7 results for Aislabie, Jackie M.

  • Co- variation in soil biodiversity and biogeochemistry in northern and southern Victoria Land, Antarctica

    Barrett, John E.; Virginia, R. A.; Wall, Diana H.; Cary, S. Craig; Adams, Byron J.; Hacker, A. L.; Aislabie, Jackie M. (2006)

    Journal article
    University of Waikato

    Data from six sites in Victoria Land (72–77°S) investigating co-variation in soil communities (microbial and invertebrate) with biogeochemical properties showthe influence of soil properties on habitat suitability varied among local landscapes as well as across climate gradients. Species richness of metazoan invertebrates (Nematoda, Tardigrada and Rotifera) was similar to previous descriptions in this region, though identification of three cryptic nematode species of Eudorylaimus through DNA analysis contributed to the understanding of controls over habitat preferences for individual species. Denaturing Gradient Gel Electrophoresis profiles revealed unexpectedly high diversity of bacteria. Distribution of distinct bacterial communities was associated with specific sites in northern and southern Victoria Land, as was the distribution of nematode and tardigrade species. Variation in soil metazoan communities was related to differences in soil organic matter, while bacterial diversity and community structure were not strongly correlated with any single soil property. There were no apparent correlations between metazoan and bacterial diversity, suggesting that controls over distribution and habitat suitability are different for bacterial and metazoan communities. Our results imply that top-down controls over bacterial diversity mediated by their metazoan consumers are not significant determinants of bacterial community structure and biomass in these ecosystems.

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  • The short-term effects of surface soil disturbance on soil bacterial community structure at an experimental site near Scott Base, Antarctica

    O’Neill, Tanya Ann; Balks, Megan R.; Stevenson, Bryan A.; López-Martínez, Jerónimo; Aislabie, Jackie M.; Rhodes, Phillipa (2013)

    Journal article
    University of Waikato

    Humans are visiting Antarctica in increasing numbers, and the ecological effect of rapid soil habitat alteration due to human-induced physical disturbance is not well understood. An experimental soil disturbance trial was set up near Scott Base on Ross Island, to investigate the immediate and short-term changes to bacterial community structure, following surface soil disturbance. Three blocks, each comprising an undisturbed control, and an area disturbed by removing the top 2 cm of soil, were sampled over a time series (0, 7, 14, 21, and 35 days), to investigate changes to bacterial community structure using DNA profiling by terminal restriction fragment length polymorphism. The simulated disturbance did not cause any major shifts in the structure of the bacterial communities over the 35-day sampling period. Ordination showed that the bacterial community composition correlated strongly with soil EC (R² = 0.55) and soil pH (R² = 0.67), rather than the removal of the top 2 cm of surface material. Although the replicate blocks were visually indistinguishable from one another, high local spatial variability of soil chemical properties was found at the study site and different populations of bacterial communities occurred within 2 m of one another, within the same landscape unit. Given the current knowledge of the drivers of bacterial community structure, that is, soil EC, soil pH, and soil moisture content, a follow-up investigation incorporating DNA and RNA-based analyses over a time frame of 2-3 years would lead to a greater understanding of the effects of soil disturbance on bacterial communities.

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  • Hexadecane mineralization activity in hydrocarbon-contaminated soils of Ross Sea region Antarctica may require nutrients and inoculation

    Aislabie, Jackie M.; Ryburn, Janine; Gutierrez-Zamora, Maria-Luisa; Rhodes, Phillipa; Hunter, David; Sarmah, Ajit K.; Barker, Gary M.; Farrell, Roberta L. (2012-02)

    Journal article
    University of Waikato

    Hydrocarbon spills on Antarctic soils occur mainly near settlements where fuel is stored and aircraft and vehicles are refuelled. To investigate those factors that may preclude hexadecane mineralization activity in long-term hydrocarbon-contaminated soils from the Ross Sea Region, samples were collected from Scott Base, the site of former bases (Cape Evans, Marble Point, Vanda Station), and two oil spill sites in the Wright Valley (Bull Pass and Loop Moraine). The soils had low levels of nitrogen (24) reflecting hydrocarbon contamination. Following soil water adjustment to 10% (v/w), the influence of nutrient addition (250 mg/kg N added as monoammonium phosphate) and inoculation (spiking with Antarctic soil containing high numbers of hydrocarbon degraders) as required on hexadecane mineralization activity was determined. Hexadecane mineralization activity occurred in contaminated soils from Marble Point, Cape Evans and one sample from Vanda Station without nutrient addition. In contrast soils from Scott Base, Cape Evans, another sample from Vanda Station and Loop Moraine required nutrients, whereas Bull Pass soil required inoculation and nutrients before hexadecane mineralization proceeded. Hydrocarbon degrader numbers were highest in coastal soils from Scott Base and Marble Point (10⁷ per gram) and less prevalent in inland soils from Wright Valley (<10⁵ per gram). The bacterial community structure of the soils differed between sites, but soils from the same sites tended to cluster together more closely, except for those from Vanda Station. Addition of nutrients did not cause large shifts in the soil bacterial communities. Results from this study indicate that hydrocarbon degradation may occur at some sites in summer when water is available. Long-term hydrocarbon-contaminated Antarctic soils may provide a valuable resource of hydrocarbon-degrading bacteria that can serve as inocula for more recent oil spills on land.

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  • Soils of western Wright Valley, Antarctica

    McLeod, Malcolm; Bockheim, James; Balks, Megan R.; Aislabie, Jackie M. (2009)

    Journal article
    University of Waikato

    Western Wright Valley, from Wright Upper Glacier to the western end of the Dais, can be divided into three broad geomorphic regions: the elevated Labyrinth, the narrow Dais which is connected to the Labyrinth, and the North and South forks which are bifurcated by the Dais. Soil associations of Typic Haplorthels/Haploturbels with ice-cemented permafrost at < 70cm are most common in each of these geomorphic regions. Amongst the Haplo Great Groups are patches of Salic and Typic Anhyorthels with ice-cemented permafrost at > 70 cm. They are developed in situ in strongly weathered drift with very low surface boulder frequency and occur on the upper erosion surface of the Labyrinth and on the Dais. Typic Anhyorthels also occur at lower elevation on sinuous and patchy Wright Upper III drift within the forks. Salic Aquorthels exist only in the South Fork marginal to Don Juan Pond, whereas Salic Haplorthels occur in low areas of both South and North forks where any water table is> 50 cm. Most soils within the study area have an alkaline pH dominated by Na+ and Cl- ions. The low salt accumulation within Haplorthels/Haploturbels may be due to limited depth of soil development and possibly leaching.

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  • Environmental pollutants from the Scott and Shackleton expeditions during the ‘Heroic Age’ of Antarctic exploration

    Blanchette, Robert A.; Held, Benjamin W.; Jurgens, Joel Allan; Aislabie, Jackie M.; Duncan, Shona Margaret; Farrell, Roberta L. (2004)

    Journal article
    University of Waikato

    Early explorers to Antarctica built wooden huts and brought huge quantities of supplies and equipment to support their geographical and scientific studies for several years. When the expeditions ended and relief ships arrived, a rapid exodus frequently allowed only essential items to be taken north. The huts and thousands of items were left behind. Fuel depots with unused containers of petroleum products, asbestos materials, and diverse chemicals were also left at the huts. This investigation found high concentrations of polyaromatic hydrocarbons in soils under and around the historic fuel depots, including anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, chrysene, fluorene, and pyrene, as well as benzo[a]anthracene, benzo[a]pyrene, and fluoranthene, which are recognized carcinogens. Asbestos materials within the huts have been identified and extensive amounts of fragmented asbestos were found littering the ground around the Cape Evans hut. These materials are continually abraded and fragmented as tourists walk over them and the coarse scoria breaks and grinds down the materials. A chemical spill, within the Cape Evans hut, apparently from caustic substances from one of the scientific experiments, has caused an unusual deterioration and defibration on affected woods. Although these areas are important historic sites protected by international treaties, the hazardous waste materials left by the early explorers should be removed and remedial action taken to restore the site to as pristine a condition as possible. Recommendations are discussed for international efforts to study and clean up these areas, where the earliest environmental pollution in Antarctica was produced.

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  • Groundwater characteristics at Seabee Hook, Cape Hallett, Antarctica

    Hofstee, Erica H.; Campbell, David I.; Balks, Megan R.; Aislabie, Jackie M. (2006)

    Journal article
    University of Waikato

    Seabee Hook is a low lying gravel spit adjacent to Cape Hallett, northern Victoria Land, in the Ross Sea region of Antarctica and hosts an Adélie penguin (Pygoscelis adeliae) rookery. Dipwells were inserted to monitor changes in depth to, and volume of, groundwater and tracer tests were conducted to estimate aquifer hydraulic conductivity and groundwater velocity. During summer (November–February), meltwater forms a shallow, unconfined, aquifer perched on impermeable ice cemented soil. Groundwater extent and volume depends on the amount of snowfall as meltwater is primarily sourced from melting snow drifts. Groundwater velocity through the permeable gravel and sand was up to 7.8 m day−1, and hydraulic conductivities of 4.7 × 10−4 m s−1 to 3.7 × 10−5 m s−1 were measured. The presence of the penguin rookery, and the proximity of the sea, affects groundwater chemistry with elevated concentrations of salts (1205 mg L−1 sodium, 332 mg L−1 potassium) and nutrients (193 mg L−1 nitrate, 833 mg L−1 ammonia, 10 mg L−1 total phosphorus) compared with groundwater sourced away from the rookery, and with other terrestrial waters in Antarctica.

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  • Effects of hydrocarbon spills on the temperature and moisture regimes of Cryosols in the Ross Sea region

    Balks, Megan R.; Paetzold, Ron F.; Kimble, John M.; Aislabie, Jackie M.; Campbell, Iain B. (2002)

    Journal article
    University of Waikato

    Hydrocarbon spills have occurred on Antarctic soils where fuel oils are utilized, moved or stored. We investigated the effects of hydrocarbon spills on soil temperature and moisture regimes by comparing the properties of existing oil contaminated sites with those of nearby, uncontaminated, control sites at Scott Base, the old Marble Point camp, and Bull Pass in the Wright Valley. Hydrocarbon levels were elevated in fuel-contaminated samples. Climate stations were installed at all three locations in both contaminated and control sites. In summer at Scott Base and Marble Point the mean weekly maximum near surface (2 cm and 5 cm depth) soil temperatures were warmer (P<0.05), sometimes by more than 10°C, at the contaminated site than the control sites. At Bull Pass there were no statistically significant differences in near-surface soil temperatures between contaminated and control soils. At the Scott Base and Marble Point sites soil albedo was lower, and hydrophobicity was higher, in the contaminated soils than the controls. The higher temperatures at the Scott Base and Marble Point hydrocarbon contaminated sites are attributed to the decreased surface albedo due to soil surface darkening by hydrocarbons. There were no noteworthy differences in moisture retention between contaminated and control sites.

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