title: Comparative sedimentology and paleoecology of fossil giant oyster beds in some tertiary strata of New Zealand and Argentina

authors: Macmillan, Larissa Claire

subjects: fossils

abstract: Shell concentrations are useful indicators of relative sea-level changes, systems tracts, and depositional sequence and boundary surfaces. Shellbeds can equally act as archives of paleoenvironmental information and aid in the reconstruction of past environmental and ecological conditions. These considerations are applied in this study to occurrences of giant oyster reefs and shellbeds in Tertiary sequences in North Island, New Zealand, and in Patagonia, southern Argentina. 

Large recliner morphotype Flemingostreini Stenzel oysters are common in the Oligocene Orahiri Limestone in the vicinity of Waitomo, New Zealand. The oysters occur in tabular beds typically 0.5-2 m, but up to 9 m thick within highly indurated biomicritic limestone. Individual valves reach 15 cm in length, 10 cm in width and 2.5 to 5 cm in thickness. The occurences at Waitomo are characteristic of multi-event shellbeds and can be interpreted as onlap (transgressive lag) and backlap shellbeds within a transgressive systems tract. Shell delta18O (-2.1 to 1.4 per mille) and delta13C (0.4 and 2.5 per mille) values, and minimal seasonal isotopic ranges with little variability, confirm that these oysters lived in a fully marine environment. The environment of Oligocene Flemingstreini Stenzel was probably similar to modern Ostrea chilensis from Foveaux Strait off southern New Zealand, living on coarse shelly and gravelly tide swept substrates in 18-40 m water depth, under normal marine salinity conditions and temperatures around 13oC, forming in situ biostromes of haphazardly packed oyster shells.

Specimens of  Ostrea  patagonica in the Late Miocene Puerto Madryn Formation, Pen nsula Vald s, Patagonia, are held in a weakly calcareous fine sand host. They reach 20 cm in length, 5 cm thick and weigh as much as 3 kg. The reef has a lens (or bioherm) geometry and is composed of articulated, well preserved oysters set in a fine sand matrix. The reef is interpreted as a downlap shellbed within a highstand systems tract. Oyster shell delta18O (-4.4 to -3.2 per mille) and delta13C (-2.0 to -3.2 per mille) values are low and show large seasonal isotopic ranges, with a large amount of variability, collectively supporting a marginal marine setting receiving extensive freshwater input and mixing. The environment of these oysters is comparable with modern Crassostrea gigas reefs at San Blas, Patagonia. Ostrea patagonica occupied a low energy intertidal zone in water depths of only 1-2 m. Temperatures ranged from 20degreesC (summer maximum) to 8degreesC (winter minimum). The oysters were not cemented firmly to the substrate, but reclined on the muddy sediment and formed an in situ bioherm of loosely packed oysters, with the living animals concentrated over time to the outside of the accumulation.

The Pliocene Wilkies Shellbed in the Wanganui Basin, New Zealand, comprises oyster accumulations up to 15 m thick involving the extinct oyster Crassostrea ingens. Individuals are up to 30 cm long, 7 cm thick and weigh as much as 2 kg. The shellbed consists of a lower onlap shellbed (transgressive lag) and an overlying backlap shellbed (biostrome). The widespread shell delta18O (-3.0 to 3.0 per mille) and delta13C (-2.6 to 1.8 per mille) isotopic values support a range of marginal marine to marine environmental conditions. The lower onlap shellbed had estuarine influence, while the upper part had affinities with a nearshore (less than 40 m) marine setting of more normal salinity. As the thick backlap shellbed migrated shoreward a depth was maintained in which Crassostrea could live in situ within a weakly calcareous very fine muddy sand in favourable conditions of low turbidity and sedimentation. 

All species of fossil oysters in this study are easily distinguished by the large size and thickness of their valves. The 'reefs' formed by these oysters provided hard substrata for a diverse community of encrusting and boring organisms which includes the likes of Gastrochaenolites (bivalve), Maeandropolydora (polychaete), Clionolithes (boring algae), Entobia (sponge), Leptichnus (bryozoan) and Radulichnus (gastropod). These communities are comparable to those seen on extant oyster reefs. They can thus be termed autogenic ecosystem engineers. Non-random distribution of euendoliths and epiliths on oyster valves may be accounted for by different survival adaptations of larvae. Shell morphotypes and exterior architectures are inferred to have prompted active rugophilic (groove-seeking), geophobic (anti-gravity) and rheophilic (current-seeking) behaviour of larvae, which enhanced their survival rate. Preference for the external surface of shells suggests that traces were created during the life time of the oysters, while most internal traces are post-mortem features.

text: Comparative sedimentology and paleoecology of fossil giant oyster beds in some tertiary strata of New Zealand and Argentina Shell concentrations are useful indicators of relative sea-level changes, systems tracts, and depositional sequence and boundary surfaces. Shellbeds can equally act as archives of paleoenvironmental information and aid in the reconstruction of past environmental and ecological conditions. These considerations are applied in this study to occurrences of giant oyster reefs and shellbeds in Tertiary sequences in North Island, New Zealand, and in Patagonia, southern Argentina. 

Large recliner morphotype Flemingostreini Stenzel oysters are common in the Oligocene Orahiri Limestone in the vicinity of Waitomo, New Zealand. The oysters occur in tabular beds typically 0.5-2 m, but up to 9 m thick within highly indurated biomicritic limestone. Individual valves reach 15 cm in length, 10 cm in width and 2.5 to 5 cm in thickness. The occurences at Waitomo are characteristic of multi-event shellbeds and can be interpreted as onlap (transgressive lag) and backlap shellbeds within a transgressive systems tract. Shell delta18O (-2.1 to 1.4 per mille) and delta13C (0.4 and 2.5 per mille) values, and minimal seasonal isotopic ranges with little variability, confirm that these oysters lived in a fully marine environment. The environment of Oligocene Flemingstreini Stenzel was probably similar to modern Ostrea chilensis from Foveaux Strait off southern New Zealand, living on coarse shelly and gravelly tide swept substrates in 18-40 m water depth, under normal marine salinity conditions and temperatures around 13oC, forming in situ biostromes of haphazardly packed oyster shells.

Specimens of  Ostrea  patagonica in the Late Miocene Puerto Madryn Formation, Pen nsula Vald s, Patagonia, are held in a weakly calcareous fine sand host. They reach 20 cm in length, 5 cm thick and weigh as much as 3 kg. The reef has a lens (or bioherm) geometry and is composed of articulated, well preserved oysters set in a fine sand matrix. The reef is interpreted as a downlap shellbed within a highstand systems tract. Oyster shell delta18O (-4.4 to -3.2 per mille) and delta13C (-2.0 to -3.2 per mille) values are low and show large seasonal isotopic ranges, with a large amount of variability, collectively supporting a marginal marine setting receiving extensive freshwater input and mixing. The environment of these oysters is comparable with modern Crassostrea gigas reefs at San Blas, Patagonia. Ostrea patagonica occupied a low energy intertidal zone in water depths of only 1-2 m. Temperatures ranged from 20degreesC (summer maximum) to 8degreesC (winter minimum). The oysters were not cemented firmly to the substrate, but reclined on the muddy sediment and formed an in situ bioherm of loosely packed oysters, with the living animals concentrated over time to the outside of the accumulation.

The Pliocene Wilkies Shellbed in the Wanganui Basin, New Zealand, comprises oyster accumulations up to 15 m thick involving the extinct oyster Crassostrea ingens. Individuals are up to 30 cm long, 7 cm thick and weigh as much as 2 kg. The shellbed consists of a lower onlap shellbed (transgressive lag) and an overlying backlap shellbed (biostrome). The widespread shell delta18O (-3.0 to 3.0 per mille) and delta13C (-2.6 to 1.8 per mille) isotopic values support a range of marginal marine to marine environmental conditions. The lower onlap shellbed had estuarine influence, while the upper part had affinities with a nearshore (less than 40 m) marine setting of more normal salinity. As the thick backlap shellbed migrated shoreward a depth was maintained in which Crassostrea could live in situ within a weakly calcareous very fine muddy sand in favourable conditions of low turbidity and sedimentation. 

All species of fossil oysters in this study are easily distinguished by the large size and thickness of their valves. The 'reefs' formed by these oysters provided hard substrata for a diverse community of encrusting and boring organisms which includes the likes of Gastrochaenolites (bivalve), Maeandropolydora (polychaete), Clionolithes (boring algae), Entobia (sponge), Leptichnus (bryozoan) and Radulichnus (gastropod). These communities are comparable to those seen on extant oyster reefs. They can thus be termed autogenic ecosystem engineers. Non-random distribution of euendoliths and epiliths on oyster valves may be accounted for by different survival adaptations of larvae. Shell morphotypes and exterior architectures are inferred to have prompted active rugophilic (groove-seeking), geophobic (anti-gravity) and rheophilic (current-seeking) behaviour of larvae, which enhanced their survival rate. Preference for the external surface of shells suggests that traces were created during the life time of the oysters, while most internal traces are post-mortem features.

year: 2010

title: Enterprises’ sustainability orientation: A natural language processing approach

authors: Culpi Mann, Evelize

subjects: sustainability orientation

abstract: Sustainability in business is widely viewed as a strategic orientation decision. However, comparatively, little is known about assessing sustainability orientation and its drivers and implications for enterprises. This thesis examines sustainability orientation from a diverse perspective and focuses on sustainability orientation using corporate narratives. Specifically, this thesis harnesses the power of natural language processing (NLP) techniques, which is a field of artificial intelligence (AI), as a tool for research in extracting insights from textual communication. 
The thesis comprises three studies along with a cohesive synthesis of their implications. First, I begin by drawing on the vast literature on corporate social sustainability (CSR) to explore contextual factors that drive enterprises' behaviour towards sustainability. Specifically, the results illustrate that CSR practices are associated with external constituents' scrutiny levels. It is strongly related to political factors and social visibility and partially to media exposure. In addition, the study provides evidence to illustrate that positive influences on CSR practices may have been short-lived when a longer time horizon is considered. 
Second, by exploring small and middle-sized enterprises (SMEs), I elucidated the implications of a communicated sustainability orientation strategy on enterprises' economic performance. I used the communication of social values as a signal of sustainability orientation and explored its impacts, also considering social actions as an additional signal of sustainability orientation. The findings suggest that the effect of communicating social values on economic performance varies between social enterprises and traditional commercial enterprises. Unlike traditional commercial enterprises, social enterprises do not achieve economic performance advantages by communicating social values. Instead, it is the social actions of social enterprises that positively influence economic performance. 
Third, I explore sustainability orientation through the Sustainable Development Goals (SDGs) lenses. The last empirical study explores the effect of a communicated SDG orientation strategy on the economic performance of traditional commercial enterprises and social enterprises. The results demonstrated a positive relationship between the communication of a narrow set of SDGs and enterprises' economic performance. The extent of this effect is similar between social and traditional commercial enterprises. The results take on the meaning that stakeholders might appreciate an enterprise's SDG orientation strategy that concentrates on a narrow set of SDGs within distinct purpose-driven institutional contexts. 
This thesis is an effort to increase transparency about critical aspects of enterprises' sustainability orientation: its assessment, influential factors and implications for economic performance. This doctoral thesis provides significant practical and theoretical contributions to understanding the complex dynamics between sustainability orientation and business context. By focusing on the evolutionary nature of social norms, this research provides an aggregated view of how environmental pressures affect an enterprise's practices towards sustainability. This thesis also offers an initial step in examining the relationship between a communicated sustainability orientation strategy and enterprises' economic performance. It highlights that social enterprises and traditional commercial enterprises experience different external pressures and should tailor their sustainability orientation strategies to their specific context. Moreover, this thesis reinforces that innovative NLP approaches can overcome challenges in measuring sustainability orientation.

text: Enterprises’ sustainability orientation: A natural language processing approach Sustainability in business is widely viewed as a strategic orientation decision. However, comparatively, little is known about assessing sustainability orientation and its drivers and implications for enterprises. This thesis examines sustainability orientation from a diverse perspective and focuses on sustainability orientation using corporate narratives. Specifically, this thesis harnesses the power of natural language processing (NLP) techniques, which is a field of artificial intelligence (AI), as a tool for research in extracting insights from textual communication. 
The thesis comprises three studies along with a cohesive synthesis of their implications. First, I begin by drawing on the vast literature on corporate social sustainability (CSR) to explore contextual factors that drive enterprises' behaviour towards sustainability. Specifically, the results illustrate that CSR practices are associated with external constituents' scrutiny levels. It is strongly related to political factors and social visibility and partially to media exposure. In addition, the study provides evidence to illustrate that positive influences on CSR practices may have been short-lived when a longer time horizon is considered. 
Second, by exploring small and middle-sized enterprises (SMEs), I elucidated the implications of a communicated sustainability orientation strategy on enterprises' economic performance. I used the communication of social values as a signal of sustainability orientation and explored its impacts, also considering social actions as an additional signal of sustainability orientation. The findings suggest that the effect of communicating social values on economic performance varies between social enterprises and traditional commercial enterprises. Unlike traditional commercial enterprises, social enterprises do not achieve economic performance advantages by communicating social values. Instead, it is the social actions of social enterprises that positively influence economic performance. 
Third, I explore sustainability orientation through the Sustainable Development Goals (SDGs) lenses. The last empirical study explores the effect of a communicated SDG orientation strategy on the economic performance of traditional commercial enterprises and social enterprises. The results demonstrated a positive relationship between the communication of a narrow set of SDGs and enterprises' economic performance. The extent of this effect is similar between social and traditional commercial enterprises. The results take on the meaning that stakeholders might appreciate an enterprise's SDG orientation strategy that concentrates on a narrow set of SDGs within distinct purpose-driven institutional contexts. 
This thesis is an effort to increase transparency about critical aspects of enterprises' sustainability orientation: its assessment, influential factors and implications for economic performance. This doctoral thesis provides significant practical and theoretical contributions to understanding the complex dynamics between sustainability orientation and business context. By focusing on the evolutionary nature of social norms, this research provides an aggregated view of how environmental pressures affect an enterprise's practices towards sustainability. This thesis also offers an initial step in examining the relationship between a communicated sustainability orientation strategy and enterprises' economic performance. It highlights that social enterprises and traditional commercial enterprises experience different external pressures and should tailor their sustainability orientation strategies to their specific context. Moreover, this thesis reinforces that innovative NLP approaches can overcome challenges in measuring sustainability orientation.

year: 2024

title: “We wanted to see if you were the real deal”: Teaching as a cultural practice in a challenging environment

authors: Lemon, Katrina Suezanne

abstract: Teaching can be viewed as a cultural practice in which teaching is embedded in the culture of the teacher and informed by the culture of the students (Bell, 2011). In this paper, a narrative is presented detailing an authentic example of teaching in New Zealand in which culture is prioritised. It describes the challenges faced by a young female teacher as she worked in a low decile secondary school with male students, the majority of whom were involved in the Mongrel Mob[1] gang. Her approach and responses were centred in her belief in culturally responsive teaching. The deliberate actions of the teacher led to a turning point for the students, allowing their mana to remain intact as she acknowledged their identity, language and culture. This teacher’s experience provides an example of how a teacher can enable learners in diverse classrooms to succeed in their learning.

text: “We wanted to see if you were the real deal”: Teaching as a cultural practice in a challenging environment Teaching can be viewed as a cultural practice in which teaching is embedded in the culture of the teacher and informed by the culture of the students (Bell, 2011). In this paper, a narrative is presented detailing an authentic example of teaching in New Zealand in which culture is prioritised. It describes the challenges faced by a young female teacher as she worked in a low decile secondary school with male students, the majority of whom were involved in the Mongrel Mob[1] gang. Her approach and responses were centred in her belief in culturally responsive teaching. The deliberate actions of the teacher led to a turning point for the students, allowing their mana to remain intact as she acknowledged their identity, language and culture. This teacher’s experience provides an example of how a teacher can enable learners in diverse classrooms to succeed in their learning.

year: 2017