WAMSI Science Leads to Jobs Growth

/in , , /by

Perth-based environmental and oceanographic consultancy, O2 Marine attributes Western Australian Marine Science Institution dredging science as a key factor that contributed to its rapid organic growth and business success.

When O2 Marine began in 2014 with just two scientists and some big ideas to fill a gap in the niche areas of marine environmental monitoring and assessment advice, the timing couldn’t have been better.

By 2017 the results from the Western Australian Marine Science Institution’s (WAMSI’s) five-years of research into environmental pressures, response and ecological sensitivity from dredging operations off the Pilbara coast, including ground-breaking experiments in the lab, had begun to hit the desk of the State’s environmental regulators.

The new understanding of environmental effects and windows of opportunity provided a significant improvement in the certainty around environmental management of dredging operations in Western Australia.

At the time, O2 Marine was working with Onslow Marine Support Base Pty. Ltd. on a ~1M cubic metre dredging proposal to allow offshore vessels to access the newly constructed Beadon Creek Maritime Facility.

O2 Marine Managing Director, Chris Lane says the WAMSI research was directly applicable to some of the benthic communities and habitats the project could potentially impact.

“The Environmental Protection Authority encouraged us to incorporate the WAMSI dredging science into the assessment,” Chris Lane said. “In doing so, we were able to use real data from Chevron’s Wheatstone project to predict the impacts and experimental laboratory data to define an appropriate monitoring and management approach. As a result, the Onslow Marine Support Base received the fastest regulatory approval for a dredging project of that size ever achieved in W.A.. We effectively halved the assessment approval timeframe from 12-18 months down to six months.”

Chris Lane attributes the opportunity to leverage the WAMSI research as a significant catalyst which effectively put O2 Marine on the map.

“Being able to leverage that science made clients sit up and take notice of what could be achieved by a West Australian small business,” Chris said. “Off the back of this client recognition and with a lot of hard work, O2 Marine has created nearly 40 new jobs, expanded our service offering to include metocean and hydrographic services and achieved annual revenue growth of over 90% per annum. Having that science readily available made it a lot easier to assist our clients in fast-tracking environmental approvals. It was the trigger for us to grow and get that market share.”

In February of 2018 the EPA confirmed that the Onslow Marine Support Base had been recommended for approval. In a statement issued by the EPA, Deputy Chariman Robert Harvey said:

“The proponent incorporated contemporary and locally relevant dredging science from the Western Australian Marine Science Institution into its predictions and proposed management of the project’s impacts. This means we had a high level of confidence during the assessment.

“The use of the latest dredging science, as well as the conditions identified by the EPA, including the implementation of a Dredging and Spoil Disposal Management Plan, means the proposal can be managed in an environmentally acceptable way,” the statement read.

The WAMSI Dredging Science Node was made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million was co-invested by the WAMSI Joint Venture partners. The Node was also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Best Practice Guideline for Dredge Plume Modelling

/in , /by

CSIRO has released a new guideline that provides current best practice for dredge plume modelling in the context of Australia’s Environmental Impact Assessment processes.

The practical guideline aims to ensure that approaches taken in setting up and executing models are more consistent and improve confidence in decision making by environmental regulators that will also lead to reduced management costs for major dredging programs.

The Guideline on dredge plume modelling for environmental impact assessment takes into consideration the findings of five years of intensive studies through the Western Australian Marine Science Institution’s Dredging Science Node to help predict the intensity and extent of potential impacts on marine habitats from dredge-related pressures.

Lead author of the guideline CSIRO’s Dr Chaojiao Sun explained modelling dredge plumes is challenging and complex.

“Large-scale dredging campaigns that typically require the excavation of millions of tonnes of soil or rock material from the seabed are essential components of major port construction and deepening projects,” Dr Sun said. “Dredging activities suspend sediment into the water and some of these sediments are then kept in suspension by coastal currents as they are carried downstream, resulting in horizontally spreading dredge plumes. The suspended sediment content in these plumes can reduce the amount of light reaching the seabed. In areas where currents (bed stresses) are low, the plume sediments are no longer able to remain in suspension, and bed deposition occurs. These are two examples of dredging-induced environmental pressures that may induce potentially widespread ecological impacts in sensitive seabed marine communities including coral, seagrass and sponges.”

To date, debates and inconsistencies in how the modelling is undertaken for environmental impact assessment (EIA) have been driven by a lack of standardised methods for predicting dredge plume dispersion and the potential effects on the environment.

The CSIRO guideline focusses on establishing a consistent and sound approach to the modelling of dredge plumes for predicting the pressure fields when seeking EIA approval.

“This will help improve the quality and robustness of decisions by environmental regulators and proponents by providing recommendations on modelling strategies and addressing specific issues around modelling,” Dr Sun said.

Dr Paul Branson, who led the modelling and analysis that contributed to the guideline, hopes that important model design decisions can be informed by the advice given.

“It is important that the site specific circulation and sediment transport processes are considered within a framework that objectively guides the development of a modelling strategy that captures the key physical processes that govern the plume spreading, settlement and resuspension,” Dr Branson said.

Co-author Dr Des Mills said that the Guideline addressed current best practice in dredge plume source term estimation.

“Source terms are an essential input to dredge plume models and can vary significantly from one dredging operation to another,” Dr Mills said.

 

 

The Guideline strongly recommends establishing a public database to support dredge plume modelling and that all relevant data be made available. The database would greatly improve the availability of reference information at the EIA stage, assisting both those responsible for the EIA preparation and those responsible for interpreting and approving the dredge activity.

The CSIRO dredge plume modelling guideline is intended as a point of reference rather than a rigid standard. It’s hoped it will provide increased confidence in modelling outcomes, leading to a reduction in the monitoring and management burden required by regulators and increased transparency and public confidence in the EIA process.

An information webinar was held on 11 December, 2020. The recording of this webcast is now available via the following link: https://webcast.csiro.au/#/videos/a3cc1634-95ca-402e-a639-daa63ab7cfc8

The Guideline and Fact Sheet are available HERE

 

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science

Dredge Plume Modelling Guidelines

/in , /by

New guidelines for dredge plume modelling are being developed by CSIRO in partnership with the Western Australian Marine Science Institution (WAMSI).

Dredging and EIAs

Dredging activities form part of many coastal developments in Australia, ranging from small maintenance activities to large scale dredging campaigns which involve the removal of large amounts of sediment. Some of the dredged sediment can be stirred up in the sea water surrounding the dredger and the smaller sediment particles can be driven considerable distances by marine currents before settling onto the seabed. These clouds of suspended sediment are referred to as dredge plumes. Many dredge campaigns are conducted near sensitive marine ecological receptors (e.g. corals) and as such are subject to Environmental Impact Assessments (EIAs).

As part of the EIA process, potential impacts of dredge plumes on benthic communities and habitats are evaluated using the output of dredge plume models which are then compared to ecological thresholds. A challenge for regulators and proponents has been a lack of consistency in the approaches taken in setting up and executing the models, given there has been a lack of suitable protocol or standards to follow.

Practical modelling guidelines

With funding support from the WAMSI Dredging Science Node, CSIRO is leading the development of a practical guideline for dredge modelling practitioners and environmental regulators. The guideline focuses on establishing a consistent and sound approach to the modelling of dredge plumes for predicting the pressure fields of suspended sediments when seeking EIA approval. This will help improve the quality and robustness predictions made by proponents through the provision of recommendations on modelling strategies and addressing specific issues around modelling, including source term estimation, 2D versus 3D modelling, ambient sediment dynamics, baseline data collection, and reporting of model parameters and data. The increased confidence should lead to a reduction in the monitoring and management burden required by regulators.

The Guideline is intended as a point of reference instead of a rigid standard and provides the current best practice for the application and review of dredge plume models in the context of Australian statutory EIA.

Contact chaojiao.sun@csiro.au or paul.branson@csiro.au to receive the Guideline when published.

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Perspectives on Dredging Symposium

/in , /by

Australia has experienced unprecedented levels of dredging over the last two decades and recently there has been a focus on dredging research in Western Australia.

As a result, there have been some incredible advances in our understanding of impacts to the marine environment from dredging and how to better predict, monitor and manage dredging programs, such as the WAMSI Dredging Science Node.

The “Perspectives on Dredging” AMSA symposium brings together scientists, regulators, managers, industry and consultants with practical experience of dredging practices in the marine environment.

The session will focus on impact prediction, monitoring and the lessons learnt from implementing the vast range of dredging programs ranging from those associated recent mega-projects in Western Australian and Queensland, to small maintenance dredging programs in coastal waterways.

“Perspectives on Dredging” provides an opportunity for dredging professionals to demonstrate their contemporary practical experience and how the impacts of dredging on the marine environment are predicted, managed and monitored in real-world scenarios.

When: Wednesday 10 July 4-6pm

Where: AMSA Conference, The Esplanade Hotel, Fremantle, WA

 

Speakers

Dr. Chaojiao Sun

Senior Research Scientist

Commonwealth Scientific and Industrial Research Organisation

New guidelines on dredge plume modelling for environmental impact assessment

Mr. Paul Branson

Research Fellow

Commonwealth Scientific and Industrial Research Organisation & The University of Western Australia

2D or not 2D: Is three-dimensional modelling required for passive dredging plume modelling?

Dr. Des Mills

N/a

N/A

Recent Developments in Estimating Source Terms for Far-Field Dredge Plume Model

Mr. Sterling Tebbett

PhD Student

James Cook University

Sediment Impacts and the Role of Algal Turfs in Sediment Dynamics on Coral Reefs

 

Prof. Paul Lavery

Professor

Edith Cowan University

Response and recovery of tropical seagrasses to variation in the frequency and magnitude of light deprivation

Dr. Brett Kettle

Visiting Scientist

Commonwealth Scientific and Industrial Research Organisation Oceans and Atmosphere

Closing the Gap: Perspectives on Using Best Practice Science in Best Practice Dredge Management

A/Prof. Kathryn Mcmahon

A/Prof

Edith Cowan University

Timing anthropogenic stressors such as dredging to mitigate their impact on marine ecosystem resilience

Mr. Ben Davis

Senior Consultant

BMT

Effectiveness of an environmental management framework in small-scale maintenance dredging

Chair

Dr Ross Jones

Australian Institute of Marine Science

Dredging report builds confidence for environmental regulators

/in , /by

A report released on one of the largest single-issue environmental research programs in Australia that gained unprecedented access to industry dredging data, has been recognised by industry and government as a ground-breaking step forward for environmental regulation.

“Strategic Integrated Marine Science: Dredging – new Knowledge for better decisions and outcomes” is a synthesis of research from the WAMSI Dredging Science Node was released today by WAMSI CEO Dr Luke Twomey at the AMSA Conference in Fremantle.

The findings from the five-year Western Australian Marine Science Institution (WAMSI) Dredging Science Node (DSN), are contributing to increased confidence, timeliness and efficiency of the environmental approval and regulatory processes associated with dredging projects, which is ultimately expected to reduce the cost to government and industry.

According to WA Environmental Protection Authority Chairman Dr Tom Hatton, it’s estimated that monitoring and management costs can exceed $100 million on a major dredging program in addition to the predictive uncertainty of risks to the environment itself.

“This program has delivered on its promise in full and in a form that has increased the confidence, timeliness and efficiency of the environmental approval and regulatory processes associated with dredging projects,” Dr Hatton said.

Woodside Energy Chief Environmental Scientist Dr Luke Smith said the $19 million program – $9.5 million of which came from industry offsets – has delivered a valuable set of information on environmental dredging thresholds.

“The Dredging Science Node was valuable for industry and the state – it provides important technical data to improve our environmental impact assessments and support industry approval documentation. By bringing together the key stakeholders – state, industry, ports and research agencies – we maximised the available funding and the scientific knowledge that came from the Node. This knowledge will support better and more concise dredging-related environmental impact assessments moving forward,” Mr Smith said.

The Node’s 114 scientists from 26 research organisations gained unprecedented access to environmental monitoring data on four large-scale capital dredging projects in the Pilbara region including the Pluto LNG project at Burrup Peninsula (Woodside), Cape Lambert A and B projects (Rio Tinto), the Gorgon project at Barrow Island (Chevron), and the Wheatstone project at Onslow (Chevron).

WAMSI Dredging Science Node Leader, Dr Ross Jones from the Australian Institute of Marine Science said the Node had brought together a raft of scientific literature on sediments in the water column in relation to dredging.

“Little of the available research on sediments was able to be used by dredging proponents and regulators to adequately assess risk, so we have designed the Node as a tool that gives industry and regulators greater confidence to better predict environmental outcomes around dredging,” Dr Jones said.

WAMSI CEO Dr Luke Twomey said the more than 55 scientific publications produced by the Node so far was an extraordinary achievement for the investment and will go a long way towards much more informed debate and decision making on how best to predict and manage the potential impacts.

WAMSI DREDGING SCIENCE RESULTS IN USE 

  • Key findings from the project have been incorporated in the newly published Maintenance Dredging Strategy for Great Barrier Reef World Heritage Area Ports by the Queensland Government, a dredging management plan for maintenance dredging in Darwin Harbour (INPEX), a series of Sustainable Sediment Management Studies underway at various ports in northern Queensland (commissioned by the North Queensland Bulk Ports Corporation), and in a forthcoming publication by PIANC on Best Practice Guidelines for Dredging and Port Construction near Coastal Plant Habitats.
  • Internationally, relevant findings of the Node are being incorporated into dredging programs in the USA, the Netherlands, Monaco, South Africa, Kazakhstan and Saudi Arabia.
  • The new insights from the program are now being translated into improved dredging guidelines that will serve to streamline monitoring by focusing on the relevant and most sensitive aspects and help to improve the effectiveness of management approaches to minimise the hazards from dredging.
  • New guidelines for dredge plume modelling are being developed by CSIRO. The guidelines focus on establishing a consistent and sound approach to the modelling of dredge plumes for predicting the pressure field of suspended sediments when seeking Environmental Impact Assessment approval.
  • The WAMSI Dredging Science Node has been shortlisted for the WA Department of Mines, Industry Regulation and Safety’s 2019 Golden Gecko Award for Environmental Excellence which recognises outstanding contributions to innovation and environmental outcomes in the resources sector.

 

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science

Dredging report builds confidence for environmental regulators

/in , /by

A report released on one of the largest single-issue environmental research programs in Australia that gained unprecedented access to industry dredging data, has been recognised by industry and government as a ground-breaking step forward for environmental regulation.

“Strategic Integrated Marine Science: Dredging – new Knowledge for better decisions and outcomes” is a synthesis of research from the WAMSI Dredging Science Node was released today by WAMSI CEO Dr Luke Twomey at the AMSA Conference in Fremantle.

The findings from the five-year Western Australian Marine Science Institution (WAMSI) Dredging Science Node (DSN), are contributing to increased confidence, timeliness and efficiency of the environmental approval and regulatory processes associated with dredging projects, which is ultimately expected to reduce the cost to government and industry.

According to WA Environmental Protection Authority Chairman Dr Tom Hatton, it’s estimated that monitoring and management costs can exceed $100 million on a major dredging program in addition to the predictive uncertainty of risks to the environment itself.

“This program has delivered on its promise in full and in a form that has increased the confidence, timeliness and efficiency of the environmental approval and regulatory processes associated with dredging projects,” Dr Hatton said.

Woodside Energy Chief Environmental Scientist Dr Luke Smith said the $19 million program – $9.5 million of which came from industry offsets – has delivered a valuable set of information on environmental dredging thresholds.

“The Dredging Science Node was valuable for industry and the state – it provides important technical data to improve our environmental impact assessments and support industry approval documentation. By bringing together the key stakeholders – state, industry, ports and research agencies – we maximised the available funding and the scientific knowledge that came from the Node. This knowledge will support better and more concise dredging-related environmental impact assessments moving forward,” Mr Smith said.

The Node’s 114 scientists from 26 research organisations gained unprecedented access to environmental monitoring data on four large-scale capital dredging projects in the Pilbara region including the Pluto LNG project at Burrup Peninsula (Woodside), Cape Lambert A and B projects (Rio Tinto), the Gorgon project at Barrow Island (Chevron), and the Wheatstone project at Onslow (Chevron).

WAMSI Dredging Science Node Leader, Dr Ross Jones from the Australian Institute of Marine Science said the Node had brought together a raft of scientific literature on sediments in the water column in relation to dredging.

“Little of the available research on sediments was able to be used by dredging proponents and regulators to adequately assess risk, so we have designed the Node as a tool that gives industry and regulators greater confidence to better predict environmental outcomes around dredging,” Dr Jones said.

WAMSI CEO Dr Luke Twomey said the more than 55 scientific publications produced by the Node so far was an extraordinary achievement for the investment and will go a long way towards much more informed debate and decision making on how best to predict and manage the potential impacts.

WAMSI Dredging Science results in use:

  • Key findings from the project have been incorporated in the newly published Maintenance Dredging Strategy for Great Barrier Reef World Heritage Area Ports by the Queensland Government, a dredging management plan for maintenance dredging in Darwin Harbour (INPEX), a series of Sustainable Sediment Management Studies underway at various ports in northern Queensland (commissioned by the North Queensland Bulk Ports Corporation), and in a forthcoming publication by PIANC on Best Practice Guidelines for Dredging and Port Construction near Coastal Plant Habitats.
  • Internationally, relevant findings of the Node are being incorporated into dredging programs in the USA, the Netherlands, Monaco, South Africa, Kazakhstan and Saudi Arabia.
  • The new insights from the program are now being translated into improved dredging guidelines that will serve to streamline monitoring by focusing on the relevant and most sensitive aspects and help to improve the effectiveness of management approaches to minimise the hazards from dredging.
  • New guidelines for dredge plume modelling are being developed by CSIRO. The guidelines focus on establishing a consistent and sound approach to the modelling of dredge plumes for predicting the pressure field of suspended sediments when seeking Environmental Impact Assessment approval.
  • The WAMSI Dredging Science Node has been shortlisted for the WA Department of Mines, Industry Regulation and Safety’s 2019 Golden Gecko Award for Environmental Excellence which recognises outstanding contributions to innovation and environmental outcomes in the resources sector.

WAMSI Dredging Science Shortlisted for Environmental Excellence Award

/in , /by

The Western Australian Marine Science Institution’s Dredging Science Node has been shortlisted for WA’s Environmental Excellence awards.

The WAMSI Dredging Science Node (DSN) is among four projects identified by the Department of Mines, Industry Regulation and Safety’s 2019 Golden Gecko Award for Environmental Excellence which recognises outstanding contributions to innovation and environmental outcomes in the resources sector.

The main focus area for the DSN was the Pilbara in WA’s tropical North West, a region with some of the largest recent proposed dredging projects and with the greatest levels of uncertainty in terms of contemporary understanding of biodiversity distribution and environmental resilience to the pressures associated with this.

Since 2000, there has been 27 dredging projects in the Pilbara region, with a combined total dredging volume of 250 million m3 of sediment all carried out in a region boasting exceptional marine biodiversity, featuring some of the least disturbed pristine waters in the world (including the World Heritage Areas of Shark Bay, Ningaloo Reef and the Kimberley National Heritage Area).


Maps of northwestern Australia, showing existing and proposed ports and significant conservation areas.

Recognising the critical importance of the potential environmental consequences of dredging in WA and the urgent need for it to be addressed, in 2013 WAMSI established the Dredging Science Node.

Eighty-one scientists from 10 collaborating research organisations were supported by $9.5 million invested by Woodside, Chevron and BHP as environmental offsets, with a further $9.5 million co-invested by the WAMSI Joint Venture partners.

The research program worked across nine integrated research themes to address key areas of uncertainty around the impacts of large-scale dredging.

“What struck me most before the start of the Dredging Science Node was just how much information there was in the scientific literature on how sediments released into the water column from dredging was a ‘hazard’, and just how little of that information could be used by dredging proponents and regulators to actually assess the risk,”  WAMSI Dredging Science Node Leader (Science) Dr Ross Jones, from the Australian Institute of Marine Science (AIMS) said.

WAMSI CEO Dr Luke Twomey said the strategic objective of the DSN was to improve the capacity within the government and private sector to predict and manage the environmental impacts of dredging in tropical regions of Western Australia, with the outcomes to support the Environmental Protection Authority’s Technical Guidance for the Environmental Impact Assessment Marine Dredging Proposals.

“The more than 55 scientific publications currently produced by the Node (so far) is an extraordinary achievement for the investment, and will go a long way towards much more informed debate and decision making on how best to predict and manage the potential impacts,” Dr Twomey said.

The winner of the Golden Gecko Award will be announced at the department’s Resources Sector Awards for Excellence on August 22, 2019, with the Community Partnership Resources Sector Award.

Link to Minister’s Media Statement

New name for a tropical whip sponge

/in , /by

The enigmatic body shape of a tropical whip sponge collected in Western Australia has resulted in the creation of a new family and genus of sponges.

The species was first described from Indonesia as Dendrilla lacunosa by Hentschel in 1912 and 100 years later found in abundance in the Pilbara and Kimberley regions of Western Australia during fieldwork for the Western Australian Marine Science Institution’s (WAMSI) Dredging Science Node project focussing on filter feeders.

This is where the puzzle begins.

Although the Western Australian specimens were identified as Dendrilla lacunosa by Dr Jane Fromont, sponge taxonomist at the Western Australian Museum (WAM), its large, whip-like morphology was extremely unusual for  Dendrilla sponges, which are usually small and delicate, so Jane decided to enlist the help of an international team to discover if this really was a Dendrilla or not.

It turns out Jane’s initial hunch that this was a strange sponge was true. With her international colleagues Drs Jean Vacelet (France), Dirk Erpenbeck and Hermann Erhlich (Germany) and Cristina Diaz (USA), a new family of sponges has been established. The new family, Ernstillidae, and the new genus Ernstilla are named for Ernst Hentschel who originally described the species.

It took some excellent sleuthing to discover where this sponge species really belongs. Molecular results placed it far away from other Dendrilla species, in fact in a different subclass! Analysis of its skeleton, which was found to contain chitin, confirmed that this sponge belonged in a different subclass and was not Dendrilla. However, some of its characters are unusual, such as the shape of its filtering chambers and the branching nature of its skeleton, so much so that it did not fit into any family or genus currently known, hence the new names.

New species of sponges are described after exhaustive research to be absolutely certain they are new, and many more sponges await new species descriptions, but it is far less common to find a new family or genus. Only the team work of international experts could have resolved this enigma.

To give context to the change of taxonomic position of this sponge from one subclass to another, the shift is comparable to humans (Homo sapiens) being taken out of the subclass Placentalia where all Primates belong, and being placed in Marsupialia with the kangaroos!

 

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science

Sticky sediments and low sperm increase risk to coral fertilisation

/in , /by

Coral fertilisation is most sensitive to sticky inshore sediments according to researchers working to define the effects of dredging-related pressures and natural high turbidity events.

The Western Australian Marine Science Institution Dredging Science Node study, published in Marine Pollution Bulletin, involved a team of scientists from the Australian Institute of Marine Science (AIMS), The University of Western Australia and James Cook University. It analysed a range of realistic mineral and organic compositions to try to determine what combination is most likely to affect coral fertilisation success.

The research, which spanned a five-year period and eight mass spawning events, identified various characteristics that make sediment ‘bind’ to coral sperm, preventing contact and fertilisation of the eggs.

Lead researcher Dr Gerard Ricardo (AIMS) explained that collecting data to assess the risk of many sediment types to coral fertilisation was difficult because corals only spawn a few times per year.

“We needed to work long into the night whenever the opportunity arose that the corals spawned,” Dr Ricardo said. “It was a massive effort from everyone who helped and volunteered, and we have benefited greatly from having access to incredible facilities like the National Sea Simulator (Seasim) at AIMS in Townsville.”

The researchers found that sediments high in ‘sticky’ components, such as mineral clays and mucous-like products of microorganisms, had the greatest impact on coral fertilisation, whereas less cohesive sediments had relatively lower impacts.

 

Coral sperm (blue) bound to fine sediment grains are incapable of fertilising eggs (Image: Gerard Ricardo)

 

The study also discovered that fertilisation success was most vulnerable to sediments when sperm concentrations were low. Lower sperm concentrations are likely to occur as coral populations become more degraded.

“Healthy reefs are at a lower risk of sediment impacting fertilisation success because even if some sperm are lost, there should be sufficient sperm to fertilise the eggs,” Dr Ricardo said. “As reefs become more degraded and there are fewer reproducing adults, this leads to lower sperm concentrations which may increase the risk of fertilisation impacts by sediments.”

The study provides a number of sediment-specific ‘thresholds’ that can be used by regulators and industry to assess whether dredging at a given location poses a risk to coral fertilisation and the ongoing health of nearby coral populations.

Links:

Ricardo G, Jones R, Clode P, Humanes A, Giofre N, Negri A. (2018) Sediment characteristics influence the fertilisation success of the corals Acropora tenuis and Acropora millepora. Marine Pollution Bulletin https://doi.org/10.1016/j.marpolbul.2018.08.001

WAMSI Dredging Science Node – Dredging Pressures on Coral project page.

 

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

Category:

Dredging Science