title: Environmental drivers of viral community composition in Antarctic soils identified by viromics

authors: Adriaenssens, Evelien M.

subjects: Viromics

abstract: Background
The Antarctic continent is considered the coldest and driest place on earth with simple ecosystems, devoid of higher plants. Soils in the ice-free regions of Antarctica are known to harbor a wide range of microorganisms from primary producers to grazers, yet their ecology and particularly the role of viruses is poorly understood. In this study, we examined the virus community structures of 14 soil samples from the Mackay Glacier region.

Methods
Viral communities were extracted from soil and the dsDNA was extracted, amplified using single-primer amplification, and sequenced using the Ion Torrent Proton platform. Metadata on soil physico-chemistry was collected from all sites. Both read and contig datasets were analyzed with reference-independent and reference-dependent methods to assess viral community structures and the influence of environmental parameters on their distribution.

Results
We observed a high heterogeneity in virus signatures, independent of geographical proximity. Tailed bacteriophages were dominant in all samples, but the incidences of the affiliated families Siphoviridae and Myoviridae were inversely correlated, suggesting direct competition for hosts. Viruses of the families Phycodnaviridae and Mimiviridae were present at significant levels in high-diversity soil samples and were found to co-occur, implying little competition between them. Combinations of soil factors, including pH, calcium content, and site altitude, were found to be the main drivers of viral community structure.

Conclusions
The pattern of viral community structure with higher levels of diversity at lower altitude and pH, and co-occurring viral families, suggests that these cold desert soil viruses interact with each other, the host, and the environment in an intricate manner, playing a potentially crucial role in maintaining host diversity and functioning of the microbial ecosystem in the extreme environments of Antarctic soil.

text: Environmental drivers of viral community composition in Antarctic soils identified by viromics Background
The Antarctic continent is considered the coldest and driest place on earth with simple ecosystems, devoid of higher plants. Soils in the ice-free regions of Antarctica are known to harbor a wide range of microorganisms from primary producers to grazers, yet their ecology and particularly the role of viruses is poorly understood. In this study, we examined the virus community structures of 14 soil samples from the Mackay Glacier region.

Methods
Viral communities were extracted from soil and the dsDNA was extracted, amplified using single-primer amplification, and sequenced using the Ion Torrent Proton platform. Metadata on soil physico-chemistry was collected from all sites. Both read and contig datasets were analyzed with reference-independent and reference-dependent methods to assess viral community structures and the influence of environmental parameters on their distribution.

Results
We observed a high heterogeneity in virus signatures, independent of geographical proximity. Tailed bacteriophages were dominant in all samples, but the incidences of the affiliated families Siphoviridae and Myoviridae were inversely correlated, suggesting direct competition for hosts. Viruses of the families Phycodnaviridae and Mimiviridae were present at significant levels in high-diversity soil samples and were found to co-occur, implying little competition between them. Combinations of soil factors, including pH, calcium content, and site altitude, were found to be the main drivers of viral community structure.

Conclusions
The pattern of viral community structure with higher levels of diversity at lower altitude and pH, and co-occurring viral families, suggests that these cold desert soil viruses interact with each other, the host, and the environment in an intricate manner, playing a potentially crucial role in maintaining host diversity and functioning of the microbial ecosystem in the extreme environments of Antarctic soil.

year: 2017

title: Depth-differentiated, multivariate control of biopore number under different land-use practices

authors: Stolze, Katharina

subjects: earthworm communities

abstract: Earthworms and (tap-)roots impact the soil structure by creating large biopores, affecting infiltration capacity, seepage, nutrient cycling, and soil aeration. Despite the importance of biopores for the functions of soils and the fact that several hundreds of biopores >2 mm in diameter may occur on one square meter of soil, knowledge on the interdependence of soil properties, land-use intensity, and biopore number is still rudimentary. In this study, we investigate the linkage of the number of biopores (>2 mm i.d.) with the earthworm community, root biomass, and soil properties, including pH, water content, soil organic carbon (SOC), as well as the land-use intensity (pasture vs. cropland) as a function of the soil depth (15, 30 and 50 cm). Hypothesized causal relationships among these factors were analyzed by piecewise structural equation modelling (SEM). We found various and novel linkages between roots, earthworms, biopores, and soil properties depending on soil depth. In topsoil (at 15 cm depth), roots directly affected the number of small-sized biopores, and anecic earthworms were related to medium-sized biopores. These effects diminished with depth. We identified land-use intensity as the factor preponderating the relations between biopores, root biomass, and earthworm number in the topsoil horizons, thereby masking other interactions among variables. This appeared as high multicollinearity among variables in the SEM of the topsoil. Land-use intensity effects were found to impact the whole soil profile but decreased with soil depth. To further elucidate the single effects of soil properties on biopore-forming biota and number of biopores in the topsoil, we excluded land-use intensity as a variable in subsequent analyses. Biopores increased with soil pH and soil water content but decreased with increasing SOC. Based on our SEM analysis, we conclude that the occurrence, frequency, and persistence of biopores are the consequence of intricate interdependencies between earthworm communities, roots, and site-specific soil properties, governed by land-use intensity.

text: Depth-differentiated, multivariate control of biopore number under different land-use practices Earthworms and (tap-)roots impact the soil structure by creating large biopores, affecting infiltration capacity, seepage, nutrient cycling, and soil aeration. Despite the importance of biopores for the functions of soils and the fact that several hundreds of biopores >2 mm in diameter may occur on one square meter of soil, knowledge on the interdependence of soil properties, land-use intensity, and biopore number is still rudimentary. In this study, we investigate the linkage of the number of biopores (>2 mm i.d.) with the earthworm community, root biomass, and soil properties, including pH, water content, soil organic carbon (SOC), as well as the land-use intensity (pasture vs. cropland) as a function of the soil depth (15, 30 and 50 cm). Hypothesized causal relationships among these factors were analyzed by piecewise structural equation modelling (SEM). We found various and novel linkages between roots, earthworms, biopores, and soil properties depending on soil depth. In topsoil (at 15 cm depth), roots directly affected the number of small-sized biopores, and anecic earthworms were related to medium-sized biopores. These effects diminished with depth. We identified land-use intensity as the factor preponderating the relations between biopores, root biomass, and earthworm number in the topsoil horizons, thereby masking other interactions among variables. This appeared as high multicollinearity among variables in the SEM of the topsoil. Land-use intensity effects were found to impact the whole soil profile but decreased with soil depth. To further elucidate the single effects of soil properties on biopore-forming biota and number of biopores in the topsoil, we excluded land-use intensity as a variable in subsequent analyses. Biopores increased with soil pH and soil water content but decreased with increasing SOC. Based on our SEM analysis, we conclude that the occurrence, frequency, and persistence of biopores are the consequence of intricate interdependencies between earthworm communities, roots, and site-specific soil properties, governed by land-use intensity.

year: 2022

title: How learning stories shape understandings of children’s learning identities in one community of practice: A narrative inquiry

authors: Sands, Lorraine May

subjects: Narrative inquiry

abstract: Mā te mahi, ka mōhio; mā te mōhio, ka mārama; mā te mārama, ka mātau; mā te mātau, ka ora.
From hard work comes knowledge; from that knowledge comes understanding; from that understanding comes strength; from that strength comes wellbeing and life.
This thesis is a listening, dialogic investigation into ways the community of learners at Greerton Early Learning Centre considers learning stories have affected their children’s learning identities—that is, how they view themselves as learners. Aotearoa New Zealand’s early childhood curriculum, Te Whāriki, focuses on responsive, reciprocal relationships wrapped around the uniqueness and mana of each child. Learning stories—a research-based sociocultural narrative assessment approach—have been used in Aotearoa New Zealand early learning settings for over two decades to capture children’s learning while honouring the intent of Te Whāriki to nurture children’s languages, cultures, and identities. In the current climate of privatisation and neoliberalism, however, the value of learning stories is increasingly contested. This study refutes such discourses and instead navigates the value of multiple ways of knowing, meaningfully embedded in the lived experiences of children in relational communities.

This study was embedded in a narrative inquiry paradigm that sees reality as a socially mediated construction contained within stories that are told and retold across times, social contexts, and places. The study aimed to understand and document how storying children’s lived experience makes a meaningful difference to ways children view themselves as learners. Six children, their families, and their teachers were invited to reengage with selected learning stories from the children’s learning portfolios and then to rethink and retell how these learning stories contributed to their views of children’s learning identities.

The study found that learning stories have powerful effects on the ways children see themselves and on the ways those around them see the children as learners. It was clear from the data that children’s learning identities are embedded in the complex social and cultural contexts that surround them. The teachers’ long-term whanaungatanga relationships with mokopuna and whānau enabled kaiako to write learning stories that connected meaningfully with children’s wider historical, social, and cultural contexts. Insights into children’s learning from the learning stories were actively taken up by the parents and shaped the ways they saw and interacted with their children as learners. Likewise, teachers listened to stories shared from home (whether in a written learning story form or simply in the course of conversations), and these contributed to the teachers’ understandings of the children as agentic learners within sociocultural contexts. The physical folders of learning stories offered children powerful ways to maintain connections and a sense of pride in their learning achievements, linked to the people and places that surrounded those achievements.

Learning stories also enabled children to review their learning growth over time, including times when they had set goals, been supported in pursuing those goals by those around them, and had their achievements and dispositions honoured through documentation as a learning story. The process of robust engagement with crafting and reviewing their own and their colleagues’ learning stories played an important role in teachers’ ongoing professional learning. Finally, it was clear that across the whole community of practice—spanning mokopuna, whānau, and kaiako—learning stories played an important role in developing and reinforcing a shared language of learning as well as a shared understanding of the importance of children’s dispositions and working theories as the most highly valued forms of learning.

Although centred in one community, this research stands on the shoulders of many and may have resonance and implications for those in broader contexts. At a time when the usefulness and appropriateness of learning stories are increasingly contested, this study provides an important demonstration of the power of thoughtfully written learning stories and the alignment of this assessment approach with the vision and values of Te Whāriki. Further, with limited past research looking at the intersection of learning stories and children’s learning identities, this study’s rich account of this interaction in one community of practice provides a valuable contribution to the literature.

text: How learning stories shape understandings of children’s learning identities in one community of practice: A narrative inquiry Mā te mahi, ka mōhio; mā te mōhio, ka mārama; mā te mārama, ka mātau; mā te mātau, ka ora.
From hard work comes knowledge; from that knowledge comes understanding; from that understanding comes strength; from that strength comes wellbeing and life.
This thesis is a listening, dialogic investigation into ways the community of learners at Greerton Early Learning Centre considers learning stories have affected their children’s learning identities—that is, how they view themselves as learners. Aotearoa New Zealand’s early childhood curriculum, Te Whāriki, focuses on responsive, reciprocal relationships wrapped around the uniqueness and mana of each child. Learning stories—a research-based sociocultural narrative assessment approach—have been used in Aotearoa New Zealand early learning settings for over two decades to capture children’s learning while honouring the intent of Te Whāriki to nurture children’s languages, cultures, and identities. In the current climate of privatisation and neoliberalism, however, the value of learning stories is increasingly contested. This study refutes such discourses and instead navigates the value of multiple ways of knowing, meaningfully embedded in the lived experiences of children in relational communities.

This study was embedded in a narrative inquiry paradigm that sees reality as a socially mediated construction contained within stories that are told and retold across times, social contexts, and places. The study aimed to understand and document how storying children’s lived experience makes a meaningful difference to ways children view themselves as learners. Six children, their families, and their teachers were invited to reengage with selected learning stories from the children’s learning portfolios and then to rethink and retell how these learning stories contributed to their views of children’s learning identities.

The study found that learning stories have powerful effects on the ways children see themselves and on the ways those around them see the children as learners. It was clear from the data that children’s learning identities are embedded in the complex social and cultural contexts that surround them. The teachers’ long-term whanaungatanga relationships with mokopuna and whānau enabled kaiako to write learning stories that connected meaningfully with children’s wider historical, social, and cultural contexts. Insights into children’s learning from the learning stories were actively taken up by the parents and shaped the ways they saw and interacted with their children as learners. Likewise, teachers listened to stories shared from home (whether in a written learning story form or simply in the course of conversations), and these contributed to the teachers’ understandings of the children as agentic learners within sociocultural contexts. The physical folders of learning stories offered children powerful ways to maintain connections and a sense of pride in their learning achievements, linked to the people and places that surrounded those achievements.

Learning stories also enabled children to review their learning growth over time, including times when they had set goals, been supported in pursuing those goals by those around them, and had their achievements and dispositions honoured through documentation as a learning story. The process of robust engagement with crafting and reviewing their own and their colleagues’ learning stories played an important role in teachers’ ongoing professional learning. Finally, it was clear that across the whole community of practice—spanning mokopuna, whānau, and kaiako—learning stories played an important role in developing and reinforcing a shared language of learning as well as a shared understanding of the importance of children’s dispositions and working theories as the most highly valued forms of learning.

Although centred in one community, this research stands on the shoulders of many and may have resonance and implications for those in broader contexts. At a time when the usefulness and appropriateness of learning stories are increasingly contested, this study provides an important demonstration of the power of thoughtfully written learning stories and the alignment of this assessment approach with the vision and values of Te Whāriki. Further, with limited past research looking at the intersection of learning stories and children’s learning identities, this study’s rich account of this interaction in one community of practice provides a valuable contribution to the literature.

year: 2022