The Effects of Benthic Organisms on Intertidal Sediment Erodibility
type: CreativeWork
description: On intertidal sandflats, the dispersal of juvenile organisms can rely on bedload transport, a critical process during small-scale disturbance recovery. The erosion of surface sediments is also vital to benthic-pelagic coupling, where resuspended microbes and organic material become available to suspension feeders and/or transported to adjacent habitats. On sandflats, the organisms living within sediments have been proven to be key drivers of ecological function, such as benthic-pelagic coupling and biogeochemical cycling. Although benthic organisms have been recognized as important to ecological function, the role of multiple species and their interactions on sediment movement is rarely described in non-cohesive sandflats. Furthermore, the role of benthic organisms in sediment movement can vary with environmental conditions, making general sediment-benthos relationships difficult to establish. In this thesis, I examined subtle variations in the biotic and abiotic factors that influence sediment movement on intertidal sandflats. The thesis comprises three research chapters, each evaluating the relationships between benthic community structure and sediment properties. I used a backdrop of environmental stressors common to intertidal sandflats in order to incorporate the natural variations in sediment-benthos relationships that occur under environmental stress. Throughout this thesis, erosion potential was characterized by: erosion thresholds (Ʈc; N m⁻²), erosion rates (ER; g m⁻² s⁻¹), and change in erosion rate with increasing bed shear stress (me; g N⁻¹ s⁻¹). When describing erosion, a decrease in (-) Ʈc signifies an increase in initial bed erosion and an increase in (+) ER represents an increase in surface erosion. Therefore -Ʈc and +ER demonstrate surface erosion. In contrast, me was recorded during a higher bed shear stress, so that an increase in (+) me denotes more rapid changes in subsurface erosion. In chapter 2, I used a spatial gradient of increasing sedimen…
abstract: On intertidal sandflats, the dispersal of juvenile organisms can rely on bedload transport, a critical process during small-scale disturbance recovery. The erosion of surface sediments is also vital to benthic-pelagic coupling, where resuspended microbes and organic material become available to suspension feeders and/or transported to adjacent habitats. On sandflats, the organisms living within sediments have been proven to be key drivers of ecological function, such as benthic-pelagic coupling and biogeochemical cycling. Although benthic organisms have been recognized as important to ecological function, the role of multiple species and their interactions on sediment movement is rarely described in non-cohesive sandflats. Furthermore, the role of benthic organisms in sediment movement can vary with environmental conditions, making general sediment-benthos relationships difficult to establish. In this thesis, I examined subtle variations in the biotic and abiotic factors that influence sediment movement on intertidal sandflats. The thesis comprises three research chapters, each evaluating the relationships between benthic community structure and sediment properties. I used a backdrop of environmental stressors common to intertidal sandflats in order to incorporate the natural variations in sediment-benthos relationships that occur under environmental stress. Throughout this thesis, erosion potential was characterized by: erosion thresholds (Ʈc; N m⁻²), erosion rates (ER; g m⁻² s⁻¹), and change in erosion rate with increasing bed shear stress (me; g N⁻¹ s⁻¹). When describing erosion, a decrease in (-) Ʈc signifies an increase in initial bed erosion and an increase in (+) ER represents an increase in surface erosion. Therefore -Ʈc and +ER demonstrate surface erosion. In contrast, me was recorded during a higher bed shear stress, so that an increase in (+) me denotes more rapid changes in subsurface erosion. In chapter 2, I used a spatial gradient of increasing sedimen…
author: Harris, Rachel Joy
keywords: macrofauna, microphytobenthos, sand, erosion, resuspension, benthic microbes, environmental stress
license: https://researchcommons.waikato.ac.nz/bitstreams/c4974de3-720a-40a6-946e-2095685afb44/download
date published: 2015
date modified: 2026-07-24T05:57:49Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Waikato