Off with the Wind: The Reproduction Story of Antarctic Lichens

How do organisms begin new life at the bare surfaces exposed by glacier retreat? A team of researchers from the Czech Republic recently published a paper on the spread of one organism, a lichen, across James Ross Island near the Antarctic Peninsula. The study found that lichens can disperse over long distances, likely by means of aerial transport. Increasing warming trends on James Ross Island will likely result in more deglaciation, providing species like lichens with the opportunity to colonize new areas.

Usnea sp Lichen on James Ross Island (Source: Elster Josef)
Usnea sp Lichen on James Ross Island (Source: Elster Josef).

There has previously been considerable debate on the reproductive and dispersal mechanisms of lichens, especially in the polar regions. The study’s findings on lichen reproduction is promising, given the important role lichens play as primary successors, contributing to soil development and the establishment of ecosystems with greater biomass and biodiversity. Combining an alga and a fungus, the lichen can grow on almost any surface, from sea level or high altitudes to the side of trees or on rocks. Lichens are also able to reproduce both sexually (through propagules, which are small, vegetative structures that get detached from the parent plant) or asexually (mini-lichens), and are transported by wind, sea currents or birds.

GlacierHub spoke with lead author Elster Josef from the Center of Polar Ecology about the study. He asserts that one of the most distinctive features of James Ross Island is the island’s so-called volcanic mesas, which are favorable locations for biomass growth. Volcanic mesas originate from superimposed subglacial volcanic eruptions and are characterized by a relatively flat highland with steep edges. Usnea sp., a lichen commonly known as the old man’s beard, is the most important lichen in this system. “It produces dense carpets in the oldest volcanic mesas. This species has many advantages in respect of dry local climate,” Josef said.

Overview of James Ross Island with its volcanic mesas (Source: Elster Josef)
Overview of James Ross Island with its volcanic mesas (Source: Elster Josef).

There is a clear gradient of lichen cover and diversity from north to south on James Ross Island, according to Josef. One important question of the research was how this lichen carpet advances with glacier retreat. Josef stated that his team was able to successfully develop a non-invasive method to measure lichen carpet diversity and biomass. Traps in the form of petri dishes fixed to rock surfaces with stick tape were the simplest and most effective way for the team to measure lichen dispersal across the island, according to Josef. A total of 100 traps were placed during the summer season of January/February 2008 and left exposed for a year. In the end, only 60 traps were found due to snow cover and strong wind disturbance.

For the Antarctic lichens, vegetative asexual reproduction was found to be more dominant due to environmental stresses. While the old man’s beard and the Leptogium fungus (Leptogium puberulum) were the two most common local species on the island, their frequency of occurrence in the traps was unrelated to local species dominance. Long-distance dispersal of vegetative parts occurs more frequently on the larger scale as a result of wind conditions.

Lichen Spore/Fragment trap designed for the research using sticky tape in a petri dish(Source: Elster Josef)
Lichen Spore/Fragment trap designed for the research using sticky tape in a petri dish (Source: Elster Josef).

Surface wind speeds on the mesas are often higher than 6m/s (roughly 12 mi/hr) on average, with extremes reaching up to 30m/s (60 mi/hr). Larger amounts of lichen spores and fragments were found in the traps located along the prevailing wind direction. Overall, the highest occurring species in the traps were of foliose and fruticose growth types, which favored wind dispersals.

The main difficulty of the research method was that the dispersal of lichens is influenced by many abiotic and also biotic factors, according to Josef. These include distance from glaciers and elevation to existing lichen diversity and cover on site. The method was also limited because it did not involve measurements of what is viably ready (in-situ) to start growth and only measured what types of lichens were dispersed.

A team member collecting the samples on the sticky tape after the trap was exposed for a year (Source: Elster Josef)
A team member collecting the samples on the sticky tape after the trap was exposed for a year (Source: Elster Josef).

The greatest confirmation to the team’s hypothesis was the strong positive correlation between the size of clast, or rock fragment, and the dispersed species assembly. Clast size is determined based on the average diameter of rocks in the area. Often, areas with larger clast size are characterized by a thriving diversity of lichen communities. They represent more stable locations for growth since larger stones shield the newly-trapped lichen fragments from being uprooted by the wind again.

Still, according to Josef, lichen development is rather rare despite the large numbers of reproductive fragments dispersed. The growth of a lichen community is a long-term process, and Josef hopes to continue to evaluate the reaction of lichens to climate change in polar regions to shed light on the colonization mechanism of pioneer species in newly-exposed surfaces.

Photo Friday: Vicuñas in the Glaciers of the Andes

This Photo Friday, take a glimpse of the beautiful vicuñas and their habitats. Vicuñas are part of the camelids family and a wild relative of alpacas and llamas. Found only in South America, they usually roam the high alpine and chilly glacier regions of the Andes Mountains. The fur of vicuñas can be made into extremely fine wool and transformed into luxurious merchandise highly sought after globally. Yet, vicuñas can only be shaved once every three years. In fact, only Inca royalty were permitted to wear vicuña fur 500 years ago.

Vicuñas were so heavily hunted for their fur that they were declared an endangered species in 1974. Although there are an estimated 350,000 vicuñas left in South America, conservation programs such as Grupo Especialista en Camelidos Sudamericanos (GECS) are still present to protect the animals from poaching and loss of habitats due to glacier melt. Vicuñas are the national animal of Peru.

A close-up shot of a vicuña (Source: Rosario Nanetti/ Pinterest).

 

Vicunas at Chungara Lake in Chile, with the glacier-covered Volcan Sajama in the background (Source: Luca Galuzzi/Flickr).

 

A vicuna spotted near Chimborazo Volcano and glaciers in Ecuador (Source: David Torres Costales/Flickr).

 

Vicuñas seen in Torres del Paine National Park, located by the Patagonia glacier (Source: Escape/Pinterest).

Video of the Week: Artificial Glaciers for Himalayan Desert

This week, take a glimpse at how an engineer built artificial glaciers during the winter season in the high desert of the Himalaya. Named ice stupa glaciers, the meltwater during spring hydrates the barren desert fields to facilitate agriculture activities in the region. Despite enduring cold winter temperatures of below -30 degrees Celsius, the area receives less than 100 mm of precipitation annually. Cropping is generally most favorable in the spring months of April and May, but these are also the region’s driest months. When meltwater from natural glaciers arrives in mid-June, it usually comes in the form of flash floods, hugely impeding agriculture.

The concept of the ice stupa glaciers involves freezing stream water from the nearby Indus River in vertical columns to form huge ice towers between 30 to 50 meters. The project won the Rolex Award for Enterprise, and further support can be provided here.

Read more glacier news at GlacierHub:

A New Discovery: Why and How Glaciers Flow?

Is the Martian Hypanis a Glacier? A New Study Says No

Loss of Contact with Ridges Below Likely Triggered Pine Island Glacier’s Retreat

Yoga for Peace: Siachen Glacier’s International Yoga Day 2018

On June 21, Indian army personnel guarding the Siachen glacier located at a disputed Himalayan border between India and Pakistan commemorated International Yoga Day. The event, led by Sadhguru, a prominent Indian yogi, entailed 250 soldiers gathering at daybreak to seek their inner peace via yoga.

Despite freezing temperatures of -4 degrees Celsius, the soldiers got atop their yoga mats to perform pranayama, gentle asanas and meditation, which are all exercises that are currently part of their daily routine to fend against various diseases such as high altitude sickness, hypoxia, pulmonary odema and the psychological stresses that can be caused by isolation and fatigue.

On a typical day, the Siachen region is far from peaceful. The glacier is a contended area between Pakistan and India. Intermittent wars have been fought in the region since 1984, and the site remains the highest battleground in the world at over 20,000 feet. Although a cease-fire agreement was established in 2003, both countries still persist with permanent military presences.

In fact, the move of practicing yoga at Siachen is not as innocent as it seems. GlacierHub spoke to professor Joseph Alter from the University of Pittsburgh, who has extensively studied the role of yoga in religion and politics. On the yoga practice session at Siachen, he said, “This strikes me as a good example of how the performance of yoga is used to make powerful political statements about nationalism and heritage.”

Alter further explained, “The thing about yoga is that it is a global phenomenon, but also a phenomenon that many people have come to regard as standing for the pure essence of Indian cultural heritage.” India is a largely Hindu country, and yoga has been frequently associated with Indian identity despite the participation of people of other religions including Muslims. As Pakistan has a Muslim majority, the act of performing yoga at a disputed zone could serve to accentuate the contrast between the two countries in the region, with yoga more widely associated with India.

Over the years, India has been working to promote yoga and its cultural significance across the world. In fact, the idea of an International Yoga Day was first proposed by Indian Prime Minister Narendra Modi in front of the United Nations General Assembly in 2014. As of 2013, the Hindu Times estimated the presence of over 200 million yoga practitioners worldwide, with over 16 million in the United States alone.

Having religious origins, yoga is meditative and seeks to help people connect with their spiritual core. However, contemporary non-religious practitioners view it as more physical. “Yoga has been made use of in various institutionalized settings to promote single-minded, single-point focus, and to help people who are otherwise agitated to relax,” Alter continued. “Besides the army, it is used in prisons, schools, and by corporations to manage employees for team work and greater productivity.”

Indian military personnel practicing yoga for International Yoga Day 2018 (Source: Sadhguru/Twitter).

The theme for International Yoga Day 2018 was “Yoga for Peace.” When asked whether practicing yoga in the military setting in Siachen could be used to promote peace, Alter indicated it could go both ways.

“It all depends on how energy is channeled, and by whom,” he said. “Yoga is basically harmless, if not also fundamentally good for you in that it both calms and energizes the mind and the body. However, it is very ironic that the performance of yoga by a large group of soldiers is so categorically at odds with the pre-modern prescriptions that say yoga must be practiced alone, in repose and in isolation from society.”

In recent years, armies including the United States have incorporated yoga in their military fitness regimes. It has come to be closely associated with promoting physical fitness and flexibility, skills that also enhance combat readiness.

To have army men performing yoga in the mountains— where many people imagine yogic sages to have gone to retreat from the world— produces a kind of revitalized, muscular, militant yoga, Alter added. After all, the ruggedness of the glacier setting serves to demonstrate the commitment of the soldiers to defending their nation. Such hardiness and strength of a soldier are also emphasized in Indian culture through iconic literature texts such as the Mahabharata.

Mahabharata, which can be translated as the great tale of the Bhārata dynasty, is an epic of ancient India. Its prominence in Indian culture can be compared to that of Shakespeare in the West. The 200,000 verses describe the fictional Kurukṣetra War, but the text also holds philosophical and religious discussions such as a discussion about the four goals of life.

“Not coincidentally at all, the figure of Sadhguru reinforces an imagined link back through time to the glory days of the Mahabharata,” Alter said. Indian yogi Sadhguru has praised the story and characters of Mahabharat, even encouraging people to “live the story [for] it will become a spiritual process for us.”

Today, modern yoga is no less political than anything else such as language, religion or water rights. Politics comes in to play when the nationalism of cultural heritage comes up against the cultural dynamics of globalization, Alter explained. Millions took part in International Yoga Day celebrations this year from Times Square to Amsterdam, and there remain historical, religious and cultural underpinnings of practicing the sport everywhere.

Roundup: Iceland Eruption, Black Flies and Black Carbon

Insights into Bárðarbunga Volcano from the Holuhraun Rifting Event

From Advancing Earth and Space Science: “The two weeklong rifting event at Bárðarbunga volcano in 2014 led to the Holuhraun eruption, which produced 1.5 km3 of lava and was the largest in Iceland in over 200 years. Predicting when and where an intrusion will lead to eruption requires detailed knowledge of the underlying stress field… Modeling of the 2014 Bárðarbunga rifting event therefore not only yields insights into the event but also provides a window into undetected volcanic activity in the past.”

Find out more about the geology behind one of the biggest eruptions on a glacier-covered volcano here.

Holuhraun eruption
Holuhraun eruption (Source: Iceland/Pinterest).

 

Distribution of Black Flies in the Andes During El Niño

From ScienceDirect: “Vector ecology is a key factor in understanding the transmission of disease agents, with each species having an optimal range of environmental requirements. Scarce data, however, are available for how interactions of local and broad-scale climate phenomena, such as seasonality and the El Niño Southern Oscillation (ENSO), affect simuliids (Black Flies). We, therefore, conducted an exploratory study to examine distribution patterns of species of Simuliidae along an elevational gradient of the Otún River in the Colombian Andes, encompassing four ecoregions. Species richness and occurrence in each ecoregion were influenced by elevation, seasonality, and primarily the warm El Niño and cool La Niña phases of the ENSO. The degree of change differed among ecoregions and was related to physicochemical factors, mainly with stream discharge.”

Read more about the distribution of black flies based on the climatology of the Andes Mountains here.

Black Fly
Simuliids/Black Flies (Source: Kallerna/M.I.I.A).

 

Glacier Retreat of the Tian Shan and Impact on Urban Growth

From IOP Earth and Environmental Science: “The retreat of mountain glaciers, notably in high Asia, provides evidence for the rise of global temperature. Analyses of satellite remote sensing data combined with the ground observations reveal a 37.5% decline of glaciered area from 1989 to 2014 in No.1 Glacier, the headwaters of the Urumqi River basin, Chinese Tian Shan, which could be linked to increased summer melting. We suggest that the decline of glacier area is driven primarily by summer melting and, possibly, linked to the combined effects of the global rise in temperatures and black carbon/CO2 emission from coal-fired power plants, cement plants and petroleum chemical plants from the nearby Urumqi regions.”

Discover more about the glacier melting in Tian Shan Mountains and its impacts here.

Number One Glacier in the mountains outside Urumqi, Xinjiang, China (Source: Remko Tanis/Flickr).

Photo Friday: Environmental Monitoring of Svalbard and Jan Mayen

The Environmental Monitoring of Svalbard and Jan Mayen (MOSJ) is an umbrella program that collects and analyzes environmental data in the arctic regions of Svalbard and Jan Mayen. Some data of interest include the extent and thickness of sea ice around Svalbard, Fram Strait and the Barents Sea; temperature and salinity of the water transported around Svalbard via the West Spitsbergen Current; ocean acidification; and local sea level changes. This Photo Friday, take a glimpse of the MOSJ researchers in action as they collect measurements in the field. Read their full report and findings here.

 

Sea Ice around Svalbard (Source: Angelika H.H. Renner, 2011).
Sea Ice around Svalbard (Source: Angelika H.H. Renner).

 

The West Spitsbergen Current (WSC) represents the northernmost reaches of the North Atlantic Current system. Warm, saline, subtropical waters are carried across the North Atlantic and along the eastern side of the Nordic seas to end up at Fram Strait. The amount of sea ice flowing through the Fram Strait varies annually, which impacts the strength of the thermohaline circulation and thus, global climate.

 

Branches of the West Spitsbergen Current (in red) and the Arctic Ocean Outflow (in blue) in Fram Strait (Source: Renner et al)
Branches of the West Spitsbergen Current (in red) and the Arctic Ocean Outflow (in blue) in Fram Strait (Source: Renner et al).

 

Collecting Conductivity, Temperature and Depth (CTD) measurements from the West Spitsbergen Current from a cruise (Source: Paul A. Dodd)
Collecting Conductivity, Temperature and Depth (CTD) measurements from the West Spitsbergen Current from a cruise (Source: Paul A. Dodd).

 

A researcher collecting newly-formed sea ice from Tempelfjorden, Svalbard (Source: Jago Wallenschus)
A researcher collect newly-formed sea ice from Tempelfjorden, Svalbard (Source: Jago Wallenschus).

 

Researchers collecting samples from sea ice from Kongsfjorden, Svalbard (Source: S. Gerland)
Researchers collect samples from sea ice from Kongsfjorden, Svalbard (Source: S. Gerland).

Observing Glacier Calving through Time-Lapse Imagery and Surface Water Waves

A recent paper published in the Journal of Glaciology explores how a team of researchers studied waves in a Patagonian lake to detect glacier calving events at Glaciar Perito Moreno. Calving events occur when an iceberg detaches from the glacier front. Such events produce waves of different magnitudes as the glacier discharges into the ocean or an adjacent lake.

The paper’s lead author, Masahiro Minowa, told GlacierHub that while calving plays a key role in the recent rapid retreat of glaciers around the world, many processes related to calving are still poorly understood because direct observations are scarce and challenging to obtain.

An example of a glacier calving event producing surface tsunami waves (Source: Masahiro Minowa)
An example of a glacier calving event producing surface tsunami waves (Source: Masahiro Minowa).

Minowa and his team employed a creative methodology to observe calving events at a distance. Employing four time-lapse cameras and a water pressure sensor, they conducted fieldwork in three separate time periods, roughly one week to three weeks long between 2013 and 2016. 420 events were noted within this relatively short period of time. They also estimated the calving volume using the time-lapse images and maximum wave amplitude.

“We did our field works twice in summer and once in winter so that we could observe the seasonality of calving activity. We also wanted to understand mechanisms driving calving if there are any,” Minowa said.

The researchers categorized the time-lapse images by separating calving events into four groups: 1) Topple, an ice tower toppling into the lake; 2) Drop, an ice block dropping into the water; 3) Serac, a small piece of serac slipping down to the lake; and 4) Subaqueous, an underwater iceberg detachment that floats up to the lake surface.

Illustration of the most common calving types at the study site (Source: Minowa et al)
Illustration of the most common calving types at the study site (Source: Minowa et al).

These images were then scrutinized in great detail. For example, Topple and Drop events were distinguished based on whether crevasse widening occurred; while Subaqueous was differentiated from other subaerial events by noting a relatively large single iceberg appearing without any geometrical change on the glacier front and a lack of sediment inclusion on the surface.

The surface wave profiles corresponding to the events were also examined. Their signals were more complex, making it difficult in some cases to distinguish events on the basis of wave profiles alone.

“Initially, we expected a clear difference in wave frequencies between subaqueous and subaerial events. While we could see some difference in frequencies, we are unsure if this is a result of different calving style,” Minowa explained. Wave frequencies also vary based on the relative location of the event to the sensor, even if it is the same calving style. A larger sample of cases is thus required to confirm the wave patterns associated with different calving events.

However, Minowa stressed the importance of choosing a strategic location for the water pressure sensor, which vastly affects the results and findings of a glacier calving study. He warned that a problem may arise from the instrument’s location. “Since waves’ amplitude decay with distance, you will not be able to detect all of the calving events if you place the sensors too far. So, you need to be close enough to the glacier, and you will easily detect many of them,” he said. Yet, this might limit the scope of the area studied, requiring a balanced consideration.

Examples of the time-lapse camera images (Source: Minowa et al)
Examples of the time-lapse camera images (Source: Minowa et al).

From the data, the team could see the seasonality of calving activity. Their results showed that calving events were 2.6 times more frequent during the austral Summer (December-March) as compared to Spring (October). Subaerial calving events occurred 98 percent of the time, although Minowa conceded that the dataset was a bit short to confirm any trigger mechanisms.

Following the research, the team is now ready to install new water sensors for a year-round measurement around the glacier in the hope of further understanding calving processes through the use of surface-waves in glacier fronts. This is a step toward reducing glacier melting in Patagonia and the rest of the world.

Pioneer Study Sounds Out Iceberg Melting in Norway

It is not difficult to envision how ice melts— just imagine a solid cube of water transforming into a liquid mess. Perhaps more surprising, this transition also produces sounds that are audible to human ears, if we listen carefully. The sounds occur because ice traps air bubbles as they are escaping from freezing water. The bigger the ice— glaciers or ice shelves, for example— the greater the number of air bubbles that it contains. Last month, a team of researchers published their work on the intensity, directionality and temporal statistics of underwater noise produced when icebergs melt. The study is a pioneer in the field of cryoacoustics research still in its nascence, since existing studies largely focus on larger forms of ice such as glaciers and ice shelves instead of icebergs.

Air Bubbles Frozen in Ice (Source: Francisco Letelier/Pinterest)
Air bubbles frozen in ice (Source: Francisco Letelier/Pinterest).

In fact, different forms of ice produce different noise signals when melting. The key, in this case, according to Oskar Glowacki, the lead author of the paper, is the quantity of air bubbles trapped in ice. “Glaciers contain more bubbles than icebergs, which is obvious taking into account differences in size,” he explained to GlacierHub. “When the glacier is melting, millions of bubbles are released into the water at the same time. As a result, what we hear is a loud, constant noise described by a normal distribution (typical in nature). But when approaching melting icebergs, we can hear individual bursts of bubbles, and so the noise is much more impulsive.”

The study was conducted at Hornsund Fjord in Svalbard, Norway. The researchers gathered measurements for icebergs in four locations by deploying hydrophones at a depth of 1m from a boat during the spring and summer seasons. Hydrophones are devices that are used to record underwater sounds. Glowack said researchers can hear the sounds even while onboard the boat. But nothing beats diving in the cold waters of the Arctic fjords and listening to the noise of melting ice, an opportunity Glowacki recalls fondly as “the most amazing experience.”

Measures of underwater hissing produced during iceberg melt at the ice-ocean boundary pointed to the need for a remote method to gather quantitative data on the rate of subsurface melting. Iceberg melt has proven to be an important parameter in regional ocean models to estimate ocean circulation patterns and local hydrographic conditions such as in Greenland. However, it is still not easy to record underwater sounds in the harsh environments of the Arctic.

“The main difficulty is to really understand what we are listening to. When the goal is to accurately measure iceberg and glacier melting using underwater sound of bursting bubbles, we need to discover the exact relationship between the intensity of melt noise and exact ice loss,” Glowacki said.

Deploying a hydrophone to measure ice sounds (Source: Phys Org)
Deploying a hydrophone to measure ice sounds (Source: Phys Org).

In the study, the researchers noted that the cackle of icebergs changes based on its relative position to the hydrophone and speed of melting. Care must be taken to remove recordings that are made within 20m of an iceberg to avoid the effects of near-field noise interference, while calls from bearded seals also had to be excluded from analysis.

Moreover, this relationship can be different according to environmental conditions, as changing water temperature causes variation in the shape and size of air bubbles trapped in the ice, and hence the specific song that the ice sings under different conditions. Other complications include sound reflection from the sea surface or ocean bottom and changes in the direction of wave propagation driven by spatial and temporal differences in water temperature and salinity.

“Fortunately, we can take into account all of these factors using accurate mathematical models, which are available as computer programs,” Glowacki said. However, he reckons that transferring cryoacoustics into a real tool in glaciology may take a few years of intensive research, requiring laboratory experiments and studies in other ice-covered regions of Greenland, Alaska and Antarctica.

With more work, noises of melting glaciers might not only identify, but also accurately measure glacier retreat. Nevertheless, the sounds of melting ice are an obvious call from nature that climate change is real.

Roundup: Plant Succession, Glacier Surges and Organic Pollutants

Phosphorus, Not Nitrogen, Limits Primary Succession

From Science Advances: “Current models of ecosystem development hold that low nitrogen availability limits the earliest stages of primary succession, but these models were developed from studies conducted in areas with temperate or wet climates. We combine field and microcosm studies of both plant and microbial primary producers and show that phosphorus, not nitrogen, is the nutrient most limiting to the earliest stages of primary succession along glacial chronosequences in the Central Andes and central Alaska. We also show that phosphorus addition greatly accelerates the rate of succession for plants and for microbial phototrophs, even at the most extreme deglaciating site at over 5000 meters above sea level in the Andes of arid southern Peru.”

Read more about the factors affecting plant succession in cold-arid regions here.

Plant succession occurring after the retreat of the Exit Glacier, Alaska (Source: National Park Service).

 

Tidewater Glacier Surges Initiated at the Terminus

From Journal of Geophysical Research: “There have been numerous reports that surges of tidewater glaciers in Svalbard were initiated at the terminus and propagated up‐glacier, in contrast with downglacier‐propagating surges of land‐terminating glaciers. We present detailed data on the recent surges of two tidewater glaciers, Aavatsmarkbreen and Wahlenbergbreen, in Svalbard. High‐resolution time series of glacier velocities and evolution of crevasse patterns show that both surges propagated up‐glacier in abrupt steps. Geometric changes near the terminus of these glaciers appear to have led to greater strain heating, water production, and storage at the glacier bed. Water routing via crevasses also likely plays an important role in the evolution of surges.“

Find out more about this proposed mechanism of glacier surges here.

Profile of a glacier during normal conditions (left) and during a surge event (right) (Source: Jean-Louis Etienne).

 

Hexachlorobenzene Accumulation in Svalbard Fjords

From Springer: “In the present study, we investigated the spatial and historical trends of hexachlorobenzene (HCB) contamination in dated sediments of three Svalbard fjords (Kongsfjorden, Hornsund, Adventfjorden) differing in environmental conditions and human impact. HCB concentrations ranging from below limit of quantification (6.86 pg/g d.w.) to 143.99 pg/g d.w. were measured… In case of several sediment cores, the HCB enrichment in surface (recent) sediments was noticed. This can indicate importance of secondary sources of HCB, e.g., the influx of HCB accumulated over decades on the surface of glaciers. Detected levels of HCB were generally low and did not exceed background concentration levels; thus, a negative effect on benthic organisms is not expected.”

Discover more about organic pollutions in Norway here.

The Arctic fox and other living organisms in Svalbard could be affected by hexachlorobenzene contamination (Source: Natalie Tapson/Flickr).

Roundup: Ice Streams, Carbon Sequestration and Glacier Recession

Instability of Northeast Greenland Ice Stream

From Nature: “The sensitivity of the Northeast Greenland Ice Stream (NEGIS) to prolonged warm periods is largely unknown and geological records documenting such long-term changes are needed to place current observations in perspective. Using cosmogenic surface exposure and radiocarbon ages, the magnitude of NEGIS margin fluctuations over the last 45  kyr (thousand years) was determined. The NEGIS experienced slow early Holocene ice-margin retreat of 30–40  meters per year, likely as a result of the buttressing effect of sea-ice or shelf-ice. This retreat was smaller than present for approximately half of the last ~45 kyr and is susceptible to subtle changes in climate, which has implications for future stability of this ice stream.”

Discover more about ice stream and melting in Greenland here.

Aerial Image of Greenland Ice Sheet showing ice streams (Source: NOAA).

 

Sea Ice, Blue Carbon and Antarctic Climate Feedbacks

From The Royal Society: “Sea ice, including icebergs, has a complex relationship with the carbon held within animals (blue carbon) in the polar regions. Sea-ice losses around West Antarctica’s continental shelf generate longer phytoplankton blooms (less sea ice increases phytoplankton blooms, benthic growth, seabed carbon and sequestration) but also make it a hotspot for coastal iceberg disturbance. Significant benthic communities establish where ice shelves have disintegrated (giant icebergs calving), and rapidly grow to accumulate blue carbon storage. When 5000 km2 giant icebergs calve, we estimate that they generate approximately 106 tonnes of immobilized zoobenthic carbon per year (t C yr−1).”

Read more about the physical, chemical and biological processes of carbon sequestration here.

Fauna growth in Antartica on places exposed due to melting
Fauna growth in Antarctica on places exposed due to melting (Source: Biomes of the World).

 

Analysis of Mt. Kenya’s Glacial Recession

From the American Journal of Environmental Science and Engineering: “In a bid to discover what has been causing the retreat of glaciers of Mount Kenya, Optical Landsat data for 1984 to 2017 and climatic data of the same years were used. Glaciers and forest coverage were extracted from Landsat images and its thermal band was used to extract temperature data. Correlation with the respective year’s climatic data and forest cover area were done to justify the assumption that the shrinkage in the glaciers coverage has been caused by changes in climate and/or deforestation… Mt Kenya glaciers are likely to have still completely disappeared by the year 2100.”

Explore more about the modelling of Mount Kenya’s glaciers here.

Mount Kenya's Lewis Glacier
Photo of Mount Kenya’s largest glacier – the Lewis Glacier (Source: Earth Day Network/ Pinterest).

Supraglacial Lakes Are Not Destabilizing Greenland’s Ice Sheet, Yet

A recent study published in the Annals of Glaciology provides the first account of supraglacial lakes, which form on surfaces of glaciers in Greenland. The paper was a collaboration between University of Cambridge’s Alison Banwell and the University of Chicago’s Douglas MacAyeal and Grant Macdonald. Supraglacial lakes have been studied in detail in Antarctica, where they were found to accelerate glacier melting and thinning while triggering ice shelf instability and break-up upon formation. However, this recent study documents a different pattern in Greenland.

Location of the Petermann Tongue and the study sites
Location of the Petermann Tongue and the study sites (Source: MacAyeal et al, 2018).

The research was conducted at Petermann Glacier’s floating tongue, a long and narrow sheet of ice protruding off the coastline. An ice tongue forms when a valley glacier advances rapidly out into the ocean. It has similar characteristics to an ice shelf, a feature more commonly found in Antarctica. Based on Landsat 8 satellite images from 2014 to 2016, the team was able to view the lakes over the area and discern when the lakes formed, their movement, and changes in surface extent across time.

In an interview with GlacierHub, MacAyeal explained, “Petermann Glacier has one of the few remaining ice tongues in Greenland and has lakes forming on it in each year. The glacier is of particular interest to the community due to its size and catchment, and the notable recent large calving events.”

The Petermann tongue underwent severe volume losses of up to 40 percent during two calving events in 2010 and 2012, for example. Fortunately, the grounded upper portion of the Petermann Glacier remains dynamically stable and showed little change in velocity or thickness.

“Glaciologists believe that supraglacial lakes store water and can become ‘dangerous’ to the continued existence of floating ice, such as the Petermann ice tongue, but more importantly to the ice shelves of Antarctica,” MacAyeal told GlacierHub. These supraglacial lakes usually form in the summer as melting is induced by an increase in air temperatures and solar radiation receipt. In the case of Greenland, the lakes at the Petermann Glacier typically fill in June, reaching their peak in July. At this time, the lakes are largest in area and volume, with their numbers at the maximum as well.

Schematic diagram illustrating the side profile of ice shelves/tongues and their underlying geology
Schematic diagram illustrating the side profile of ice shelves/tongues and their underlying geology (Source: Julian Thompson/Andrill).

“The meltwater can fill cracks and cause them to extend through the ice. Also, when water flows into a depression and forms a lake, the lake is heavy and can cause the ice shelf to flex. Ice-shelf flexure can promote fracturing,” Macdonald further explained to GlacierHub. Fittingly, MacAyeal compares this to hydrofracking in the oil industry, except that this is a natural process when ice disintegrates as “heavy dense water fills crevasses and makes them crack farther open.”

Blue River, Greenland
Blue River flowing through the Petermann Glacier (Source: Pixohub/Pinterest)

As for the Petermann tongue, supraglacial lakes are less potent at inducing glacier thinning since lake drainage occurs relatively quickly. By July and August, even with the sustained high temperatures during the summer, total number, volume, and surface area of lakes were observed to have decreased. Drainage occurs in two ways: across the tongue surface and through the tongue. The former is enabled by the surface river system known as the Blue River which transports meltwater into the ocean across the tongue. The latter requires the process of rapid hydrofracking to occur, causing local lake drainage on the tongue. Overall, limited volume of meltwater storages on the tongue was noted, causing the research to lean toward the former mechanism.

Supraglacial lakes were under the spotlight when the formation of over 3,000 lakes caused the catastrophic disintegration of the Larsen B Ice Shelf in Antarctica in 2002. According to Grant, ice shelves are important as they shore up more than half of the Antarctic coast and several glaciers in Greenland. When this buttressing effect is removed the glaciers feeding the ice shelf accelerate. Without the ice shelves, more ice will enter the ocean at a faster rate, contributing to sea level rise.

Currently, the study indicates that supraglacial lakes cover less than 2.8 percent of the Petermann tongue, as compared to the 5.3 percent surface area prior to Larsen B’s collapse. However, there are warnings of higher density lakes with larger volumes that start developing earlier in the summer season due to higher air temperatures that could potentially destabilize ice shelves and tongues worldwide. “If we are to understand the future of ice shelves in a warming climate, we must understand supraglacial lakes,” Macdonald advised.

The End of the Temporary Protected Status for Nepal

By June 2019, thousands of refugees from the glacier-rich region of Nepal could lose their homes in the United States once their Temporary Protection Status (TPS) expires. They were granted TPS following the devastating earthquake in 2015. The expiration of Nepali’s TPS status comes after the Trump administration announced plans in April to end TPS for refugees from Haiti, Honduras and El Salvador, sparking concern among these displaced populations. The end of the TPS has also been discussed in the Nepali press.

TPS is only granted to citizens of countries that are deemed impossible for safe return as a result of circumstances such as ongoing armed conflict, natural disasters or other extraordinary or temporary situations. Currently, ten countries are part of the TPS list, including: Haiti, El Salvador, Syria, Nepal, Honduras, Yemen, Somalia, Sudan, Nicaragua and South Sudan. As of 2017, around 320,000 people hold TPS, including 8,950 Nepalis. Despite holding TPS, an individual may still be detained by the Department of Homeland Security (DHS) on the basis of his or her immigration status. The TPS is also merely a temporary benefit that does not lead to lawful permanent resident status or immigration status.

Many Nepalis were granted TPS after the devastating 7.8-magnitude earthquake killed almost 9,000 people on April 25, 2015, It was the worst earthquake in Nepal since 1934 and triggered an avalanche on the glacier-covered Mount Everest. Following the avalanche, 250 people were reported missing, with Fox News coining it the “deadliest day on the mountain in history.” After the event, 3.5 million Nepalis were left homeless with the region, which faced around $10 billion in damages. Living near the high Himalayas and Mount Everest, the Sherpa ethnic group was badly hit. They also form a portion of the TPS population in the United States.

For many of these Nepalis, TPS has granted them a new lease on life. One such recipient of the TPS is Gyaljen Nuru Sherpa, who was granted TPS status by President Obama after the earthquake. The owner of several Nepali Tibetan fusion restaurants located in Westchester Country, just north of New York City, he mentioned in an interview with News12 that with the help of his TPS he had “raised $25,000 to help rebuild the homes of 16 relatives and a temple in his hometown following the earthquake.”

GlacierHub spoke with Alex de Sherbinin, from the Center for International Earth Science Information Network, about his work on outmigration from mountain areas. He points out that the Nepalis are not an isolated case.

“After the Haitian earthquake in 2010, there were some Haitians who received temporary protected status in the United States, but they were a small minority. There have been other cases of transboundary movements (for example, the Caribbean islands after the multiple hurricanes in 2017), but I would say these are the exception rather than the rule,” de Sherbinin told Glacierhub.

He added that displaced populations often lack any concrete plan for the time they plan to stay abroad. In fact, the majority return home eventually.“This is highly context-specific. It depends on the disaster, and on the region,” de Sherbinin said. “I think the disaster displaced figure things out as best they can, and are informed by social media and reports from their home towns about the ability to return home.”

Sites such as the Platform for Disaster Displacement are usually recommended for the migrants seeking information on their homelands.

Aftermath of the Nepal Earthquake (Source: Nigeria Circle News/ Twitter)
Aftermath of the Nepal Earthquake (Source: Nigeria Circle News/ Twitter).

“I hope this time the President will also understand and study a little bit about the conditions of Nepal. We hope for the best, Mr President will grant [TPS] again,” Gyaljen Nuru Sherpa added in his interview with News12. “I am very much worried about my people here and in Nepal. They are hardworking people, good people, but all they want is just to work and support their families.”

Pasang Sherpa, an anthropologist from the Sherpa community in Nepal, agrees that Nepalis depend a lot on agriculture or rely on daily wages and would have a hard time taking care of themselves following a disaster like the earthquake in 2015.

“The end of TPS program can mean that many Nepalis would lose their ability to support their families,” she said. “The opportunities they have gained over the past three years to build their lives will be suspended. This would mean that the effects of the earthquake continues to be felt three years later.”

Both De Sherbinin and Sherpa told GlacierHub that they are in favor of a TPS extension “on humanitarian grounds.” But as de Sherbinin points out, if things are stabilized, then perhaps they could return.

Mayor de Blasio recently sent an appeal to President Trump suggesting an extension of the TPS for Nepalis by 18 months. He is not the only politician to make a request based on a study of the region and its current status of recovery. To date, Nepalis continue to face difficult circumstances back home and many of the TPS immigrants may hope to stay in the United States longer to help those back home who still need assistance.