Robot sowing the seeds for healthy seagrass meadows

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A robot that plants seagrass seeds directly into the seabed is being trialled in Cockburn Sound as part of a program to speed up the restoration of badly depleted underwater meadows.

Seagrass, the ocean’s only flowering plant, is vital as a habitat for wildlife, for stabilising sediment and storing carbon. But pollution, marine heatwaves and development have wiped out vast areas of seagrass meadows.

Emeritus Professor Gary Kendrick, from The University of Western Australia’s School of Biological Sciences, who is a seagrass restoration project leader on the Western Australian Marine Science Institution (WAMSI) Westport Marine Science Program said it wasn’t enough to let ‘nature takes its course’ because the process was too slow.

“In Cockburn Sound, south of Perth, we are talking about a system that lost more than 3,000 hectares of seagrass from the mid-1950s to the 1980s,” Professor Kendrick said.

“Less than 100 hectares has come back.

“Even when we disperse seagrass seeds where the plants are needed, it can take two or three weeks for them to attach to the sediment and in that time, most are lost.”

The specially designed autonomous robot, which is powered by batteries, injects seeds into the seafloor which the research team said improves their chances of taking hold and growing into healthy, new plants.

It was developed by Ulysses Ecosystem Engineering, which is based in San Francisco.

Their team travelled to Perth to operate the machinery trial. The robot works by taking collected seeds and depositing them directly into the seabed. This has been shown to have a greater germination rate than traditional methods of restoration, which see the seeds scattered at the surface.

Professor Kendrick said the trial had come a long way.

“I have worked with the Ulysses engineers for one year and in that time, we have now got a full robotic system working.”

“Next year we are hoping we can demonstrate you can plant a hectare in a day.

“We are seeing a slow recovery at Kwinana Shelf and what we are really trying to do is speed it up and build resilience in a whole community.”

Researchers from UWA will return to the trial sites to assess for restoration success over the next year.

Will O’Brien, one of the co-founders of Ulysses said it is crucial that we develop automated solutions for seagrass restoration.

“Existing methods are too expensive and slow to achieve the results that are needed,” Mr O’Brien said.

“This trial is the first step in restoring WA’s seagrass coverage to historic levels and we are off to a very promising start.”

The trial will be supported by a $230,000 investment by Westport.

Photo credit : Nina Ho, UWA

Squid on camera in sediment project

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Cameras set up in large tanks are capturing what impact varying levels of fine limestone sediment in the water has on the feeding habits of squid, as part of a project for the WAMSI Westport Marine Science Program.

The project, which started recently, is led by Dr Ben Saunders, a Senior Lecturer in the School of Molecular and Life Sciences at Curtin University.

It will be used to inform the Westport project in Cockburn Sound.

Dr Saunders said traditionally research had focused on the lethal effects of sediment on marine life during dredging operations.

“What we are interested in is the lowest measurable effects, where the behaviour of the animal starts to change,” Dr Saunders said.

“They may start to feed differently and there could be changes to their body condition and overall health.”

Three levels of sediment are being used to replicate what is likely to be in the water during a dredging operation.

“We are testing 25 milligrams per litre, then 44 milligrams per litre, and a control without added sediment.”

The highest level is based upon the turbidity levels where previous research suggests that 5% of fish species begin to be affected.

“We feed the 17 squid in front of the video cameras and we try to get them to come in so we can record any delay between the fish going into the tank and the squid realising it is there and coming in to eat it.”

One sign the squid may not be able to see their prey is fish remaining uneaten at the base of the tank.

Two trials will be conducted, and each trial runs for 10 days.

The squid are fed and monitored three times a day and researchers regularly test water quality and monitor the video footage.

Ocean soundscapes as varied as landscapes

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Underwater soundscapes are as varied as landscapes, according to acoustics researcher Dr Iain Parnum.

Dr Parnum gave a presentation for the Western Australian Marine Science Institution’s Thinking Blue school outreach program about marine soundscapes, which are a growing area of research interest.

Dr Parnum is a Senior Research Fellow at the Centre for Marine Science and Technology (CMST) at Curtin University and the Centre’s Deputy Director. He is also a Noise theme researcher on the WAMSI Westport Marine Science Program.

“In marine ecosystems, sound is vital to many species for navigation, communication and finding prey,” Dr Parnum said.

“For about 12 hours a day we have no light, so sound is important for a lot of marine life because sound waves are not inhibited by a lack of light.”

“But different areas of the ocean have vastly different sounds.”

He said there was an increased research focus on underwater soundscapes and the impact of noise on animals.

Dr Parnum said one of the soundscapes he had studied was the Perth Canyon, which is a deep submarine canyon 20 kilometres west of Rottnest Island. It is an important feeding ground for many animals and the area is also traversed by ships and other vessels.

He said between 2008 and 2016 an acoustics laboratory recorded the canyon’s underwater soundscape, including migrating whales, fish choruses and earthquakes, as part of a program designed to improve the understanding of noise and its impact on marine life.

Data from the sound recorders are used to create spectrograms which illustrate the energy, pitch and patterns of sounds.

“These then become an efficient way of monitoring the presence of these whales in the canyon and in other areas because we know their distinctive sounds,” Dr Parnum said.

He said Antarctic minke whales produced a noise, which submariners referred to as  ‘bioduck’ when they first recorded the mystery sound.

“Humpback whales meanwhile are the showoffs of the whale world and produce more complex songs with high and low frequencies.”

“The males will sing songs for hours at a time and elements of the song will be picked up and used by other pods.”

By understanding the various noises made by the whales, researchers have been able to identify when they are using the canyon.

“Pygmy blue whales are present in the canyon from November to June and peak between March and June.”

“The peak times for humpback whales in the Perth Canyon are June and July, during the northern migration and August to October when the species migrates south to Antarctica.

You can find out more about Dr Parnum’s work in Cockburn Sound here.

You can see Dr Parnum’s full Thinking Blue presentation here and find more information about the Perth Canyon acoustic observatory including access to the data here.

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.

Noisy oceans and the threats to the biggest animals on Earth

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Blue whales feast on several tonnes of krill a day, accumulate earwax that can be used to determine their age and the species of cetaceans, which are the biggest animals to have ever lived on Earth, have tongues that weigh as much as an elephant.

The fascinating facts were outlined during a presentation by Curtin University PhD candidate Brodie Elsdon as part of the Western Australian Marine Science Institution’s Thinking Blue outreach program.

Ms Elsdon said while the world’s population of humpback whales had recovered well since most countries stopped whaling, blue whales remained endangered globally.

Her presentation, ‘Talking Whales in a Noisy Ocean’ covered her research on whale sounds and song and the noises that pose threats to the animals including shipping.

“We can distinguish between species just by listening to the unique sounds they produce,” Ms Elsdon said.

Her research involves analysing recordings of pygmy blue whales captured from deep-sea areas and canyons around Western Australia, some reaching depths of 4,000 meters.

She then analyses the data using spectrograms, and specialised acoustic algorithms to identify the species’ unique low-frequency, high-intensity vocalisations, which are on the edge of the human hearing threshold.

“By listening to whales sing, vocalise and communicate in a noisy ocean we can identify patterns in their presence and their exposure to threats. It helps us identify the timing and the important locations the whales go, which can play a part in informing improved protection for this iconic, ‘data-deficient’ species.”  – Brodie Elsdon

“We know the Perth Canyon is an important feeding area for pygmy blue whales, but it has seen an increase in shipping traffic.”

Ms Elsdon said the ocean soundscape comprised noises caused by animals (biophony), humans (anthropogenic) and noise from the environment (geophony) including wind, rain and breaking sea ice.

“Whales live in an acoustic world and rely on sound for just about every aspect of their life including communicating, finding a mate, hunting for food and navigating,” Ms Elsdon said.

“Unfortunately, they are under increasing pressure from marine industries, habitat degradation and prey depletion.”

Ms Elsdon said her surveys revealed that the Western Australian community places significant value on whales and their conservation. She emphasized this value should be considered in a more holistic approach to managing natural assets, such as pygmy blue whales.

“These marine giants hold immense environmental value through the ecosystem services they provide us and they possess incredible socio-cultural and economic significance.”

“Whales are celebrated in many cultures and societies around the world, and they play a crucial role in maintaining marine ecosystem balance,” Ms Elsdon said.

She told students the ‘blue whale poo’ provided vital nutrients for phytoplankton to grow, which in turn produced about half the world’s oxygen.

Brodie Elsdon is based at Curtin University’s Centre for Marine Science and Technology (CMST).

She completed a marine and environmental science degree at Murdoch University and is co-founder of the Marine Industry Mentoring Network.

You can see the presentation, which includes recordings of different whale species here.

World first as marine mammal experts migrate to Perth for international conference

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Have you ever wondered what a whale thinks, sought to understand a sea lion, pondered a porpoise, or had dolphins dive through your dreamtime? Do you want to know how our finned friends are faring in a changing sea?

For the first time in the international Society for Marine Mammalogy’s 50+ year history, the world’s marine mammal experts will convene in Australia to tackle these issues and more.

Perth will play host, with over 1,300 attendees from 80 nations gathering to discuss the latest innovations and research from around our blue planet.

The conference theme is “Culture and Conservation: Fishing for Change”, shining a light on two key areas; the interplay between marine mammal and human cultures and conservation, and marine mammal interactions with fishing gear, the biggest threat to extinction they face.

“We are thrilled to bring this meeting to Perth, where we’ll workshop how best to blend western science with Traditional Ecological Knowledge, and quantify the winners and losers in the face of human activity in our rivers and seas”, said Dr Krista Nicholson, of the Local Organising Committee.

Scientists will also present findings from the WAMSI Westport Marine Science Program, including on the hearing, movement, and dive behaviour of Australian sea lions, and dolphin whistles in Cockburn Sound.

WAMSI Westport Marine Science Program Theme Leader, Dr Delphine Chabanne, said the conference provided a wonderful opportunity to share some of the research coming out of Cockburn Sound with an international audience.

“The exchange of ideas and experiences at this conference will not only enhance our understanding of marine mammals, but also inspire innovative solutions to the challenges they face in a rapidly changing world,” Dr Delphine Chabanne.

The 25th Biennial Conference on the Biology of Marine Mammals will take place at the Perth Convention and Exhibition Centre from the 11-15 the November 2024.

 

Conference Art by Sarah Humphries

 

 

The varied life of coral reefs: from warm and tropical to arctic depths

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The popular image of coral reefs is colourful life forms, in clear, tropical water. But marine scientist Dr Shannon Dee said some exist in chilly Arctic seas and others thrive in warm, turbid water where there is limited visibility. Finding out more about the many types of coral reefs could improve understanding of reef vulnerabilities and resilience under climate change.

Dr Dee, from Edith Cowan University, gave her presentation ‘Characteristics of coral communities’ as part of WAMSI’s Thinking Blue school outreach program.

The scientist, whose career has included working on a bull shark aid project in Fiji, a tourist vessel in Queensland and with an environmental consultancy, said the ‘Hollywood’ image of coral reefs only represented one element of what were varied ecosystems.

“Coral reefs are architectural and biological masterpieces,” Dr Dee said.

“Corals, which are animals, are critical for biodiversity, they are a source of food and medicine around the world, and coral reefs help with flood protection in low lying coastal areas.”

Dr Dee has undertaken most of her research on turbid reefs. Exmouth Gulf, in Western Australia, was one example of a turbid reef site and an area where fine sediment gets resuspended or flushed on to the reef by tides.

Other coral systems include Arctic and mesophotic (low light) reefs, such as the 350 metre deep Røst Reef in Norway and temperate reefs including those off Perth and WA’s south coast.

Dr Dee said one of the biggest threats to corals globally was from climate change along with disease, pollution, cyclones and the crown of thorns starfish.

“Corals will be stressed when waters rise above their thermal limits. They then start expelling zooxanthellae, the symbiotic photosynthetic algae within them, which then makes the coral turn white.”

Coral polyps are clear but algae within them gives them their colour.

“At this stage the corals are alive but starving, as the algae aids in coral digestion and nutrient take up”

“If this continues the coral will die.”

“Even if corals survive a bleaching event, the skeleton is more fragile, and the coral may be more susceptible to bleaching in the future.”

“Branching corals can be more susceptible to bleaching.”

Dr Dee said turbid reefs were usually covered in slow growing corals which were generally more stress tolerant.

“Some may be more resilient in the future.”

Dr Dee said there were some simple ways everyone could help protect corals: Don’t touch or step on them, use sunscreen that doesn’t contain ingredients that harm corals and eat seafood that is sustainably caught.

Dr Shannon Dee’s presentation: Characteristics of coral communities is available to view on WAMSI’s YouTube channel.

Museum veteran carefully conserving shipwreck treasures
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Shipwrecks may capture the imagination, but the job of retrieving what is left behind from reefs, rocky coastlines and the seabed beneath wild oceans is painstaking and at times challenging.

Western Australian Museum conservator Jon Carpenter, who has dived on ship and aircraft wrecks around Australia and overseas, said safely delivering the historic pieces to shore required meticulous planning and careful packing.

Mr Carpenter has worked at the museum since 1974 and gave a presentation to senior school students as part of the Western Australian Marine Science Institution’s Thinking Blue outreach program.

Some of the objects he’s helped recover and conserve are displayed at the WA Shipwrecks Museum in Fremantle. These include a cast iron cannon from Australia’s earliest shipwreck, Trial (wrecked in 1622) and a wrought iron anchor from the Zuytdorp (1712). Other objects, now located at the Museum of Tropical Queensland, are a silver pocket watch and pistol from HMS Pandora (1791).

“Objects that we recover from the ocean have absorbed water and incorporated salts and have been altered by it,” Mr Carpenter said.

“It is important that they are kept in wet storage, to prevent damage due to drying, corrosion and crystallization of salts,” he said.

“If an organic object such as one made of waterlogged wood dries out before impregnation or consolidation treatment it will irreversibly shrink, crack and distort.”

To avoid the potential for osmotic shock, ceramic objects recovered from the sea are initially soaked in seawater diluted with freshwater, and eventually desalinated completely in freshwater.

“Legislation protects underwater archaeological sites so you cannot indiscriminately recover material. You must also know how to conserve it properly,” he said.

On a wreck site, buried objects are uncovered using an airlift or water dredge which operate like an underwater vacuum cleaner. It is safer to expose an object by using a hand to fan the sand to mobilize it and allow the vacuum to carry it away.

Mr Carpenter said the material a vessel was made of, the location where it sank and the prevailing environment on the seafloor all affect how well it is preserved more than the time it’s spent underwater.

“When a ship is buried, and the environment is stable it is usually conducive to preservation and that is why the remains of many shipwrecks are more than 2,000 years old,” Mr Carpenter said.

Dozens of ships have been wrecked along Western Australia’s coast and include Batavia (1629), the Vergulde Draeck or Gilt Dragon (1656), Zeewijk (1727), Xantho (1872) and Omeo (1905).

“When you uncover personal belongings like the watch from HMS Pandora, it is a reminder that people were on board and may have lost their lives.”

The Zuytdorp, wrecked near present day Kalbarri, is the only Dutch East India Company ship to have run into the coast of the Australian mainland rather than on a reef or island.

Mr Carpenter said ships wreck because they are in the wrong place either by human error or by loss of control. Working these sometimes dangerous locations can also pose challenges to marine archaeologists and conservators centuries later.

Diving on the Zuytdorp, at the base of coastal cliffs, was one area where the diving team had to be aware of the risks and take particular caution.

Mr Carpenter said while the objects have been recovered from many shipwrecks and after conservation displayed in museums some wrecks such as HMAS Sydney II are designated war graves and will remain untouched.

Jon Carpenter’s presentation: Shipwreck to Showcase is available to view on WAMSI’s YouTube channel.

 

 

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.

 

 

 

‘More than just teeth’: Shark Deck inspires respect for sharks

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Spotting a shark while snorkelling as a child then, in a flash, realising it was gone was an early lesson on these supposed ‘monsters of the deep’ for marine biologist Dr Charlotte Birkmanis.

“I was 10 when I first saw a shark and I remember thinking that here was an animal that I’m supposed to be afraid of, but it couldn’t get away fast enough,” Dr Birkmanis said.

It fuelled a passion for ocean life in the scientist, who recently released Shark Deck, featuring 50 species of sharks with images of sharks on one side and information, including their diet, size, and one of her ‘fin facts’ on the back.

When the Director of the philanthropic Jock Clough Marine Foundation wrote Shark Deck, she made a point of including lesser-known species as well as the better-known tiger and great white sharks.

“There are more than 530 species of sharks in the world, yet we commonly only hear about a handful of them,” she said.

The variety is extraordinary —there is the bus-sized whale shark, the yellowish lemon shark and the tiny ‘glow in the dark’ pocket shark.

“The more I have learned about sharks, the more I am fascinated by them and I love sharing this with others through books, radio and television,” Dr Birkmanis said.

“I do a lot of public talks and interviews about sharks and our oceans, and I try to get people to think about sharks as more than just their teeth. I like to remind them the largest sharks eat plankton.”

Despite the facts about the animals, headlines scream about sharks stalking, lurking, attacking and prowling. They are described as rogues and monsters.

Many have alarmingly low populations and are threatened so Dr Birkmanis was delighted when The Washington Post recommended Shark Deck as “engaging” with “cool facts about the shark’s biology, habitat, range and more”.

Dr Birkmanis, an Adjunct Research Fellow at The University of Western Australia’s Oceans Institute, said the interest shown for the animals when she gives talks to schools and community groups and shares information on television and in social media was encouraging. So much so she’s been given the title of ‘PR Manager for sharks’.

“I think there is a genuine interest in sharks, but a lot of the scientific material is inaccessible,” she said.

Dr Birkmanis has tagged and dived with sharks across the Indian Ocean, in places such as the Chagos, Mozambique and South Africa, including white sharks.

“The way they move is incredible,” Dr Birkmanis said.

She is now continuing her research on sharks as a Postdoctoral Research Fellow with the Max Planck Centre, looking at shark movement, behaviour and how they may even be able to help us heal.

The Shark Deck follows Dr Birkmanis’ children’s book Little Shark Lulu is sleeping, a fun fact-filled fable about what goes on in the ocean when the sun goes down, told through the eyes of a little shark named Lulu. Notably Lulu has no teeth.