Perspectives on Dredging Symposium

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

This article was originally published on an archived WAMSI website. Some media or links may appear missing or broken. You can use the search function to look for these, or contact info@wamsi.org.au for a specific request.

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

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.

South coast on national stage

The waters off Western Australia’s south coast will be a focus of discussion at a special symposium of a national marine science conference to be held in Fremantle in July.

Western Australian Marine Science Institution Research Director Jenny Shaw says the symposium is an opportunity to bring the south coast to the attention of government bodies and the wider marine science community.

“This is the first step in understanding what knowledge is available ahead of canvassing government, industry, community and research views on management and what’s important to them about the south coast,” Dr Shaw says.

Click here for the full story in Voiceofthesouth

WAMSI Bulletin July 2019

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Symposium: The South Coast of Western Australia: research for management

The South Coast of Western Australia: research for management symposium aims to uncover previous and current research being conducted off the south coast and to bring the south coast to the attention of the wider marine science community and government bodies.

The economic, social and environmental dimensions of the waters off the isolated south coast of Western Australia are poorly understood. Knowledge gaps identified by researchers and the impacts the south coast faces under a changing climate will help to develop a strong case for a future Western Australian Marine Science Institution (WAMSI) research program to support marine management in this region.

This symposium brings together 15 researchers working off the south coast of Western Australia and welcomes collaborative input into informing management with good science.

When: Tuesday 9 July 10.30am-3.30pm
Where: AMSA Conference, The Esplanade Hotel, Fremantle, WA
Chair: Jenny Shaw, Research Director, WAMSI

Speakers:
Dr. Mark Buckley
Research Fellow
The University of Western Australia Wave Energy Research Centre
Observations and modeling of waves and currents in Albany, WA

Dr. Michael Cuttler
Research Associate
The University of Western Australia
Seasonal and interannual variability of the wave climate at a wave energy hotspot off the southwestern coast of Australia

Connor Gorham
Edith Cowan University
CARBON STORAGE BY TIDAL MARSH ECOSYSTEMS IN WESTERN AUSTRALIA

Mr. Jeffrey Norriss
Research Scientist
Western Australian Department of Primary Industries and Regional Development
Bycatch of Flesh-footed shearwaters (Ardenna carneipes) recorded by a purse seine fishery is closely associated with their annual breeding cycle

Dr. Harriet Paterson
Lecturer
UWA
Seasonal Dynamics of Plastic on the South Coast of WA and its Impact on Flesh-footed Shearwaters

Mr. Thomas Crutchett
Master’s Student
The University of Western Australia
Microplastics identified in commercially caught Western Australian Sardines (Sardinops sagax)

Dr. Claire Ross
Research Scientist
Western Australian Department of Biodiversity, Conservation And Attractions
Growth and physiology of high-latitude corals in Bremer Bay, Western Australia (34.4°S)

Mr David Juszkiewicz
Honours Student
Curtin University
Phylogeography of Plesiastrea versipora (Cnidaria: Scleractinia: Plesiastreidae): an integrated taxonomic approach reveals cryptic speciation

Miss Savita Goldsworthy
Student, Curtin University
The Composition of Shallow Water Temperate Reef Assemblages in Western Australia

Mr. Jack Parker
Master Student, Curtin University
The changes in distributions and function of Labridae in temperate South Western Australia.

Kyle Stewart
Murdoch University
Food resource partitioning among three key fishery species in the Walpole-Nornalup Estuary

Mr. Tim Leary
Technical Officer
Western Australian Department Primary Industries And Regional Development
Human capital in the south coast WA fishing industry: an exceptional ageing workforce or in line with broader demographic trends?

Dr. Wiebke Ebeling
Centre Manager, Wave Energy Research Centre
The University of Western Australia
Great Southern Marine Research Facility – a new hub for Australia’s Blue Economy

Dr. Elke Reichwaldt
Environmental Officer
Western Australian Department of Water and Environmental Regulation
Linking the management of catchment and sandbar opening to estuary health – a case study from Wilson Inlet, Western Australia

Mrs Alessandra Mantovanelli
Environmental Officer
Western Australian Department of Water and Environmental Regulation
Integrated approach for managing estuaries of South-West Australia

Triaxus – One Ten East log

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator will be posted on the WAMSI website during the month long voyage.

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Date: June 08, 2019 Time:  1200 AWST
Latitude: 18°S Longitude: 111°E
Wind direction: W Wind speed: 5 knots
Swell direction: SSW 2m, S 1m Depth: 4938 m
Air temperature: 23°C Sea temperature: 26°C

Notes: It’s World Oceans Day 2019! We had a special lunch in the marine-themed decorated mess. Dessert was a stratified layer cake complete with blue oceanic water, green chlorophyll maximum layer and the deep, dark ocean of chocolate! The students are now presenting their “3 minute thesis” about their research.

Triaxus

By Dr Helen Phillips

The ocean is never still. It warms by day and cools by night. Winds stir up the surface, mixing warmer surface waters with cold, deeper ones. Ocean currents bring waters from other regions and ocean eddies carry whole biological communities within their centres far from where they were first trapped inside the eddies.

RV Investigator moved slowly along the 110° East line because there were so many measurements to make at each station and they all took time. One station per day is what we could achieve to capture the physical, chemical and biological information we need to understand the major changes since the 1960s.

The rapid changes are also important and we use Triaxus to map these in a few places where we know there are fast currents with strong changes in water properties across them. Triaxus flies like a plane through the ocean, towed along behind the ship. It dives from the surface to 300 m depth and back to the surface in around seven minutes. As it flies, controlled by the electronics engineer on board, it measures ocean temperature, salinity, oxygen, nutrients and biological measurements. These variables can tell us how life in the ocean is influenced by ocean currents.

The focus for our Triaxus measurements are eastward currents called the Eastern Gyral Current and the South Indian Countercurrent. They carry waters from the Indonesian Seas and across the Indian Ocean into the coastal waters of Western Australia. The fisheries of WA depend on the nutrients supplied by these currents. Our measurements will help us understand what drives them and how they might change with global warming.

It’s a 110°E wrap! – One Ten East log

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator have been posted on the WAMSI website during the month long voyage.

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Date: June 13, 2019 Time:  1200 AWST
Latitude: 31°S Longitude: 115°E
Wind direction: W Wind speed: 6 knots
Swell direction: SW 2 m Depth: 587 m
Air temperature: 17°C Sea temperature: 21°C
Notes: People are busily packing up all their gear in preparation for docking tomorrow. We have humpbacks singing!
Last Log from One Ten East
It’s a 110°E wrap!
By Professor Lynnath Beckley (Chief Scientist)
Four thousand nautical miles and twenty-five oceanographic stations later, the forty scientists and MNF support staff on board the RV Investigator are returning to Fremantle, Western Australia armed with huge amounts of data and samples obtained from temperate to tropical waters in the south-east Indian Ocean. We have undertaken an ambitious bio-physical, ecosystem-scale examination of Australia’s International Indian Ocean Expedition line (110°E) last visited in 1963 by scientists aboard the HMAS Diamantina.
The 110°E voyage is Australia’s main contribution to the second International Indian Ocean Expedition which currently has 30 participating countries. Our objectives were to examine ecosystem-scale change from the 1960’s benchmark, characterise microbes that contribute to the regional biogeochemistry, determine the pelagic food web structure and relate information on phytoplankton and particles to bio-optical quantities derivable from satellite radiometry. We have achieved this, and much more, almost without missing a beat, thanks to the remarkable scientific team and technical support on board the ship.
The 54 CTD deployments have been at the heart of operations with nearly half of them to depths exceeding 5,000 m. This is a long way down into the abyss and the physical and chemical measurements made, and the seawater obtained from the Niskin bottles fired at about 20 different depths, have been the life blood for the scientists on board for their experiments on nutrients, microbes, phytoplankton and micro-zooplankton. Various netting operations ranging from tiny 20-micron mesh nets to coarse 1 mm mesh nets have provided samples of the plankton. Forty EZ net deployments have collected stratified samples from 500m depth to the surface and the samples from the Indian Ocean Standard Net, a replica of one used in the original IIOE, provide a direct comparison with those collected in the 1960s.
We have made various measurements of optical properties and mixing in the water column, recorded acoustics from sonobuoys, towed a continuous plankton recorder between stations and deployed 14 weather drifters, two JAMSTEC deep ARGO floats and one IMOS ARGO float. On the return leg of the voyage, we towed the undulating Triaxus for 50 hours assessing the flow of the Eastern Gyral Current and crossing a large eddy generated nearly three months ago by Tropical Cyclone Veronica.
All the while, the 20-strong ship’s complement kept the ship running smoothly, the deck crew assisted us with various winching and crane activities, wrestled with nets and expertly deployed and retrieved valuable scientific gear whilst the chefs and their team kept us exceptionally well fed. We even had a World Oceans Day celebration with our post-graduate students competing in the first ever “3-minute thesis” competition afloat in the Indian Ocean!
In between packing up our gear for demobilisation in Fremantle, we have had many fruitful discussions about our data, sample processing, integration and how we will relay our findings to the world. We trust that our daily “Log from One Ten East” posted on the IIOE-2 and WAMSI websites with informative texts written by our scientists and wonderfully illustrated by photographs taken during the voyage by Micheline Jenner have suitably conveyed our science and quest for knowledge about this special part of the blue planet adjacent to Australia.
Thanks to all who have contributed to making this RV Investigator voyage IN2019_V03 so successful. This is our final log entry as we dock at 08:00 AWST on Friday in the Port of Fremantle, our gateway to the Indian Ocean.
Captain Koolhof, Scientists and MNF Support staff wearing their fluoro vests and red beanies, form IIOE 2 on the foredeck of RV Investigator. Photo: Micheline Jenner AM.

 

Beanies off to the completion of a memorable IN2019_V03 voyage along the 110°East meridian in the south-east Indian Ocean as part of the second International Indian Ocean Expedition. Note the beautiful rainbow by the mast that accompanied us for the remainder of the day. Photo: Micheline Jenner AM.

 

It’s a wrap of the 110°East line voyage IN2019_V03! Photo: Micheline Jenner AM.

Thank you for following the daily posts of our Log from One Ten East at https://iioe-2.incois.gov.in and www.wamsi.org.au

Please share these links with friends and colleagues who may be interested in the Indian Ocean.

On the Humpback Highway – One Ten East Log

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator will be posted on the WAMSI website during the month long voyage.

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Date: June 12, 2019 Time:  1200 AWST
Latitude: 28°S Longitude: 113°E
Wind direction: SW Wind speed: 11 knots
Swell direction: SW 4-5 m Depth: 125 m
Air temperature: 18°C Sea temperature: 24°C
Notes: We heard humpback whales singing this morning. Indeed, what a lovely song it was!
On the Humpback Highway!
By Micheline Jenner AM and Curt Jenner AM
‘We’ve got whales!’
Excitedly, I was referring to the two blows just sighted only a couple of miles ahead of our small inflatable research vessel. With a pair of humpback whales in front and another two animals travelling behind us, moments later I yelled, ‘we are on the humpback highway!’
That was August 5th 1990 and this was the very first research trip of our thirty years of cetacean research in Western Australia. Now, from the deck of the RV Investigator we are plying the same waters along the west coast of Australia. A few hundred kilometres inshore, blows and breaches of humpback whales indicate the northern migration is on cue and underway, they are travelling to their tropical breeding grounds. Humpback whales have spent the austral summer in their Antarctic feeding grounds where they have gorged on krill, Euphausia superba–the keystone species of the Southern Ocean. Ready for 4-5 months on the breeding grounds, they have thick blubber layers, up to one-third of a metre.
The early birds travelling along the coast are the immature males. They will not have access to the females this year, but they know they have to migrate and they have to go somewhere! Learning the route and the successful technique of migrating north and south, without even engaging in the mating activity, is all part of the growing up process. Next on the northern migration are the immature females, the mature males and resting mature females (often with their soon to be separated yearlings) and then last, but not least, the pregnant whales make the journey north to give birth in warm, tropical coastal waters.
Humpback whales are renowned for their spectacular breaching displays. Leaping clear of the water, breaches can be interpreted as defensive, inquisitive or even playful behaviour. Photo: Micheline Jenner AM.
On our computer, as we are heading south towards Fremantle, the sonobuoys are revealing singing humpback whales. Seven years ago, when we first travelled this coast using this type of sophisticated listening equipment, we recorded a marvellous cacophony of humpback whale song–so boisterous and varied, we called it “Ningaloo Jamboree”. In the spirit of repeating surveys, we hope to record an “Abrolhos Jamboree” with all the beautiful trills, squeals, grunts and groans that humpback whales utter as they travel along the WA coastline.
Humpback whale song is sung by the males–one hypothesis poses that they are advertising their availability to the females during this breeding season. Having heard decades of humpback song ourselves, we can see why the female whales are swayed and the population is doing so well! Another hypothesis proposes that humpback whale song can also be used by “sentinels”, perhaps positioned at prominent landmarks like Northwest Cape, as a means of guiding their fellow humpback whales on their northward or southward migrations. After all, humpback whales make one of the longest migrations of any animals in the animal kingdom of around 13,000 km–a little help along the way might be necessary!
Newborn humpback whales are plentiful along the west coast of Australia. Photo: Micheline Jenner AM.
Humpback whales are flourishing population-wise and, particularly off Western Australia, are most likely near their pre-whaling numbers. With only 200-300 humpback whales left in 1962, it is delightful to see the crop of newborns and yearlings each year as the population steadily increases. With between 40-45,000 whales in the Western Australian population travelling the coast, we might see a large proportion of these whales on this journey. Photos of individual animals collected from RV Investigator will be added to our Centre for Whale Research Humpback Whale Photo-ID Catalogue, which now houses more than 8000 images of over 5500 individuals.

Vertical Microstructure Profiles – One Ten East Log

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator will be posted on the WAMSI website during the month long voyage.

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Date: June 11, 2019 Time:  1200 AWST
Latitude: 23°S Longitude: 112°E
Wind direction: SSW Wind speed: 19 knots
Swell direction: SW 3.5 m Depth: 1071 m
Air temperature: 20°C Sea temperature: 24°C
Notes: The third Triaxus section has been completed. RV Investigator is bolting for the barn!

 

Vertical Microstructure Profiles

Dr Helen Phillips

Waves breaking on the beach are a familiar sight to many people. Ocean swells, generated by storms out at sea, constantly move toward the coast. As the swell waves move into shallow water, they steepen and then finally break. The same thing happens below the surface of the ocean.

Waves inside the ocean are known as internal waves. Instead of existing at the boundary between air and ocean, they exist between layers of water of different density – warmer, lighter surface waters lie above colder, denser waters. Internal waves ride these density layers, and often steepen and break. Their breaking causes mixing inside the ocean, which is vital for distributing heat.

We measure ocean mixing with a Vertical Microstructure Profiler (VMP), also affectionately known as the “toilet brush”. The VMP has very sensitive probes that measure the small changes in ocean temperature and velocity that are caused by breaking internal waves. The mixing rate not only tells us how fast heat moves between the surface and the deep ocean, but also how rapidly nutrients can be brought to the surface to supply vital ingredients for the plankton at the base of the marine food chain.

Dr Jessica Benthuysen (AIMS) and Maxime Marin (PhD student University of Tasmania) prepare to deploy the VMP which measures small changes in ocean temperature and velocity caused by internal waves. Photo: Micheline Jenner AM.

 

The VMP, also known as the “toilet brush”, has been deployed from the stern of RV Investigator at each of the twenty stations on the 110°East line, providing vital understanding of ocean mixing and heat distribution in the south-east Indian Ocean. Photo: Micheline Jenner AM.

 

Be sure to follow the daily posts of our Log from One Ten East at https://iioe-2.incois.gov.in and www.wamsi.org.au