The dataset consists of 21 physico-chemical parameters (moisture concentration, pH value, electrical conductivity, the concentrations of total organic C and N, Ca, Cu, Fe, K, Mg, Mn, Ni, P, Zn, and those of water-extractable phosphate ions, sulphate ions, chloride ion, ammonium-N ions, nitrate/nitrite-N ions and dissolved organic carbon) measured in 29 soils gathered from along a latitudinal transect between Signy Island (60 degrees South) and south-eastern Alexander Island (72 degrees South) in November 2007-February 2008. Funding was provided by NERC grants NE/D00893X/1; AFI 7/05

Soil moisture measurements taken at various sites on Signy Island during the 2008-2009 field season. These measurements were used as part of an investigation to understand the effect of temperature and moisture on the availability of different nitrogen forms.

Soil temperature measurements taken at various sites on Signy Island during the 2008-2009 field season. These measurements were used as part of an investigation to understand the effect of temperature and moisture on the availability of different nitrogen forms.

Soil temperature was monitored at 5 soil sampling times and ambient air temperature was monitored at each site throughout the field season. The sampling sites were: Bare soil at higher elevations, namely Observation Bluff, Factory Bluffs, Jane Col and lower parts of Spindrift Col; Soils from below mosses on the Backslope and on Moss Braes. Soils from below higher plant species at Bernsten Point, Factory Bluffs, Moss Braes and North Point. Orthinogenic soils from around penguin colonies at Gourlay Peninsula, Spindrift Rocks and North Point and disturbed soil from around Signy Base.

To identify and quantify soil N species over a full growth season, small volumes of soil were removed from each sampling site 5 times during the field season and extracted in the laboratory. Bare soil at higher elevations, namely Observation Bluff, Factory Bluffs, Jane Col and lower parts of Spindrift Col; Soils from below mosses on the Backslope and on Moss Braes. Soils from below higher plant species at Bernsten Point, Factory Bluffs, Moss Braes and North Point. Orthinogenic soils from around penguin colonies at Gourlay peninsula, Spindrift rocks and North Point and disturbed soil from around Signy Base were collected.

Three plant species, the leafy liverwort Cephaloziella varians and the angiosperms Deschampsia antarctica and Colobanthus quitensis, were sampled from 12 islands across a 1480 km latitudinal gradient from South Georgia through to Adelaide Island. Samples were collected to determine the abundance of dark septate fungi in Antarctic plant and soil communities and the effects of these organisms on plant growth. Where the target species were found in sufficient numbers to allow sampling, it proved possible to collect at least 10 samples of each species. At least 10 soil samples were collected from each site where Deschampsia was found. Plants, with intact roots and soil, were transported back to the UK using cool and frozen stowage. Additionally, intact live plants were transported to the UK in an illuminated cabinet. Seeds of the two key species (Deschampsia antarctica and Colobanthus quitensis) were also collected at Bird Island and South Georgia. As the exact months of the data collection were not provided, and the metadata standard requires a YYYY-MM-DD format, this dataset has been dated as 1st January for start date, and 31st December for stop date.

Field measurements were used to determine the availability of peptide nitrogen to photosynthetic organisms and soil microbes. In order to fully understand their significance in the Maritime Antarctic nitrogen cycle it was also necessary to examine the ability of organisms to utilise the available peptides. For this reason, isotopically-labelled (15N and 13C) nitrogen compounds, including various peptides, were used to determine their rate of uptake by soil microorganisms and plants. These experiments were carried out on Signy to minimise any changes to organisms during transit.

To investigate the availability of peptides in the soils on Signy Island, soil solutions were sampled throughout the summer season, from mid November 2008 until early March 2009. Soil solution samples were extracted under vacuum, with minimal disturbance to the soil, through small porous tubes. A total of 19 sites across the island were sampled in areas dominated by all the major primary producers, vascular plants, mosses, algae and lichens. The collected soil solution samples were analysed for different forms of nitrogen, including peptides.

To identify and quantify soil N species over a full growth season, small volumes of soil were removed from each sampling site 5 times during the field season and extracted in the laboratory. Bare soil at higher elevations, namely Observation Bluff, Factory Bluffs, Jane Col and lower parts of Spindrift Col; Soils from below mosses on the Backslope and on Moss Braes. Soils from below higher plant species at Bernsten Point, Factory Bluffs, Moss Braes and North Point. Orthinogenic soils from around penguin colonies at Gourlay Peninsula, Spindrift Rocks and North Point and disturbed soil from around Signy Base were collected. At the same time, soil pore water was extracted using Rhizon soil water samplers. DON (Dissolved organic Nitrogen) and Microbial biomass measurements were made by standard CHCl3 fumigation-extraction techniques. Turnover of DON in the soil was determined by the addition of 14C-labelled plant protein (purified from 14C-labelled algal cells) or 14C-labelled glucose to the soil at a range of concentrations, and their turnover (soil label depletion in combination with NH4 +, NO3-and 14CO2 production) was determined. Gross rates of N mineralization and nitrification were determined using 15N isotope dilution methodology. Laboratory analysis of N speciation and quantification, 14C uptake and respiration, 13C PLFA signatures and 15N analysis was done. Amino acid turnover times have been determined using 14C labelled amino acids. For the final stage of the project a mathematical model to describe plant-soil-microbial N fluxes in Antarctic soils was constructed.

This study investigated the status of dark septate (DS) fungi in Antarctic plant and soil communities, with the aim of determining the abundance of DS fungi in plant roots and rhizoids, their taxonomic affinities and their symbiotic status. Abundances of fungal hyphae were recorded in roots and rhizoids, and fungi were isolated and identified. Sequencing of ITS (internal transcribed spacer) regions of rDNA indicated that some isolates share taxonomic affinities with fungi of known symbiotic status. Synthesis experiments assessed the effects of DS fungal isolates, including H. ericae, on the growth and nutrient balance of their host plants. Seeds of Deschampsia antarctica and Colobanthus quitensis were collected for use in ecophysiological experiments.