Posts Tagged "antarctica"

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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Roundup: Penguins, Antarctica, and Geological Games

Posted by on Feb 27, 2017 in All Posts, Featured Posts, Roundup | 0 comments

Roundup: Penguins, Antarctica, and Geological Games

Spread the News:ShareRoundup: Penguins, Antartica, and Geology Board Games Looking for New Emperor Penguin Colonies From ScienceDirect: “Knowledge about the abundance and distribution of the emperor penguin is far from complete despite recent information from satellites. When exploring the locations where emperor penguins breed, it is apparent that their distribution is circumpolar, but with a few gaps between known colonies. The purpose of this paper is therefore to identify those remaining areas where emperor penguins might possibly breed. Using the locations of emperor penguin breeding colonies, we calculated the separation distance between each pair of geographically adjacent colonies. Based on mean separation distances between colonies following a circumpolar distribution, and known foraging ranges, we suggest that there may yet be six undiscovered breeding locations with half of these in Eastern and the remainder in Western Antarctica.” Read more about it here.   Patterns of Plant Succession in Antarctica From Infona: “Maritime Antarctica is severely affected by climate change and accelerating glacier retreat forming temporal gradients of soil development. Successional patterns of soil development and plant succession in the region are largely unknown, as are the feedback mechanisms between both processes. Here we identify three temporal gradients representing horizontal and vertical glacier retreat, as well as formation of raised beaches due to isostatic uplift, and describe soil formation and plant succession along them.” Learn more about it here.   19th Century Geology Board Game From Geology Today: “Wonders of Nature in each Quarter of the World was an early nineteenth century educational board game designed to teach children about some of the natural wonders of the world, such as volcanoes. The game was produced at a time of advances in geological thinking and geographical expeditions and this study places such changes and events within the context of the pastime, and presents an interesting window on the way geology was perceived almost two centuries ago.” Learn more here. Spread the...

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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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Iceberg Killing Fields Threaten Carbon Cycling

Posted by on Nov 24, 2016 in Adaptation, All Posts, Featured Posts, Science | 0 comments

Iceberg Killing Fields Threaten Carbon Cycling

Spread the News:ShareThe vast, unpopulated landscape of Ryder Bay, West Antarctica gives the impression of complete isolation. However, despite its barren, cold exterior, Antarctica plays an important role in regulating the Earth’s climate system. Located along the southeast coast of Adelaide Island, Ryder Bay is helping mitigate impacts of climate change by removing greenhouse gases from the atmosphere to the ocean, where these gases can remain for centuries. This repurposing is being done by benthos, microorganisms like phytoplankton that bloom during summer months and provide critical food supplies that maintain the marine ecosystem in Ryder Bay. Quietly residing on the floor of the Southern Ocean, benthos are encountering increased risks due to a changing climate. While the potential carbon recycling capacity of local marine ecosystems remains significant, the collapsing glaciers and ice shelves in Ryder Bay may threaten this productivity, according to an article in the journal of Global Change Biology. The carbon recycling process in the marine ecosystems is one of the strongest mechanisms helping to reduce the impacts associated with historic carbon emissions. Located along the continental shelf, benthos absorb carbon through photosynthesis; when these organisms die and fall to the ocean floor, this carbon is then stored in sediments. Undisturbed, the ocean can help thwart warming due to an enhanced greenhouse effect by removing carbon from the atmosphere and storing it in the ocean. David Barnes, a Marine Benthic Ecologist with the British Antarctic Survey and an author of the article,  pointed out to GlacierHub, “Trends in carbon accumulation and immobilization, which occur on the seabed, could be considered most important as these involve long-term carbon storage. [These trends] are perhaps the largest negative feedback on climate change.” However, because of shifting land dynamics, the increased frequency of iceberg creation is having a direct impact on the ability of the marine ecosystems to recycle carbon. As the Earth continues to warm, ice sheets and glaciers in Antarctica advance and become thinner, causing cracks and crevasses to form. These fissures, in turn, lead to unpredictable, large-scale breaks which create icebergs that discharge into the ocean. At the time of detachment, ice formations hit the ocean floor, obliterating the marine ecosystems below. Icebergs can continue to impact the benthos as they travel on the ocean. Barnes described this problem to GlacierHub:  “At places like Ryder Bay, it would be very difficult to provide forecasting, because it is very frequent and a bit chaotic. The direction an iceberg travels depends on its shape, how deep its keel is, wind, and current speed. A smaller iceberg with a vertically flat side above water will easily catch wind like a sail, so if the wind is strong it will mainly follow wind direction. Conversely, a bigger iceberg with a deep vertical flat side might more easily catch current.” According to NOAA, these icebergs— typically rising 5 meters above the sea surface and covering 500 square meters in area— are large enough to inflict significant destruction. Dubbed “iceberg killing fields,” these places of impact can cause extensive disruption to the beneficial marine ecosystems along the ocean floor. David Barnes works with the British Antarctic Survey to study the iceberg killing fields and measure the impact of iceberg-seabed collisions on marine ecosystems. The British Antarctic Survey has been monitoring the local marine ecosystems in Ryder Bay due to their sensitivity to environmental change and the surprisingly large role benthos play in removing carbon from the atmosphere. According to the report, “The scour monitoring has probably become the longest continuously running direct measurement of disturbance on the seabed anywhere in the world.” With roughly 93 percent of carbon...

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Small Particles Have Big Impact on Glacial Health

Posted by on Nov 16, 2016 in All Posts, Featured Posts, News, Science | 0 comments

Small Particles Have Big Impact on Glacial Health

Spread the News:ShareA recent study by Heidi Smith et al. in the desolate McMurdo Dry Valleys of Antarctica has shown that microbial life in biofilms is present across a large part of the region’s ice, suggesting that the stability of polar ice can be influenced by even the smallest of organisms. Biofilms—thin, slimy bacterial layers that can adhere to a surface—were discovered in conjunction with the windblown dust that accumulates on snow and ice called cryoconite. The research found that a combination of biofilms and cryoconite is capable of enhancing the rate of glacial melting, meaning that the planet may be more vulnerable to sea level rise than previously imagined. As an important component in the planet’s hydrological and carbon cycles, glacial melting affects sea levels and the chemistry of our oceans. This meltwater enhances the movement of fluids from terrestrial environments to oceans, as well as the transport of nutrients to aquatic ecosystems. In the McMurdo Dry Valleys, the activity of microorganisms on the glacier surface enables the accumulation of organic matter on minerals found in the ice’s dusty cryoconite layers. This relationship results in the darkening of ice over time, making it less efficient at reflecting incoming sunlight than it would be normally. As most of Antarctica’s ice lies atop the continental landmass,  increased melting at the Earth’s southern pole may lead to an appreciable rise in global sea levels. Prior research in alpine glacial environments and on the Greenland Ice Sheet (Langford et al. 2010) established a correlation between biofilm development and the darkening of cryoconite particles, pointing towards the synergistic possibility of biologically enhanced rates of melting. Until the recent publication of key research by Heidi Smith et al., the role of biofilms in Antarctica was largely unknown. In conversation with GlacierHub, Smith stated that “the role of biofilms in different glacial locations has not been explored.” She added “due to differences in environmental pressures (temperature extremes, nutrient availability, levels of UV radiation, and rates of flushing), it is possible that the role of biofilms in glacial surface processes varies by location.” Smith’s team was able to establish the precedence of biofilms at extreme southern latitudes in their research and also contributed to the larger body of scientific evidence supporting the role of microbes in influencing reflectivity, otherwise known as albedo, of glaciers. Smith and her research colleagues employed a variety of methods to investigate the interactions between the biological and mineralogical components of Antarctic ice. Microbial species were identified in the lab via pyrosequencing (which determines the order of nucleotides in DNA by detecting the release of the pyrophosphate ion) as well as epifluorescent microscopy (which utilizes a compound microscope equipped with a high-intensity light source). The team’s research yielded four unique bacterial components in biofilms found in cryoconite holes. Interestingly, Smith told GlacierHub that “while some organisms identified in this study have also been found in cryoconite holes from the Greenland Ice sheet, the relative abundance of individual organisms in each of these locations appears to be geographically distinct.” The primary region for fieldwork and sampling for the study was an ice-lidded cryoconite hole on the Canada Glacier, located near Victoria Land, Antarctica. When asked about why the team chose to work in this isolated region, Smith replied: “There are previous studies from this region that have focused on cryoconite hole geochemistry, rates of microbial activity and microbial assemblage composition; therefore, we could place samples from this study into a larger framework.” Following fieldwork on the glacier, subsequent laboratory analysis showed that enriched levels of nitrogen and carbon isotopes were present when Bacteroidetes...

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