry patches of floating ice in a circular pattern. These blocks of ice crash into each other and pile up along the northern edges of Greenland and Canada. Researchers, however, know little about how ice in this region moves and melts during the year.


This lack of knowledge prompted Moore and his colleagues to track changes in the Last Ice Area. In the new study, the team modeled sea ice cover, thickness and motion across the zone from 1979 to 2018. Their model, based on satellite observations and atmospheric data, revealed two regions with distinct seasonal and inter-annual fluctuations - one to the east and one to the west.

In both regions, sea ice was thinner and covered less area in the summer and early fall than in the Arctic winter, though ice thickness in the west tended to hit its minimum earlier in the season. Ice motion in the eastern portion of the Last Ice Area appeared to be more stable. Western ice - controlled by winds blowing clockwise - has begun moving faster, which could be the result of thinning ice.

According to Moore, the loss of ice in the Last Ice Area is likely due to ice movement out of the region, particularly in the west. If sea ice is thinner and moving faster, pieces at the margins will flow first into the open ocean, followed by larger bits from the center, like a big traffic jam.

"Historically, we thought of this place as an area that just receives ice," said David Barber, an Arctic climatologist from the University of Manitoba in Canada who was not involved in the new study. "But these results are teaching us that this is a dynamic area."

Source: American Geophysical Union [November 12, 2019]

Abrupt shifts in Arctic climate projected

By: Thomas Schmitt Attorney on October 30, 2019 / comment : 0 Arctic, Climate Change, Natural Heritage

Researchers from McGill University project that as the permafrost continues to degrade, the climate in various regions of the Arctic could potentially change abruptly, in the relatively near future. Their research, which was published in Nature Climate Change, also suggests that as the permafrost degrades, the severity of wildfires will double from one year to the next and remain at the new and higher rate for regions in the Northwestern Territories and the Yukon.

Researchers from McGill University project that as the permafrost continues to degrade, the climate in various regions of the Arctic could potentially change abruptly in the relatively near future [Credit: Northwest Territories Geological Survey]

"We study climate-engineering infrastructure (e.g. roads, ports, buildings, pipelines and mining infrastructure) interactions in a changing climate. Arctic infrastructure is particularly impacted by permafrost degradation and associated soil moisture changes, among other factors" said Laxmi Sushama. Sushama is a Professor in McGill's Department of Civil Engineering and the Trottier Chair in Sustainability in Engineering and Design.

"As we started analyzing more closely climate model simulations for the Arctic region, we noticed abrupt changes in soil moisture, as well as abrupt increases in intense rainfalls with a probable increase in lightning and wildfires too."

Discovery of climatic shifts

Prior research in the field has tended to project a gradual degradation of the permafrost, with few direct effects on climate. Typically, researchers will model climate changes by looking backwards and forwards in 20-30 year blocks, making it easier to miss the abrupt changes that are taking place. The McGill researchers analyzed the effects of changes in the permafrost on a completely different level.

McGill researchers study how changes in the climate are affecting engineering infrastructures (e.g. roads, ports, buildings, pipelines and mining infrastructure) in the Arctic. Arctic infrastructure is particularly impacted by permafrost degradation and associated soil moisture changes, among other factors [Credit: Government of the Northwest Territories]

"There's not much high-resolution climate modelling done of the Arctic. Our initial climate model experiments at 50km resolution allowed us to extract critical information on climate shifts" says Bernardo Teufel, the first author on the paper, who is currently working on his PhD research at McGill.

"We used climate model data spanning the 1970-2100 period to understand probable changes in the Arctic climate and permafrost. What we came away with, was a picture of alarming changes to climate driven by permafrost degradation."

The researchers are currently working on very high resolution simulations of likely effects of climate change on the permafrost and climate-infrastructure interactions. They hope that this will also provide a better understanding of the various climate change feedback processes in the Arctic for others working in the field and for stakeholders and engineers in the North.

Source: McGill University [October 30, 2019]

Last year's extreme snowfall wiped out breeding of Arctic animals and plants

By: Thomas Schmitt Attorney on October 15, 2019 / comment : 0 Arctic, Climate Change, Ecosystems, Natural Heritage, Wildlife

In 2018, vast amounts of snow were spread across most of the Arctic region and did not melt fully until late summer, if at all. Publishing in the open-access journal PLOS Biology, researchers documented the consequences of this extreme weather event at Zackenberg, Northeast Greenland by extensively monitoring all components of the local ecosystem for more than 20 years, allowing them to compare life in the extreme year of 2018 to other, more "normal," years.

The Zackenberg valley in Northeast Greenland, summer 2018 - huge amounts of snow still covered the ground in late June, where the snow-covered season usually is coming to an end [Credit: Lars Holst Hansen]

The Arctic is home to a diverse and specialized group of organisms, highly adapted to life under the severe climatic conditions. But now the Arctic is changing, and the region is experiencing both long-term warming and retreating snow-cover. At the same time, climatic variability and the risk of extreme events is increasing. While the consequences of longer-term change are well-documented, we know almost nothing about the impacts of climatic variability and extreme events on the Arctic ecosystems.

The 2018 snow conditions resulted in the most complete reproductive failure ever encountered at Zackenberg, and only few plants and animals were able to reproduce due to abundant and late-melting snow. While poor reproduction had been observed in individual species before, such poor reproduction across all levels of the ecosystem had never been seen.

"One non-breeding year is hardly that bad for high-arctic species", says Niels Martin Schmidt (Aarhus University, Denmark), lead author of the study. "The worrying perspective is that 2018 may offer a peep into the future, where increased climatic variability may push the arctic species to - and potentially beyond - their limits. Our study shows that climate change is more than 'just' warming, and that ecosystems may be hard hit by currently still rare but extreme events. What it also brings out is the unparalleled value of long-term observations of the Arctic. Only by keeping an eye on full arctic ecosystems can we understand the havoc brought by the changing climate".

Source: Public Library of Science [October 15, 2019]

The last mammoths died on a remote island

By: Thomas Schmitt Attorney on October 07, 2019 / comment : 0 Arctic, Early Mammals, Fossils, Palaeontology

The last woolly mammoths lived on Wrangel Island in the Arctic Ocean; they died out 4,000 years ago within a very short time. An international research team from the Universities of Helsinki and Tubingen and the Russian Academy of Sciences has now reconstructed the scenario that could have led to the mammoths' extinction. The researchers believe a combination of isolated habitat and extreme weather events, and even the spread of prehistoric man may have sealed the ancient giants' fate. The study has been published in the latest edition of Quaternary Science Reviews.

This is a mammoth tooth on the riverbank on Wrangel Island [Credit: Juha Karhu]

During the last ice age - some 100,000 to 15,000 years ago - mammoths were widespread in the northern hemisphere from Spain to Alaska. Due to the global warming that began 15,000 years ago, their habitat in Northern Siberia and Alaska shrank. On Wrangel Island, some mammoths were cut off from the mainland by rising sea levels; that population survived another 7000 years.

The team of researchers from Finland, Germany and Russia examined the isotope compositions of carbon, nitrogen, sulfur and strontium from a large set of mammoth bones and teeth from Northern Siberia, Alaska, the Yukon, and Wrangel Island, ranging from 40,000 to 4,000 years in age. The aim was to document possible changes in the diet of the mammoths and their habitat and find evidence of a disturbance in their environment. The results showed that Wrangel Island mammoths' collagen carbon and nitrogen isotope compositions did not shift as the climate warmed up some 10,000 years ago. The values remained unchanged until the mammoths disappeared, seemingly from the midst of stable, favorable living conditions.

This result contrasts with the findings on woolly mammoths from the Ukrainian-Russian plains, which died out 15,000 years ago, and on the mammoths of St. Paul Island in Alaska, who disappeared 5,600 years ago. In both cases, the last representatives of these populations showed significant changes in their isotopic composition, indicating changes in their environment shortly before they became locally extinct.

Earlier aDNA studies indicate that the Wrangel Island mammoths suffered mutations affecting their fat metabolism. In this study, the team found an intriguing difference between the Wrangel Island mammoths and their ice age Siberian predecessors: the carbonate carbon isotope values indicated a difference in the fats and carbohydrates in the populations' diets. "We think this reflects the tendency of Siberian mammoths to rely on their reserves of fat to survive through the extremely harsh ice age winters, while Wrangel mammoths, living in milder conditions, simply didn't need to", says Dr. Laura Arppe from the Finnish Museum of Natural History Luomus, University of Helsinki, who led the team of researchers. The bones also contained levels of sulfur and strontium that suggested the weathering of bedrock intensified toward the end of the mammoth population's existence. This may have affected the quality of the mammoths' drinking water.

Why then did the last woolly mammoths disappear so suddenly? The researchers suspect that they died out due to short-term events. Extreme weather such as a rain-on-snow, i.e. an icing event could have covered the ground in a thick layer of ice, preventing the animals from finding enough food. That could have led to a dramatic population decline and eventually to extinction. "It's easy to imagine that the population, perhaps already weakened by genetic deterioration and drinking water quality issues could have succumbed after something like an extreme weather event," says professor Herve Bocherens from the Senckenberg Center for Human Evolution and Palaeoenvironment at the University of Tubingen, a co-author of the study.

Another possible factor could have been the spread of humans. The earliest archaeological evidence of humans on Wrangel Island dates to just a few hundred years after the most recent mammoth bone. The chance of finding evidence that humans hunted Wrangel Island mammoths is very small. Yet a human contribution to the extinction cannot be ruled out.

The study shows how isolated small populations of large mammals are particularly at risk of extinction due to extreme environmental influences and human behavior. An important takeaway from this is that we can help preserve species by protecting the populations that are not isolated from one another.

Source: University of Helsinki [October 07, 2019]

March of the multiple penguin genomes

By: Thomas Schmitt Attorney on September 17, 2019 / comment : 0 Arctic, Biodiversity, Ecosystems, Evolution, Genetics, Wildlife

The Penguin Genome Consortium sequences all living penguin species genomes to understand the evolution of life on the ice

Gentoo Penguins in Antarctica form a line as they march down a 'penguin highway' to collect rocks for their nests [Credit: Laurie Goodman]

Published  in the open-access journal GigaScience is an article that presents the first effort to capture the entirety of the genomic landscape of all living penguin species. The Penguin Genome Consortium --bringing together researchers from China, Denmark, New Zealand, Australia, Argentina, South Africa, the UK, the US, France and Germany-- has produced 19 high-coverage penguin genome sequences that, together with two previously published genomes, encompass all surviving penguin species. This extensive study provides an unparalleled amount of information that covers an entire biological order, which will promote research in a wide variety of areas from evolution to the impact of human activities and environmental changes.

Penguins are a diverse order of species that span the Southern hemisphere, ranging from the Galapagos Islands on the equator, to the oceanic temperate forests of New Zealand, to the rocky coastlines of the sub-Antarctic islands, finally reaching the sea-ice around Antarctica. This iconic bird group have transitioned from flying seabirds to powerful, flightless marine divers. With their specialized skin and feathers and an enhanced thermoregulation system they are able to inhabit environments from the extreme cold Antarctic sea ice to the tropical Galapagos Islands.

These birds also serve as the figurative "canary in a coal mine"; warning of environmental and climate change. Many penguin populations have experienced rapid declines in recent decades, some having extreme population drops, such as the crash of the King penguin population, which has declined by 88% in just 3 decades. And more penguin species are predicted to decline in the near future.

The dwindling populations have been linked to climate warming, environmental degradation, exploitation of the marine environment, fisheries bycatch, pollution, and the introduction of exotic predators. Penguins have thus become the focus of many ecosystem monitoring studies. Having high-quality genomes sequences of all extant penguin species serves as an outstanding new resource for understanding the specific reasons for species population loss.

A Chinstrap Penguin in Antarctica [Credit: Laurie Goodman]

Author Theresa Cole from the University of Otago in New Zealand says of this work: "The population history of different penguin species can be seen in their genome. We will provide new insights into the population history of all penguins over dramatic climate events, to predict population trends under future climate change scenarios. This research will help us understand how future climate change may affect other species, to help us develop conservation strategies."

As with the work done on Darwin's finches, studying the radiation of the 20 penguin species provides similar enlightening case study for researching unique penguin morphological and physiological adaptations. The consortium are also sequencing the genomes of recently extinct penguin taxa, as well as undertaking population genomic studies using multiple genomes per species.

Senior author Guojie Zhang from the University of Copenhagen, BGI, and Kunming Institute of Zoology says of this: "The penguin ancestor experienced rapid radiation leading to the current approximate 20 extant species, accompanied by many ancient lineages that are now extinct. The radiation of penguin thus provides an excellent example for the study of speciation."

There were logistical challenges to get hold of high-quality specimens for all of these species as many come from some of the most inhospitable and far-flung corners of the globe. However, an additional challenge was cultural rather than technical. The process by which this consortium handled these sensitive issues serves as a model for building trust and collaboration with cultures that have equally important links to other native species.

Gentoo Penguins in Antarctica, Dec. 2018 [Credit: Laurie Goodman]

Co-author Bruce McKinlay from the New Zealand Department of Conservation highlights this, saying: "Genome research in New Zealand is currently moving into novel cultural contexts, especially for penguins, which are Taonga or treasured possessions in Maori culture. As such, our consortium have undertaken rigorous indigenous consultation to sequence the genomes from six New Zealand Taonga species. We believe these genomes will be important for a cultural context."

The goal of the first stage of the Penguin Genome Consortium project was purely to sequence high-quality genomes, but initial validation studies have demonstrated these genomes are already producing valuable insight into evolutionary history of the penguin tree of life and the evolutionary patterns of their adaptation to Antarctica. For example, an initial phylogenetic tree presented in this study demonstrates that penguins have adapted to Antarctica on multiple occasions.

This and further comparative and evolutionary genomic analyses are currently being carried out, and the penguin genome consortium welcomes new members interested in joining the open consortium and contributing to this work. While this work is still underway early access to the 19 penguin genomes data has been provided, while the researchers ask groups intending to use this data for similar cross-species comparisons to follow the long running Fort Lauderdale and Toronto rules.

Source: GigaScience [September 17, 2019]

Turning the Arctic brown

By: Thomas Schmitt Attorney on September 17, 2019 / comment : 0 Arctic, Climate Change, Ecosystems, Environment, Natural Heritage

Professor Gareth Phoenix has been visiting Abisko, in the Arctic circle of Sweden, for years. He's been there in the depths of winter when the snow is several feet deep, and in the height of summer when mosquitoes are buzzing around every person (and reindeer) in sight. If there's one thing he's learnt from his years of research in the Arctic circle, it's to be prepared for extremes.

Credit: University of Sheffield

Phoenix, a professor at the University of Sheffield, studies Arctic ecosystems. In particular, the impacts of climate change on the ecosystem structure and function. The Arctic is vast and the changes occurring here—retreating glaciers, melting permafrost and shrinking ice caps—have the potential to dramatically impact the rest of the world.

Despite this, from a scientific point of view, much of the Arctic is unexplored and unknown. One thing we know for certain is that for approximately 35 years it has seen increasing growth of vegetation—a process known as "Arctic greening." However, now it looks as though some of it might actually be turning brown.

When satellites in space detect plants on Earth they measure the "greenness index," in other words, how green the ground cover of plants is. How lush the foliage on the ground appears from space can represent a number of aspects down on earth, from plant growth to leaf area. But if areas of the Arctic are browning, it may indicate something else as well: plant death.

The plant death can be a result of extreme weather events, which are becoming more frequent in the Arctic as the climate warms. A sudden period of warmth in the middle of winter tricks the plants into thinking it's spring, so they burst bud early and lose their cold hardiness, leaving them unprepared for a return to normal cold winter temperatures. The plant die-back that follows the events of this 'extreme winter warming' also appear to be significantly reducing the ability of Arctic ecosystems to help combat climate change.

"We know that an increase in extreme weather events is a challenge we now face around the world as part of ongoing climate change. The fact that extreme events in the Arctic are killing tundra plants is a big concern because those damaged ecosystems are less able to take up CO2 to help combat climate change, and less able to provide habitat and food for the animals that rely on a healthy tundra ecosystems for survival." Professor Gareth Phoenix, department of animal and plant sciences

The more the effects of climate change are felt by the Arctic the more they are felt by the rest of the world. What happens here has consequences beyond it's icy boundaries. Therefore reducing greenhouse gas emissions, a primary contributor to climate change, is fundamental to reducing its impacts. Without making changes soon we might find the Arctic contributes to rising CO2 levels, rather than helping to combat it.

Author: Emma Griffiths | Source: University of Sheffield [September 17, 2019]

Geologists found links between deep sea methane emissions and ice ages

By: Thomas Schmitt Attorney on September 11, 2019 / comment : 0 Arctic, Climate Change, Earth Science, Geology, Oceans, Palaeoclimate, Palaeontology

Since 2012, researchers at the Division of Bedrock Geology in the Department of Geology of Tallinn University of Technology Aivo Lepland and Tonu Martma have been engaged in the research of an international research group investigating the factors controlling methane seepages and reconstructing the chronology of past methane emissions in one of the world's most climate-sensitive regions - the Barents Sea in the Arctic.

Sampling of methane-derived carbonate crust at 1200 m deep seafloor offshore Svalbard [Credit: Aivo Lepland]

"Methane is one of the most aggressive climate-warming greenhouse gases, while being also an important energy resource. Changes of methane concentrations in the atmosphere have a major impact on the Earth's climate. Optimal use of methane with minimal climate effects therefore requires a very good understanding of the processes of methane generation and migration. To better understand the processes and forecast future trends, the scientists analyse not only current processes, but those that occurred during the geologic evolution of the Earth, i.e. the processes related to methane circulation that have taken place over millions of years," says a member of the research group, geologist Aivo Lepland.

The respected scientific journal Science Advances published recently the article "A 160,000-year-old history of tectonically controlled methane seepage in the Arctic" co-authored by TalTech geologists in cooperation with their colleagues at the Geological Survey of Norway, British Geological Survey and the University of Tromso and the University of Bremen, who studied the chronology and geological factors controlling methane release in the Barents Sea off Svalbard.

To study the past deep-sea methane release episodes, the scientists analysed carbonate crusts that form when methane emanating vigorously from the seafloor comes into contact with sulphate in seawater. In the course of this process small amounts of uranium contained in sea water are incorporated into the crystallizing carbonates. Uranium is a radioactive element, which decays to form thorium. By measuring the concentrations of uranium and thorium in carbonate crusts, the scientists can determine the time of crystallisation of the minerals. "Opening of the "birth certificates" of the carbonate crusts through uranium and thorium analysis makes it possible to reconstruct the chronology of past seabed methane emissions and assess their causes," says Lepland.

The samples collected from the 1,200 m deep seabed revealed three major emission episodes from the Arctic seabed in the last 160,000 years: after the end of the last ice age around 23,000 years ago, 40-50 000 years ago, and 150,000 years ago. Each methane release episode lasted 10,000 to 20,000 years. Such chronology suggests that the methane emissions are linked to the glacial cycles. The pressure caused by the weight of a couple of kilometres thick ice sheet caused tensions in seabed rocks and opening of fracture systems allowing the upward flow of gases from deep subsurface strata.

The novelty of the findings lies in the fact that it is the first time that deep-sea methane emissions have been linked to ice ages. The growing and melting of ice sheet affect the tectonic regime in the earth's crust, triggering methane release episodes, which could have had an impact on the climate. So it is a kind of a closed circle. "How much methane was emitted exactly this way and what were the climate effects, however, requires further investigation," Lepland adds.

Source: Estonian Research Council [September 11, 2019]

Early start of 20th century Arctic sea ice decline

By: Thomas Schmitt Attorney on August 30, 2019 / comment : 0 Arctic, Climate Change, Natural Heritage, Oceans

Arctic sea-ice has decreased rapidly during the last decades in concert with substantial global surface warming. Both have happened much faster than predicted by climate models, and observed Arctic warming is much stronger than the global average. Projections suggest that Arctic summer sea-ice may virtually disappear within the course of the next fifty or even thirty years.

Study area and surface air temperature trends. (A) Map of Svalbard archipelago in the arctic North Atlantic, with location of Mosselbukta study site in northern Spitsbergen (rectangle, enlarged in B), where long-lived encrusting coralline algal buildups were collected in June 2016. Red arrow indicates approximate path of West Spitsbergen Current (WSC). (B) Detailed shaded-relief map of study site with sampling location Ellingsenodden in Mosselbukta (red asterisk). Source of shaded-relief map: https://toposvalbard.npolar.no/. (C) Global winter surface-air temperature trends since C.E. 1980 (linear trends in °C/decade for December–February). Geographic locations of the Svalbard archipelago (this study, white open circle), Newfoundland, Canada (Hill and Jones [1990] sea-ice record, blue circle), and Labrador–Canadian Arctic (Halfar et al. [2013] algal sea-ice proxy, black circle) are shown. Data source: http://data.giss.nasa.gov/gistemp [Credit: Hetzinger et al. 2019/Geology]

Although Arctic-wide warming during the 20th century is well documented, little is known about the response of sea-ice to abrupt warming and it is unclear when the sea-ice decline started. Data coverage in this region is highly restricted, with observation-based satellite data only available since the 1970s, too short to accurately calibrate climate models.

Limited observational records therefore hamper the assessment of long-term changes in sea-ice, leading to large uncertainties in predictions of its future evolution under global warming. In the absence of instrumental data, natural archives of environmental changes, so-called proxies can be used to extend climate data further back in time.

In this study published in Geology, Steffen Hetzinger and colleagues present the first annually resolved 200-year record of past sea-ice variability from High Arctic Svalbard (79.9°N) using a newly developed in situ proxy from long-lived encrusting coralline algae. Annual growth and Mg/Ca ratios in this photosynthesizing benthic marine plant are strongly dependent on light availability on the shallow seafloor, recording the duration of seasonal sea-ice cover.

This proxy opens up a new possibility to study past sea-ice variability, and unlike previously available reconstructions from mainly land-based archives, it provides an annually resolved direct in situ proxy from the surface ocean.

Due to the limited availability of instrumental data, current research largely focuses on sea-ice decline since the late 20th century. The results of this study provide evidence for an earlier start of Arctic sea-ice decline at the beginning of the 20th century, not captured by shorter observational records and land-based reconstructions.

The algae also show that lowest sea-ice values within the past 200 years occurred from the 1980s to the early 2000s. These results may help reduce the large uncertainties that exist among ocean model simulations, providing a new approach for the detection and verification of long-term Arctic sea-ice changes.

Source: Geological Society of America [August 30, 2019]

HMS Terror shipwreck offers up secrets of lost Arctic expedition

By: Thomas Schmitt Attorney on August 29, 2019 / comment : 0 Archaeology, Arctic, Canada, Underwater Archaeology

Almost two centuries after descending to its watery grave, the HMS Terror could offer up new clues to its demise -- and solve one of the most enduring mysteries in the history of Arctic discovery.

Plates and other artifacts sitting on shelves next to a mess table where a group of lower-ranking  crew members would have taken their meals [Credit: Ryan Harris/AFP]

Canadian parks department officials announced Wednesday the results of a survey of the shipwreck's near-pristine interior -- and revealed that artifacts preserved in the deep might help explain what happened to the polar exploration vessel.

The Terror vanished alongside the HMS Erebus during explorer Sir John Franklin's storied Arctic expedition that left Britain in 1845 to discover the Northwest Passage linking the Atlantic and Pacific Oceans.

After passing two whaling boats in Baffin Bay in August of that year, the ill-fated ships would never be seen afloat again.

The Erebus was found in Victoria Strait in 2014, while the Terror was located under 24 meters (80 feet) of water two years later in what is now known as Terror Bay, off King William Island, Nunavut.

Underwater archaeologists spent seven days exploring the Terror this summer and in a statement said they were stunned to discover its "extraordinary state of preservation" during the dives.

They believe that the captain's desk, map cabinets with closed drawers and boxes could contain charts and logs preserved by the cold deep water, which may shed light on what exactly happened to the expedition.

'Tantalizing'

"Sedimentation provides the best conditions for preservation as it allows for an environment with less oxygen, which helps preserve organics, like paper," the statement said.

Map showing an area in the Canadian Arctic where HMS Terror vanished in 1848 along with HMS Erebus during an expedition [Credit: Gal Roma/AFP]

Project director Ryan Harris told a news conference the prospect of learning its secrets from what was left behind was "very tantalizing."

"Written materials could shed all kinds of light on what happened, the chronology of events, when the ships parted company and how they got to where they were found abandoned," he said.

Harris noted that the ship was upright on the sea floor, its propeller in place. No anchors were deployed, and skylights were not boarded over to protect from harsh Arctic conditions.

"It looked like it was in operating condition, and suggests with other clues that the ship sank unexpectedly and was deserted very, very quickly," he said.

The archaeological team earlier this month "focused on 3D structural mapping and exploring the interior" of the Terror during the first systematic exploration of the vessel.

They obtained clear images of more than 90 percent of the lower deck, which includes the crew's living quarters.

Only the sleeping quarters of Captain Francis Crozier remained inaccessible, behind a closed door.

Video shows beds and desks in place, shelves with plates, glass bottles, tumblers and stemware in what is believed to have been the officers' mess pantry.

Grim message

Rows of shelves with plates, bowls and glasses –- all intact -– can also be seen in the common sailors' quarters.


Sediment that seeped through the stern gallery windows covers most of the captain's cabin. A tripod and a pair of thermometers were identified there.

Harris said the team hopes to return to the site next year to resume exploration of the vessel.

When the two ships set sail, they were well-equipped and prepared with stout, iron-sheathed hulls and steam engines, and enough food and supplies for three years in the high Arctic.

Following their disappearance, a vessel chartered by Franklin's widow Lady Jane in 1859 came across a grim message on King William Island: Franklin and 23 crew members had died on June 11, 1847 in unspecified circumstances.

It seems the ships had become stuck in ice and, on April 22, 1848, 105 survivors left in an attempt to reach solid ground on foot, but none survived.

Canadian researchers in the 1980s said the remains of expedition members found on Beechey Island indicated they had died of cold, hunger and lead poisoning from canned food.

Author: Michel Comte | Source: AFP [August 29, 2019]

Arctic permafrost melting will aggravate the greenhouse effect

By: Thomas Schmitt Attorney on August 27, 2019 / comment : 0 Arctic, Climate Change, Earth Science, Environment, Natural Heritage, Siberia

Scientists from Russia and the United States studied the composition of the deep layers of permafrost in Eastern Siberia to better understand the hazards of the permafrost thawing to our planet and its inhabitants. Their findings suggest that the release of organic matter from the permafrost will intensify the greenhouse effect. The results of their study were published in the Journal of Geophysical Research.

Credit: Skolkovo Institute of Science and Technology

An ice-coated ground that never thaws, permafrost accounts for nearly 25% of land on Earth. Permafrost has increasingly drawn the attention of scientists due to global warming, since permafrost thawing may trigger extensive releases of ancient organic carbon and possibly result in a huge environmental disaster. There is no clear understanding of the consequences of the permafrost meltdown, which may be fraught with other risks aside from a global rise in sea levels.

Scientists from the Skolkovo Institute of Science and Technology and Lomonosov Moscow State University in collaboration with researchers from Florida State University undertook the first ever study of organic matter contained in the deep permafrost layers in the Kolyma River basin in Eastern Siberia, aiming to understand what happened during permafrost thawing periods in the past and predict how present-day global warming may affect permafrost and what this could lead to.

In an attempt to find out what organic material is buried under the layers of ice and what would happen if it breaks loose, the scientists took soil samples at depths of 3 to 15 meters from two deposits of different geological ages to study the soil molecular structure using mass spectrometry. The experiment showed that permafrost thawing may produce microbially degradable rich organic matter, which, in turn, will cause massive greenhouse emissions and speed up global warming.

One of the authors of the study and junior research scientist at Skoltech, Alexander Zherebker, Ph.D. (Chemistry), stressed the significance of the study:

"We examined Pleistocene and Holocene deposits representing a pool of carbon which is best conserved and was only partly transformed during the melting periods; it is made up of 2% organic matter and 90% ice. We pinpointed the components that underwent the biggest change and those that are most susceptible to microorganism action. It transpired that biodegradable components are present both at great depths and very close to the permafrost surface. According to our projections, the Arctic region will very soon have a marked impact on global warming."

Source: Skolkovo Institute of Science and Technology [August 27, 2019]

Switching on the Atlantic Ocean heat pump

By: Thomas Schmitt Attorney on August 22, 2019 / comment : 0 Arctic, Climate Change, Earth Science, Environment, Natural Heritage, Oceans

34 million years ago the warm 'greenhouse climate' of the dinosaur age ended and the colder 'icehouse climate' of today commenced. Antarctica glaciated first and geological data imply that the Atlantic meridional overturning circulation, the global ocean conveyor belt of heat and nutrients that today helps keep Europe warm, also started at this time. Why exactly, has remained a mystery.

The circulation patterns in the North Atlantic Ocean. Cold, dense water is shown in blue, flowing south from upper latitudes, while warm, less dense water, shown in red flows north from low latitudes [Credit: NASA]

"We have found a new trigger to explain the start-up of the Atlantic current system during the greenhouse-icehouse climate transition: During the warm climate, buoyant fresh water flooded out of the Arctic and prevented the ocean-sinking that helps power the conveyor. We found that the Arctic-Atlantic gateway closed due to tectonic forces, causing a dramatic increase in North Atlantic salinity. This caused warming of the North Atlantic and Europe, and kickstarted the modern circulation that keeps Europe warm today," says David Hutchinson, researcher at the Department of Geological Sciences, Stockholm University, and lead author of the article published in Nature Communications.

The team of scientists, from the Bolin Centre for Climate Research, used a combination of geophysical data and climate modelling to show that the freshwater transport through the Arctic-Atlantic gateway plays a critical role in controlling the overturning circulation.

"Not only did deep water start forming in the Atlantic Ocean, it also stopped forming in the North Pacific at the same time, which matches geological evidence. We were surprised to find that our computer simulations can explain both of these changes due to salty ocean currents connecting the Pacific to the Atlantic. Our study is the first to show that these two events are linked, which is very exciting," says Hutchinson.

The climate at this time was very warm, with atmospheric CO2 levels two to three times the present day levels, and this contributed to extremely fresh Arctic waters. The study begs the question of whether in a future warm world, in which the Arctic may again be very fresh, the sinking in the Atlantic may cease again, which may dramatically alter the climate of Europe. Without the Atlantic conveyor belt, Europe can experience both colder winters and hotter and drier summers, making a more extreme and inhospitable climate.

"Our study helps to bridge the gap between climate modelling and geological observations of the deep past. We hope this will inspire further research from both communities on the deep circulation of the ocean," says Hutchinson.

Source: Stockholm University [August 22, 2019]

Extreme wildfires threaten to turn boreal forests from carbon sinks to carbon sources

By: Thomas Schmitt Attorney on August 21, 2019 / comment : 0 Arctic, Canada, Climate Change, Ecosystems, Environment, Natural Heritage

Carbon reservoirs in the soil of boreal forests are being released by more frequent and larger wildfires, according to a new study involving a University of Guelph researcher.

The research team sampled more than 200 plots in the forests of Canada's Northwest Territories to see whether "legacy" carbon left over from previous fire cycles was threatened by the intense 2014 fires. They found that forests less than 60 years old and located in drier climates had a higher risk of losing legacy carbon in the fires than older, wetter forests [Credit: NASA/Xanthe Walker, Center for Ecosystem Science and Society at Northern Arizona University]

As wildfires continue to ravage northern areas across the globe, a research team investigated the impact of these extreme fires on previously intact carbon stores by studying the soil and vegetation of the boreal forest and how they changed after a record-setting fire season.

"Northern fires are happening more often, and their impacts are changing," said U of G Prof. Merritt Turetsky, who holds the Canada Research Chair in Integrative Biology. She worked on the study with lead authors Xanthe Walker and Michelle Mack from the Center for Ecosystem Science and Society at Northern Arizona University (NAU), as well as a team of Canadian scientists including Wilfrid Laurier University professor Jennifer Baltzer.

The work was supported by NASA, the Natural Sciences and Engineering Research Council of Canada and the Government of the Northwest Territories.

In 2014, the Northwest Territories suffered its largest fire season in recorded history. This series of mega-fires created the ideal environment to study whether carbon stores are being combusted by these types of fires.

"Between fires, boreal soils accumulate carbon, and in most cases only some of this carbon is released when the forests experience the next fire," said Baltzer. "Over time, this explains why the boreal forest is a globally significant carbon sink. We wanted to see whether the extreme 2014 fires tapped into these old-legacy carbon layers or whether they were still preserved in the ground."

Soil cores showing accumulation of old carbon taken from one of the Northwest Territories field sites [Credit: Merritt Turetsky]

For the study, published in the journal Nature, the research team collected soil samples from more than 200 forest and wetland plots across the territory. They applied a novel radiocarbon dating approach to estimate the age of the carbon in the samples.

"Carbon accumulates in these soils like tree rings, with the newest carbon at the surface and the oldest carbon at the bottom," said Mack. "We thought we could use this layering to see how far back in time, in the history of the forest, fires were burning."

The researchers found combustion of legacy carbon in nearly half of the samples taken from young forests (less than 60 years old). This carbon had escaped burning during the previous fire cycle but not during the record-setting fire season of 2014.

"In older stands that burn, this carbon is protected by thick organic soils," said NAU's Walker. "But in younger stands that burn, the soil does not have time to re-accumulate after the previous fire, making legacy carbon vulnerable to burning. This pattern could shift boreal forests into a new domain of carbon cycling, where they become a carbon source instead of a sink."

As wildfires are expected to occur more frequently and burn more intensely, old carbon may be released to the atmosphere more often.


"Understanding the fate of this stockpile of boreal carbon is really important in the context of atmosphere greenhouse gases and the Earth's climate," Turetsky said. "This is carbon the atmosphere lost hundreds or sometimes even thousands of years ago. Fire is one mechanism that can release that old carbon back to the atmosphere quickly where it can contribute to the greenhouse gas effect."

She said the potential switch of the boreal forest from carbon storage to carbon source directly impacts global climate and is not well represented in global models.

"In the context of territorial and pan-Canadian planning for climate change adaptation and mitigation, the Government of Northwest Territories recognizes the critical need to understand the role of our boreal forests in carbon storage, sequestration and release, and how our forest management practices can affect these processes," said Erin Kelly, the territory's assistant deputy minister of environment and natural resources.

Turetsky said this research is important both because of its scientific findings and because it involved stakeholders in tracking the effects of climate change in Canada.

Source: University of Guelph [August 21, 2019]

Microplastic drifting down with the snow

By: Thomas Schmitt Attorney on August 14, 2019 / comment : 0 Arctic, Environment, Natural Heritage

Over the past several years, microplastic particles have repeatedly been detected in seawater, drinking water, and even in animals. But these minute particles are also transported by the atmosphere and subsequently washed out of the air, especially by snow—and even in such remote regions as the Arctic and the Alps. This was demonstrated in a study conducted by experts at the Alfred Wegener Institute and a Swiss colleague, recently published in the journal Science Advances.

Scientists from the Alfred Wegener Institute use the board helicopter from the icebreaking research vessel Polarstern to collect snow samples [Credit: Alfred-Wegener-Institut/Mine Tekman]

The fact that the oceans are full of plastic litter has by now become common knowledge: Year after year, several million tonnes of plastic litter find their way into rivers, coastal waters, and even the Arctic deep sea. Thanks to the motion of waves, and even more to UV radiation from the sun, the litter is gradually broken down into smaller and smaller fragments—referred to as microplastic. This microplastic can be found in marine sediment, in seawater, and in marine organisms that inadvertently ingest it. In comparison, there has been little research to date on whether, and if so, to what extent, microplastic particles are transported by the atmosphere. Only a handful of works are available, e.g. from researchers who were able to confirm the particles' presence in the Pyrenees and near major urban centers in France and China.

A team of experts from the Alfred Wegener Institute, Helmholtz center for Polar and Marine Research (AWI) has now found that microplastic particles can apparently be transported over tremendous distances by the atmosphere and are later washed out of the air by precipitation, particularly snow. As the team led by Dr. Melanie Bergmann and Dr. Gunnar Gerdts report in the journal Science Advances, the analyses they conducted on snow samples from Helgo-land, Bavaria, Bremen, the Swiss Alps and the Arctic confirm that the snow at all sites contained high concentrations of microplastic—even in remote reaches of the Arctic, on the is-land Svalbard, and in snow on drifting ice floes. "It's readily apparent that the majority of the microplastic in the snow comes from the air," says Melanie Bergmann. Her hypothesis is supported by past research conducted on grains of pollen, in which experts confirmed that pollen from the middle latitudes is transported by the air to the Arctic. These grains are roughly the same size as the microplastic particles; similarly, dust from the Sahara can cover distances of 3,500 km or more, reaching the northeast Atlantic.

Fresh snow is filled with a chrome steel towel to lockable galss containers. Later the samples are analysed for microplastic concentrations in the lab. The whole sampling takes place without the use of any plastics to prevent the samples  from contamination [Credit: Alfred-Wegener-Institut/Jurg Trachsel, WSL-Institut fur Schnee- und Lawinenforschung SLF]

The AWI researchers found the highest concentration in samples gathered near a rural road in Bavaria—154,000 particles per litre. Even the snow in the Arctic contained up to 14,400 particles per liter. The types of plastic found also varied greatly between sampling sites: in the Arctic, the researchers chiefly found nitrile rubber, acrylates and paint, which are used in a host of applications. Given its resistance to various types of fuel and broad temperature range, nitrile rubber is often used in gaskets and hoses. Paints containing plastic are used in several different areas, e.g. to coat the surfaces of buildings, ships, cars and offshore oil rigs. Near the rural road in Bavaria, the samples especially contained various types of rubber, which is used in countless applications, such as automotive tires.

One intriguing aspect of the AWI study: the microplastic concentrations found are considerably higher than those in studies conducted by other researchers, e.g. on dust deposits. According to Gunnar Gerdts, this could be due to one of two reasons: "First of all, snow is extremely efficient when it comes to washing microplastic out of the atmosphere. Secondly, it could be due to the infrared spectroscopy we used, which allowed us to detect even the smallest particles—down to a size of only 11 micrometers." Gerdts and his colleagues melt the snow and pour the meltwater through a filter; the residue trapped in the filter is then examined with an infrared microscope. Depending on the type of plastic, different wavelengths of the infrared light are absorbed and reflected; in this way, an optical fingerprint can be used to determine what type of plastic they've found.

Even in the Arctic the snow is polluted with microplastics [Credit: Mine Tekman, Alfred-Wegener-Institut]

Whereas other experts sort out microplastic from their samples by hand under the micro-scope, which can easily cause some particles to be overlooked, Gerdts uses his infrared microscope to test all of the residue, ensuring that he and his team hardly miss a thing. "We've automated and standardized the technique so as to rule out the errors that can creep in when manual analysis is used." As such, it's hardly surprising that the analyses conducted at the AWI yielded especially high particle concentrations.

In light of the meteorological realities, the AWI experts are convinced that a major portion of the microplastic in Europe, and even more so in the Arctic, comes from the atmosphere and snow. According to Melanie Bergmann: "This additional transport route could also explain the high amounts of microplastic that we've found in the Arctic sea ice and the deep sea in previous studies."

Lastly, there's another key question that motivates her work. "To date there are virtually no studies investigating the extent to which human beings are subject to microplastic contamination." In addition, most research has focused on how animals or human beings absorb microplastic from what they eat. As Bergmann explains: "But once we've determined that large quantities of microplastic can also be transported by the air, it naturally raises the question as to whether and how much plastic we're inhaling. Older findings from medical research offer promising points of departure for work in this direction." Yet another aspect that warrants a closer look in the future.

Source: Alfred Wegener Institute [August 14, 2019]

Melting ice may change shape of Arctic river deltas

By: Thomas Schmitt Attorney on July 26, 2019 / comment : 0 Arctic, Climate Change, Ecosystems, Environment, Natural Heritage

Thawing ice cover and easily erodible permafrost may destabilize Arctic river deltas, according to new research.

Yukon Delta, AK. Landsat natural color satellite image. May 17, 2002 [Credit: USGS]

A new study in the AGU journal Geophysical Research Letters finds sea ice and permafrost both act to stabilize channels on Arctic river deltas.

"Your channels tend to stay in one place when you have really thick ice or when you have permafrost that's really hard to erode," said Rebecca Lauzon, environmental educator at the Rochester Museum and Science Center's Cumming Nature Center in New York and the lead author of the new study.

Ice cover on Arctic deltas is expected to thin while permafrost is expected to thaw along the banks of Arctic rivers due to climate change.

The new study finds these changes could destabilize deltas in the far north of the globe, making them less resilient to rising sea levels. Less stable deltas could also impact Arctic ecosystems, creating winners and losers among delta species and even affecting the global carbon cycle.

Changing deltas

The new study examined how ice cover and permafrost affect sediment transport in Arctic deltas and provides insight as to how coastal dynamics may change in a warming Arctic. Sediment movement is important because it defines the shape river deltas take. It also provides food and habitat for delta species and oceanic creatures that feed off the organic matter which makes it out to sea.

Kolyma Delta, Russia. Landsat natural color satellite image. May 30, 2013 [Credit: USGS]

Previous research on Arctic river deltas found that permafrost along the banks of rivers affected riverbank erosion rate, and thick ice covers resulted in constricted and faster river flow.

Lauzon, who was working an internship at Los Alamos National Laboratory during the time of the research, and her co-authors, created two versions of a model: One to predict the effects that ice thickness might have on Arctic river deltas and another to predict the effects of permafrost strength.

The study's authors found that when ice cover is thicker on rivers, or with more stable permafrost along the banks, river deltas tended to be characterized by deeper, more stable channels which acted as funnels, carrying sediment out to the ocean.

But thinner ice or more easily erodible permafrost along the banks caused the deltas to destabilize, with shallower water channels cutting through shifting sediment banks.

Lena Delta, Russia. Landsat natural color satellite image. June 4, 2015 [Credit: USGS]

Part of the reason these channels become less stable is due to a loss of overbank flooding, which decreases with thinner ice and more erodible permafrost. Overbank flooding, which happens with thick ice cover and more resistant permafrost, causes sediment to be deposited along the tops of channel banks. Over time this results in higher riverbanks, which increases the stability of deltas.

But with less overbank flooding, deltas may become more vulnerable to the effects of climate change, according to Anastasia Piliouras, an earth scientist at Los Alamos and a co-author of the new study.

"They then might be less resilient to sea level rise," she said.

Ecological, carbon cycle impacts

Piliouras said changes to the geography of river deltas could have ecological impacts and create winners and losers among species which live in the delta, favoring those that prefer more frequent flooding while negatively impacting species that prefer dry land.

Lena Delta, Russia. European Space Agency Proba-V satellite image. July 27, 2014 [Credit: ESA]

Lauzon said there could also be impacts on the carbon cycle as more organic material could be released from the delta areas, though more research is needed to determine the overall effects thinner ice and unstable permafrost would have on carbon release.

The study's authors hope to use their model to help understand what might happen to real deltas such as those of the Yukon or Mackenzie rivers in Canada or the Lena River in Russia. Piliouras said they have done some follow up research to check if real river deltas exhibit the characteristics they predicted from their models, and that future research should now look at tracking how less stable permafrost and thinner ice affects river deltas.

Furthermore, they are also working on research which shows how both factors taken together may affect river delta stability rather than only looking at permafrost or ice thickness in isolation as they did in this study.

Author: Joshua Learn | Source: GeoSpace [July 26, 2019]