"Of Moss and Microclimate. Spatial variation in microclimate

"Of Moss and Microclimate. Spatial variation in microclimate of Antarct" by Krystal Louise Randall

There is a general lack of biologically relevant climate data to facilitate ecological research in Antarctica. Climate data that exist for Antarctic regions are derived from satellite and automated weather station observations. However, the climate conditions at ground level, where the bulk of Antarctica’s terrestrial biodiversity lives, often vary considerably from those at or above weather station height. Climate data at this finer scale at or beneath the ground surface in the thermal boundary layer (termed microclimate), are poorly represented by meteorological climate data. Currently, ground-level microclimate variation in Antarctic regions is extremely difficult to predict through modelling techniques. The dominant terrestrial plant life in Antarctica are mosses which form turfs that display highly variable micro-topography. Such turfs can play a large role in biogeochemical cycling and permafrost insulation with associated links to microclimate and moss health, however these links are poorly understood due to a lack of quantitative and spatially explicit data at a relevant scale. Furthermore, the soil insulation properties of moss cover in permafrost regions are poorly understood and often mis-represented in climate models, leading to erroneous predictions of soil temperatures and permafrost thaw rates for alpine, Arctic and Antarctic regions. In this thesis, I address these knowledge and methodological gaps and present a range of novel fieldwork, modelling and experimental methodologies to quantify spatially explicit links between micro-topography, microclimate and moss health and physiology over centimetre scales for moss turfs in Maritime Antarctica. Additionally, I present a method for generating Antarctic ground surface/moss canopy microclimate data at a centimetre resolution without the need for empirical microclimate data to fit the model. Lastly, I use a novel experimental method to explore mechanisms involved in creating ground surface and soil microclimate variation in moss covered soils, specifically, how a decline in moss health and how water at the ground surface affect soil and surface microclimates. Moss canopy (ground surface) temperatures differed significantly from weather station temperatures, and micro-topography drove considerable spatial variation in moss canopy temperatures, light intensity and moss turf water content among Antarctic moss turfs. Specifically, at centimetre scales, moss canopy temperatures differed up to 29 °C at a single point in time, maximum canopy temperature differed up to 15 °C, and light intensity differed up to 1000 μmol.m-2.s-1. Moss turf micro-topography was the predominant driver over landscape scale topography, while variation in moss turf water content was mostly driven by landscape scale topography but still

Related Keywords

Antarctica , , Microclimate , Icroclimate Model , Icro Topography , Antarctic Moss ,

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