title: Moisture Associated Microbial Communities in Antarctic Dry Valley Soils

authors: Anderson, Rachelle

subjects: Climate change

abstract: Climate change is having a dramatic impact on the natural environment and is one of the most imminent and important issues of the 21st century. With limited vegetation and few large terrestrial organisms, Antarctica offers a unique opportunity to understand the impact of abiotic, climatic factors on microbial ecosystems (free of many of the confounding biological variables in more complex systems). 

Recent in situ studies indicate that microbial communities within Antarctic soils may respond to environmental changes within far shorter time frames than originally believed. In a landmark study, Tiao et al. (2012) investigated the rate at which microbial communities responded to a unique soil modification experiment. To this end, a mummified seal carcass (dated at 250 years) was shifted from its original site in Miers Valley, to a new, geomorphically similar site in close proximity. Remarkably, increased microbial biomass, decreased biodiversity, and shifts in the microbial community composition were observed within just two summers. While the seal carcass altered the underlying soil’s nitrogen and organic carbon content, pH, and conductivity; statistical analysis revealed that none of these physicochemical changes could satisfactorily explain the changes in the microbial community. Instead the data suggest that the changes observed may have been caused by physical, abiotic factors induced by the seal carcass (i.e. increased and more stable relative humidity (RH), reduced UV exposure, and reduced daily temperature fluctuations). However, due to the un-replicated, observational nature of the study, this is merely speculation. 

In order to verify these findings and resolve the drivers of the microbial community changes observed, a controlled, in situ experiment was designed to replicate the abiotic effects of the seal carcass (stabilise temperature, reduce UV exposure, and increase and stabilise RH in the underlying soil). To do this, overturned or upright black and translucent plastic trays were set up on undisturbed regions of Antarctic Dry Valley soil; soil samples were taken every January for a five-year period; and Ion Torrent sequencing of 16S rRNA gene amplicons was used to assess changes in the microbial community composition and structure. However, based on RH data and visual observations of the site it would appear that the tray experiment was unknowingly set up in either a flat, low lying area where moisture accumulated; or in a subsurface water track. Due to the constant high moisture content within the soil on which the experiment was deployed, the effect of the tray treatments on the local environment (i.e. RH and temperature) was negligible.
		
The microbial community composition in the tray treatment experiment stayed quite consistent across all years and treatments, however there was a significantly greater abundance of Cyanobacteria/ Chloroplasts in the translucent overturned (TO) treatment than in the black upright (BU) or black overturned (BO) treatments. Interestingly, the moist tray treatment soil had a greater relative abundance of Cyanobacteria/ Chloroplasts, Proteobacteria, and Bacteroidetes than the drier seal control site, in keeping with the observations of other studies investigating microbial community composition within wet environments. These findings hint at the importance of small-scale topographic factors in microbial community structure, and/or highlight the potential of using microbial community composition as a bio-indicator of hidden water tracks.

text: Moisture Associated Microbial Communities in Antarctic Dry Valley Soils Climate change is having a dramatic impact on the natural environment and is one of the most imminent and important issues of the 21st century. With limited vegetation and few large terrestrial organisms, Antarctica offers a unique opportunity to understand the impact of abiotic, climatic factors on microbial ecosystems (free of many of the confounding biological variables in more complex systems). 

Recent in situ studies indicate that microbial communities within Antarctic soils may respond to environmental changes within far shorter time frames than originally believed. In a landmark study, Tiao et al. (2012) investigated the rate at which microbial communities responded to a unique soil modification experiment. To this end, a mummified seal carcass (dated at 250 years) was shifted from its original site in Miers Valley, to a new, geomorphically similar site in close proximity. Remarkably, increased microbial biomass, decreased biodiversity, and shifts in the microbial community composition were observed within just two summers. While the seal carcass altered the underlying soil’s nitrogen and organic carbon content, pH, and conductivity; statistical analysis revealed that none of these physicochemical changes could satisfactorily explain the changes in the microbial community. Instead the data suggest that the changes observed may have been caused by physical, abiotic factors induced by the seal carcass (i.e. increased and more stable relative humidity (RH), reduced UV exposure, and reduced daily temperature fluctuations). However, due to the un-replicated, observational nature of the study, this is merely speculation. 

In order to verify these findings and resolve the drivers of the microbial community changes observed, a controlled, in situ experiment was designed to replicate the abiotic effects of the seal carcass (stabilise temperature, reduce UV exposure, and increase and stabilise RH in the underlying soil). To do this, overturned or upright black and translucent plastic trays were set up on undisturbed regions of Antarctic Dry Valley soil; soil samples were taken every January for a five-year period; and Ion Torrent sequencing of 16S rRNA gene amplicons was used to assess changes in the microbial community composition and structure. However, based on RH data and visual observations of the site it would appear that the tray experiment was unknowingly set up in either a flat, low lying area where moisture accumulated; or in a subsurface water track. Due to the constant high moisture content within the soil on which the experiment was deployed, the effect of the tray treatments on the local environment (i.e. RH and temperature) was negligible.
		
The microbial community composition in the tray treatment experiment stayed quite consistent across all years and treatments, however there was a significantly greater abundance of Cyanobacteria/ Chloroplasts in the translucent overturned (TO) treatment than in the black upright (BU) or black overturned (BO) treatments. Interestingly, the moist tray treatment soil had a greater relative abundance of Cyanobacteria/ Chloroplasts, Proteobacteria, and Bacteroidetes than the drier seal control site, in keeping with the observations of other studies investigating microbial community composition within wet environments. These findings hint at the importance of small-scale topographic factors in microbial community structure, and/or highlight the potential of using microbial community composition as a bio-indicator of hidden water tracks.

year: 2017

title: Implications of Climate Change for the Livelihoods of Urban Dwellers in Kiribati

authors: Corcoran, John

subjects: Climate change

abstract: As a result of climate change, coastal erosion, sea water intrusion into the fresh water lenses, destruction of trees that are important sources of food, medicines and building materials, and the destruction of settlements due to higher king tides and storm surges, accompanying higher mean sea levels, are threatening the sustainable survival of human societies on the atoll islands of Kiribati. Climate change is also having detrimental effects on important cultural heritage including customary practices, traditional knowledge and native languages.  The people have continued to live with the physical changes to the landscape, vegetation and water supply, despite significant deterioration in the quality of the water, and the loss of important traditional plants and trees that are used for ornamental, constructional, and medicinal purposes. 
The Kiribati government, along with governments of other countries comprising low-lying atolls and reef islands, has placed considerable emphasis on strategies to manage problems caused by climate change, especially the prospect of higher sea levels. Population and urban development pressures have further compounded existing problems associated with climate change. Land shortage and increasing population on South Tarawa have made the climate change issue more critical. This thesis examines the contemporary environmental issues linked with climate change and its impacts on the livelihoods of urban dwellers of Kiribati. 
The focus is on the country’s two main urban areas: South Tarawa in the Gilbert group and Kiritimati in the Line group. The study assesses the dependence of urban dwellers on their urban environment as well as examining their increasing vulnerability to climate change. The study concludes that there is a need for further consultation and discussion between the government of Kiribati, non-government organizations, private institutions, church institutions and the local people, as well as with interested overseas development partners and major financial donors, to plan strategies not only to provide for better living conditions for the current population but, more importantly, to ensure the islands are able to sustainably support the existence of the people now and in years to come.

text: Implications of Climate Change for the Livelihoods of Urban Dwellers in Kiribati As a result of climate change, coastal erosion, sea water intrusion into the fresh water lenses, destruction of trees that are important sources of food, medicines and building materials, and the destruction of settlements due to higher king tides and storm surges, accompanying higher mean sea levels, are threatening the sustainable survival of human societies on the atoll islands of Kiribati. Climate change is also having detrimental effects on important cultural heritage including customary practices, traditional knowledge and native languages.  The people have continued to live with the physical changes to the landscape, vegetation and water supply, despite significant deterioration in the quality of the water, and the loss of important traditional plants and trees that are used for ornamental, constructional, and medicinal purposes. 
The Kiribati government, along with governments of other countries comprising low-lying atolls and reef islands, has placed considerable emphasis on strategies to manage problems caused by climate change, especially the prospect of higher sea levels. Population and urban development pressures have further compounded existing problems associated with climate change. Land shortage and increasing population on South Tarawa have made the climate change issue more critical. This thesis examines the contemporary environmental issues linked with climate change and its impacts on the livelihoods of urban dwellers of Kiribati. 
The focus is on the country’s two main urban areas: South Tarawa in the Gilbert group and Kiritimati in the Line group. The study assesses the dependence of urban dwellers on their urban environment as well as examining their increasing vulnerability to climate change. The study concludes that there is a need for further consultation and discussion between the government of Kiribati, non-government organizations, private institutions, church institutions and the local people, as well as with interested overseas development partners and major financial donors, to plan strategies not only to provide for better living conditions for the current population but, more importantly, to ensure the islands are able to sustainably support the existence of the people now and in years to come.

year: 2016

title: Te Raupatu o Tauranga Moana : Volume 2, Documents relating to tribal history, confiscation and reallocation of Tauranga lands.

authors: Stokes, Evelyn

subjects: Tauranga lands

abstract: A report providing a historical and geographical overview on the confiscation of Tauranga lands. In two volumes, volume one comprises a narrative of the events described as the raupatu, the confiscation of lands in the Tauranga Moana tribal area under the New Zealand Settlements Act 1863.  Volume two is a collection of documents, edited and annotated which were compiled in support of the report. These documents include personal accounts, tribal history, land purchases, lands returned and crown transactions.

text: Te Raupatu o Tauranga Moana : Volume 2, Documents relating to tribal history, confiscation and reallocation of Tauranga lands. A report providing a historical and geographical overview on the confiscation of Tauranga lands. In two volumes, volume one comprises a narrative of the events described as the raupatu, the confiscation of lands in the Tauranga Moana tribal area under the New Zealand Settlements Act 1863.  Volume two is a collection of documents, edited and annotated which were compiled in support of the report. These documents include personal accounts, tribal history, land purchases, lands returned and crown transactions.

year: 1993