Posts by Nellie Van Driska

Glacier Retreat Ushers in Arachnids

Posted by on Feb 3, 2016 in All Posts, Featured Posts, Science | 0 comments

Glacier Retreat Ushers in Arachnids

Spread the News:ShareHarvestmen— a spider-like arachnid— are among the first creatures to inhabit land in the wake of glacier retreat, according to a recent study by Sigmund Hågvar and Daniel Flø in the Norwegian Journal of Entomology. The land where glaciers have recently melted is an ideal habitat for creepy-crawlies including spiders, beetles, and other invertebrates. Perhaps surprisingly, these predators are often the first species found on this new land, before herbivores and even plants, although classical theories in ecology state that it should be the other way around. The authors suggest that this reversal is made possible by the availability of two types of prey: insects that fly in from neighboring areas or are carried in by the wind, and midges that hatch in the carbon-rich puddles formed by meltwater from the retreating glaciers. Although Hågvar and Flø mention other species in their article, the study focuses on Mitopus morio, a common spider-like creature in the arachnid family called a harvestman (Opiliones). In America, harvestmen are commonly known as daddy-longlegs. These creatures are both predators and scavengers, since they consume living and dead invertebrates. Having a relatively short life cycle of only one year, young harvestmen hatch during snowmelt in spring and die as mature adults in the fall. Due to their habit of living on newly uncovered land, harvestmen are considered pioneer invertebrates. Harvestmen are found across Norway, but Hågvar and Flø focused on the ones living in areas of glacier retreat, specifically at the Midtdalsbreen Glacier near the mountain village Finse. This glacier drains the eastern portion of the Hardangerjøkulen (Hardanger Ice Cap). The study was conducted in different areas— on land that was uncovered 205 years ago and on more recently uncovered terrain. Hågvar and Flø found that harvestmen greatly outnumbered spiders except at the oldest site, and also outnumbered the total number of carabid beetles located at three of the sites (areas uncovered 40, 160 and 205 years ago). In the land that has been uncovered for three years, harvestmen follow the glacier retreat, living alongside the glacier’s edge. The creatures live on barren ground, meaning there doesn’t need to be any vegetation for them to thrive. The lack of vegetation allows them to move freely, and the empty land is better heated by the sun— an important benefit for these cold-blooded organisms. The study found that the harvestmen thrive best during warm and dry years. Because of the quick establishment of life on what is considered inhospitable land, harvestmen serve as a reminder that nature is remarkable and surprising. Spread the...

Read More

Roundup: Glaciers Lose Old Timber, Gain Dust and Carbon

Posted by on Jan 25, 2016 in All Posts, Featured Posts, News, Roundup, Science | 0 comments

Roundup: Glaciers Lose Old Timber, Gain Dust and Carbon

Spread the News:ShareEfforts to Clean Up Switzerland “A lot of infrastructure in the Alps dilapidates due to a missing use, the absence of owners or an unclear legal status. The infrastructure built in the latter half of the 20th century consists of solidified, impregnated wood, and metal. A recent survey by mountain wilderness has shown that there are – just as an example – over 600 ski lifts without being used, left for decomposition. The aim of this Mountain Wilderness Switzerland’s project is the deconstruction of a decayed hut in commune of Safien, the canton of Graubünden, in an appropriate way (professional recycling and waste disposal). It involves all the necessary work to deconstruct the building: Obtaining the permission to do so, inspecting the material used, organising their appropriate recycling or disposal (where not possible elsewhere), and – finally – the deconstruction. Hence, the local habitat is able to regenerate, biodiversity and the ecosystem will profit from our action in the long term. The spot once covered by the building will be restored to its natural state with long term benefits for plants, animals (and mountaineers).” To learn more about this project click here. Dust from Sahara found in European Alps “Deposition of Sahara dust (SD) particles is a frequent phenomenon in Europe, but little is known about the viability and composition of the bacterial community transported with SD. The goal of this study was to characterize SD-associated bacteria transported to the European Alps, deposited and entrapped in snow. During two distinct events in February and May 2014, SD particles were deposited and promptly covered by falling snow, thus preserving them in distinct ochre layers within the snowpack.” To find out more about the dust from the Sahara that blew all the way to the Alps, click here. Antarctic Glaciers Act as Carbon Sinks “Glacier surface ecosystems, including cryoconite holes and cryolakes, are significant contributors to regional carbon cycles. Incubation experiments to determine the net production (NEP) of organic matter in cryoconite typically have durations of 6-24 hours, and produce a wide range of results, many of which indicate that the system is net heterotrophic. We employ longer term incubations to examine the temporal variation of NEP in cryoconite from the McMurdo Dry Valleys, Antarctica to examine the effect of sediment disturbance on system production, and to understand processes controlling production over the lifetimes of glacier surface ecosystems. The shorter-term incubations have durations of one week and show net heterotrophy. The longer term incubations of approximately one year show net autotrophy, but only after a period of about 40 days (~1000 hours). The control on net organic carbon production is a combination of the rate of diffusion of dissolved inorganic carbon from heterotrophic activity within cryoconite into the water, the rate of carbonate dissolution, and the saturation of carbonate in the water (which is a result of photosynthesis in a closed system). We demonstrate that sediment on glacier surfaces has the potential to accumulate carbon over timescales of months to years.” Spread the...

Read More

Photo Friday: John Singer Sargent’s Glaciers

Posted by on Jan 8, 2016 in All Posts, Art/Culture, Featured Posts, Images | 0 comments

Photo Friday: John Singer Sargent’s Glaciers

Spread the News:ShareThe Metropolitan Museum of Art houses several works by the artist John Singer Sargent. Born in Florence in January 1856 to an American couple, Sargent is known for his landscapes and his portraits. Growing up, the artist traveled extensively around Europe. Several of the drawings below come from a sketchbook Sargent had at age 14 and include images of glaciers and mountains. The book was titled “Splendid Mountain Watercolours” by the author and contains watercolor,  graphite, and black crayon drawings. In 1950 this sketchbook, along with several other drawings and paintings, was donated to the Metropolitan Museum of Art by Singer’s younger sister Violet Sargent Ormond. Currently not on display,  the images can be viewed online at the museum’s website. Piz Albris and Glacier du Paradis, St. Moritz Artist: John Singer Sargent (American, Florence 1856–1925 London) Date: September 21, 1869 Medium: Watercolor and graphite on off-white wove paper Aletsch Glacier from Eggishorn Artist: John Singer Sargent (American, Florence 1856–1925 London) Date: July 10, 1870 Medium: Watercolor and graphite on off-white wove paper Aletsch Glacier from Eggishorn Artist: John Singer Sargent (American, Florence 1856–1925 London) Date: 1870 Medium: Watercolor and graphite on off-white wove paper Rhône Glacier Artist: John Singer Sargent (American, Florence 1856–1925 London) Date: July 15, 1870 Medium: Watercolor and graphite on off-white wove paper Glacier du Brouillard from Below Artist: John Singer Sargent (American, Florence 1856–1925 London) Date: ca. 1906–7 Medium: Graphite on off-white wove paper Glacier on the Ortler Artist: John Singer Sargent (American, Florence 1856–1925 London) Date: September 4, 1873 (?) Medium: Graphite and gouache on gray wove paper Glacier Artist: John Singer Sargent (American, Florence 1856–1925 London) Date: ca. 1908–9 Medium: Watercolor and graphite on white wove paper Spread the...

Read More

Even You Can Contribute to Glacier Research

Posted by on Jan 7, 2016 in All Posts, Featured Posts, Science | 0 comments

Even You Can Contribute to Glacier Research

Spread the News:ShareA new method proposed by Gloria Bordogna and her team allows researchers to make use of data that volunteers have collected about glaciers and other topics. In this way, researchers can avoid errors that can occur when relying on people who lack proper training. In the Age of Technology, the proliferation of smart phones and geo-apps has allowed many people to become actively involved in data collection. They provide information through texts and pictures, many with precise locations. Their efforts contribute to what is called citizen science–broad public participation in data collection for scientific research. Such data can be provided by people who care about glaciers, including tourists, climbers, residents of mountain regions,  and others who are affected by glacier retreat. Datasets of volunteered information can be used by different researchers for different purposes.  Some of those who study glaciers might want to know the location of glacier features, which shift slowly, while others might want to know the date when the first snowfall arrived in a specific portion of the glacier. Still others might want very sharp photographs of glaciers for reproduction. Citizen science creates an opportunity by providing a great deal of free data from volunteers. It also poses a challenge, since the data can be of uneven quality, making it burdensome for researchers to decide one-by-one on the validity of each data entry. At present,  many scientists and policy-makers reject the use of volunteered information, since they believe that it is not reliable.  Research on the assessment of the quality of volunteered data is quite recent, dating back to the early years of this decade. Without systems in place to assess the quality of the data, it can be hard to ensure that information was gathered with the necessary level of scientific accuracy. A recent article in the ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences  introduces credible ways to evaluate Volunteered Geographic Information – another term for citizen science in environmental fields. The lead author Gloria Bordogna, a researcher at the Institute for Electromagnetic Sensing of the Environment of the Italian National Research Council, and her team members  suggest that setting quality levels for data sources as well as minimum acceptance levels and thresholds for specific quality indicators can assure the scientific soundness of volunteered data. In order to set quality  levels, the researchers would decide what factors are important to the credibility of the information. They then establish scores for categories of characteristics of the volunteers and of the organizations to which they belong, as well as characteristics of observational data, whether recorded as images or texts. Specific features include the length of the notes, the precision of the recording of the location and the time, and the length of the field visit, as well as other variables.  In this way, says Bordogna, a researcher can rank incoming data based on quality. The information is numerically ranked. A researcher who wishes to conduct a study based on such data is able to weigh the factors, giving the most important factors higher weight. For example, observations of the location of a glacier front taken from a highly trained volunteer would be more reliable and thus receive more weight than specific observations from a less trusted source, if the researcher believes volunteer background to be an important factor in their study. For a study of the timing of the first snowfall in autumn, a researcher might choose to place greater weight on the date of the collection of information. Data quality concerns come up in other areas of citizen science. There are two major areas where citizen science is well established: ornithology (the Christmas Bird Count from Audubon Society being a major example) and astronomy. For the amateur astronomers...

Read More

Life on the Edge: The Science of Glaciers that Meet Oceans

Posted by on Dec 15, 2015 in All Posts, Featured Posts, Science | 0 comments

Life on the Edge: The Science of Glaciers that Meet Oceans

Spread the News:ShareIn an October 2015 article in Earth & Space Science News, David Holland and Denise Holland suggest steps to increase the understanding of glacier melt to improve projections of sea level rise. IPCC (Intergovernmental Panel on Climate Change) reports have concluded that anthropogenic causes are to blame for glacier retreat in the last century. They predict that increased melt in the present century will rise global sea levels. The authors report that the contribution of the West Antarctic Ice Sheet, alone will change low-lying coastal and communities worldwide and threaten marine ecosystems. They note that the rate of sea level rise will be influenced by a number of factors, including the local shifts in the gravitational pull of land masses, along with changes in water currents, wind patterns, and water temperature and salinity. The rebound of land masses, once the weight of glaciers and ice sheets is removed, will also influence sea levels. The complex nature of the interface between ice sheets and the ocean also creates uncertainty about the future of many of the West Antarctic glaciers, as it is difficult to make predictions of how the ice will react in the future. In one possible scenario, the circulation of warm ocean waters that is currently held off by continued cold meltwater runoff from Antarctica could grow larger, and the cold water barrier would no longer block it from teaching the continent. The warm water would thus be able to make direct contact with the underside of the glacier and warm it from below, greatly increasing the glacier melt. Holland and Holland note that many problems with predicting the effects of West Antarctic glacier melt stem from a deficit of data. Though satellites are able to measure glacier volume, they are unable to observe the water resting underneath glaciers or the land mass upon which some glaciers rest. Another area of difficulty in predicting the melting of the West Antarctic glacier involves a shortfall in scientific understanding of calving—the process in which the section of a glacier front breaks and falls into the ocean. Scientists compare the difficulties of constructing models of calving to the challenges of predicting earthquakes. They remain unable to make long-term predictions about when they will occur. Holland and Holland state that in order to create accurate predictions for the contributions of the West Antarctic Ice Sheet to sea level rise, scientists need to couple glacier and ocean models. Currently there is little cooperation between glaciologists and oceanographers, even though both work on sea level rise since each uses separate models specific to their disciplines. To address this problem Holland and Holland report, the World Climate Research Programme (WCRP) has established a project, Climate and Cryosphere (CliC). This project held a meeting in October 2014, in which the Marine Ice Sheet–Ocean Model Intercomparison Project (MISOMIP) was established. The project seeks to draw on the efforts glaciological and oceanographic modelers. The participants in the project work together to create coupled and interactive glacier-ocean models. The goal is to follow this suite of glacier-ocean models with regional simulations of specific outlet glaciers such as those found in West Antarctica. Holland and Holland say that scientists, by coupling glacier and ocean models, can greatly improve the accuracy of future sea level rise projections attributed to the West Antarctic Ice Sheet and its outlet glaciers. Because of the increasing threat of sea level rise to communities around the world, the accuracy of such projections is of great value. It is to be hoped that this importance will support efforts to produce these projections, which require increased...

Read More