Posts by Sarah Kai Zhen Toh

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...

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Photo Friday: Jotunheimen National Park

Posted by on Mar 3, 2017 in All Posts, Featured Posts, Images, Tourism | 0 comments

Photo Friday: Jotunheimen National Park

Spread the News:ShareJotunheimen National Park in southern Norway contains more than 250 mountains, including Norway’s two tallest peaks, Galdhøpiggen (2469 metres above sea level) and Glittertind (2465 metres above sea level). Its name means “Home of the Giants” and it is located within the Scandinavian Mountains. Its glacier-carved landscape is a popular camping, hiking and fishing location, as the park’s official website explains. With up to 60 glaciers, the spectacular scenery and diverse wildlife – including reindeer, elk, deer, wolverine and lynx – make it a popular tourist destination.               The park attracts thousands of people every year, ranging from those looking for easier hikes, to those seeking thrilling adventures, as can be seen in this video.     Check out more photos of Jotunheimen National Park here.   Spread the...

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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...

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Roundup: Chemistry, Dams and Elevations

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

Roundup: Chemistry, Dams and Elevations

Spread the News:ShareRoundup: Meltwater Chemistry, Hydroelectric Dams and Glacier Elevation   Diurnal Changes in the Chemistry of Glacier Meltwater From Chemosphere: “An evaluation of glacial meltwater chemistry is needed under recent dramatic glacier melting when water resources might be significantly impacted. This study investigated trace elements variation in the meltwater stream, and its related aquatic environmental information, at the Laohugou glacier basin (4260 m a.s.l.) at a remote location in northeast Tibetan Plateau… Results showed evident elements spatial difference on the glacier surface meltwater, as most of the elements showed increased concentration at the terminus compared to higher elevations sites… The accelerated diurnal and temporal snow-ice melting (with high runoff level) were correlated to increased elemental concentration, pH, EF (enrichment factor,the minimum factor by which the weight percent of mineral in is greater than the average occurrence of that mineral in the Earth’s crust) and elemental change mode, and thus this work is of great importance for evaluating the impacts of accelerated glacier melting to meltwater chemistry and downstream ecosystem in the northeast Tibetan Plateau.” Read more about it here.   Locals Oppose Dam Construction in the North Western Himalayas From the International Journal of Interdisciplinary and Multidisciplinary Studies: “Since early 1970s dam development projects witnessed severe opposition in India. The remote tribal groups and rural population rejected the idea of large scale displacement, land alienation, economic insecurity and endless suffering that came along with ‘development’ projects… In recent past the construction of hydroelectricity projects has faced severe opposition in the tribal regions in Himachal Pradesh. The locals in Kinnaur are facing numerous socio-economic and environmental consequences of these constructions in fragile Himalayan ecology… More than 30 hydro projects proposed in Lahaul & Spiti are also being challenged by the people in Chenab valley… The paper summarises the ongoing struggle and diverse implications added with climate change in the rural structures.” Read more about local opposition to these projects here.   Uneven Changes in Ice Sheet Elevation in West Antarctica From Geophysical Research Letters: “We combine measurements acquired by five satellite altimeter missions to obtain an uninterrupted record of ice sheet elevation change over the Amundsen Sea Embayment, West Antarctica, since 1992… Surface lowering has spread slowest (<6 km/yr) along the Pope, Smith, and Kohler (PSK) Glaciers, due to their small extent. Pine Island Glacier (PIG) is characterized by a continuous inland spreading of surface lowering, notably fast at rates of 13 to 15 km/yr along tributaries draining the southeastern lobe, possibly due to basal conditions or tributary geometry… Ice-dynamical imbalance across the sector has therefore been uneven during the satellite record.” Read more about the changes in ice sheet elevation here. Spread the...

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Large Populations of Jellyfish Found in West Antarctic Fjords

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

Large Populations of Jellyfish Found in West Antarctic Fjords

Spread the News:ShareJellyfish can often be found in abundance in communities living in the benthic boundary layer, the water directly above the seafloor. The cold high-latitude systems surrounding the poles are no exception. A recent study published by Grange et al. in PLOS One reports on unusually high abundances of Ptychogastria polaris Allman in fjords in the glacier-rich West Antarctic Peninsula. P. polaris is a cold-water species that has been found in a variety of locations in the high latitudes of the Northern and Southern Hemisphere. It was first described in 1878 by A.G. Allman, based on a single specimen collected off East Greenland. Since then, it has been found to have a patchy, circumpolar distribution in Arctic and sub-Arctic areas, while only a few specimens have been documented in Antarctica. Between January and February 2010, Grange et al. conducted surveys of benthic megafauna in three subpolar fjords along the West Antarctic Peninsula – Andvord, Flandres and Barilari Bays. “Arctic fjords are heavily impacted by meltwater inputs and sedimentation that yield low seafloor abundance and biodiversity, so we wanted to see if that was also the case in the Antarctic,” Grange explained to GlacierHub. They analyzed live specimens, conducted photosurveys of the seafloor, and measured background environmental conditions to gain a better understanding of the distribution of P. polaris. Molecular analysis and DNA sequencing were also used to confirm the species identifications of specimens. P. polaris was found to be a common component of seafloor communities in both Andvord and Flandres Bays, but was absent in Barilari Bay. “We noted the conspicuous occurrence and high abundance of P. polaris,” Grange stated. She noted that the densities in these locations up to 400 times higher than previously recorded in northeast Greenland and the Barents Sea. These levels could be a result of higher productivity within the benthic boundary layer in the fjords. Reasons for this productivity include higher nutrient inputs that occur when the remains of sustained phytoplankton blooms sink to the ocean floor, or when macroalgae (large-celled algae such as seaweed) cascade down fjord walls, providing food sources that support larger populations of P. polaris. In addition, migrating Antarctic krill and baleen whales can transport nutrients to these regions in the form of feces and krill carcasses. P. polaris was also observed in smaller densities in the water column in all three bays. Although this species is known to undertake short swimming expeditions of up to fifteen seconds, these observations were relatively frequent, suggesting that P. polaris in Antarctica may behave differently from counterparts in Arctic and boreal environments. This could be driven by feeding opportunities, localized regions of turbulent mixing at the seafloor, or distinct circulation patterns, but further research is needed, according to Grange et al.   Both findings also suggest that P. polaris may form a link between pelagic (open water) and benthic food-webs within the region. For example, they may play an important role as ecological predators of benthic organisms like zooplankton, while providing food inputs to the seafloor when they die. This contributes to nutrient and energy transfers between the ecosystems, helping to integrate the dynamics of food-webs in different layers of the marine environment. This study was also the first to provide a phylogenetic (evolutionary history and relationship) analysis of the Ptychogastriidae family, to which P. polaris belongs. “We found relatively large genetic differentiation among P. polaris compared to that for other hydrozoan (the larger taxonomic class of organisms) species,” Grange explained. “This discovery may suggest the species contain multiple cryptic species (different species with identical physical forms) or an unusually high degree of sequence...

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