Roundup: Melting Glaciers Move Borders, Peruvian Study Opens Door for Glacial Research, and Glacier Meltwater Acoustics

As The Climate Shifts A Border Moves

Not all natural boundaries are as stable as they might appear. Italy, Austria, and Switzerland’s shared borders depend on the limits of the glaciers and they have been melting at increased rates due to climate change. This has caused the border to shift noticeably in recent years. The border lies primarily at high altitudes, among tall mountain peaks where it crosses white snowfields and icy blue glaciers.

Read the story by Elza Bouhassira on Glacierhub here.

Rifugio Guide Del Cervino. Source: Franco56/ Wikimedia Commons

Peruvian Study Opens Doors for Glacial Research

A study published in March of this year by researchers from the University of Quebec presents a new avenue for glacier retreat research. While most water-related glacier studies are concerned with water availability, the research presented in this article is distinctive in that it draws a link between glacier retreat and water quality. This work has important implications for populations in the study area and others living in glacierized regions around the world.

Read the story by Zoë Klobus on GlacierHub here.

Dissolved pyrite causes red deposit on rocks along a river in the Rio Santa watershed (Source: Alexandre Guittard)

Acoustics of Meltwater Drainage in Greenland Glacial Soundscapes

Remember the age-old adage, “If a tree falls in the forest and no one is around, does it make a sound?” For centuries philosophers have tested our minds with such questions, and certainly the answer depends on how the individual chooses to define the word sound. Scientists would say that if by sound, we mean the physical phenomenon of wave disturbance caused by the crash, we would undoubtedly concur. Indeed, in recognizing the uniqueness of audio frequencies, the scientific practice of studying environmental soundscapes has proven effective at providing information across a varied range of phenomena. But glaciers represent a relatively new soundscape frontier. 

“Glaciologists just opened their eyes to studying glaciers about 150 years ago. We started to look at glaciers from different angles, perspectives, satellites — but we forgot to open our ears,” said Dr. Evgeny Podolskiy, an assistant professor at the Arctic Research Center at Hokkaido University in Sapporo, Japan. “I’ve been studying glacier geophysics for quite some time and I found that there is this kind of natural zoo, or a universe, of sounds which we kind of totally ignored until recently.”

Read the full story by Audrey Ramming on GlacierHub here

Dr. Evgeny Podolskiy daily work at the calving front of Bowdoin Glacier. Source: Evgeny Podolskiy

Acoustics of Meltwater Drainage in Greenland Glacial Soundscapes

Remember the age-old adage, “If a tree falls in the forest and no one is around, does it make a sound?” For centuries philosophers have tested our minds with such questions, and certainly the answer depends on how the individual chooses to define the word sound. Scientists would say that if by sound, we mean the physical phenomenon of wave disturbance caused by the crash, we would undoubtedly concur. Indeed, in recognizing the uniqueness of audio frequencies, the scientific practice of studying environmental soundscapes has proven effective at providing information across a varied range of phenomena. But glaciers represent a relatively new soundscape frontier. 

Dr. Evgeny Podolskiy daily work at the calving front of Bowdoin Glacier. Source: Evgeny Podolskiy

“Glaciologists just opened their eyes to studying glaciers about 150 years ago. We started to look at glaciers from different angles, perspectives, satellites — but we forgot to open our ears,” said Dr. Evgeny Podolskiy, an assistant professor at the Arctic Research Center at Hokkaido University in Sapporo, Japan. “I’ve been studying glacier geophysics for quite some time and I found that there is this kind of natural zoo, or a universe, of sounds which we kind of totally ignored until recently.”

His research then became directed toward the glacial soundscape, and last month he published an article in Geophysical Research Letters about the sounds he recorded, not with expensive geophysical sensors, but with a smartphone from Bowdoin Glacier (Kangerluarsuup Sermia), located in northwestern Greenland. His recordings captured a unique sound which he used to describe a specific drainage process within the glacier — one that is impossible to observe from the surface: Meltwater drainage through a crevasse. 

Ponds of meltwater that pool on top of the glacial surface drain through the crevasses, entering into the drainage system of the glacier. As the water travels to subglacial environments, it warms up the ice, makes it softer, and increases the subglacial water pressure that causes the glacier to slide faster into the ocean. In his paper, Podolskiy presented the first evidence of unexplained acoustic phenomena being generated by water drainage through a crevasse. 

Unstable Water Flow Through a Crevasse

This acoustic signal is distinct from other drainage processes due to the “two-phase” interaction between air and water. “The main point I want to make is that we totally forgot that there’s air,” he said. The air produces vibrations on water in the near surface environment where they mix. “By listening to these sounds, we can actually determine the type of flow regime — the way fluid flows in these systems — just by looking at the analysis of the signals,” he said.

Water-filled crevasses on Bowdoin Glacier. Source: Evgeny Podolskiy
Water-filled crevasses on Bowdoin Glacier. Source: Evgeny Podolskiy

After many years in the field as a glaciologist, Podolskiy found that different types of glacial environments produce their own unique soundscapes. For instance, during the daytime at a Himalayan debris-covered glacier, exposed ice cliffs slowly melt and the rocks on top tumble down the slope, producing noisy avalanches. Podolskiy noticed that during the afternoon, there is a lot of this particular sound. At night, if a glacier is not shielded by insulating debris cover, the ice begins to contract as it gets extremely cold, and the tensile contraction of the ice produces cracking sounds

Podolskiy’s most recent research concerns the soundscape of Bowdoin, a tidewater glacier. These fast-flowing valley glaciers begin in mountains or on more distant ice sheets and reach their terminus at the ocean where their icy cliff edges occasionally break off, or calve, into the sea. Glaciers recede when the rate of calving and/or englacial melt exceeds the rate of new snow accumulation at higher elevations.

Helicopter view of Bowdoin tidewater glacier, northwestern Greenland (July 29, 2019). Snowfall in the Greenland Ice Sheet feeds the glacier that ends in a cliff at its terminus in the ocean. (Source Evgeny Podolskiy) 

Bowdoin was initially being monitored by Podolskiy and his colleagues because melt and glacier retreat recently began accelerating in the area. Amazingly, the scientists were able to walk right up to the calving front where the icebergs detach, something that is quite uncommon in these environments, making Bowdoin a great study site for all types of glacial research.

The idea of using sensors to passively study the ocean has been around for awhile. In the 1950s, Navy surveillance systems discovered unknown repetitive pulses of traveling through the sea, and they were later attributed to finback whale courting displays. This actually provided much of the stimulus for the early design of ocean acoustic equipment and techniques for observation. According to Acoustics Today, the proposal that “these powerful [acoustic] tools could be applied to a pressing and difficult measurement problem in polar regions: the monitoring of tidewater glaciers with hydroacoustics,” came about in 2008 at a workshop in Bremen, Germany. 

Though his paper only references sounds recorded from his smartphone, Podolskiy pointed to a drawing he made behind him on his whiteboard and explained: “We also have seismic and GPS stations to observe tide-modulated motion of the ice and its fracturing. We have hydroacoustic sensors under water so we can hear processes like bursting or pressurized air bubbles within the melting ice, calving, and even whales. On a mountain nearby we have infrasound sensors, which are basically sensors used to measure air pressure because when icebergs fall, they displace air and produce air pressure waves that can tell us where calving occurred,” he said. 

Podolskiy held up handfuls of hard drives and explained that instead of going through terabytes of complex geophysical data, he realized a simple fact: “Audible sounds recorded with my smartphone over various drainage systems contain a lot of unique acoustic information. Every place you look has a very different signature. We can fingerprint different ways of water flowing into the ice by sound and the fingerprinting of different flow regimes is useful for understanding the glacial hydrology”

Dr. Evgeny Podolskiy with a steam drill and seismic equipment on Bowdoin Glacier. Source: Lukas Preiswerk

“But when I walk on that glacier I just close my eyes and I realize there are so many sounds, audible sounds — not these fancy seismic, infrasound, hydroacoustic recorded sounds we have been collecting there for years — just sounds audible to our ears,” he said. 

Podolskiy explained that, after the many summers at Bowdoin, one of the things that directed him to studying acoustics was the sounds of seabirds at the calving front. Birds, like the black-legged kittiwake, are attracted to tidewater glacier discharge plumes which form when meltwater exits from underneath the glacier and, due to its low density, rises in the seawater toward the surface, bringing with it nutrients and zooplankton on which arctic seabirds feed.

Seabird Sounds at Calving Front. Source: Evgeny Podolskiy

Seabirds Feeding in Subglacial Discharge Plume at Calving Front

“On the surface I listen to the birds and then I listen to the crevasses,” Podolskiy said. Crevasses are deep, open fractures on the glacier surface that form as a result of changing stresses as the ice moves and flows toward the ocean. Crevasses can open up overnight. “It is the most intense process on Bowdoin. We can hear it as shooting sounds, like gunshots,” he said. This ice splitting process should not be confused with the description of meltwater drainage through the crevasse which was articulated at the beginning of the article. 

Calving, Podolskiy explained, does not happen as frequently, just several events per day. But calving is very distinct and very loud and can last ten minutes when the ice is collapsing. It produces an array of strong seismo-acoustic signals. 

Moulins are circular-like shafts within a glacier through which water enters from the surface. They are normally found in areas that are heavily crevassed and they too produce their own unique sounds. 

Stable Water Flow Through Moulin
Moulin at Bowdoin Glacier. Source: Evgeny Podolskiy 

As the climate warms, understanding the various flow regimes in the englacial conduits is valuable because of their influence on glacial mass flux. In addition to contributing to global sea level rise, the influx of fresh glacial water to the ocean affects global scale heat transport by weakening circulation patterns. Fresh surface water does not sink like dense, salty water, so it slows the overturning movement of the ocean, a powerful regulator of global climate.

“What is clear is that the Greenland Ice Sheet, the Antarctic Ice Sheet, and all the glaciers around the world are getting wet because they’re melting over increasingly larger areas, and all this produced meltwater is bringing our cryosphere into a new state” Podolskiy said. The meltwater flows through the englacial system and affects glaciers from the inside, and he presumed part of this story could be studied with microphones. Certainly, near-source acoustic methods offer advantages over more conventional remote sensing methods because satellites are unable to see how the meltwater enters and flows through the crevasses.

Meltwater Stream at Bowdoin Glacier. Source: Evgeny Podolskiy 
Supraglacial Pond at Bowdoin Glacier. Source: Evgeny Podolskiy 
Supraglacial Meltwater Pond Bubbling

Polar explorers and mountaineers were sensitive to glacial sounds for centuries, but now with acoustic instruments we have the ability to learn the things we missed without them. “I hope it will inspire people,” he said, “to pay attention and to just try to see the world like whales or dolphins do because these guys, they don’t see much — they hear the configuration. They are living in soundscapes.”

Read More on GlacierHub:

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Kashmir’s Water: New Weapon of War for India and Pakistan?

India and Pakistan were separated at birth, established in 1947 when they gained independence from Britain. Since then, these two countries have been engaged in a violent, 70-year-long dispute over control of Kashmir, waging three wars, countless skirmishes, attacks, and subsequent retaliations. Today, India occupies 45 percent of Kashmir, Pakistan occupies 35 percent, and China occupies the remaining 20 percent.

Map of Kashmir boundaries and the Indus river basin on GlacierHub
Map of Kashmir boundaries and the Indus river basin (Source: Wikimedia Commons).

Water is an important aspect of India and Pakistan’s fight over Kashmir. Kashmir, a small mountainous region tucked between India and Pakistan, is home to glacier headwaters for several of the Indus River’s tributaries. The Indus River begins in the Himalayas of Tibet, then continues through to India, Kashmir, and finally Pakistan––and provides water resources to almost 270 million people.

The Indus Waters Treaty (IWT) of 1960, which was brokered by the World Bank, divided up control of Indus rivers to Pakistan and India. It also established the Permanent Indus Commission to facilitate communication between the two countries and resolve any disputes. Under the treaty, Pakistan retains primary control of Kashmir’s western glacier-fed rivers––Chenab, Jhelum, and Indus––while India holds the water rights for the eastern rivers––Beas, Ravi, and Satluj.

Indian and Pakistani-controlled land areas are demarcated by the Line of Control (LOC) with one huge exception: the Siachen Glacier. The two international agreements defining the LOC did not include the Siachen Glacier area, leading both India and Pakistan to compete for control. India claimed the entire glacier in 1984, and has maintained a military presence there since.

Recent Events

Tensions between the two countries subsided for several years following a 2003 ceasefire, however, more recent conflicts between India and Pakistan have brought the long-standing dispute in Kashmir, and its roots in water, back into focus.

In 2016, 19 Indian soldiers were killed in the Uri attack, prompting Prime Minister Narendra Modi to say, “blood and water can’t flow together at the same time.” In the following weeks, India suspended meetings of the Permanent Indus Commission, then engaged a policy shift to begin exerting full control over their allotted water under the IWT.

Fast forward to February 21, 2019, when Nitin Gadkari, India’s Minister of Water Resources, River Development and Ganga Rejuvenation, tweeted:

Gadkari’s declaration came one week after a car bombing in Pulwama (India-controlled Kashmir) left 41 dead, making it the deadliest attack in Kashmir’s history. India charged Pakistan as responsible for the attacks and vowed to retaliate, but the Pakistani government denied any involvement. The next day, Pakistan-based terrorist group Jaish-e-Mohammed claimed responsibility.

In the wake of the Pulwama terror attacks, media frenzy around this tweet quickly ensued. Several news sources speculated that India was attempting to put pressure on Pakistan, or that it was violating the Indus Waters Treaty by halting all water flow to Pakistan. Ministry officials later clarified on Twitter that Gadkari was simply reaffirming an existing policy. In accordance with their plan, India recently began construction of a dam on the Ravi river and plans only to use the eastern rivers, of which they have primary control under the treaty, for their proposed water diversions.

Caught in the Crossfire

In the month following, tensions between India and Pakistan have escalated, with Kashmir caught in the middle of their crossfire.

Making good on their promise of retaliation, Indian warplanes crossed the LOC for the first time since 1971 to carry out an airstrike. Pakistan responded by shooting down two Indian fighter jets, capturing one of the pilots, and releasing a controversial video of the pilot in custody before announcing they would release the pilot back to India as an act of good faith.

Uncharted Waters

Now two weeks after the pilot’s release, tensions in Kashmir have diffused somewhat, and both India and Pakistan have made it clear they intend to avoid further escalation. Historically, it didn’t take much to provoke hostile exchanges into an all-out war between the two, so what is making them more hesitant this time around?

First, both countries are now nuclear powers. And while India has a “No First Use” policy, meaning it will only engage in retaliatory nuclear strikes, Pakistan has yet to adopt such a policy. Any future hostilities run the risk of nuclear escalation and subsequent devastation, making Pakistan and India weary of reaching “the point of no return.” Though certainly possible, escalations of nuclear proportion remain unlikely.

Water as an Emerging Weapon

Person holding up a Pakistani flag on the world's highest battlefield, Siachen Glacier on GlacierHub
Person holding up a Pakistani flag on the world’s highest battlefield, Siachen Glacier (Source: junaidrao/Flickr).

Additionally, throughout all of South Asia, future water availability is a monumental concern. In an article published by the New York Times, Arif Rafiq, a political analyst at the Middle East Institute in Washington, said, “we may be getting a glimpse of the future of conflict in South Asia. The region is water-stressed. Water may be emerging as a weapon of war.”

It is no secret that political turmoil can wreak havoc on an environmental landscape, and in India, Pakistan, and Kashmir, this is further complicated by the impact of climate change. According to the Hindu Kush Himalaya Assessment, rising temperatures will melt at least one-third of glaciers in the Himalayas by 2100, and up to two-thirds if we fail to meet ambitious climate change targets. Some glaciers are predicted to reach peak discharge as early as 2020.

Less water availability coupled with population growth will likely exacerbate tensions between India and Pakistan as they continue their fight for control over Kashmir’s water resources. The Assessment noted that future glacier and snow cover changes in the Indus river basin may not occur equitably, meaning the water quantities allocated to India and Pakistan under the IWT could change drastically. Since the IWT has no provision to deal with water in the context of climate change, the two countries could very well have to re-negotiate the treaty in coming years.

Roundup: Microbial Mats, Hidden Heat, and Tree Infection

Benthic Microbial Mats in Meltwater from Collins Glacier

From Polar Biology: “Most of Fildes Peninsula is ice-free during summer thereby allowing for formation of networks of creeks with meltwater from Collins Glacier and snowmelt. A variety of benthic microbial mats develop within these creeks. The composition of these microbial communities has not been studied in detail. In this report, clone libraries of bacterial and cyanobacterial 16S rRNA genes were used to describe the microbial community structure of four mats near a shoreline of Drake Passage. Samples were collected from four microbial mats, two at an early developmental stage (December) and two collected latter in late summer (April). Sequence analysis showed that filamentous Cyanobacteria, Alphaproteobacteria, and Betaproteobacteria were the most abundant ribotypes.”

Learn more about the microbial mats here.

Microbial mat on a sandy depositional surface (Source: GSA).

 

Geothermal Heat Flux Hidden Beneath Greenland Ice Sheet

From Nature: “The Greenland ice sheet (GIS) is losing mass at an increasing rate due to surface melt and flow acceleration in outlet glaciers… Recently it was suggested that there may be a hidden heat source beneath GIS caused by a higher than expected geothermal heat flux (GHF) from the Earth’s interior. Here we present the first direct measurements of GHF from beneath a deep fjord basin in Northeast Greenland. Temperature and salinity time series (2005–2015) in the deep stagnant basin water are used to quantify a GHF of 93 ± 21 mW m−2 which confirm previous indirect estimated values below GIS. A compilation of heat flux recordings from Greenland show the existence of geothermal heat sources beneath GIS and could explain high glacial ice speed areas such as the Northeast Greenland ice stream.”

Learn more about the hidden heat flux here.

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

 

Blister Infection on the Whitebark Pine in the Greater Yellowstone Ecosystem

From University of Wyoming National Park Service Research Center: “Whitebark pine is a keystone and foundation tree species in high elevation ecosystems of the Rocky Mountains. At alpine treelines along the eastern Rocky Mountain Front and in the Greater Yellowstone Ecosystem, whitebark pine often initiates tree islands through facilitation, thereby shaping vegetation pattern. This role will likely diminish if whitebark pine succumbs to white pine blister rust infection, climate change stress, and mountain pine beetle infestations. Here, we established baseline measurements of whitebark pine’s importance and blister infection rates at two alpine treelines in Grand Teton National Park.”

Read more about the blister infection on Whitebark pine here.

Whitebark pine on the Continental Divide of the the Greater Yellowstone Ecosystem, which includes Yellowstone and Grand Teton National Parks (Source: Taisie Design).

Large Populations of Jellyfish Found in West Antarctic Fjords

Jellyfish 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.

Fjords are partially submerged steep-sided valleys carved out by glacial action (Source: Richard Martin/Creative Commons).
Fjords are partially submerged steep-sided valleys carved out by glacial action (Source: Richard Martin/Creative Commons).

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.

The locations of the three fjords: Andvord (1), Flandres (2) and Barilari (3) Bays (Source: Grange et al.).
The locations of the three fjords: Andvord (1), Flandres (2) and Barilari (3) Bays (Source: Grange et al.).

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.

P. polaris are up 2-3 cm in diameter and are often found attached to rock surfaces (Source: Laura Grange)
P. polaris are up 2-3 cm in diameter and are often found attached to rock surfaces (Source: Laura Grange)

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 variation between the extreme ends of its distributional range.”

Further research will help to elucidate the findings of this study. The complex interplay between wind, tidal and glacial processes in subpolar fjords also creates a variety of conditions in different fjords, suggesting that glacier-related environments such as these may yield more surprising discoveries.