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The Atacama Desert is a coastal desert in South America spanning both Peru and Chile. While the desert experiences a range of climate regimes, perhaps the most unique region of the desert lies in the north of Chile where annual precipitation is less than 2 mm. This hyperarid region of the desert often goes decades without precipitation and is believed to have maintained a semi-continuous hyperarid climate for the last few million years. Hyperaridity has had a profound impact on the geochemical and biological processes of the region. One of the most notable and economically important features of the desert are the salars. Salars are the location of past lakes that have lost their surface water due to changes in climate and/or tectonic activity. They provide minable concentrations of iodine, boron, and other salts, and are recognized as one of the only habitats for microbial life in this region. Presently, they are covered in thick and rugged salt crusts, often made of sodium chloride (halite) and calcium sulfate (gypsum). Due to the extreme and persistent aridity, shallow groundwater is pulled upward towards the surface via capillary flow. This upward water movement is the reverse direction of most well drained desert soils, and leaves a diagnostic imprint in the soil chemistry. The first chapter of my dissertation explores how soils in salars differ from those found in other more humid deserts, and proposes changes to the USDA Soil Taxonomy that would allow for a more accurate and informative classification of them.To further understand and catalogue the rates and processes of soil formation in this unique environment, in my second chapter I examine the chemical and isotopic profiles of two soils of differing ages in the Salar Llamara, Chile. I found that soil development is actively occurring, with evaporation of shallow groundwater driving the major geochemical processes. The upward movement of water produces a distinctive salt profile, with the most soluble salts concentrated on the surface and the least soluble salts near the base. Through monitoring and experimental work, I calculated long-term evaporation rates, and found that they decrease with soil age as the salt crust thickness increases. While it has been suggested that these salars are part of an ancient landscape, this work provides evidence that they are dynamic and evolve on relatively short timescales. Finally, despite the lack of rainfall, I found that the crusts are able to sustain microbial growth by buffering environmental changes in temperature and relative humidity. While the hyperarid region of the Atacama Desert only receives rare and infrequent precipitation, it is exposed to marine fog from the Pacific Ocean on a regular basis. The amount of fog changes predictably from west to east as the distance from the coast increases. For many years the Atacama Desert was suggested to be the dry limit to life. However, in the last decade it has been recognized that microbial communities are capable of surviving in salt crusts on the surface of salars. At a relative humidity over 75%, halite is able to absorb enough moisture from the atmosphere to create a saline solution in its mineral pores. In this way, salt crusts can provide organisms with liquid water in the absence of precipitation.My third chapter is a detailed investigation of the microbial community composition and structure in this unique ecosystem. Using next metagenomics techniques, I reconstructed 124 distinct draft quality genomes from three sites along a fog frequency transect. All communities are comprised of a large variety of Halobacteriales, Salinibacter, Chlorophyta, and Cyanobacteria. Additionally, some communities contain lower abundances of Nanohaloarchaea, Actinobacteria, Gammaproteobacteria, Thermoplasmatales, and Naegleria. Candidate Phyla Radiation bacteria (OD1 and TM7) not previously reported from hypersaline environments before, were also found in low abundance in some of the communities.While there is a lot of overlap in community membership across sites, samples cluster by site based on bacterial and archaeal abundance patterns. The concentration of photosynthetic organisms declines with increasing distance from the fog source (Pacific Ocean), and radiocarbon dating showed that carbon cycling is occurring more rapidly in sites with more fog events. I conclude that the strongest driver of community membership is fog delivered moisture, controlled by proximity to the coast.The final chapter of my dissertation explores a unique late Quaternary paleoenvironmental record in loess deposits. Within what is largely a deflationary landscape, I found small loess dunes that have been slowly accreting for the last 20,000 years in depressions of the highly eroded Soledad formation. One of the unique local climate characteristics of this area is the strong and persistent on-shore winds.Radiocarbon ages of organic matter embedded within the deposits show that the dunes began accumulating rapidly at the Last Glacial Maximum, and that the accumulation of sediment slowed considerably after the Pacific Ocean attained its present post-glacial level. Chemical and isotopic analysis of the sediment and fatty acids preserved within the dunes provide evidence for increased marine fog density and intensity of onshore westerly winds beginning 10,000 yr BP. At this time, grain size increases while accumulation rates simultaneously decrease, suggesting greater wind speeds and/or decrease in sediment supply. Organic sediment δ15N values steadily decrease, suggesting a shorter path length between N upwelling (Pacific Ocean) and N deposition in the dunes. This unique and continuous record of paleo-conditions provides a window into local processes occurring over the last 20,000 years.

English abstract: Background: This research was initiated by a request from Gausdal municipality to have a master’s thesis written about the sensori-motoric project the Gausdal Model. One of the aims of the Gausdal Model is to better prepare children for school through a programme based on proportionate universalism. Aim: The aim was to explore key stakeholders understandings of school readiness and generate in-depth knowledge about their processes of implementation of the Gausdal Model. This could shed light on processes that develop children’s motor proficiency and its possible relation to school readiness. Methods: A case study of the implementation of the Gausdal Model was carried out in order to explore key stakeholders’ understanding of school readiness. The sample was strategic and the nine kindergarten teachers and parent informants were recruited from four municipal kindergartens in Gausdal. The health nurse connected to the programme was also an informant. Data were collected through qualitative interviews, partly informed by prior observations of the activities in the programme. The data analysis was inspired by principles from grounded theory as described by Charmaz (2014). The analysis aimed to identify components that could shed light on the processes that was studied. Bronfenbrenner’s ecological systems theory and Bandura’s social cognitive theory (SCT) and concept self-efficacy (SE), in particular were used as sensitising concepts in order to analyse the data and generate an understanding of how the Gausdal Model could develop children’s motor proficiency, and how this might be related to children’s school readiness. Results: The findings from the implementation of the Gausdal Model show that children’s motor proficiency can be understood as being developed through a process of socialisation where support through strong mesosystems and significant others, in this case kindergarten teachers and parents, could help develop the children’s mastery of their own bodies. At the mesosystem-level, quality and quantity of communication and aiming consistently towards the same goals was important. At the microsystem level, a combination of the four sources of SE and relational qualities between the kindergarten teachers and children seemed to develop children’s motoric SE and mastery of their own bodies. Motor proficiency seems to be related to school readiness through both the transferability of certain components of motoric SE as well as a social dimension, as social inclusion was an important component of school readiness. Hence, motor proficiency was related to a multidimensional understanding of school readiness. Conclusion: The Gausdal Model is in line with public health recommendations of early intervention and proportionate universalism, and has the potential to better prepare children for school as well as contributing to children’s socialization in general. Norsk sammendrag: Bakgrunn: Denne forskningen ble initiert av en forespørsel fra Gausdal kommune om å skrive en masteroppgave om det sanse-motoriske programmet Gausdalsmodellen. Et av målene for Gausdalsmodellen er å gi barn et bedre utgangspunkt for skolestart gjennom tiltak for alle – for å nå de få og styrke alle. Mål: Å utforske barnehagelærere, foreldre og helsesøsters forståelse av hva det vil si å være skoleforberedt og generere kunnskap om gjennomføringen av Gausdalsmodellen. Dette kan belyse prosesser som utvikler barnas motoriske ferdigheter, samt en mulig sammenheng mellom dette og det å være skoleforberedt. Metoder: En kasus-studie av gjennomføringen av Gausdalsmodellen og barnehagelærere, foreldre og helsesøsters forståelse av hva det vil si å være skoleforberedt. Utvalget er strategisk og ni informanter (barnehageansatte og foreldre) ble rekruttert fra fire kommunale barnehager i Gausdal. En helsesøster som arbeider med Gausdalsmodellen er også informant. Data ble samlet inn gjennom kvalitative intervjuer som blant annet ble utarbeidet på bakgrunn av observasjoner av aktiviteter i Gausdalsmodellen. Analysen av datamaterialet er inspirert av prinsipper fra grounded theory beskrevet av Charmaz (2014). Analysen tar sikte på å identifisere komponenter som kan kaste lys over de prosessene som ble studert. Bronfenbrenners utviklingsøkologiske modell og Banduras sosial kognitive teori og konseptet mestringsforventning, ble brukt for å for analysere datamaterialet og forstå hvordan gjennomføringen av Gausdalsmodellen kan utvikle barnas motoriske ferdigheter, samt hvordan disse ferdighetene kan knyttes til det å være skoleforberedt. Resultater: Funnene viser at barns motoriske ferdigheter kan forstås som å bli utviklet i en sosialiseringsprosess der støtte fra sterke mesosystemer og signifikante andre, i dette tilfellet barnehagelærere og foreldre, er av betydning. På mesosystem-nivå gjennom kvantitet og kvalitet på kommunikasjon og en felles målsetning rundt barnets utvikling. På mikronivå synes en kombinasjon av relasjonelle kvaliteter mellom barnehagelærerne og barna, og kilder til utvikling av barnas mestringsforventning, å bidra til barnas motoriske utvikling og kroppslige mestring. Motoriske ferdigheter synes å være knyttet til det å være skoleforberedt, både gjennom overførbarhet av visse komponenter av motorisk mestringsforventning, samt gjennom en sosial dimensjon hvor sosial inkludering var viktig for at barna skal være skoleforberedt. Derfor er motoriske ferdigheter knyttet til en helhetlig forståelse av hva det vil si å være skoleforberedt. Konklusjon: Gausdalsmodellen er i tråd med folkehelseanbefalinger om tidlig intervensjon og proposjonell universalisme og har potensiale til å forberede barna til skolestart i tillegg til å bidra i en generell sosialiseringsprosess.