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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Subglacial Meltwater Boosts Greenland Ecosystems and Locks Carbon

Following news of the arrival of a Manhattan-sized iceberg from a retreating glacier next to a village in Greenland, a recent paper published in the Journal of Geophysical Research has unveiled new research on how subglacial meltwater in Greenland is pumping nutrients and carbon from the deep sea to drive a boom of microorganisms in the upper layers. This effect fuels the ecosystems around it and impacts carbon cycling within the fjords and ocean close to the glaciers, further increasing the carbon uptake from the atmosphere.

Since 2002, Greenland has lost around 270 billion tons of ice per year. The glaciers and ice sheets of Greenland are key to the magnitude of future sea level rise, prompting scientists and researchers from around the globe to travel to the glacier-laced land to study and measure the physics of glacier melting and retreat. A team of researchers from Hokkaido University, led by Naoya Kanna and Shin Sugiyama, found a new perspective to understand the interactions of glaciers with ecosystems under a changing climate.

Bowdoin Glacier and Fjord. Bowdoin is a tidewater glacier in northwestern Greenland (Source: Shin Sugiyama).

Since 2012, the team’s focus has been measurements of the ice in the region, with specific interest in the mechanisms of the Bowdoin glacier’s rapid retreat. Shin Sugiyama, the second author of the paper, wrote to GlacierHub, “We recognized the glacier-ocean interaction as the key process and expanded our activity to the ocean.”

The researchers moved from geophysical measurements to geochemical measurements over time. They started to camp in the nearby village of Qaanaaq beginning in the summer of 2016, surveying the water temperature, salinity, ocean currents and other physical properties.

A researcher collects water samples from the front of Bowdoin Glacier using a fishing rod (Source: Shin Sugiyama).

They collected biogeochemical samples from the top of Bowdoin Glacier, the plume along the glacier front, and nearby fjords. They found that the plume water is more turbid, and its chemical composition is significantly different from waters in other locations due to a higher concentration of nutrients and salts. At the same time, phytoplankton blooms were also detected.

They then found an underwater nutrient and carbon transfer route that may explain these observations. Sugiyama describes the transfer as a “nutrient pump.”

At the bottom of the sea, due to the gravity and ocean currents, there are water flows from the fjord moving toward the glacier front. These flows carry a lot of descended nutrients and dissolved carbon. There is also subglacial freshwater discharge that is turbid because of the subglacial weathering. The two flows meet at the deep sea and create massive fluxes of sediments along the glacier fronts.

When the sediment-laden upwell water reaches the sea surface, it forms an opaque layer below the relatively fresher sea surface water. During the upwelling process, the mixture of subglacial discharge water and flows from the fjord pumps nutrients and carbon from the deep water to the upper layers.

Schematics of the nutrient and carbon rich subsurface plume water formation at the front of Bowdoin Glacier (Source: Kanna et al.).

Later, phytoplankton blooms were observed in between the sea surface and the near surface plume water. Phytoplankton are plant-like marine microorganisms at the base of the ocean’s food pyramid. These tiny organisms absorb nutrients and carbon to fuel their growth. Some of the nutrients and carbon fall to the bottom with the phytoplankton when they wither. Other portions of the nutrients and carbon further pass into the food web through organisms that graze on the phytoplankton.

The growth burst of the phytoplankton went unnoticed until recent years. Through their analysis of samples from supraglacial meltwater, proglacial stream discharge, fjord surface water, and plume surface water, the authors identify a distinct vertical distribution of nutrients and carbon along the centerline of the fjord. The data prove that the upwelling associated with the subglacial discharge has been pumping the nutrients and carbon from the deep water toward the surface, catalyzing the formation of phytoplankton blooms.

As the planet warms, glacier melting is increasing in Greenland. For its implication on their findings, Sugiyama said, ”Our study implies that nutrient supply to fjord surface water is enhanced by an increase in meltwater discharge under the warming climate. This results in higher primary production [of microorganisms]. On the other hand, turbid plume water also disturbs the production by limiting light availability in water.” He noted the team will continue their research to understand how these positive and negative impacts counterbalance.

The researcher conduct measurements near the Bowdoin Glacier front with a boat operated by a local hunter (Source: Shin Sugiyama).

The study not only showed a critical role of freshwater discharge in the primary productivity of microorganisms in front of the glaciers, but it also indicated that changes in glacier melt might impact the fjord ecosystems.

“Tidewater glacier front is a biological ‘hot spot.’ We see many birds and sea mammals near the front of Bowdoin Glacier. Change in the ecosystem is not clear at this moment, but we suspect such a highly productive ecosystem is sensitive to the warming Arctic climate,” Sugiyama said.

The ocean also acts as an immense carbon sink, which scientists need to explore. This finding may provide ideas for how carbon transfers within the marine ecosystem.

Sugiyama added, “A possible influence on the carbon cycle is more carbon storage in the ocean when primary production is enhanced by increasing amount of upwelling meltwater. Nevertheless, the plume process is not directly related to the intake of carbon from the atmosphere.”

Bowdoin Glacier is smaller than other rapidly retreating glaciers in Greenland, such as the Jakobshavn and Helheim glaciers. The team hopes to find out if the processes observed in Bowdoin Fjord resemble the situations in the fjords of larger glaciers.

Roundup: Bowdoin Glacier, Floods, and Bacterial Populations

Speeding-up of the Bowdoin Glacier

From People Publications: “Glaciers are subject to sudden ice flow speed-up events in response to rapid increase of meltwater in the subglacial hydrological network after a prolonged warm period or the drainage of a supraglacial lake…. lasting a few hours, a period too short to be captured by satellite remote sensing. We used a cost-effective Vertical Take-Off and Landing and Unmanned Aerial Vehicle to monitor bi-daily the movements of Bowdoin Glacier. Our results show four distinct short-lived speed-up events, which were in phase with fluctuations of air temperature and meltwater plumes at the glacier snout, showing that recorded accelerations were triggered by an increase of buoyant forces in response to a surplus of subglacial meltwater.”

Read more speed-up events here.

Tongue of the Bowdoin Glacier (Source: ETH Zurich/Creative Commons).

Glacial Lake Outburst Floods at Imja Lake

From MDPI: “Glacial retreat causes the formation of glacier lakes with the potential of producing glacial lake outburst floods (GLOFs). Imja Lake in Nepal is considered at risk for a GLOF. Communities in the path of a potential Imja GLOF are implementing adaptation projects. We develop and demonstrate a decision-making methodology. The methodology is applied to assess benefits in Dingboche of lowering Imja Lake by 3, 10 and 20 m. The results show that the baseline case (no lake lowering) has the lowest expected cost because of low valuation of agricultural land and homes in the literature.”

Read more about Imja Lake here.

Imja Lake in the middle of the Himalayas of Nepal (Source: Kiril Rusev/Creative Commons).

Bacterial Populations of East Antarctic Glaciers

From Frontiers in Microbiology: “Glacial forelands are extremely sensitive to temperature changes and are therefore appropriate places to explore the development of microbial communities in response to climate-driven deglaciation. We investigated the bacterial communities that developed at the initial stage of deglaciation using space-for-time substitution in the foreland of an ice sheet in Larsemann Hills. Our results show that abundant bacterial communities were more sensitive to changing conditions in the early stages of deglaciation than rare community members.”

Learn more about the bacteria populations of East Antarctic glaciers here!

Mineral treasures of Larsemann Hills, Antartica (Source: National Science Foundation/Creative Commons).
 

 

Using Kayaks and Drones to Explore Glaciers

Field study sounds cool: a group of scientists take boats out into untraveled waters on an important scientific mission, even witnessing extraordinary scenery like an iceberg calving event along the journey. However, the breathtaking beauty of such a trip can also come at a price, sometimes even human life!

“I like working in Alaska, but I face the difficulties of any ice or ocean research project,” said Erin Pettit, an associate professor at University of Alaska Fairbanks. Pettit finds it hard to find a reliable boat and captain for her trips, and too much ice in the fjord often limits how close she can get to the glaciers. The risks to her personal safety rise when she has to work on cold or rainy days.

A group of scientists are collecting data from Le Conte Glacier (source: Cal Dail/Flickr).

“It can be really dangerous in Alaska, so we send the kayaks out,” said June Marion, the principal engineer for a new study using remote-controlled kayaks to research Le Conte Glacier. The oceanic robotic kayaks are controlled by a laptop a few miles away, according to Marion.

“When the calving event happens and an iceberg falls onto the kayak, we do not need to sacrifice valuable human life,” she said. “More importantly, the kayak can go further into unexplored regions. We are more hopeful to collect data.”

Mechanical engineer June Marion works on the kayak’s engine assisted by her dad, Bobby Brown. Working on the rear kayak is robotics science students Nick McComb and Corwin Perren (source: Angela Denning / NOAA).

With a radio controller or a computer, the researchers navigate the kayak by clicking on points on a map, sending the kayak directly to the location for study. The engine can even be started using a computer program.

“There are always new technologies being used on glaciers,” said Pettit.

Guillaume Jouvet et al. figured out another way for scientists to avoid danger during field work. They used unmanned aerial vehicles (UAVs), also known as drones, to study calving of the Bowdoin Glacier in Greenland in 2015. They combined satellite images, UAV photogrammetry, and ice flow modeling, drawing important conclusions from the results.

With UAVs, researchers are able to obtain high-resolution orthoimages taken immediately before and after the initiation of a large fracture, including major calving events. In this way, Jouvet et al.’s study demonstrates that UAV photogrammetry and ice flow modeling can be a safer tool to study glaciers.

Measurement of surface temperature of a glacier using an unmanned aerial vehicle (UAV) (source: W. Immerzeel et al.).

This technology has also been successfully applied to monitor Himalayan glacier dynamics: the UAVs can be used over high-altitude, debris-covered glaciers, with images of glacier elevation and surface changes derived at very high resolutions, according to W. Immerzeel et al.. UAVs can be further revolutionized to develop current glacier monitoring methods.

Scientists like Marion and Pettit are excited to see these new technologies developed to study glaciers and save lives. They are hoping for more methods to achieve this goal.

Roundup: Kayaks, Snow Machines and Drones

Roundup: Kayaks, Regrowing Glaciers, and the Bowdoin

 

Research Using Remote-Controlled Kayaks

From Alaska Public Media: “LeConte Glacier near Petersburg… [is] the southern-most tide water glacier in the northern hemisphere and scientists have been studying it to give them a better idea of glacial retreat and sea level rise around the world… to get close to the glacier, which is constantly calving, a team of scientists is relying on unmanned, remote controlled kayaks… these kayaks have been completely tweaked by Marion and an ocean robotics team from Oregon State University… The boats are customized with a keel, antennas, lights and boxes of computer chips and wires.”

Find out more about the kayaks and research here.

LeConte Glacier’s calving front (Source: Gomada / Creative Commons)

 

Regrowing Morteratsch Glacier with Artificial Snow

From New Scientist: “The idea is to create artificial snow and blow it over the Morteratsch glacier in Switzerland each summer, hoping it will protect the ice and eventually cause the glacier to regrow… The locals had been inspired by stories that white fleece coverings on a smaller glacier called Diavolezzafirn had helped it to grow by up to 8 metres in 10 years… Oerlemans says it would take 4000 snow machines to do the job, producing snow by mixing air blasts with water, which cools down through expansion to create ice crystals. The hope is that the water can be “recycled” from small lakes of meltwater alongside the glacier… But the costs… are immense.”

Find out more about how this works here.

Snow cannons like this could help regrow Morteratsch Glacier (Source: Calyponte / Creative Commons)

 

Drones Capture a Major Calving Event

From The Cryosphere: “A high-resolution displacement field is inferred from UAV orthoimages (geometrically corrected for uniform scale) taken immediately before and after the initiation of a large fracture, which induced a major calving event… Modelling results reveal (i) that the crack was more than half-thickness deep, filled with water and getting irreversibly deeper when it was captured by the UAV and (ii) that the crack initiated in an area of high horizontal shear caused by a local basal bump immediately behind the current calving front… Our study demonstrates that the combination of UAV photogrammetry and ice flow modelling is a promising tool to horizontally and vertically track the propagation of fractures responsible for large calving events.”

Find out more about the study here.

Drones are increasingly being used to study glaciers (Source: Creative Commons)