Late Quaternary Meltwater Pulses and Sea Level Change
From Journal of Quaternary Science: “After the Last Glacial Maximum (LGM) global mean sea level (GMSL) rise was characterized by rapid increases over short (decadal to centennial) timescales superimposed on a longer term secular rise and these have been termed meltwater pulses (MWPs). In this paper we review the timing, impact and nature of these and the effects of rapid drainage of large post‐glacial MWPs into the world’s oceans. We show that drainage of the known post‐glacial lakes in total produced less than around 1.2 m of the 125 m of GMSLR since the LGM.”
Island Biogeography of Cryoconite Hole Bacteria in Antarctica
From Frontier in Ecology and Evolution: “Cryoconite holes are holes in a glacier’s surface caused by sediment melting into the glacier. These holes are self-contained ecosystems that include abundant bacterial life within their sediment and liquid water, and have recently gained the attention of microbial ecologists looking to use cryoconite holes as “natural microcosms” to study microbial community assembly. This article applies models of island ecosystems to these holes because they are very much like islands in the sea, surrounded by a barrier to entry. ”
From JGR Atmospheres:” A study of using the bulk method to quantify the turbulent air flow and sublimation/condensation over glacier in August-One Glacier, Qilian Mountains, China. This article addresses the patterns of warming at different wind speeds. We tried to acquire reliable varying and intrinsic aerodynamic roughness length for momentum through its parametric analysis.”
From Chinese Academy of Sciences: “Xinjiang, a land of mountains, forests and deserts, is four times the size of California and is home to 20,000 glaciers — nearly half of all the glaciers in China. Since the 1950s, all of Xinjiang’s glaciers have retreated by between 21 percent to 27 percent.”
From Sonic Skills: “In early 2015, an international group of geophysicists published an article claiming that particular patterns in the sounds of glaciers might reveal where and how those glaciers were calving. They had made sound recordings with hydrophones—underwater microphones—and taken photos at the same time. This enabled them to link various glacier sounds to distinct forms of ablation through ‘acoustic signatures.’”
Read more about glaciers’ signature acoustics here.
Cryoconite Holes on the Qaanaaq Glacier
From Annals of Glaciology: “Cryoconite holes are water-filled cylindrical holes formed on ablation ice surfaces and commonly observed on glaciers worldwide.. Results suggest that the dimensions of holes drastically changed depending on the weather conditions and that frequent cloudy, warm and windy conditions would cause a decay of holes and weathering crust, inducing an increase in the cryoconite coverage on the ice, consequently darkening the glacier surface.”
Read more about cryoconite holes and glacial darkening here.
Drifting Icebergs, Bacterial Activity and Aquatic Ecosystems
From BioOne Complete: “The number of icebergs produced from ice-shelf disintegration has increased over the past decade in Antarctica. These drifting icebergs mix the water column, influence stratification and nutrient condition, and can affect local productivity and food web composition. Data on whether icebergs affect bacterioplankton function and composition are scarce, however. We assessed the influence of iceberg drift on bacterial community composition and on their ability to exploit carbon substrates during summer in the coastal Southern Ocean. An elevated bacterial production and a different community composition were observed in iceberg-influenced waters relative to the undisturbed water column nearby.”
The Tibetan Plateau and Cryoconite Bacterial Communities
From Oxford Academic: “Cryoconite holes, water-filled pockets containing biological and mineralogical deposits that form on glacier surfaces, play important roles in glacier mass balance, glacial geochemistry and carbon cycling. The presence of cryoconite material decreases surface albedo and accelerates glacier mass loss, a problem of particular importance in the rapidly melting Tibetan Plateau.”
From BioOne Complete: “This paper contributes to studies on the lichen biota of Arctic glacier forelands. The research was carried out in the moraines of three different glaciers in Svalbard: Longyearbreen, Irenebreen and Rieperbreen. In total, 132 lichen taxa and three lichenicolous lichens were recorded. Eight species were recorded for the first time in the Svalbard archipelago: Arthonia gelidae, Buellia elegans, Caloplaca lactea, Cryptodiscus pallidus, Fuscidea kochiana, Merismatium deminutum, Physconia distorta, and Polyblastia schaereriana. One species, Staurothele arctica, was observed for the first time in Spitsbergen (previously recorded only on Hopen island).”
In recent years, scientists have found other locations on planets, moons and exoplanets where life might exist. Different animals and organisms like tardigrades (eight-legged microscopic animals commonly known as water bears) have also been sent into space to explore the conditions for survival away from Earth. However, a recent paper published in the journal Contemporary Trends in Geoscience argues that we can look closer to home to understand survival strategies of extraterrestrial life.
More concretely, the authors propose we look to glacier cryoconites, which are granular or spherical mineral particles aggregated with microorganisms like cyanobacteria, algae, fungi, tardigrades and rotifera (another type of multicellular, microscopic animal). Glaciers are among the most extreme environments on Earth due to the high levels of ultraviolet (UV) radiation received and the permanently cold conditions. These factors make them analogous to icy planets or moons.
The associations of cryoconites and microorganisms on glaciers are held together in biofilms by extracellular polymeric substances (natural polymers of high molecular weight) secreted by cyanobacteria. They exist as sediment or in cryoconite holes (water-filled reservoirs with cryoconite sediment on the floor) on glacier surfaces.
Cryoconites have been found on every glacier where researchers have looked for them. Cryoconite holes form due to the darkening of color (also termed a decrease in the albedo, or reflectivity of solar radiation) of cryoconite-covered surfaces. The darker color leads to greater absorption of radiation, with an associated warming and increasing melt rates.
“Today we think that simple life forms might have survived on Mars in glacial refugia or under the surface. They can and could have evolved on Saturn and Jupiter’s icy moons,” Krzysztof Zawierucha, the lead author from Adam Mickiewicz University in Poland, shared with GlacierHub. “Imagine a multicellular organism, even a microscopic one, which is able to live and reproduce on an icy moon… It is a biotechnological volcano.”
Organisms that live in glaciated regions are adapted to survive in extreme conditions and could provide insights into the survival strategies of extraterrestrial life. Some possess lipids (organic compounds that are not water-soluble), and produce proteins and extracellular polymeric substances that protect them from freezing and drying. Others are able to enter cryptobiotic states in which metabolic activity is reduced to an undetectable level, allowing them to survive extremely harsh conditions.
The microorganisms in cryoconites cooperate and compete, affecting each other’s survival responses. Therefore, previous astrobiological studies, which have only been conducted on single strains of microorganisms, may not reflect the true survival mechanisms of these microorganisms.
In addition, previous astrobiological studies involving some of these microorganisms used terrestrial or limno-terrestrial (moist terrestrial environments that go through periods of immersion and desiccation) taxa, such as moss cushions, which are less likely to be well-adapted to icy planets than their glacier-dwelling cousins.
Tardigrades found in cryoconite have black pigmentation, which probably protects them from high UV radiation. Along with tardigrades, glacier-dwelling rotifera, specifically Bdelloidea, also possess a great ability to repair DNA damage, which confers high resistance to UV radiation. Both may also be better adapted to surviving in constantly near-freezing conditions than terrestrial forms.
“So far, a number of processes analogous to those on Mars and other planets or moons have been found in the McMurdo Dry Valley as well as other dry valleys or brines in sea ice, both of which were considered to be extraterrestrial ecosystem analoguos. There is a great body of evidence that some bacteria and microscopic animals like tardigrades may survive under Martian conditions,” Zawierucha explained.
“Of course, to survive does not mean to be active and to reproduce. Undoubtedly, however, it triggers consideration regarding life beyond Earth, especially in close proximity or connection with permafrost or ice,” he added.
As such, further research about cryoconites could provide insight to mechanisms that enable organisms to survive such extreme conditions. At the same time, cryoconites could also be used in future astrobiological studies to understand how life on other planets functions.
Each week, we highlight three stories from the forefront of glacier news.
Holes in Glaciers May Harbor Unique Flora
From Czech Polar Reports – Masaryk University:
“Cryoconite holes are small, extreme habitats, widespread in the ablation zones of glaciers worldwide. They can provide a suitable environment for microorganisms including bacteria, cyanobacteria, algae, fungi, and invertebrate
s. Diatoms have been previously recovered from cryoconite holes of Greenland and of Svalbard, and recent findings from Antarctica suggest that cryoconite holes may harbor a unique diatom flora distinct from other aquatic habitats nearby. In the present study, we characterize the diatom communities of Nordenskiöld glacier cryoconite holes in Billefjorden (Svalbard, Spitsbergen), and multivariate approaches were used to compare them with three freshwater localities in the immediate vicinity to investigate possible sources of the species pool.”
Read more about what may be using holes in glaciers as habitats.
Wedding Inside Icelandic Glacier
From Iceland Magazine:
“The first wedding ceremony to take place inside Langjökull, Iceland’s second largest glacier, happened last week when British couple Anthony and Mari were joined in marriage.
Travel organiser Pink Iceland assisted the couple with their wedding plans, which began over a year ago. The bride and groom and their guests stayed at Hótel Húsafell, West Iceland, and the wedding location was kept secret up until the last moment. “After breakfast we made sure all the guests were well dressed. Then a number of super jeeps picked up the group and drove them up onto the glacier,” Eva María Þórarinsdóttir, one of Pink Iceland’s owners, told Vísir.”
“Argentina’s massive Perito Moreno glacier this week began the process leading to its cyclical rupture, a spectacular event involving the collapse of huge masses of ice that draw thousands of tourists and that has not happened since 2012.
“The Perito Moreno Glacier began its breakup process. We’re waiting! (We) came to experience it firsthand!,” said the Tourism Secretariat of El Califate, a city some 80 km (50 mi.) from the glacier, Tuesday on Twitter.
Before the big show, a huge number of tourists and the news media began arriving at the Los Glaciares National Park in the southern province of Santa Cruz, which receives some 700,000 tourist each year.
“It’s not known how long it’s going to take. We only know from earlier experiences. In the last breakups starting from the moment when the outflow starts, which is what happened this morning, the process normally takes … three or four days,” park official Matilde Oviedo told EFE.”
See more of the video here and read more about the event here.