The average air temperature at the Earth's surface has increased by 0.06 degrees C per decade during the 20th century, and by 0.19 degrees C per decade from 1979 to 1998. Climate models generally predict amplified warming in polar regions, as observed in Antarctica's peninsula region over the second half of the 20th century. Although previous reports suggest slight recent continental warming, our spatial analysis of Antarctic meteorological data demonstrates a net cooling on the Antarctic continent between 1966 and 2000, particularly during summer and autumn. The McMurdo Dry Valleys have cooled by 0.7 degrees C per decade between 1986 and 2000, with similar pronounced seasonal trends. Summer cooling is particularly important to Antarctic terrestrial ecosystems that are poised at the interface of ice and water. Here we present data from the dry valleys representing evidence of rapid terrestrial ecosystem response to climate cooling in Antarctica, including decreased primary productivity of lakes (6-9% per year) and declining numbers of soil invertebrates (more than 10% per year). Continental Antarctic cooling, especially the seasonality of cooling, poses challenges to models of climate and ecosystem change.
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... The Antarctic continental deserts, specifically McMurdo Dry Valleys, are considered the coldest and driest on the World (Goordial et al., 2016) comprising the only permafrost with a dry soil layer over ice-cemented ground (Canini et al., 2021;Ottoni et al., 2022). Intriguingly, Doran et al. (2006) registered the large-scale perennial cooling in this area. However, the increasing warming in the Antarctic Peninsula and some other parts of Maritime Antarctica is reported at the same time (Doran et al., 2006;Pires et al., 2017;Royles et al., 2012). ...
... Intriguingly, Doran et al. (2006) registered the large-scale perennial cooling in this area. However, the increasing warming in the Antarctic Peninsula and some other parts of Maritime Antarctica is reported at the same time (Doran et al., 2006;Pires et al., 2017;Royles et al., 2012). All of the processes in the polar regions generated by climate changing listed above affect the living-organism communities (Makhalanyane et al., 2016) and global carbon fluxes (Jenny Liu et al., 2022). ...
Fungi are widely distributed on our planet, including in extremely harsh habitats, such as the polar regions. The extreme conditions of those habitats limit the number of organisms capable of living there, but some fungi are adapted to the polar conditions and play essential roles in nutrient cycling. However, knowledge about their diversity, distribution, and functioning is fragmented, and approaches used to study them are diverse, often yielding difficult-to-compare results. We present maps with locations of mycological studies in the Arctic and Antarctica, as well as a list of mycelial fungi found on various terrestrial substrates through cultivation on nutrient media and/or molecular methods. These fungi were identified to the species level based on morphological-cultural features or gene-sequence analysis. Analysis of the methods applied to study fungi in different substrates shows that a combination of multiple methods is optimal to study species composition. The taxonomic affiliation of the identified species to different fungal divisions is largely determined by habitat conditions and research methods. The largest number of species belongs to the divisions Ascomycota and Basidiomycota. The predominant ecological groups were saprotrophic and symbiotic fungi. The majority of 1324 discovered fungal species are known as cosmopolitan species. Approximately one-fifth of the fungi were identical between the Arctic and Antarctica, only a few species are known to be endemic to Antarctica or Arctic, and there are 1–6 identified bipolar species. Claims of endemism of polar-region fungi are relatively weakly supported.
... Hence, an additional T850 criterion (T850 > 280 K) is included to further distinguish the two systems. Given that the gap that separates the T850 of the vast majority of the polar systems and the T850 threshold is large (∼10 K), and the fact that most of these polar systems reside near the Antarctic continent, where climate cooling has been observed over the past decades (Doran et al., 2002;Oliva et al., 2017), we expect this condition to hold even under worstcase scenarios of global warming, in which the global average temperature is predicted to increase by 4-5 K by the end of the century (Masson-Delmotte et al., 2021). ...
We propose the first unified objective framework (SyCLoPS) for detecting and classifying all types of low‐pressure systems (LPSs) in a given data set. We use the state‐of‐the‐art automated feature tracking software TempestExtremes (TE) to detect and track LPS features globally in ERA5 and compute 16 parameters from commonly found atmospheric variables for classification. A Python classifier is implemented to classify all LPSs at once. The framework assigns 16 different labels (classes) to each LPS data point and designates four different types of high‐impact LPS tracks, including tracks of tropical cyclone (TC), monsoonal system, subtropical storm and polar low. The classification process involves disentangling high‐altitude and drier LPSs, differentiating tropical and non‐tropical LPSs using novel criteria, and optimizing for the detection of the four types of high‐impact LPS. A comparison of our labels with those in the International Best Track Archive for Climate Stewardship (IBTrACS) revealed an overall accuracy of 95% in distinguishing between tropical systems, extratropical cyclones, and disturbances. SyCLoPS produces a better TC detection skill compared to the previous algorithms, highlighted by an approximately 6% reduction in the false alarm rate compared to the previous TE algorithm. The vertical cross section composite of the four types of high‐impact LPS we detect each shows distinct structural characteristics. Finally, we demonstrate that SyCLoPS is valuable for investigating various aspects of LPSs in climate data, such as the evolution of a single LPS track, patterns of LPS frequencies, and precipitation or wind influence associated with a particular LPS class.
... Atmospheric rivers are associated with enhanced precipitation and the extreme temperatures of East Antarctica in March 2022 (Maclennan et al., 2023). After decades of the McMurdo Dry Valleys not demonstrating significant response to anthropogenic greenhouse warming (Doran et al., 2002;Gooseff et al., 2017) as other regions of Antarctica have (Siegert et al., 2023), the 18 March 2022 weather anomaly may be a portent of future climate with warmer temperatures and greater thaw, characteristics of a changing climate regime in this region of Antarctica and new drivers of organismal and ecosystem dynamics. ...
Record high temperatures were documented in the McMurdo Dry Valleys, Antarctica, on 18 March 2022, exceeding average temperatures for that day by nearly 30°C. Satellite imagery and stream gage measurements indicate that surface wetting coincided with this warming more than 2 months after peak summer thaw and likely exceeded thresholds for rehydration and activation of resident organisms that typically survive the cold and dry conditions of the polar fall in a freeze‐dried state. This weather event is notable in both the timing and magnitude of the warming and wetting when temperatures exceeded 0°C at a time when biological communities and streams have typically entered a persistent frozen state. Such events may be a harbinger of future climate conditions characterized by warmer temperatures and greater thaw in this region of Antarctica, which could influence the distribution, activity, and abundance of sentinel taxa. Here we describe the ecosystem responses to this weather anomaly reporting on meteorological and hydrological measurements across the region and on later biological observations from Canada Stream, one of the most diverse and productive ecosystems within the McMurdo Dry Valleys.
... A study and spatial and deep analysis of Antarctic weather data found that the continent cooled between 1966 and 2000, particularly in summer and autumn. The McMurdo Dry Valleys cooled by 0.7 0 C per decade between 1986 and 2000, with similar seasonal trends [16]. ...
It is accepted that energy is among the main, if not the most important, anthropogenic source of carbon dioxide (CO2) emissions. It is for this reason that many efforts are aimed at finding alternative, non-CO2-emitting energy sources. For several decades, large-scale projects have been invested in the construction of solar and wind power plants, which are claimed to be the most environmentally friendly way to obtain energy. Today, the European Green Deal and international climate policy are currently among most actual topical political and economic topics. How true is this and is this energy capable of solving the “greenhouse effect” problem? Is it capable of meeting our needs for reliable, consistent and cheap energy? Is the “greenhouse effect” caused by human activity at all? These are questions that this article seeks to answer. I am well aware that I am going to violate the purportedly consensual, common understanding of these matters I am also aware of the existence of certain, albeit unwritten, limitations in expressing opinions on these issues. But I am convinced that science is a sequence of stated hypotheses, their denial, challenge, improvement, modification and so on. That is, science is not a place for searching for consensus, but for a productive dispute leading to the correct conclusions.
... Differently from the large increase in temperature over the Arctic and the Third Pole, the variations in Antarctic temperature show regional differences and are sensitive to the selected time period. For the second half of the 20th century, the Antarctic Peninsula and West Antarctica displayed rapid warming, whereas the analysis of Antarctic meteorological data reflects a net cooling on the Antarctic continent in this period [23][24][25][26]. However, the spatial distribution of changes in Antarctic temperature has changed since the beginning of the 21st century. ...
Polar amplification appears in response to greenhouse gas forcing, which has become a focus of climate change research. However, polar amplification has not been systematically investigated over the Earth’s three poles (the Arctic, Antarctica, and the Third Pole). An index of polar amplification is employed, and the annual and seasonal variations of land surface temperature over the Earth’s three poles are examined using MODIS (Moderate Resolution Imaging Spectroradiometer) observations for the period 2001–2018. As expected, the warming of the Arctic is most conspicuous, followed by the Third Pole, and is weakest in Antarctica. Compared to the temperature changes for the global land region, positive polar amplification appears in the Arctic and the Third Pole on an annual scale, whereas Antarctic amplification disappears, with a negative amplification index of −0.72. The polar amplification for the Earth’s three poles shows seasonal differences. Strong Arctic amplification appears in boreal spring and winter, with a surface warming rate of more than 3.40 times the global mean for land regions. In contrast, the amplification of the Third Pole is most conspicuous in boreal summer. The two poles located in the Northern Hemisphere have the weakest amplification in boreal autumn. Differently from the positive amplification for the Arctic and the Third Pole in all seasons, the faster variations in Antarctic temperature compared to the globe only appear in austral autumn and winter, and the amplification signal is negative in these seasons, with an amplification index of −1.68 and −2.73, respectively. In the austral winter, the strong negative amplification concentrates on West Antarctica and the coast of East Antarctica, with an absolute value of amplification index higher than 5 in general. Generally, the polar amplification is strongest in the Arctic except from June to August, and Antarctic amplification is the weakest among the Earth’s three poles. The Earth’s three poles are experiencing drastic changes, and the potential influence of climate change should receive attention.
... Unlike more temperate desert environments on Earth, the MDVs host significant reservoirs of water stored as glacial ice, shallow subsurface ice (i.e., permafrost), and surficial snow deposits. Climate models predict significant warming over East Antarctica through the year 2100 at a projected rate of +0.03 • C yr −1 [79], despite the modest cooling observed in the MDVs in the 1990s and early 2000s [80]. Ref. [47] demonstrates how some of these reservoirs are only metastable under current Antarctic environmental conditions, not only due to rising temperatures, but also due to the complex interplay between soil thermophysics and sediment/albedo feedback, resulting in insolation-driven melting. ...
Available soil moisture is thought to be the limiting factor for most ecosystem processes in the cold polar desert of the McMurdo Dry Valleys (MDVs) of Antarctica. Previous studies have shown that microfauna throughout the MDVs are capable of biological activity when sufficient soil moisture is available (~2–10% gravimetric water content), but few studies have attempted to quantify the distribution, abundance, and frequency of soil moisture on scales beyond that of traditional field work or local field investigations. In this study, we present our work to quantify the soil moisture content of soils throughout the Fryxell basin using multispectral satellite remote sensing techniques. Our efforts demonstrate that ecologically relevant abundances of liquid water are common across the landscape throughout the austral summer. On average, the Fryxell basin of Taylor Valley is modeled as containing 1.5 ± 0.5% gravimetric water content (GWC) across its non-fluvial landscape with ~23% of the landscape experiencing an average GWC > 2% throughout the study period, which is the observed limit of soil nematode activity. These results indicate that liquid water in the soils of the MDVs may be more abundant than previously thought, and that the distribution and availability of liquid water is dependent on both soil properties and the distribution of water sources. These results can also help to identify ecological hotspots in the harsh polar Antarctic environment and serve as a baseline for detecting future changes in the soil hydrological regime.
... They are considered important refuges for species during extreme temperature and drought events and support microbial interactions, element cycling and ecosystem functions (Dupraz et al., 2009). Antarctic glacier ecosystems are characterized by low annual average temperatures (below −19.8°C) and precipitation (below 100 mm/year water equivalent) and a dry atmosphere (rapid evaporation is driven by low humidity due to katabatic winds), which place severe limitations on biological activity (Doran et al., 2002). However, the potential role of microbial mats in the alteration of Earth's biogeochemical cycling is challenging to determine because these mats are generally not well studied (Bolhuis & Stal, 2011;Liu et al., 2011). ...
Glaciers cover nearly 10% of the Earth's surface and are unique biomes dominated by microbial communities that support key ecosystem processes. The melting of glaciers is among the most conspicuous consequences of global climate change, with impacts on microbial ecology and associated biogeochemistry. However, we are still missing an integrative understanding of microbial biodiversity from divergent habitats associated with glaciers.
Here, we compiled global microbiome metadata from 93 representative glaciers over 180 locations and used random forest, microbial ecological networks and structural equation modelling to evaluate the biodiversity and environmental factors associated with the glacier microbiomes of seven contrasting habitats: water, epilithic biofilm, cryoconite, mat, ice, sediment and permafrost soil.
The results showed that microbial diversity largely changed across habitats, with the highest in permafrost soil, followed by sediment, ice, mat, cryoconite, water and epilithic biofilm. More importantly, we provided critical evidence that the environmental and climatic factors associated with the microbiomes of glaciers varied with glacier habitats. Microbial diversity in water was highly correlated with latitude, cryoconite microbial diversity was significantly (p = 0.01) correlated with pH, and permafrost soil and sediment microbial diversity were mainly explained by temperature (17.05% and 13.37% respectively).
Using ecological association network analysis, we identified some tightly linked common microbial taxa (e.g. Proteobacteria and Bacteroidetes) that were present in all the habitats and were vulnerable to climatic factors, such as temperature and precipitation. This study demonstrated that microbial diversity, drivers and co‐occurrence patterns differ among glacier habitats globally, and diverse habitat‐dependent glacier microbiomes could serve as early warning sentinels for the study of life on glaciers and its potential future in a warming world.
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Existence of life outside the Earth is a mystery that human beings have been searching for centuries. In the past few decades, discovering microbes in extremely terrestrial habitats has opened a gateway to the possible existence of life on Mars. This review presented evidence of microbial life in extremely dry environments such as the Atacama Desert and McMurdo Dry Valleys, which serve as possible analogues for Martian conditions. The survival strategies of microbes, including their ability to penetrate rock pores and cave-like features in these extreme environments, highlighted the potential parallels in life strategies on Mars. It offered insights into how extraterrestrial life might have originated, evolved, and migrated between planets. Moreover, the review discussed the challenges associated with finding extraterrestrial life and proposed strategies to overcome these obstacles. Deep multidisciplinary investigations, approached with great caution, are imperative for detecting signs of life on the Red Planet and ensuring the survival of the human community.
High-latitude meromictic lakes such as those in the Antarctic McMurdo Dry Valleys (MDV) harbor aquatic ecosystems dominated by the microbial loop. Within this habitat, which is limited year-round by light and nutrients, protists, or single celled eukaryotes, play outsized roles in the food web as the dominant primary producers and the apex predators. Thus, the MDV lake ecosystem represents an ideal system to study the role of sentinel protist taxa in carbon and nutrient cycling. The perennially ice-covered lakes are part of the McMurdo Long Term Ecological Research (McM LTER; mcmlter.org) established in 1993. In this review we will highlight the diversity and trophic roles of the MDV lake protist community and compare environmental factors driving spatiotemporal patterns in key protist taxa in two lakes within the McM LTER, Lakes Bonney and Fryxell. We will then discuss lessons learned from manipulated experiments on the impact of current and future climate-driven environmental change on sensitive protist taxa. Last, we will integrate knowledge gained from 25 years of lab-controlled experiments on key photosynthetic protists to extend our understanding of the function of these extremophiles within the MDV aquatic food webs. Our research group has studied the distribution and function of the MDV microbial community for nearly two decades, training the next generation of scientists to tackle future problems of these globally significant microbes. This review article will also highlight early career scientists who have contributed to this body of work and represent the future of scientific understanding in the Anthropocene.
Soils in the Antarctic Dry Valleys have been significantly influenced by soil formation factors such as parent material, climate, and topography. Factors common in more temperate zones, including chemical weathering and leaching of minerals, occur to a much lesser extent in these cold arid soils, leading to an accumulation of salts and bases, which will likely affect the distribution of soil biota. Since the intensity of these factors may vary with topography, this study examined the soil properties and soil invertebrate communities along an elevational gradient in Taylor Valley, Antarctica. We sampled from two spatial scales (1 X 1 m and 10 X 10 m) at three sites (83, 121, and 188 m a.s.l) on the south side of Lake Hoare in Taylor Valley, and examined soil moisture, nitrogen, carbon, pH, and electrical conductivity (which provides an estimation of soil salinity), as well as the distribution and community structure of soil invertebrates. We found significant differences in soil properties with elevation, along with associated differences in soil communities. Biodiversity was greatest at the lowest elevation, closest to the shore of Lake Hoare, where soil moisture, carbon, and nitrogen were highest, and salinity was lowest. Scottnema lindsayae dominated the nematode communities found at all sites. Electrical conductivity was higher and carbon and nitrogen contents were lower at the upper elevations. The distribution of both Eudorylaimus and Plectus appeared to be influenced by soil moisture; electrical conductivity affected the mortality of all three nematode genera found. Soil properties did differ with sampling scale, suggesting that changes in microhabitats not detected at sampling intervals of a meter or more may be more reliably detected by sampling at a smaller scale.
We are studying the distribution, biodiversity, and abundance of nematodes in the most extreme terrestrial environment on earth, the Dry Valley region of Antarctica. Here we report that the nematode community structure of 1-3 species in two functional groups may be the simplest soil food web of any terrestrial ecosystem. Nematodes were widespread and not correlated with moisture, C, or N, factors that define soil biotic complexity elsewhere. In a field experiment, treatments increasing soil water, carbon, and temperature, alone or in combination, generally decreased the abundance of the single omnivore-predator species and increased the abundance of its microbivorous prey species. These low-diversity nematode communities, limited to ≤3 species, apparently lack species redundancy and appear sensitive to environmental change. Our findings suggest that Antarctic soil ecosystems are sensitive to anthropogenic disturbance.