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

authors: O’Neill, Tanya Ann

subjects: Antarctica

abstract: 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.

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

year: 2013

title: Murray-Darling basin freshwater shells: riverine reservoir effect

authors: Gillespie, Richard

subjects: carbon isotopes

abstract: We report carbon isotope measurements on pre-bomb museum samples of freshwater mussel shells collected alive from riverine locations in New South Wales, Australia. The calculated reservoir ages, ranging from -60 to +112 years, are much smaller than those for Australian marine shells and not considered significant for the radiocarbon dating of Late Pleistocene freshwater shells from the Murray-Darling Basin.

text: Murray-Darling basin freshwater shells: riverine reservoir effect We report carbon isotope measurements on pre-bomb museum samples of freshwater mussel shells collected alive from riverine locations in New South Wales, Australia. The calculated reservoir ages, ranging from -60 to +112 years, are much smaller than those for Australian marine shells and not considered significant for the radiocarbon dating of Late Pleistocene freshwater shells from the Murray-Darling Basin.

year: 2009

title: Is the web being used to speak our language?

authors: Keegan, Te Taka Adrian Gregory

subjects: WWW

abstract: This paper presents results from extensive surveys of the usage of Maori language on the World Wide Web(www, Web) conducted in 1998 and 2002. Issues both supportive and detrimental relating to the use and publication of indigenous languages in the WWW will be highlighted. Specifically: how is the WWW being used to articulate the Maori language?

text: Is the web being used to speak our language? This paper presents results from extensive surveys of the usage of Maori language on the World Wide Web(www, Web) conducted in 1998 and 2002. Issues both supportive and detrimental relating to the use and publication of indigenous languages in the WWW will be highlighted. Specifically: how is the WWW being used to articulate the Maori language?

year: 2004