A Comparison of Relict and Active Terrestrial Patterned Ground as an Analog for Mars

Patterned ground is a ubiquitous landform in periglacial regions of Earth and is also present across the mid to high latitudes of Mars. The association of terrestrial patterned ground to the presence of subsurface water ice in the form of permafrost that develops a seasonal ‘wet’ active layer during the summer thaw prompted further investigation of patterned ground on Mars. The Phoenix spacecraft was sent to the surface of the north polar plains of Mars to investigate an area of patterned ground where water ice was predicted to occur. The confirmation of subsurface water ice at the Phoenix landing site confirmed the hypothesis that water ice and patterned ground on Mars are intricately linked, however outstanding questions remain regarding the mode of formation of martian patterned ground. Dry modification via sublimation and thermal-driven processes are possible under present-day climate conditions, however warmer climate conditions are predicted to have occurred during past periods of high obliquity and could have supported periglacial freeze-thaw modification of patterned ground on Mars. Understanding the extent to which liquid water may have been available in the recent geological history of Mars is important to constraining past habitability as well as identifying resources for future long-duration human exploration. It is suggested that if patterned ground on Mars experienced periglacial modification in the past, then it currently exists in a relict form. This research examines the morphometry and surface roughness parameters of active and relict terrestrial patterned ground sites in conjunction with evaluations of martian patterned ground to identify parameters that may assist with ongoing efforts to determine the age and modes of historical modification of patterned ground on Mars

Leveraging the UAV to support Chinese Antarctic expeditions: a new perspective

Recent developments in Unmanned Aerial Vehicles (UAVs) and their applications in various subjects are of interest to polar communities. Due to the harsh climate and dangerous environment, these regions pose challenges for the expedition teams. Several countries have tested the UAV technology to support Antarctic research and logistics. In this trend paper, we provide insightful reviews and discussions on such a prospective topic. Based on a comprehensive literature survey, we firstly summarize the key research progress of UAV in Antarctic studies. Then the examples of risk scenarios during the field exploration are given, after which several promising applications of the UAVs in safety guarantee are illustrated. In particular, we present a case of site-selection for the Chinese first ice sheet airfield, using the data collected in the 34th Chinese National Antarctic Research Expedition (CHINARE). In the end, we highlight the unique value of the UAVs in the popularization of polar science before concluding the advantages and limitations. Considering their excellent performance, we expect more innovations for UAV’s applications in the following Antarctic expeditions

UAVs for Science in Antarctica

Remote sensing is a very powerful tool that has been used to identify, map and monitor Antarctic features and processes for nearly one century. Satellite remote sensing plays the main role for about the last five decades, as it is the only way to provide multitemporal views at continental scale. But the emergence of small consumer-grade unoccupied aerial vehicles (UAVs) over the past two decades has paved the way for data in unprecedented detail. This has been also verified by an increasing noticeable interest in Antarctica by the incorporation of UAVs in the field activities in diversified research topics. This paper presents a comprehensive review about the use of UAVs in scientific activities in Antarctica. It is based on the analysis of 190 scientific publications published in peer-reviewed journals and proceedings of conferences which are organised into six main application topics: Terrestrial, Ice and Snow, Fauna, Technology, Atmosphere and Others. The analysis encompasses a detailed overview of the activities, identifying advantages and difficulties, also evaluating future possibilities and challenges for expanding the use of UAV in the field activities. The relevance of using UAVs to support numerous and diverse scientific activities in Antarctica becomes very clear after analysing this set of scientific publications, as it is revolutionising the remote acquisition of new data with much higher detail, from inaccessible or difficult to access regions, in faster and cheaper ways. Many of the advances can be seen in the terrestrial areas (detailed 3D mapping; vegetation mapping, discrimination and health assessment; periglacial forms characterisation), ice and snow (more detailed topography, depth and features of ice-sheets, glaciers and sea-ice), fauna (counting penguins, seals and flying birds and detailed morphometrics) and in atmosphere studies (more detailed meteorological measurements and air-surface couplings). This review has also shown that despite the low environmental impact of UAV-based surveys, the increasing number of applications and use, may lead to impacts in the most sensitive Antarctic ecosystems. Hence, we call for an internationally coordinated effort to for planning and sharing UAV data in Antarctica, which would reduce environmental impacts, while extending research outcomes.info:eu-repo/semantics/publishedVersio

Minulé a současné charakteristiky a formy vázané na permafrost a činnou vrstvu jako indikátory pozdně kvartérních změn přírodního prostředí

Late Quaternary has seen numerous major permafrost expansions and retreats associated with alternating glacial and interglacial periods as well as stadials and interstadials, the research of which is necessary to understand the past environmental evolution, but also provides useful analogues for its present-day and future behaviour. How- ever, observations of permafrost and active-layer phenomena are still limited, and sometimes misleading, even in many present-day permafrost regions, and naturally less comprehensive evidence is available from areas where permafrost existed in the past. The thesis provides comprehensive information on the distribution and morphology of mostly relict patterned ground and rock glaciers in the High Sudetes Mts. and in the Western and High Tatra Mts., respectively, which are the most widespread permafrost features that occur in these Central European mountain ranges situated north of the Alps. It shows that the landforms are closely related to increased severity of climates and/or sparser vegetation at higher elevations and as such they attest to the environmental conditions, which prevailed there towards the end of the Last Glacial Period to the early Holocene, but also to their current states. Similar elevation trends in the pattern morphology are also documented for...V pozdním kvartéru došlo v d̊usledku sťrídání glaciálních a interglaciálních období i stadiál̊u a interstadiál̊u k ̌cet- ným rozší̌rením a ústup̊um permafrostu, jehož výzkum je nezbytný pro pochopení vývoje p̌rírodního prosťredí v minulosti, ale poskytuje cenné informace i z hlediska jeho soǔcasné a budoucí dynamiky. Pozorování charak- teristik a forem vázaných na permafrost a ̌cinnou vrstvu jsou však stále nedostatěcná a ňekdy také zaváďející i v mnoha oblastech se soǔcasným výskytem permafrostu a mnohem méňe informací je k dispozici z region̊u, kde se permafrost nacházel v minulosti. Disertǎcní práce poskytuje ucelené informace o rozší̌rení a morfologii p̌revážňe reliktních strukturních p̊ud a kamenných ledovc̊u ve Vysokých Sudetech a Západních a Vysokých Tatrách, jež jsou nejrozší̌reňejšími formami vázanými na permafrost, které se v ťechto sťredoevropských pohǒrích severňe od Alp vyskytují. Je ukázáno, že tyto tvary reliéfu mají ťesnou vazbu na zvyšující se drsnost klimatických podmínek a ubývání vegetace sm̌erem do vyšších nadmǒrských výšek a jako takové sv̌eďcí o p̌rírodních podmínkách, které zde panovaly ke konci posled- ního glaciálu a na pǒcátku holocénu, jakož i o jejich soǔcasném stavu. Obdobné výškové trendy v morfologii struk- turních p̊ud jsou dokumentovány také pro...Department of Physical Geography and GeoecologyKatedra fyzické geografie a geoekologiePřírodovědecká fakultaFaculty of Scienc

A Periglacial Landsystem Analysis in the Canadian High Arctic: A Tool for Planetary Geomorphology

Permafrost underlies 50% of Canada’s terrain and underlies 24% of the Earth’s total land area. It is a major driving force in the generation and evolution of patterned ground landforms such as polygons, stone circles, mud boils, and stripes, etc. that are seen on both the surface of the Earth and Mars, specifically in periglacial domains. The distribution of subsurface ice in these landforms (i.e. polygonal terrain) on Earth is a key constraint on past climate and process-form relationships in high arctic and periglacial regions. These landforms also have the potential of storing ice in the subsurface meaning that the volumetric concentration of buried ice can provide information about the processes that led to its deposition. In this research, two Canadian High Arctic study sites were analyzed: Strand Fiord, Axel Heiberg Island (ᐅᒥᖕᒪᑦ ᓄᓈᑦ, Umingmat Nunaat) and Haughton River Valley, Devon Island (ᑕᓪᓗᕈᑎᑦ, Tallurutit). Methods in this research involved the utilization of (1) ground penetrating radar (GPR) for 3D ice-wedge volume estimation, (2) Light Detection and Ranging (LiDAR) for hyper-resolution digital elevation model (DEM) generation and quantifying the degree of spatial sorting in patterned ground using Kernel Density Estimation (KDE), (3) sedimentology for grain size and facies association in order to infer depositional environment, (4) fieldwork notes and measurement, and (5) drone and aerial photos for 3D photogrammetry models. In Strand Fiord, ice-wedge geometry and volume were calculated to be asymmetric and 43.28 m3 respectively in a 25 m x 25 m grid within the study area; ice-wedge polygons were associated with areas of active transition (i.e. secondary/tertiary polygons that have experienced multiple episodes of cracking). In the Haughton River Valley, patterned ground spatial distribution and sorting were related to the local periglacial region such as microtopography, slope and lithology wherein fine (clay, sand) sediments were often associated with the formation of frost-shattered nets, polygons, and mud boils in plateau tops, while the coarse (gravel, cobble) sediments were associated with stone circles and stripes on the valley floor/slopes. This research establishes the constituents of a periglacial landsystem and its significance as a foundation for the development of more comprehensive models that may be used to enhance understanding of the process-form relationships in the periglacial Arctic and further, ice-rich planetary systems

On active layer processes and landforms in western Dronning Maud Land, Antarctica

Permafrost is a variable in Antarctic terrestrial ecosystems, and the role it plays in the cryosphere is not well understood. There is much still to be learnt about the thermal state, physical properties, thickness and age of permafrost in Western Dronning Maud Land (WDML). Active layer dynamics and observed change over time have the potential to improve our knowledge of climate change. Understanding the effects of a warming climate on permafrost can also be of benefit to infrastructure, especially in areas with a large amount of frozen ground such as Scandinavia, Canada and Russia. Active layer and permafrost dynamics of WDML, Antarctica, are presented and discussed using data from six study sites, namely the Robertskollen, Vesleskarvet, Flarjuven, Grunehogna, Slettjfell nunataks and the Troll research station in the Jutulsessen area. Ground and ambient air temperature, as well as ground moisture data were collected for each site. An inventory of active layer and permafrost landforms was compiled, as were the frequency of cycles over the zero-degree isotherm, and the depth of the active layer. Furthermore, 3D models, geo-referenced maps and Digital Elevation Models were created of study areas with the use of an Unmanned Aerial Vehicle (UAV). Polygonal features are the most common landscape feature and are common to most of the study sites. Robertskollen has the deepest active layer at over 66cm and Slettfjell the shallowest at 9cm. A maximum recorded air temperature of 8.76°C (10/11/2014) occurred at Troll with the second highest maximum of 6.77°C (22/12/2010) recorded at Vesleskarvet. Robertskollen has the highest observable biological growth and a maximum recorded ground temperature of 22.84°C (10/01/2014). Troll and Valterkulten, registered the second and third highest ground temperatures respectively. The high ground Temperature observed for Robertskollen may be ascribed to it being the lowest altitude site. The highest number of cycles over the zero-degree isotherm was observed at Troll (11.01%), followed by Robertskollen (10.99%). For relatively warm areas, such as Robertskollen it is recommended that two metre borehole loggers are installed in order to capture a detailed understanding of the active layer. The UAV proved to be a beneficial tool for capturing aerial photographs for post fieldwork analysis and 3D modelling

Predicting Water Availability in the Antarctic Dry Valleys using Geographic Information Systems and Remote Sensing

Water is one of the most important ingredients for life on Earth. The presence or absence of biologically available water determines whether or not life will exist. Antarctica is an environment where abiotic constraints, particularly water, strongly influence the distribution and diversity of biota. As Antarctic biology is relatively simple when compared to more temperate climates, it is a prime location for researching constraints on biodiversity, and what may be the impacts of changes to these constraints resulting from climate change and human disturbance. This research uses Geographic Information Systems (GIS) and remote sensing to develop a relative water availability index of three Dry Valleys in Southern Victoria Land, Antarctica. This study area is being used for the IPY Terrestrial Biocomplexity project, an international collaboration researching the distribution, diversity and complexity of biology in the Dry Valleys. The development of a predictive water availability model will contribute greatly to their research goals. This thesis describes the sources of biologically available water in the Dry Valleys and its interaction with biota. Remotely sensed data of these sources is gathered and various methods of analysing the data are explored. This includes creating a mean snow cover distribution model from MODIS data over 4 summer seasons, and Landsat7 ETM+ surface temperature data. These data sets, combined with a high resolution LIDAR Digital Elevation Model and glacier and lake locations, are then analysed with GIS to produce a Compound Topographic Index (CTI), a model showing the likely accumulation and dispersal of liquid water given the spatial distribution of water sources and the flow of water over the terrain according to the influence of gravity. Visualisation techniques are used to validate the resulting model, including the use of 3D visualisation and comparison of drainage patterns using overlays of a high resolution ALOS image. This research concludes that GIS and remote sensing are valuable tools for predicting water distribution in Antarctica. Although cloud cover, varied illumination and differing spatial resolutions can create limitations, remote sensing's cost effective and environmentally sound method of data capture and the computational and spatial modelling capabilities of GIS make their use well suited to the Antarctic environment

Antarctic ice rises and rumples: Their properties and significance for ice-sheet dynamics and evolution

Locally grounded features in ice shelves, called ice rises and rumples, play a key role buttressing discharge from the Antarctic Ice Sheet and regulating its contribution to sea level. Ice rises typically rise several hundreds of meters above the surrounding ice shelf; shelf flow is diverted around them. On the other hand, shelf ice flows across ice rumples, which typically rise only a few tens of meters above the ice shelf. Ice rises contain rich histories of deglaciation and climate that extend back over timescales ranging from a few millennia to beyond the last glacial maximum. Numerical model results have shown that the buttressing effects of ice rises and rumples are significant, but details of processes and how they evolve remain poorly understood. Fundamental information about the conditions and processes that cause transitions between floating ice shelves, ice rises and ice rumples is needed in order to assess their impact on ice-sheet behavior. Targeted high-resolution observational data are needed to evaluate and improve prognostic numerical models and parameterizations of the effects of small-scale pinning points on grounding-zone dynamics

Phylogeography of Austral soil invertebrates

Soil invertebrates are terrestrial animals belonging to ancient phyla that emerged almost half a billion years ago. They have since spread throughout all known landmasses, with contemporary distributions governed by geological and environmental change across spatial and temporal gradients across the globe. However, limited knowledge of southern hemisphere (Austral) species hampers our ability to discern the general patterns of distribution and speciation. The lack of robust taxonomic information has also constrained our understanding of the evolutionary relationships and functional roles of the diverse soil fauna. This thesis capitalises on the development in molecular tools and improved sequence libraries to explore the factors that define the distribution and diversity of common soil invertebrates, specifically oribatid mites (Acari), springtails (Collembola) and nematodes (Nematoda). I investigated communities at continental-scales from maritime Antarctica and Australia to enable greater resolution of the drivers of distribution that might be applicable to southern hemisphere taxa more broadly. In a literature review I introduce the bioinformatic approaches using phylogeography to resolve evolutionary theories concerning soil fauna indigenous to Antarctica. Phylogenetic evidence supports most soil faunal groups as having ancient origins, refugial survival and repeated colonisation, whilst also highlighting the benefits of comparative analyses over larger scales. In addition, I show in a perspectives paper that morphological and functional traits are phylogenetically constrained in nematodes and springtails, allowing function to be partially conferred for ‘unknown’ species using sequencing approaches. Baseline biodiversity across a transect through maritime Antarctica found contrasting distributions of mites and springtails and the influences of climatic factors at broad scales and soil microhabitat conditions at local scales. Detailed population genetic analysis of genotypes of the oribatid mites Podacarus auberti and Membranoppia loxolineata alongside the springtail Cryptopygus antarcticus revealed the importance of multiple dispersal events in their ancestral past, supporting theories of refugial survival. Comparative analysis of phylogeographic reconstructions with an analogous Australian transect highlighted that the importance of dispersal differs among mites and springtails and supported the influences of climate and edaphic factors on assemblage structure. These different influences of biogeography and climatic variability related to inherent morphological and physiological traits of the study organisms demonstrate potentially contrasting responses to future episodes of environmental change. With such knowledge, conservation strategies of Austral soil fauna can be re-focussed to ensure their continued persistence in terrestrial ecosystems

Do terrestrial ectoparasites disperse with penguins?

Dispersal plays a critical role in evolution. Rare long-distance movements can lead to allopatric speciation, whereas frequent movements can facilitate gene flow among disjunct populations and prevent divergence. Dispersal between populations of a species may be difficult to observe directly, and is often inferred from indirect measures such as species occurrence data. Increasingly, however, high resolution genomic data are being used to clarify dispersal and gene flow, in many cases contradicting past assumptions. Islands are excellent model regions for investigating dispersal as they offer replicated habitats with clear geographic boundaries. The sub-Antarctic comprises some of the most geographically isolated island ecosystems in the world, representing an ideal model system for assessing the evolutionary consequences of long-distance dispersal. Strong winds, circumpolar oceanic currents, and extreme climatic cycles are thought to have effectively isolated many sub-Antarctic ecosystems, but a growing body of molecular evidence is beginning to question this rhetoric, with numerous species showing connectivity across the region. Connectivity patterns are, however, complex and are not always predictable from an organism’s inferred dispersal capacity. With environmental change placing unprecedented pressure on isolated ecosystems, there is a pressing need for improved understanding of dispersal processes and population connectivity via genomic analyses of diverse taxa. A number of sub-Antarctic species exhibit gene flow across the region despite lacking active long-distance dispersal capabilities. Brooding, sedentary crustaceans have, for example, rafted on buoyant kelp across thousands of kilometres of open ocean in the sub-Antarctic. The close symbiotic or parasitic relationships that such species maintain with the kelp has resulted in whole communities dispersing together. Indeed, active dispersal is often limited in parasites, which can depend almost entirely on mobile hosts for long-distance movement. A parasite that is unable to travel far with its host would, therefore, be expected to show considerable phylogeographic structure. For example, penguins primarily travel underwater but are hosts to terrestrial ectoparasites (most commonly ticks - Ixodes spp.) when they come ashore to breed. Aquatic host movements may represent a challenge to the survival of penguin ticks, restricting gene flow across their range. This thesis first reviews connectivity patterns and challenges throughout the sub-Antarctic, and then uses a multidisciplinary approach (genomic and physiological data) to test whether some terrestrial parasites (ticks: Acari) are able to travel long distances at sea with their aquatically dispersing hosts (penguins). Results indicate that penguin ticks are physiologically resilient, and may be capable of surviving the conditions faced during aquatic penguin movements between colonies. However, these movements appear to be too sporadic to maintain gene flow across the ticks’ ranges, resulting in broad-scale geographic structure. In contrast, movement on fine scales (within colonies) is inferred – based on lack of genomic structure – to be common, possibly facilitated by social interactions of hosts. These results emphasise the important role of dispersal in isolated regions for range expansion and diversification, and highlight the adaptability of parasites to their hosts’ environments