Particulate fluxes in the subtropical convergence region and other marine environments of New Zealand
type: CreativeWork
description: The thesis was designed to address two themes: (1) sediment trap methods and technique development; and (2) oceanic sediment fluxes within the Chatham Rise-Subtropical Convergence ecosystem, east of New Zealand. Accordingly, the principal objectives of Theme 1 were to design, construct and deploy a sediment trap system for sampling sinking marine particles and to evaluate hydrodynamic biases in sediment traps from field studies. Theme 2 focuses on biological and physical processes affecting modem particulate sedimentation in the vicinity of the Subtropical Convergence Zone, and the magnitude and composition of particulate fluxes within the Chatham Rise-Subtropical Convergence region. An overall conservative strategy was adopted for the sediment trap design criteria since critical aspects of the bio-physical environment of Chatham Rise-Subtropical Convergence were poorly known. A multiple arrangement of 8 to 12 baffled cylindrical traps deployed at set water depths on free-floating sediment trap arrays was the preferred design. Basal high density brines with formalin as a poison/preservative were employed for deployments scheduled to last 2-3 days in the winter and spring of 1993. Pilot studies in autumn 1992 and 1993 allowed practicalities of sediment trap deployments to be evaluated. Field experiments in Evans Bay, Wellington Harbour, showed that there were' minimal hydrodynamic interactions between traps on the same array. Furthermore, baffles did not significantly affect trapping efficiency, whereas brine volume had a profound effect. In the latter case, traps filled completely with a high-density salt brine collected 2-3 times less material than traps with basal brine thicknesses equal in height to 1- and 2.5-cylinder diameters. The resultant free-floating sediment trap arrays were deployed as part of the multi-disciplinary New Zealand Joint Global Ocean Flux Study (JGOFS) in winter and spring 1993. This study was designed to determine the trophic pathways and t…
abstract: The thesis was designed to address two themes: (1) sediment trap methods and technique development; and (2) oceanic sediment fluxes within the Chatham Rise-Subtropical Convergence ecosystem, east of New Zealand. Accordingly, the principal objectives of Theme 1 were to design, construct and deploy a sediment trap system for sampling sinking marine particles and to evaluate hydrodynamic biases in sediment traps from field studies. Theme 2 focuses on biological and physical processes affecting modem particulate sedimentation in the vicinity of the Subtropical Convergence Zone, and the magnitude and composition of particulate fluxes within the Chatham Rise-Subtropical Convergence region. An overall conservative strategy was adopted for the sediment trap design criteria since critical aspects of the bio-physical environment of Chatham Rise-Subtropical Convergence were poorly known. A multiple arrangement of 8 to 12 baffled cylindrical traps deployed at set water depths on free-floating sediment trap arrays was the preferred design. Basal high density brines with formalin as a poison/preservative were employed for deployments scheduled to last 2-3 days in the winter and spring of 1993. Pilot studies in autumn 1992 and 1993 allowed practicalities of sediment trap deployments to be evaluated. Field experiments in Evans Bay, Wellington Harbour, showed that there were' minimal hydrodynamic interactions between traps on the same array. Furthermore, baffles did not significantly affect trapping efficiency, whereas brine volume had a profound effect. In the latter case, traps filled completely with a high-density salt brine collected 2-3 times less material than traps with basal brine thicknesses equal in height to 1- and 2.5-cylinder diameters. The resultant free-floating sediment trap arrays were deployed as part of the multi-disciplinary New Zealand Joint Global Ocean Flux Study (JGOFS) in winter and spring 1993. This study was designed to determine the trophic pathways and t…
author: Nodder, Scott D.
license: https://researchcommons.waikato.ac.nz/bitstreams/0a4e7c36-f775-4d20-91b4-5d0f6110d7ca/download
date published: 1997
date modified: 2026-07-24T05:57:38Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato