title: New evidence for a mid to late-Holocene change in the marine reservoir effect across the South Pacific Gyre

authors: Petchey, Fiona

subjects: archaeology

abstract: Holocene climate change in the South Pacific is of major interest to archaeologists and Quaternary researchers. Regional surface ocean radiocarbon (¹⁴C) values are an established proxy for studying changing oceanographic and climatic conditions. Unfortunately, radiocarbon variability in the marine environment over the period of specific importance to human colonization of the remote Pacific islands—the last 3500 years—has been poorly studied. In order to build robust and accurate archaeological chronologies using shell, it is important to rectify this. In this paper, radiocarbon marine reservoir offsets (ΔR) are presented from eight archaeological sites, ranging in age from 350 cal BP to 3000 cal BP, and compared to coral datasets from the east Australian coastline. The results indicate that a significant decrease in the South Pacific Gyre ΔR occurred between 2600 and 2250 cal BP, most likely caused by changes in ocean circulation and climate. Accurately recording the timing of variability in reservoir offset is critical to untangling changes in society that took place in the Pacific, in particular, the development of Ancestral Polynesian Society.

text: New evidence for a mid to late-Holocene change in the marine reservoir effect across the South Pacific Gyre Holocene climate change in the South Pacific is of major interest to archaeologists and Quaternary researchers. Regional surface ocean radiocarbon (¹⁴C) values are an established proxy for studying changing oceanographic and climatic conditions. Unfortunately, radiocarbon variability in the marine environment over the period of specific importance to human colonization of the remote Pacific islands—the last 3500 years—has been poorly studied. In order to build robust and accurate archaeological chronologies using shell, it is important to rectify this. In this paper, radiocarbon marine reservoir offsets (ΔR) are presented from eight archaeological sites, ranging in age from 350 cal BP to 3000 cal BP, and compared to coral datasets from the east Australian coastline. The results indicate that a significant decrease in the South Pacific Gyre ΔR occurred between 2600 and 2250 cal BP, most likely caused by changes in ocean circulation and climate. Accurately recording the timing of variability in reservoir offset is critical to untangling changes in society that took place in the Pacific, in particular, the development of Ancestral Polynesian Society.

year: 2019

title: Transient wind-driven coastal upwelling on a shelf with varying width and orientation

authors: Longdill, Peter C.

subjects: upwelling

abstract: Cross-correlations between along-shelf wind stress and both along- and cross-shelf currents within the central Bay of Plenty, New Zealand show the circulation during spring–summer to be highly responsive to wind events. Current meter records indicate that upwelling-favourable wind stresses generate upwelling dynamics in both mean and fluctuating senses. Both thermistor moorings and satellite inferred temperature data record the outcropping of this cool water following upwelling-favourable wind stresses. The upwelling circulation provides an efficient mechanism for the periodic delivery of cool (c. <15°C), nutrient rich (NOx- N >80 µg litre–1 ) water to the coastal zone during spring. Historical wind forcing data suggest that the wind-forced dynamics described were responsible for a major toxic algal bloom within the Bay of Plenty during 1992–93.

text: Transient wind-driven coastal upwelling on a shelf with varying width and orientation Cross-correlations between along-shelf wind stress and both along- and cross-shelf currents within the central Bay of Plenty, New Zealand show the circulation during spring–summer to be highly responsive to wind events. Current meter records indicate that upwelling-favourable wind stresses generate upwelling dynamics in both mean and fluctuating senses. Both thermistor moorings and satellite inferred temperature data record the outcropping of this cool water following upwelling-favourable wind stresses. The upwelling circulation provides an efficient mechanism for the periodic delivery of cool (c. <15°C), nutrient rich (NOx- N >80 µg litre–1 ) water to the coastal zone during spring. Historical wind forcing data suggest that the wind-forced dynamics described were responsible for a major toxic algal bloom within the Bay of Plenty during 1992–93.

year: 2008

title: Development and care of pā harakeke in 19th century New Zealand: Voices from the past

authors: McAllum, Priscilla M

subjects: Raranga

abstract: Māori weaving is experiencing a resurgence. Some weavers are involved in the planting of pā harakeke so that they have a high quality resource on hand ready for use.  A number of recent scientific publications, undertaken jointly with weavers, have explored the unique fibre qualities of different harakeke varieties along with specific aspects of Māori use of these varieties. In this paper, I examine Māori planting practices of pā harakeke and other aspects of resource management as revealed in literature sources from the late 18th to the early 20th centuries.  Although some of the practices outlined here may have fallen into disuse over time, they may, nevertheless, continue to be appropriate for contemporary pā harakeke. It is hoped, therefore, that the information provided here will be of interest to contemporary weavers.

text: Development and care of pā harakeke in 19th century New Zealand: Voices from the past Māori weaving is experiencing a resurgence. Some weavers are involved in the planting of pā harakeke so that they have a high quality resource on hand ready for use.  A number of recent scientific publications, undertaken jointly with weavers, have explored the unique fibre qualities of different harakeke varieties along with specific aspects of Māori use of these varieties. In this paper, I examine Māori planting practices of pā harakeke and other aspects of resource management as revealed in literature sources from the late 18th to the early 20th centuries.  Although some of the practices outlined here may have fallen into disuse over time, they may, nevertheless, continue to be appropriate for contemporary pā harakeke. It is hoped, therefore, that the information provided here will be of interest to contemporary weavers.

year: 2005-02