Science

Roundup: Alpine Streams, Divergence and Ocean Acidification

Posted by on Mar 13, 2017 in All Posts, Featured Posts, Roundup, Science | 0 comments

Roundup: Alpine Streams, Divergence and Ocean Acidification

Spread the News:ShareRoundup: Streams, Oceans and Tiny Flies Climate Change and Alpine Stream Biology From Biological Reviews: “In alpine regions worldwide, climate change is dramatically altering ecosystems and affecting biodiversity in many ways. For streams, receding alpine glaciers and snowfields, paired with altered precipitation regimes, are driving shifts in hydrology, species distributions, basal resources, and threatening the very existence of some habitats and biota. Alpine streams harbour substantial species and genetic diversity due to significant habitat insularity and environmental heterogeneity. Climate change is expected to affect alpine stream biodiversity across many levels of biological resolution from micro- to macroscopic organisms and genes to communities.” Learn more about alpine stream biology here.   Ecological Divergence of the Alpine Mayfly From Molecular Ecology: “Understanding ecological divergence of morphologically similar but genetically distinct species – previously considered as a single morphospecies – is of key importance in evolutionary ecology and conservation biology. Despite their morphological similarity, cryptic species may have evolved distinct adaptations. If such ecological divergence is unaccounted for, any predictions about their responses to environmental change and biodiversity loss may be biased. We used spatio-temporally replicated field surveys of larval cohort structure and population genetic analyses (using nuclear microsatellite markers) to test for life-history divergence between two cryptic lineages of the alpine mayfly Baetis alpinus in the Swiss Alps… Our results indicate partial temporal segregation in reproductive periods between these lineages, potentially facilitating local coexistence and reproductive isolation. Taken together, our findings emphasize the need for a taxonomic revision: widespread and apparently generalist morphospecies can hide cryptic lineages with much narrower ecological niches and distribution ranges.” Read more about ecological divergence here. Ocean Acidification in the Antarctic Coastal Zone From ScienceDirect: “The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Ω) for two biologically-important calcium carbonate minerals calcite and aragonite was observed in Ryder Bay, in the coastal sea-ice zone of the West Antarctic Peninsula. Glacial meltwater and melting sea ice stratified the water column and facilitated the development of large phytoplankton blooms and subsequent strong uptake of atmospheric CO2 of up to 55 mmol m-2 day-1 during austral summer. Concurrent high pH (8.48) and calcium carbonate mineral supersaturation (Ωaragonite ~3.1) occurred in the meltwater-influenced surface ocean… Spatially-resolved studies are essential to elucidate the natural variability in carbonate chemistry in order to better understand and predict carbon cycling and the response of marine organisms to future ocean acidification in the Antarctic coastal zone.” Read more about ocean acidification here. Spread the...

Read More

Hardangerjøkulen: The Real-Life Hoth is Disappearing

Posted by on Mar 9, 2017 in All Posts, Art/Culture, Featured Posts, News, Science, Tourism | 0 comments

Hardangerjøkulen: The Real-Life Hoth is Disappearing

Spread the News:ShareAny Star Wars fan will recognize the remote ice planet Hoth, the location of some of the most iconic scenes from Episode V: The Empire Strikes Back, including the attack on the Rebel Alliance’s Echo Base by Imperial Walkers and Han Solo’s daring rescue of Luke Skywalker after his tauntaun was attacked by a wampa. Not many people, however, would know that those legendary scenes were filmed on a Norwegian ice cap called Hardangerjøkulen. When the movie was filmed in 1980, the crew had to cope with subzero temperatures and freezing winds. However, nearly forty years later, the real-life Hoth is disappearing. According to a recent paper by Henning Akesson et al., published in The Cryosphere, the ice cap is extremely sensitive to small changes in temperature, and therefore vulnerable to climate change as global temperatures continue to increase. Akesson explains in an article for ScienceDirect that due to increasing temperatures, it is feasible that Hardangerjøkulen could fully melt by 2100 if the trends continue. Once it melts, he and his team maintain that the ice cap will never return. As the authors of the study explain, Hardangerjøkulen is located in southern Norway and measured 73 square kilometers as of 2012. It is generally flat in the interior and has several steeper glaciers along the edge of the ice cap that drain the plateau. Two of these glaciers, Midtdalsbreen and Rembesdalsskaka, have retreated 150 meters and 1386 meters respectively since 1982. Akesson et al. base their study of Hardangerjøkulen on modeling, as opposed to measurements or observations. The team used a numerical ice flow model to produce a plausible ice cap history of Hardangerjøkulen thousands of years before the Little Ice Age. Using a modelled history of the ice cap, they examined the sensitivity to different parameters. They found that it is “exceptionally sensitive” to changes in temperature. These changes in temperature impact the ice cap’s surface mass balance, which is the gain and loss of ice from a glacier system. The possible disappearance of Hardangerjøkulen has many implications, including impacting Norway’s tourism and hydropower industries. 99 percent of all power production in Norway comes from hydropower, which depends on glaciers’ water storage and seasonal water flow. Glaciers help contribute to water reservoirs used for the hydropower, and Norway itself contains nearly half of the reservoir capacity in Europe. The ice cap is also a popular destination for hiking and glacier walking, as well as for Star Wars fans hoping to visit the location of Hoth scenes. Local residents have remarked on noticeable differences in Hardangerjøkulen. Grete Hovelsrud, a senior researcher at the Nordland Research Institute and vice-president of the Norwegian Scientific Academy for Polar Research, told GlacierHub that the potential loss of Hardangerjøkulen is “very sad.” She added, “It is such a beautiful place. I skied across it last spring, and it really feels like being on top of the world.” Spread the...

Read More

Glacier Retreat Exposes New Breeding Ground for Kelp Gulls in Antarctica

Posted by on Mar 7, 2017 in All Posts, Featured Posts, Science | 0 comments

Glacier Retreat Exposes New Breeding Ground for Kelp Gulls in Antarctica

Spread the News:ShareGlacier retreat caused by anthropogenic climate change is often in the news because of its impacts on sea level rise and shrinking habitats. However, a recent study published by Lee et al. in the Journal of Ethology has found that glacier retreat on King George Island could have a positive impact on kelp gulls, exposing new ground with suitable breeding sites. The kelp gull, Larus dominicanus, breeds on coasts and islands throughout the Southern Hemisphere, as detailed on the IUCN Red List. It has a large range, from subantarctic islands and the Antarctic peninsula to coastal areas of Australia, Africa and South America. Breeding occurs between September and January, with nests usually built on bare soil, rocks or mud in well-vegetated sites. King George Island, the largest of the South Shetland islands, is part of the kelp gull’s range. It can be found off the coast of the Antarctic peninsula and is a nesting ground for seabird species during the summer months. Numerous research stations are located on the island, and its coasts are home to a variety of wildlife, such as elephant and leopard seals, and Adelie and Gentoo penguins. Research has shown that breeding nests of kelp gulls have been recorded in ice-free areas of King George Island since the 1970s. Studies of Gentoo penguin populations  also suggest that rapid glacier retreat could give species that favor ice-free environments a chance to expand their habitats. As such, Lee et al. used a combination of satellite photographs and field observations of kelp gull nests in newly exposed locations to study possible correlations between glacier retreat and nest distribution in the Barton Peninsula on King George Island. Based on eight different satellite images, Lee et al. determined that glaciers on the Barton Peninsula have retreated 200-300m from the coast since 1989, exposing an area of approximately 96,000 square kilometers. Within this area, they found up to 34 kelp gull breeding nests between 2012 and 2016, along with evidence that kelp gulls have been breeding on newly exposed ground for decades. As the glaciers on the Barton peninsula retreat inland, moraine surfaces made up of glacial soil and rock debris are left on the coast. Rocks within these moraines provide shelter from harsh Antarctic coastal winds, reducing the stress to the gulls arising from these winds. This makes the exposed areas more attractive for breeding. Previous studies have suggested that kelp gulls select nest sites in favorable locations with rock and vegetation cover, and kelp gull populations are known to nest in neighboring areas like Potter Peninsula and Admiralty Bay. In this study, kelp gull nests were found between 40-50cm away from the rocks, suggesting that a combination of rocks and vegetation present on the moraines help to create favorable nesting conditions. These gulls probably originated from neighboring kelp gull populations, such as those on King George Island or the Nelson Islands. Continued retreat of glaciers on King George Island could expose larger areas of suitable breeding ground, attracting more gulls from neighboring islands and increasing kelp gull populations. Anthropogenic climate change and glacier retreat have many adverse effects, but research like this sheds light on the ways in which some species might benefit in unexpected ways. Spread the...

Read More

Ice-core Evidence of Copper Smelting 2700 Years Ago

Posted by on Feb 28, 2017 in All Posts, Featured Posts, Science | 0 comments

Ice-core Evidence of Copper Smelting 2700 Years Ago

Spread the News:ShareThe mysterious Moche civilization originated on the northern coast of Peru in 200-800 AD. It was known for its metal work, considered by some to be the most accomplished of any Andean civilization. But were the Moche the first Andean culture to originate copper smelting in South America? While the Moche left comprehensive archaeological evidence of an early sophisticated use of copper, the onset of copper metallurgy is still debated. Some peat-bog records (records of spongy decomposing vegetation) from southern South America demonstrate that copper smelting occurred earlier, around 2000 BC. The question motivated Anja Eichler et al. to launch a massive study of copper emission history. The details of the findings were subsequently published in a paper in Nature. Eichler, an analytical chemistry scientist at the Paul Scherrer Institute in Switzerland, and her team presented a 6500-year copper emission history for the Andean Altiplano based on glacier ice-core records. This is a new methodology applied to trace copper smelting. “Copper is often referred to as the ‘backbone of Andean metallurgy – the mother of all Andean metals,’” Eichler explained to GlacierHub. “However, in contrast to the early copper metallurgy in the Middle East and Europe, very little information existed about its onset in the Andes.” The ice-core they used for their research was drilled at the Illimani Glacier in Bolivia in 1999, nearby sites of the ancient cultures. It provides the first complete history of large-scale copper smelting activities in South America and revealed extensive copper metallurgy. Illimani is the highest mountain in the Cordillera Oriental and the second highest peak in Bolivia. When asked about how she started her research, Eichler told GlacierHub, “I got involved in the project in 2012. At that time, PhD students and a post-doc had already obtained exciting findings and secrets revealed by ice-core records. We started looking at copper and lead as traces from copper and silver mining and smelting in the Andes.” The results of Eichler et al.’s study suggest that the earliest anthropogenic copper pollution occurred between 700–50 BC, during the central Andean Chiripa and Chavin cultures, around 2700 years ago, meaning that copper was produced extensively much earlier than people originally thought. “For the first time, our study provides substantial evidence for extensive copper metallurgy already during these early cultures,” said Eichler. One of the most challenging parts of the research is that copper can show up in the ice core from natural as well as human sources. Eichler’s team accounted for this by calculating the copper Enrichment Factor, which is applied widely to distinguish the natural and anthropogenic origin of metal. The principle of this methodology is to measure the occurrence of different metals. If copper appeared naturally due to wind erosion, it would be found in association with other metals that co-occur with it naturally. However, according to Eichler’s findings, there was only copper in central Andean Chiripa and Chavin cultures, without cerium or the other metals that occur with it in natural deposits. Hence, it was anthropogenic. The Chiripa culture existed from 1400 BC to 850 BC along the southern shore of Lake Titicaca in Bolivia,  near Illimani Glacier. Soon after the Chiripa, came the Chavin culture, a prehistoric civilization that developed in the northern Andean highlands of Peru from 900 BC to 200 BC, named for Chavín de Huantar, the principal archaeological site where their artifacts have been found. Copper objects from these earlier cultures are scanty. The reason why there is no sufficient archaeological evidence of copper usage, according to Eichler, is that very often artifacts were reused by subsequent cultures. “It is known that metallic objects cast by civilizations were typically scavenged from artifacts of their predecessors,”...

Read More

Rock Glaciers Help Protect Species in a Warmer Climate

Posted by on Feb 22, 2017 in Adaptation, Featured Posts, Images, Interviews, Science | 0 comments

Rock Glaciers Help Protect Species in a Warmer Climate

Spread the News:ShareIn a recent study by Duccio Tampucci et al., rock glaciers in the Italian Alps have been shown to host a wide variety of flora and fauna, supporting plant and arthropod species during temporary decadal periods of climatic warming. Certain species that thrive in cold conditions have been prone to high environmental stress during warm climate stages in the past, but given the results of Tampucci’s research, it is now clear that these species may be able to survive in periglacial settings on the edge of existing glaciers. Active rock glaciers, commonly found on the border of larger glaciers and ice sheets, are comprised of coarse debris with intermixed ice or an ice-core. The study has valuable implications on how organisms may respond to changes in temperature, offering a possible explanation for species’ resiliency. Jonathan Anderson, a retired Glacier National Park ranger, spoke to GlacierHub about the importance of periglacial realms in providing a habitat for animals displaced by modern climate change. “In the years spent in and around the park, it’s clear that more and more animals are feeling the impact of climate change and global warming,” he said. “The areas surrounding the larger glaciers are becoming even more important than before and are now home to many of the species that lived on the receded glacier.” In their study, Tampucci and team analyzed abiotic dimensions of active rock glaciers such as ground surface temperature, humidity and soil chemistry, as well as biotic factors related to the species abundance of plants and arthropods. This data was then compared to surrounding iceless regions characterized by large scree slopes (small loose stones covering mountain slopes) as an experimental control for the glaciated landforms of interest. Comparisons between these active scree slopes and rock glaciers revealed similar soil geochemistry, yet colder ground surface temperatures existed on the rocky glaciers. Thus, more cold-adapted species existed on rock glaciers. The distribution of plant and arthropod species was found to be highly variable, dependent upon soil pH and the severity of mountain slope-instability. This variability is because the fraction of coarse debris and quantity of organic matter changes with the landform’s activity, or amount of mass wasting occurring downslope. The study notes that the heterogeneity in landforms in mountainous regions augments the overall biodiversity of the region. Anderson affirmed this idea, noting, “The difference in habitats between glaciated terrain and the surrounding, more vegetated regions is crucial for allowing a wide range of animals to coexist.” This variety of landforms contributes to a wide variety of microclimates in which ecologically diverse organisms can reside in close proximity. Cold-adapted species are likely the first to be affected by region-wide seasonal warming. As temperatures increase, cold-weather habitats are liable to reduce in size and shift to higher altitudinal belts, resulting in species reduction and possible extirpation. Tampucci et al.’s study affirmed the notion that active rock glaciers serve as refugia for cold-adapted species due to the landscape’s microclimate features. The local periglacial environment in the Italian Ortles-Cevedale Massif, for example, was shown to be decoupled from greater regional climate, with sufficient thermal inertia (resistance to temperature change) to support cold-adapted species on a decadal timescale. Despite the conclusive findings that largely affirm previous assumptions about biodiversity in active rock glaciers, the authors carefully point out that the glacier’s ability to serve as refugia for certain species depends entirely on the length of the warm-climate stage, which can potentially last for millennia. Additionally, the macroclimatic context in which the glaciers reside is important and can influence the landform’s thermal inertia, affecting the temporal scale at...

Read More

Research Shows How Climate Change Drives Glacier Retreat

Posted by on Feb 21, 2017 in All Posts, Featured Posts, Science | 0 comments

Research Shows How Climate Change Drives Glacier Retreat

Spread the News:ShareShrinking glaciers are oft-cited examples of the effects of anthropogenic climate change, providing dramatic imagery in different parts of the world. However, this has mostly been based on global aggregates of glacier extent. Differing opinions also exist about the best way to measure glacial change all over the world.  A recent study by Roe et al., published in Nature Geoscience, confirms that climate change has contributed to the shortening of numerous glaciers around the world, but the study is not immune to controversy surroundings the methods used. Using a combination of meteorological data and observations of glacier length, Roe et al. studied the influence of climate on 37 glaciers between 1880 and 2010. The glaciers were selected based on the continuity of length observations and the need for a wide geographical distribution. Glacier mass-balance records are a more direct measure of the effect of climate than glacier length as they measure the difference between the accumulation and ablation (sublimation or melting) of glacier ice. However, most mass-balance records do not extend for more than two decades, contributing to the previous lack of confirmation of the effect of climate change on individual glaciers around the world. The use of observations of glacier length helped to overcome this obstacle, but challenges were still encountered in obtaining long, continuous data sets, particularly for regions such as Asia and South America. In conversation with GlacierHub, Roe shared that many factors can affect the availability of continuous data sets. “For example, the collapse of the Soviet Union led to many glacier observation programs being abandoned,” he stated. An additional challenge arose from the variation in conditions experienced by each glacier. “Every glacier is a unique product of its local climate and landscape,” Roe shared, citing the example of maritime glaciers, which typically experience a large degree of wintertime accumulation variability. “This can mask the signal of a warming that, so far, has mainly impacted the summertime mass balance,” he added. Nevertheless, Roe et al. found that there was at least a 99% chance that a change in climate was needed to account for the retreat of 21 of the glaciers studied. “Even for the least statistically significant (Rabots Glacier in Sweden), there was still an 89% chance that its retreat required a climate change,” Roe said. As glaciers tend to have decadal responses to changes in climate, their retreat since 1880 is likely to be a result of twentieth-century temperature trends. They also act as amplifiers of local climate trends, providing strong signal-to-noise ratios that serve as strong evidence for the effects of anthropogenic climate change. For example, one of the glaciers included in the study, Hintereisferner in the Austrian Alps, retreated 2,800m since 1880, with a standard deviation (a measure of the deviation of values from the mean) of 130m. This value is small compared to the amount of retreat, providing a strong signal of change. “We hope that these results will lead to a stronger scientific consensus about the cause of glacier retreat. The last round of the Intergovernmental Panel on Climate Change was quite timid, concluding only that it was ‘likely’ that a ‘substantial’ part of glacier retreat was due to human-caused climate change,” Roe added. IPCC nomenclature would make it “very likely” (≥90%) that all but one of the glaciers in this study have retreated because of climate change, allowing for stronger conclusions to be drawn. Excitement about the results of this study was shared by Joerg Schaefer, professor at the Lamont-Doherty Earth Observatory: “Under Roe’s lead, the really smart glacier people find ways to explain this strange...

Read More