title: Aspects of late quaternary stratigraphy and evolution of some coastal embayments on the east Coromandel Peninsular, New Zealand

authors: Abrahamson, Linda

abstract: The stratigraphy, morphology and sedimentology of the late Quaternary deposits of eastern Coromandel coastal embayments are described, and depicted on a series of ~1:12 500 scale geological and morphological maps. Five stratigraphic units are recognised on the basis of morphology, chronology and depositional environment. The sequence consists of sediments deposited as barrier shorelines, and in the lee of barriers in estuarine and fluvial settings. Prograded, stationary and, rarely, receded barriers are identified, giving rise to three major coastal embayment categories, namely prograded barrier spit embayments, bay barrier embayments, and strand plain embayments. The various barrier types formed in response to different environmental controls, mainly sediment supply rates, coastal configuration and shelf dimensions.

The barrier sediments are mainly mature quartzofeldspathic-rich medium sands derived from reworking within the nearshore system. The fluvial sediments are typically immature, poorly sorted gravels, sand and muds transported from the hinterland by rivers. Estuarine sediments are commonly organic- or shell-rich medium to fine sand containing in situ plant remains and in situ estuarine shells. Ultimately, the sediments have been derived from stream and coastal cliff erosion of surrounding Whitianga and Coromandel Group Volcanics.

Distinctive tephras (Rotoehu Ash, c. 50 ky BP; Tuhua Tephra Formation, c. 6.2 ky BP; Taupo Pumice Formation, c. 1.8 ky BP; and Loisels Pumice, c. 650 y BP) constitute marker horizons in the deposits and, along with radiocarbon dates, have enabled the age structure of the barriers to be determined. Other relative age methods, including vegetation succession, soil development and weathering products, support the coastal chronosequence established from the interbedded tephras .

A model is synthesised to explain the accumulation of sand within the coastal embayments during the late Quaternary. Sea level changes are inferred to be the major control on sedimentation. Two main depositional phases are recorded by the barrier deposits (Pleistocene and Holocene barriers), and are associated with the last interglacial (c. 125 ky BP) and Holocene (6.5 ky BP to present) sea level stillstands. Since sea level reached its present position 6.5 ky BP, the Holocene barriers have experienced several phases of accretion and erosion due to variations in wave regime and sand supply into the embayments. Depositional environments are inferred for Pleistocene barrier samples from multivariate discriminant function analyses of sample textural data, and enable the estimation of the·last interglacial sea level position and subsequent tectonic movements along the east Coromandel coast from the relative displacement of this level.

text: Aspects of late quaternary stratigraphy and evolution of some coastal embayments on the east Coromandel Peninsular, New Zealand The stratigraphy, morphology and sedimentology of the late Quaternary deposits of eastern Coromandel coastal embayments are described, and depicted on a series of ~1:12 500 scale geological and morphological maps. Five stratigraphic units are recognised on the basis of morphology, chronology and depositional environment. The sequence consists of sediments deposited as barrier shorelines, and in the lee of barriers in estuarine and fluvial settings. Prograded, stationary and, rarely, receded barriers are identified, giving rise to three major coastal embayment categories, namely prograded barrier spit embayments, bay barrier embayments, and strand plain embayments. The various barrier types formed in response to different environmental controls, mainly sediment supply rates, coastal configuration and shelf dimensions.

The barrier sediments are mainly mature quartzofeldspathic-rich medium sands derived from reworking within the nearshore system. The fluvial sediments are typically immature, poorly sorted gravels, sand and muds transported from the hinterland by rivers. Estuarine sediments are commonly organic- or shell-rich medium to fine sand containing in situ plant remains and in situ estuarine shells. Ultimately, the sediments have been derived from stream and coastal cliff erosion of surrounding Whitianga and Coromandel Group Volcanics.

Distinctive tephras (Rotoehu Ash, c. 50 ky BP; Tuhua Tephra Formation, c. 6.2 ky BP; Taupo Pumice Formation, c. 1.8 ky BP; and Loisels Pumice, c. 650 y BP) constitute marker horizons in the deposits and, along with radiocarbon dates, have enabled the age structure of the barriers to be determined. Other relative age methods, including vegetation succession, soil development and weathering products, support the coastal chronosequence established from the interbedded tephras .

A model is synthesised to explain the accumulation of sand within the coastal embayments during the late Quaternary. Sea level changes are inferred to be the major control on sedimentation. Two main depositional phases are recorded by the barrier deposits (Pleistocene and Holocene barriers), and are associated with the last interglacial (c. 125 ky BP) and Holocene (6.5 ky BP to present) sea level stillstands. Since sea level reached its present position 6.5 ky BP, the Holocene barriers have experienced several phases of accretion and erosion due to variations in wave regime and sand supply into the embayments. Depositional environments are inferred for Pleistocene barrier samples from multivariate discriminant function analyses of sample textural data, and enable the estimation of the·last interglacial sea level position and subsequent tectonic movements along the east Coromandel coast from the relative displacement of this level.

year: 1987

title: Formal methods for interactive system: (FMIS 2013)

authors: Reeves, Steve

subjects: computer science

abstract: The workshop focuses on use of formal methods in the development and analysis of Interactive Systems. The workshop is particularly concerned with issues relating to Human Computer Interaction and to the analysis of interaction in a variety of computing environments (safety critical, ubiquitous etc.). In the latter case the complexities of dynamic context, including location and large numbers of interacting entities, pose particular challenges to formal modelling.

text: Formal methods for interactive system: (FMIS 2013) The workshop focuses on use of formal methods in the development and analysis of Interactive Systems. The workshop is particularly concerned with issues relating to Human Computer Interaction and to the analysis of interaction in a variety of computing environments (safety critical, ubiquitous etc.). In the latter case the complexities of dynamic context, including location and large numbers of interacting entities, pose particular challenges to formal modelling.

year: 2013

title: eDNA-based detection of New Zealand freshwater mussel (kākahi) populations using digital PCR

authors: Ferris, Kelsey

subjects: eDNA

abstract: Globally, freshwater mussels are one of the most endangered taxa due to pollution, nutrient loading, habitat fragmentation, and species introduction attributable to anthropogenic activities. New Zealand freshwater mussels (kākahi) are ecological engineers and integral species in freshwater ecosystems. However, kākahi populations are expected to decline 70% by 2024 in part due to their unique reproductive cycle involving an obligatory phoretic relationship with declining native fish. Kākahi distribution and abundance throughout New Zealand is poorly understood due to time-consuming surveying techniques of concealed and morphologically cryptic species. A rapid and reliable method is required for the detection and identification of these ‘Threatened’ kākahi populations for conservation and management. Therefore, this study aimed to i) validate an environmental DNA (eDNA) based detection method for New Zealand freshwater mussels using digital PCR (dPCR); ii) determine the most appropriate sampling season for kākahi eDNA; and iii) determine whether eDNA could be used to detect effects of fish barriers on kākahi distribution.
In vivo trials determined that filtration of field samples within 24 hours of collection minimised eDNA degradation and that prefiltration effectively removed inhibitory detritus and glochidia. The lowest concentration of eDNA which could accurately be detected to infer abundance (≥3.2 copies/µL) or presence (0.32-3.19 copies/µL) of kākahi eDNA was determined.  Duplicate field samples were collected from the Waingaro River and Kahuhuru Stream at sites downstream of fish barriers and upstream of low-flow or all-flow barriers in December, May, and August to investigate spatial and temporal variation in eDNA concentrations. As hypothesised, December was the most effective month to sample, yielding the highest eDNA concentrations due to reduced dilution and heightened water temperatures. Based on eDNA, kākahi species distribution did not appear correlated with fish barriers, but all-flow barriers likely impeded fish host movement to significantly reduce the total kākahi eDNA concentrations found upstream. 
eDNA detection can be used by regional councils to effectively infer presence/absence of kākahi populations and direct further conventional surveying efforts to the most impactful locations. This method allows rapid determination of distribution and densities at a national scale to aid conservation management of this taonga (treasured) species.

text: eDNA-based detection of New Zealand freshwater mussel (kākahi) populations using digital PCR Globally, freshwater mussels are one of the most endangered taxa due to pollution, nutrient loading, habitat fragmentation, and species introduction attributable to anthropogenic activities. New Zealand freshwater mussels (kākahi) are ecological engineers and integral species in freshwater ecosystems. However, kākahi populations are expected to decline 70% by 2024 in part due to their unique reproductive cycle involving an obligatory phoretic relationship with declining native fish. Kākahi distribution and abundance throughout New Zealand is poorly understood due to time-consuming surveying techniques of concealed and morphologically cryptic species. A rapid and reliable method is required for the detection and identification of these ‘Threatened’ kākahi populations for conservation and management. Therefore, this study aimed to i) validate an environmental DNA (eDNA) based detection method for New Zealand freshwater mussels using digital PCR (dPCR); ii) determine the most appropriate sampling season for kākahi eDNA; and iii) determine whether eDNA could be used to detect effects of fish barriers on kākahi distribution.
In vivo trials determined that filtration of field samples within 24 hours of collection minimised eDNA degradation and that prefiltration effectively removed inhibitory detritus and glochidia. The lowest concentration of eDNA which could accurately be detected to infer abundance (≥3.2 copies/µL) or presence (0.32-3.19 copies/µL) of kākahi eDNA was determined.  Duplicate field samples were collected from the Waingaro River and Kahuhuru Stream at sites downstream of fish barriers and upstream of low-flow or all-flow barriers in December, May, and August to investigate spatial and temporal variation in eDNA concentrations. As hypothesised, December was the most effective month to sample, yielding the highest eDNA concentrations due to reduced dilution and heightened water temperatures. Based on eDNA, kākahi species distribution did not appear correlated with fish barriers, but all-flow barriers likely impeded fish host movement to significantly reduce the total kākahi eDNA concentrations found upstream. 
eDNA detection can be used by regional councils to effectively infer presence/absence of kākahi populations and direct further conventional surveying efforts to the most impactful locations. This method allows rapid determination of distribution and densities at a national scale to aid conservation management of this taonga (treasured) species.

year: 2020