Physical Sciences and Mathematics Commons^™

Sediment Burial Stress Response, Bio-Indicators And Thresholds For A Tropical Multi-Species Seagrass Assemblage: Report Of Theme 5 - Project 5.5.2 Prepared For The Dredging Science Node, John Statton, Kathryn Mcmahon, Roisin Mccallum, Gary Kendrick, Paul Lavery

Research outputs 2014 to 2021

Deterioration in water clarity by resuspension of dredged sediments is presumed to be a major mechanism by which dredging can impact seagrasses. This report presents findings from a controlled light experiment that aimed to determine the effects of low light stress on the growth of three seagrass species found in the northwest of Western Australia.

Aims

• To determine the effects of sediment burial stress under dredge-simulated conditions on the growth and health of three seagrass species found in the northwest of Western Australia.
• Provide guidance and protocols for the application of the research outputs (e.g. seagrass burial stress:response relationships, sub-lethal …

Response And Recovery Of A Mixed Tropical Seagrass Assemblage To Variation In The Frequency And Magnitude Of Light Deprivation. Report Of Theme 5 - Project 5.5.3 Prepared For The Dredging Science Node, John Statton, Kathryn Mcmahon, Rosin Mccallum, Gary Kendrick, Paul Lavery

Research outputs 2014 to 2021

The capacity of seagrasses to cope with episodes of light deprivation from overlying turbid waters may not only depend on the absolute quantity of light they receive during that episode, but also on how the light deprivation varies through time. For example, turbidity and therefore light reduction may be relatively constant over the episode or it may fluctuate depending on the frequency of pulsed turbidity events.

This report presents findings from a controlled mesocosm experiment that aimed to determine the responses of seagrasses to, and recovery from, differences in the pattern of the delivery of light. The study focussed on …

Seagrasses Of The North West Of Western Australia: Biogeography And Considerations For Dredging-Related Research: Report Of Theme 5 - Project 5.1.2 Prepared For The Dredging Science Node, Kathryn Mcmahon, John Statton, Paul Lavery

Research outputs 2014 to 2021

This review was undertaken to identify which seagrass primary producers (species or different functional groups) that collectively cover the bio-geographic range of key primary producers in the northwest of Western Australia are most appropriate for the focus of subsequent research into thresholds and indicators of response to dredging-related pressures (i.e. Theme 5). An assessment framework was developed based on six criteria: biogeographic range; ecological relevance (life-history strategy, habitats, natural dynamics and ecological services); current knowledge on thresholds and bioindicators; likelihood that species are sensitive and resilient to dredging related stressors; extent of improvement in applied knowledge; and likelihood of being …

Current State Of Knowledge Regarding The Effects Of Dredging-Related ‘Pressure’ On Seagrasses: Report Of Theme 5 - Project 5.1.1 Prepared For The Dredging Science Node, Kathryn Mcmahon, Paul Lavery, John Statton, Roisin Mccallum, Udhi Hernawan

Research outputs 2014 to 2021

This review summarises our understanding, from a northwest of Western Australia and global perspective, the pressures seagrasses are exposed to from dredging, their tolerance thresholds and responses to dredging related stressors, and the bioindicators of dredging related stressors. From this information, we also identified gaps in our knowledge and areas where environmental management and monitoring approaches could be improved.

Aims

To determine the levels of stress (light reduction/sediment deposition) that occur under dredging conditions and evaluate the likely effect of these levels of pressure based on the existing seagrass literature, considering the range of variability and environmental quality conditions associated …

Effects Of Dredging-Related Pressures On Critical Ecological Processes For Organisms Other Than Fish Or Coral. Report Of Theme 9 - Project 9.1 Prepared For The Dredging Science Node, Jessie Short, Matthew Fraser, Dianne Mclean, Gary Kendrick, Maria Byrne, Julian Caley, Doug Clarke, Andy Davis, Paul Ertemeijer, Stuart Field, Sam Gustin-Craig, John Huisman, John Keesing, Mick Keough, Paul Lavery, Ray Mansini, Kathryn Mcmahon, Kerrie Mergersen, Michael Rasheed, John Statton, Jim Stoddart, Paul Wu

Research outputs 2014 to 2021

This study reviewed environmental windows for organisms other than corals and fish such as sessile invertebrates, macroalgae and seagrasses. Environmental windows are periods of critical importance to the life history of a marine species, like reproduction and recruitment.

Aims

• To review the scientific literature on the timing and spatial extent of critical ecological processes relevant to tropical WA for marine primary producers and invertebrates (i.e. organisms other than coral and finfish) and the state of knowledge regarding potential effects of dredging on these key ecological processes. The review also had a particular focus on ecological processes in marine primary producers …