title: Geochemical, Spatial, and Temporal Drivers of Microbial Community Heterogeneity in the Meltwater Ponds of Antarctica

authors: Archer, Stephen David James

subjects: microbial

abstract: Antarctic meltwater ponds are an abundant, dynamic and sensitive yet poorly understood ecosystem. In this thesis, bacterial communities from surface waters, the water column and benthic zone in geochemically variable meltwater ponds in the Ross Sea Region of Antarctica were investigated. The primary objective of this research was to provide a detailed description of the community composition and to determine the temporal, geochemical and geomorphological drivers of community structure.
	A coordinated comparable analysis method was used for all samples so that, although separated into the previously mentioned zones, findings could be directly compared across studies. Bacterial community structure between samples was initially investigated by Automated Ribosomal Intergenic Spacer Analysis (ARISA) of the 16S rRNA gene which, combined with in-situ collected geochemistry data was used to identify trends requiring high throughput sequencing (454 pyrosequencing of the V5-V6 hypervariable region of the 16S rRNA gene) analysis coupled with nutrient and elemental data.
	A preliminary study in December 2009 compared the water columns of five geochemically distinct ponds. Communities between ponds were distinct, their structure driven primarily by pH and conductivity. One geochemically stratified pond formed distinct surface and bottom clusters with increasing diversity and changes to phyla structure with depth. 
	Temporal and geomorphological (Bratina Island and Miers Valley) drivers of variation in the microbial community structure between the surface waters of 41 ponds were examined. Conductivity was identified as the most significant driver across all ponds for the dominant cosmopolitan community, however trace elements were more significant drivers of community structure for the unique community (those sequences absent in at least one pond). Pronounced variation was identified between December and January samples and although the bacterial components of the community were similar between January 2012 and 2013 the community structure varied significantly. Despite different environments, communities from the Miers Valley were not well differentiated from Bratina Island, suggesting biological exchange between locations.
	The stratified water column of six Bratina Island and two Miers Valley ponds was investigated. Strongly geochemically stratified ponds exhibited a heterogeneous vertical community structure related to conductivity and dissolved oxygen. Variation in community structure was primarily driven by the abundance of a small number of cosmopolitan OTUs that changed with depth. Although the biological constituents were the same, minor variation in community structure was identified within Huey pond between years (2012 and 2013). Variation between Huey pond (Bratina Island) and Morepork pond (Miers Valley) was correlated with variation of iron and mercury concentration.
	Lastly the benthic zone of six ponds from Bratina Island and six from the Miers Valley was examined. The community structure was highly heterogeneous and diverse with 21 phyla identified. No distinction was identified between the two locations with the majority of pyrosequencing reads shared. Potassium, sodium and cobalt were identified as the most significant explanatory variables to the cosmopolitan community and aluminium, uranium and magnesium to the unique community.
	This study has granted an unprecedented understanding of the bacterial communities in the meltwater ponds of the Ross Sea Region. Geochemical inter pond heterogeneity is matched with an equally heterogeneous bacterial communities, primarily driven by conductivity. Although harboring a complex and diverse community the majority is comprised of a small number of shared OTUs across spatial and temporal scales.

text: Geochemical, Spatial, and Temporal Drivers of Microbial Community Heterogeneity in the Meltwater Ponds of Antarctica Antarctic meltwater ponds are an abundant, dynamic and sensitive yet poorly understood ecosystem. In this thesis, bacterial communities from surface waters, the water column and benthic zone in geochemically variable meltwater ponds in the Ross Sea Region of Antarctica were investigated. The primary objective of this research was to provide a detailed description of the community composition and to determine the temporal, geochemical and geomorphological drivers of community structure.
	A coordinated comparable analysis method was used for all samples so that, although separated into the previously mentioned zones, findings could be directly compared across studies. Bacterial community structure between samples was initially investigated by Automated Ribosomal Intergenic Spacer Analysis (ARISA) of the 16S rRNA gene which, combined with in-situ collected geochemistry data was used to identify trends requiring high throughput sequencing (454 pyrosequencing of the V5-V6 hypervariable region of the 16S rRNA gene) analysis coupled with nutrient and elemental data.
	A preliminary study in December 2009 compared the water columns of five geochemically distinct ponds. Communities between ponds were distinct, their structure driven primarily by pH and conductivity. One geochemically stratified pond formed distinct surface and bottom clusters with increasing diversity and changes to phyla structure with depth. 
	Temporal and geomorphological (Bratina Island and Miers Valley) drivers of variation in the microbial community structure between the surface waters of 41 ponds were examined. Conductivity was identified as the most significant driver across all ponds for the dominant cosmopolitan community, however trace elements were more significant drivers of community structure for the unique community (those sequences absent in at least one pond). Pronounced variation was identified between December and January samples and although the bacterial components of the community were similar between January 2012 and 2013 the community structure varied significantly. Despite different environments, communities from the Miers Valley were not well differentiated from Bratina Island, suggesting biological exchange between locations.
	The stratified water column of six Bratina Island and two Miers Valley ponds was investigated. Strongly geochemically stratified ponds exhibited a heterogeneous vertical community structure related to conductivity and dissolved oxygen. Variation in community structure was primarily driven by the abundance of a small number of cosmopolitan OTUs that changed with depth. Although the biological constituents were the same, minor variation in community structure was identified within Huey pond between years (2012 and 2013). Variation between Huey pond (Bratina Island) and Morepork pond (Miers Valley) was correlated with variation of iron and mercury concentration.
	Lastly the benthic zone of six ponds from Bratina Island and six from the Miers Valley was examined. The community structure was highly heterogeneous and diverse with 21 phyla identified. No distinction was identified between the two locations with the majority of pyrosequencing reads shared. Potassium, sodium and cobalt were identified as the most significant explanatory variables to the cosmopolitan community and aluminium, uranium and magnesium to the unique community.
	This study has granted an unprecedented understanding of the bacterial communities in the meltwater ponds of the Ross Sea Region. Geochemical inter pond heterogeneity is matched with an equally heterogeneous bacterial communities, primarily driven by conductivity. Although harboring a complex and diverse community the majority is comprised of a small number of shared OTUs across spatial and temporal scales.

year: 2015

title: After the education disciplines: teaching theory on-line.

authors: Middleton, Sue

subjects: education

abstract: Like all social theorising, the academic study of education is 'reflexive'- complicated by the fact of our immersion in it. This paper discusses an on-line version of an undergraduate teacher-education course, 'Social Issues in New Zealand Education,' that is designed to teach its students how to do such 'situated' educational theorising. Consistent with this theme, the paper is written as a stream-of-consciousness narrative. In an attempt to fix in print the 'counterpoint' of pedagicical theorising in general, as well as more specifically in an on-line setting, it is episodic in structure - more like the lateral leaps of hypertext than the disciplined hierarchies of headings characteristic of the linearity of conventional academic argument. It falls into three parts. The first introduces the online virtual classroom environment in which the teaching takes place. Part two locates the course within more general epistemological issues confronting designers of education (foundations) courses in pre-service teaching degrees in the twenty-first century. In Part three, the syllabus of the course is outlined. The paper concludes with examples of students doing 'situated' educational theorising as they engage with course readings and assignments. Through this multi-layered account, I raise for discussion some broad questions about pedagogy in educational foundations courses in today's environment.

text: After the education disciplines: teaching theory on-line. Like all social theorising, the academic study of education is 'reflexive'- complicated by the fact of our immersion in it. This paper discusses an on-line version of an undergraduate teacher-education course, 'Social Issues in New Zealand Education,' that is designed to teach its students how to do such 'situated' educational theorising. Consistent with this theme, the paper is written as a stream-of-consciousness narrative. In an attempt to fix in print the 'counterpoint' of pedagicical theorising in general, as well as more specifically in an on-line setting, it is episodic in structure - more like the lateral leaps of hypertext than the disciplined hierarchies of headings characteristic of the linearity of conventional academic argument. It falls into three parts. The first introduces the online virtual classroom environment in which the teaching takes place. Part two locates the course within more general epistemological issues confronting designers of education (foundations) courses in pre-service teaching degrees in the twenty-first century. In Part three, the syllabus of the course is outlined. The paper concludes with examples of students doing 'situated' educational theorising as they engage with course readings and assignments. Through this multi-layered account, I raise for discussion some broad questions about pedagogy in educational foundations courses in today's environment.

year: 2003

title: Local Cryo-history: Redefining the creation, transformation and circulation of Aotearoa’s nineteenth century glacier knowledge

authors: Annandale, Claudi - Ann

abstract: The creation, transformation and dissemination of knowledge constantly shapes the narrative of glacier history. However, the intersecting layers that human encounters with the frozen environment, Indigenous knowledge, and popular thought add to glacier histories is often overlooked. By analysing the trends and intellectual traditions that emerged in nineteenth century New Zealand, a period defined as glaciology's 'classical' era of study, this thesis aims to broaden the Southern Alps’ local science-focused glacier discourse.   

Māori, for example, possessed unique mātauranga (knowledge) that was documented through Europeans employing local guides to accompany them across the Southern Alps. This mātauranga shaped some encounters nineteenth-century scientists, surveyors, and travellers had with Kā Tiritiri o te Moana’s glacier environment. New Zealand scholars like Julius von Haast and James Hector, on the other hand, further refined their understanding of New Zealand glaciers through the transnational exchange of knowledge and intellectual debates. A combination of Enlightenment rationalism and Romantic aesthetic also influenced popular glacier narratives that emerged during the nineteenth century. For example, the imagination of journalists, mountaineers and travellers reflected the broader cultural trends that circulated from Europe to New Zealand before their knowledge was disseminated to the public.  

By interrogating mātauranga Māori, formal scientific study, and popular settler imagination about glaciers, this thesis redefines New Zealand’s nineteenth-century glacier history as inherently multilayered through the circulation, creation, transformation and dissemination of glacier knowledge. In doing so, it highlights glaciers not only as physical entities defined by scientific study but as ideas shaped by diverse knowledge systems, cultural perceptions, and historical contingencies.

text: Local Cryo-history: Redefining the creation, transformation and circulation of Aotearoa’s nineteenth century glacier knowledge The creation, transformation and dissemination of knowledge constantly shapes the narrative of glacier history. However, the intersecting layers that human encounters with the frozen environment, Indigenous knowledge, and popular thought add to glacier histories is often overlooked. By analysing the trends and intellectual traditions that emerged in nineteenth century New Zealand, a period defined as glaciology's 'classical' era of study, this thesis aims to broaden the Southern Alps’ local science-focused glacier discourse.   

Māori, for example, possessed unique mātauranga (knowledge) that was documented through Europeans employing local guides to accompany them across the Southern Alps. This mātauranga shaped some encounters nineteenth-century scientists, surveyors, and travellers had with Kā Tiritiri o te Moana’s glacier environment. New Zealand scholars like Julius von Haast and James Hector, on the other hand, further refined their understanding of New Zealand glaciers through the transnational exchange of knowledge and intellectual debates. A combination of Enlightenment rationalism and Romantic aesthetic also influenced popular glacier narratives that emerged during the nineteenth century. For example, the imagination of journalists, mountaineers and travellers reflected the broader cultural trends that circulated from Europe to New Zealand before their knowledge was disseminated to the public.  

By interrogating mātauranga Māori, formal scientific study, and popular settler imagination about glaciers, this thesis redefines New Zealand’s nineteenth-century glacier history as inherently multilayered through the circulation, creation, transformation and dissemination of glacier knowledge. In doing so, it highlights glaciers not only as physical entities defined by scientific study but as ideas shaped by diverse knowledge systems, cultural perceptions, and historical contingencies.

year: 2025