Current systems crucial to life on earth

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A crucial system of currents that takes 1,000 years to circulate the globe is being impacted by increasing ocean temperatures and will have a profound effect on the world’s climate if it further slows or shuts down altogether, by triggering more atmospheric temperature extremes.

Professor Nicole Jones, a physical oceanographer from The University of Western Australia, explained the meridional overturning circulation as part of the Western Australian Marine Science Institution’s Thinking Blue school outreach program.

“Cold and salty water forms in the Labrador Sea, between Canada and Greenland, as well as in the Weddell and Ross Seas, close to Antarctica, and then it descends into the deepest depths of the ocean and circulates around the ocean before coming back up to the surface closer to the equator,” Professor Jones said.

“It takes a millennium to transport the water from the surface, down to the bottom of the ocean and back to the surface again.”

She said the ocean system was crucial to many processes including transporting gases from the atmosphere down into the deep sea.

“This helps to regulate the amount of carbon dioxide in the atmosphere and also supplies oxygen to the deep ocean,” Professor Jones said.

“It also traps heat so plays a strong role in modulating what is happening in the atmosphere.”

But climate change is impacting the system.

“With climate change, water at the Poles is becoming fresher and also warmer and so it is not going to be able to sink to the same deep depths and that will weaken the return currents such as the Gulfstream,” Professor Jones said.

“So, it’s not only the cold currents that get weakened it’s the warmer currents at the surface.”

Professor Jones said measuring the circulation was challenging but there was evidence it was slowing. She said if it shut down, there would be dramatic atmospheric temperature decreases across Europe. In the southern hemisphere temperatures would be expected to increase.

Professor Jones’ presentation also covered sea level changes and climate change.

The presentation can be found here.

The messy, muddy work retrieving recorders from the sea floor

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They are moments of excitement mixed with relief when researchers pull up their mud and weed covered hydrophones and recorders which have spent months on the seafloor quietly capturing the sounds of weather, marine life, boats and ships.

The equipment used for the ‘Noise’ theme project in the WAMSI Westport Marine Science Program was put out three times over a year in Cockburn Sound and left under water for four months.

The research team carefully noted the coordinates of the devices when they lowered them under water and connected them by rope to weights to stop them drifting.

The underwater recorders contain enough batteries to sustain them through the months of data collection and are built to withstand the pressures of saltwater, sediment and sometimes rough weather conditions.

Because of the boating and fishing activity in Cockburn Sound the team decided not to attach the devices to floats which would increase the possibility of ropes becoming snagged in propellers.

When it comes time to retrieve the devices, the team takes its boat to the drop sites using the GPS coordinates and uses a hook to grab the line. It can feel like looking for a needle in a haystack.

When they are found, the recorders are usually covered in mud and some are tangled in seagrass but once they are cleaned the precious data is retrieved.

What’s downloaded are the sounds of the Sound. There are wind and bubbles, jet skis, boats, large ships but also fish, dolphins, crabs and many noisy shrimp.

 

 

 

Ship safety system helping Sound’s noise research

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A safety system that tracks ships and helps prevent collisions is being used as part of a study of noise levels in Cockburn Sound and their potential impact on marine life.

Cristina Tollefsen from Curtin University said researchers were using ship location information from the worldwide Automatic Identification System along with data from recorders on the seabed.

At the start of the project, researchers placed recorders with hydrophones (underwater microphones) at nine locations in and around the Sound.

“AIS gives us details of ships and their location which means we can attribute portions of the recording to certain vessel types,” Dr Tollefsen said.

“Because we can combine this information with data from the recorders, we have been able to measure the sound levels of all the different vessel classes from tugboats and the pilot vessel to the massive bulk carrier ships,” Dr Tollefsen said.

“Port activities require more than one vessel typically, so we wanted to capture a set of activities including the pilot boats meeting larger ships as they arrive and the tug boats assisting ships as they come into port.

“It’s less common in research to measure the combined noises but that is much more realistic.”

Dr Tollefsen, who is working on the project for the WAMSI Westport Marine Science Program, said there was growing awareness of the impact of noise on animals.

“Because light doesn’t penetrate very well under water, a lot of animals use sound to communicate,” Dr Tollefsen said.

“The best-known animals to do this are whales and dolphins but invertebrates and fish also use sound.

“If it’s too noisy from human activities, you can imagine that it’s harder for the animals to find a mate or find food.

“That’s why we’re doing this work is to understand the sounds in Cockburn Sound and whether there are ways to estimate a potential increase in noise or mitigate any increase if shipping traffic were to increase.”

Dr Tollefsen said a port in Vancouver, Canada had implemented a strategy to slow vessels on approach as a way of protecting the endangered population of orcas in the area.

She said by slowing the vessels, similar to a maritime equivalent of a traffic school zone, they had made the waters less noisy with the aim of reducing the impact of human-caused noise on the marine mammals.

Indigenous led research vessel launched with dockside cultural smoking ceremony

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A newly-refurbished vessel was launched today to be used for a landmark research, training and environment rehabilitation collaboration in Shark Bay – an area which has been hit hard by devastating marine heatwaves.

The 23-metre ‘Marine 2’ is owned by The Jock Clough Marine Foundation, which offered it to the Indigenous-owned and operated Tidal Moon for its exclusive use. The event took place with a dockside cultural smoking ceremony at Fremantle’s Sardine Jetty.

Tidal Moon has a sea cucumber harvesting business and has applied for a license to help rehabilitate up to 1,000 square kilometres of seagrass in Shark Bay. The meadows were lost just over a decade ago in a series of marine heatwaves.

‘Marine 2’ will enable the training and employment of local Malgana People, as well as marine research delivered by the Western Australian Marine Science Institution (WAMSI) with its partners.

“Seagrass provides a vital habitat and breeding area for marine animals,” Mr Wear said.

“It also prevents the release of thousands of tonnes of carbon dioxide and is regarded as the ocean’s lungs.”

“Myself and Malgana Elders are honoured that Shark Bay’s Traditional Custodians will lead this exciting collaboration which brings together important marine research and innovative projects that benefit the environment.”

“We are combining Western marine science and Indigenous Sea Country knowledge.”

“This is also going to create new private sector job opportunities and give our young people new opportunities to care for Sea Country,” Mr Wear said.

WA philanthropist, businessman and Jock Clough Marine Foundation Co-Trustee, Jock Clough said he was looking forward to supporting the collaborative effort.

“This is a wonderful opportunity for Tidal Moon, with its Traditional Owners and custodians, WAMSI and the Jock Clough Marine Foundation to work together, and really make a difference to the knowledge of a very special place,” Mr Clough said.

WAMSI CEO Dr Luke Twomey said the organisation had developed a Science Plan for Shark Bay (Gathaagudu) and further research would provide essential data to help inform the way local and global marine ecosystems were managed. “Shark Bay is like the canary in the coalmine for climate change and our partner scientists will be able to make a real difference through this initiative,” Dr Twomey said.

Tidal Moon has been working with scientists from WAMSI’s partner institutions and with CSIRO to better understand the role of seagrass in Shark Bay’s ecosystem and the best ways to prevent future losses.

WAMSI manages major marine science projects through its partnership with Curtin University, Edith Cowan University, Murdoch University, The University of Western Australia as well as the Department of Biodiversity Conservation and Attractions, the Department of Water and Environmental Regulation, the Western Australian Museum, Australian Institute of Marine Science and the Department of Primary Industries and Regional Development.

Penguin ‘poop study’ to help unlock colony’s diet

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Researchers from The University of Western Australia and Murdoch University are analysing DNA from the excrement of little penguins in Cockburn Sound to find out what, other than fish, they are eating and whether it is affecting their breeding.

Penguin researcher Dr Belinda Cannell, from UWA, said analysing the animals’ diet in greater detail would provide an insight into their breeding and how it related to the availability of their primary diet, which is fish.

Little penguins in Cockburn Sound (their northern most range in Western Australia) primarily eat anchovies, pilchards, scaly mackerel and sandy sprat.

Penguins are known to also feed on crustaceans, cephalopods and even jellyfish.

“If it’s a poor year and there are not a lot of fish around, the little penguins may be feeding more on other things such as jellyfish,” Dr Cannell said.

This could then have an impact on their ability to produce and raise young.

“This other food may not get them into the condition where they can breed and feed their young,” Dr Cannell said.

“It may be that the chicks don’t fatten up as quickly.”

She said diet made up one element of the project, which is part of the WAMSI Westport Marine Science Program.

Another methodology being used to determine diet composition is the analysis of stable isotopes of carbon, nitrogen and sulphur from the down of little penguin chicks and feathers from adults.

“Stable isotopes of carbon reflect primary production sources and is more enriched in inshore, seagrass dominated areas, compared to offshore food webs,” Dr Cannell said.

“The stable isotope of nitrogen increases up the food chain and can also increase between size classes of the same prey species.”

“Stable isotopes of sulphur can be useful to distinguish between offshore and inshore components in food webs and can also indicate if producers are using sulphur from seawater, which is more enriched, or from sediments which are less enriched.

“This gives us a better idea of the whole diet of these birds.”

Dr Cannell said stable isotopes assist with establishing diet composition.

“I presume little penguins are eating jellyfish, but we haven’t had stable isotopes for jellyfish until now.”

The Western Australian Museum provided samples to assist with the research.

Cockburn Sound research reports now online

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Cockburn Sound research teams have started delivering project reports for their work on the WAMSI Westport Marine Science Program.

These are now published on WAMSI’s Cockburn Sound webpage under ‘Research Themes and Reports‘.

More than 100 scientists and researchers are working across 33 projects, helping to build a picture of the Sound’s environment and provide key input into the port design.

In one of the latest reports to be released, scientists have carried out a detailed literature review identifying potential invasive marine species which may have become established in Cockburn Sound, with procedures to mitigate the risk of introducing these to future Westport facilities.

Another project explores the potential effects of suspended sediment on fishes from dredging, while a social science study has identified and mapped 31 non-fishing recreational activities and 11 associated values for the Sound.

Reports will continue to be published on our website over the next few months.

 

Eco-design and pre-seeding among options to encourage healthy port marine life

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Pre-seeding new port structures to encourage the colonisation of native species is one of the mitigation measures against invasive marine plants and animals, outlined in a new report prepared for the WAMSI Westport Marine Science Program.

The literature review by Curtin University School of Molecular and Life Sciences Adjunct Professor Fred Wells lists many of the invasive marine species that have been recorded in waters around Perth and mitigation measures that could be used during any port construction.

Pre-seeding works by attaching local, fast-growing species to a new structure. The common mussel is one option identified in the report.

Professor Wells said invasive marine species were a worldwide problem and shipping was the most common way they spread to coastal areas. Ninety-eight percent of trade in and out of Australia is on vessels.

“Invasive marine species are concentrated on artificial surfaces and eco-engineering is a new field that attempts to encourage biodiversity and prevent potential marine pests taking hold,” Professor Wells said.

“The risk of introducing new species is greatest during construction but experience during the construction boom in the Pilbara demonstrated the issue is manageable.”

Professor Wells said eco-design was a new and evolving field that could help improve the biodiversity of the marine community that develops underwater, while minimising the risk of invasive species.

“Current design procedures tend to create uniform habitats, such as seawalls with smooth vertical faces. The lack of habitat diversity reduces the biodiversity of the marine community that develops on the structure. “

“Increasing the habitat diversity of new immersed structures and pre-seeding them with native species appear to be the most promising ways for mitigating against species that can cause ecological harm and prove expensive.”

Professor Wells said the biggest threats from invasive species to marine ecosystems were introducing disease, displacing native species, changing the ecology of native communities, clogging pipes and damaging other critical infrastructure.

The report, which was done to understand potential risks, is a literature review of invasive marine species from Cottesloe to Cockburn Sound, including waters around Fremantle and the Swan River.

A comprehensive survey more than a decade ago recorded 60 introduced marine species living in WA waters. Three were on the national marine pest list. Four additional marine pests were subsequently recorded in WA.

“Fortunately, most introduced marine species are apparently innocuous, causing no known adverse effects and we know only a small portion become pests,” Professor Wells said.

 

 

Volunteers spring into action to help seagrass recovery in Cockburn Sound

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A seagrass restoration program, that is helping to regenerate Cockburn Sound’s underwater meadows, has had a record number of volunteers helping to spread hundreds of thousands of seeds from the plants.

About 80 per cent of Cockburn Sound’s meadows were wiped out in the 1950s and 60s because of poor water quality. Seeds for Snapper harnesses community help, backed by scientific knowledge, to collect seagrass seeds and disperse them where they are most needed.

Research officer Rachel Austin, from The University of Western Australia’s School of Biological Sciences, who helps run Seeds for Snapper with fishing conservation charity OzFish, said volunteers helped disperse 670,000 seeds over 10 sites during November. They donated 1500 hours.

“It’s very simple, very scalable and results in much higher seeding density than what happens naturally,” Ms Austin said.

“We estimate that more than 90 percent of seagrass fruit ends up where it cannot grow, including on the beach and in deep water.

“We are able to collect the seeds and throw them into specially chosen areas where they are more likely to take hold.”

Rachel Austin with a beaker of seagrass seeds.

Rachel Austin from UWA with seagrass seeds at a volunteers’ day in Cockburn Sound.

“By doing what we are doing we can get substantially more seedlings in an area compared to what can happen naturally.”

She said the program had not only had a practical benefit in helping regenerate parts of the seabed but had also increased awareness of the importance of seagrass for storing carbon, stabilising the seabed and providing breeding areas and habitat for marine animals.

 

 

“If you want squid, fish and octopus you’ve got to have somewhere for them to live and that is your seagrass meadows,” Ms Austin said.

“About 200 hectares has regrown but we’re still missing 2,000 hectares.”

Seagrass restoration is among the research projects currently underway as part of the WAMSI Westport Marine Science Program.

OzFish Western Australia Program Manager, Steve Pursell, said 2023 was the second biggest year for Seeds for Snapper in terms of the number of seeds released into Cockburn Sound. Last year was the highest since it started six years ago.

“The program has really gained momentum,” Mr Pursell said.

“We had people from a range of backgrounds and all ages, helping out this year.

“We even had a volunteer fly in from New York, just to work on the project,” he said.

“Some volunteers who come along don’t initially realise the difference between seagrass and seaweed but they soon learn that, and many go on to become great advocates for the importance of seagrass and our habitat restoration work.”.

He said volunteer divers collected seagrass fruit in nets and other groups on shore worked at tanks to sort husks from the seeds. Volunteers and recreational boaters then took the seeds into Cockburn Sound to throw them back in the water at selected sites.

Ms Austin said she was heartened by the response to Seeds for Snapper from fishers they met at boat ramps.

“Public awareness around the importance of seagrass has really grown and the fishers we speak to are really enthusiastic. It gives you hope for the future.”

She said the program involving monitoring sites where seeds were dispersed.

“Our main species Posidonia australis (ribbon-weed) is quite a slow growing species so you’re talking a good five to 10 years before you have a dense meadow.

“But we have found incredible growth in some areas.

“Some sites are not as good, and we learn every year.

“At all our sites it does look like we are getting higher seedling densities than if it was left to nature.”

People who are interested in volunteering for the 2024 Seeds for Snapper program can find more information here or email seedsforsnapper@ozfish.org.au

WAMSI coral researcher a Student Scientist of the Year finalist

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Marine scientist Josh Bonesso said he was honoured to be a ‘Student Scientist of the Year’ finalist in the Premier’s Science Awards and hoped it shone a light on the impact of climate change on coral reefs.

Josh is a PhD student at The University of Western Australia’s Oceans Institute and works part time at the Western Australian Marine Science Institution. The Premier’s Science Awards winners were announced at a ceremony in Perth on 11 September.

Josh was named as a finalist for his work developing ways to rapidly assess the sensitivity of coral islands to climate change.

“I hope being a finalist helps draw attention to the impacts of climate change and the vulnerability of the world’s coral reefs and their islands,” Josh said.

“Coral reef-islands are the landform most threatened by the effects of climate change such as rising sea levels and ocean warming,” Josh said. “But much of our knowledge of changes to these islands has come from two-dimensional satellite images. My research, using three-dimensional mapping technology, captured the largest regional-scale group of islands globally, here in WA’s Pilbara.”

“This led me to develop a unique tool to rapidly assess changes to key features which could act as a crucial warning of imminent threats to the islands.”

He said he was thrilled for the winner, medical researcher Denby Evans, from Telethon Kids Institute and Curtin University.

The awards recognise remarkable achievement and innovation of scientists and science students in the state.

WAMSI CEO Dr Luke Twomey said Josh was an innovative scientist with a passion for educating and inspiring people about marine science and he congratulated him on being an award finalist.

“Josh’s research, which has now been published in a leading scientific journal, has broad ranging benefits worldwide,” Dr Twomey said.

“Josh’s ability to think laterally has established opportunities to lead and collaborate across government and scientific institutions to better safeguard WA’s marine assets.”

“Josh has been a regular speaker with WAMSI’s Thinking Blue outreach program and is always happy to share his knowledge about coral reefs and islands. He does terrific work communicating marine science within the community.”

Water quality improving but Cockburn Sound still impacted by pollution legacy

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Water quality in Cockburn Sound has been steadily improving for decades but seagrass and some fish stocks are still struggling to recover from the days of unrestricted pollution discharge, according to marine scientist Dr Fiona Webster.

Dr Webster, who works at the Department of Water and Environmental Regulation assessing marine proposals, was speaking to students about the impacts of marine pollutants as part of WAMSI’s Thinking Blue education outreach program.

The program features lectures by some of the state’s top marine scientists, including from WAMSI’s partner organisations.

Dr Webster told the students that in the 1970s there were concerns about the environmental impact of industry discharging pollutants such as nutrients and heavy metals straight into Cockburn Sound.

“Around 80 percent of seagrass was lost and there were concerns people couldn’t swim or couldn’t fish and many were worried,” Dr Webster said.

“Whilst the extent of environmental deterioration sounds extreme, you have to remember that the Environmental Protection Act didn’t exist until 1986,” she said.

To protect Cockburn Sound, the State Government introduced two key initiatives; firstly direct discharges were banned and secondly the State Environment Policy for Cockburn Sound was developed.

Dr Webster said that while parts of Cockburn Sound will remain industrialised, the State Environment Policy ensured environmental, social and cultural values were protected and the water was safe to swim in and fish were safe to eat.

“Monitoring has shown the water quality has been improving since then and most areas now have good water quality,” Dr Webster said. “But seagrass is not recovering so well.”

“Part of that could be the organic nutrient load in the sediment.”

“Some fish stocks are also still depressed including the garfish and blue swimmer crabs.”

Whilst water quality in Cockburn is looking good, there are always new and emerging contaminants to watch out for such as PFAS (a key constituent in fire fighting foam) and microplastics.

Dr Webster told the students there was good work going on to support the environment including the replenishment of fish stocks and the Seeds for Snapper program. This involved volunteers collecting seagrass seeds and dropping them in areas needing regeneration.

Early inspiration

One of the aims of Thinking Blue is to inspire students to study marine science.

Dr Webster told the students, until her dad gave her a pair of goggles when she was six years old, she’d been nervous of seaweed.

“When I had my goggles on, suddenly I could see fish and bubbles and kelp.”

She later studied science and did a PhD after completing researching at Ningaloo Reef.

She told the students her career had ‘meandered’ from measuring crayfish on commercial vessels at the Abrolhos Islands to spending 18 months on a yacht off Madagascar to working with an Australian aid organisation in Tonga.

It’s a career journey that certainly inspires.

You can watch Dr Fiona Webster’s lecture here.