Curious Kids: why are there waves?



Nina Maile Gordon/The Conversation, CC BY-NC-ND

Mark Hemer, CSIRO

Curious Kids is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.


Why are there waves? – Evie, age 5.


Thanks for a great question, Evie.

When you look at the waves breaking at the beach, those waves might be at the end of a long journey. The waves might have been created thousands of kilometres away, or they could have been created near you.

There are lots of types of waves in the ocean, but the waves you usually see at a beach are created by the wind. When the wind blows over a smooth ocean, it creates little waves or ripples on the surface. If the wind continues to blow, the waves grow bigger.

A big wave lands at Dee Why Beach in Sydney.
Taro Taylor/Flickr, CC BY



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Faster, bigger, longer

The faster the wind blows (like in a strong storm out at sea), the bigger the waves will grow.

The further the wind blows (or the bigger the area of the storm), the bigger the waves will grow.

And the longer the wind blows (like in a storm that lasts a long time), the bigger the waves will grow.

If the wind stops, or changes direction, the waves will stop growing, but they won’t stop travelling.

They will keep travelling away from where they were created in a straight line, sometimes for days, until they run into something like a beach where they are stopped because they break. That’s why there are still waves at the beach, even when it is not windy.

Waves trip over themselves

Imagine you were running really quickly. But then suddenly, you ran into thick gloopy mud. Your feet would slow down, but the top half of your body would still be going fast. You’d trip over.

Waves do the same thing and that is when they break.

As waves approach the shore, the water is shallower, and the bottom of the wave starts to feel the sand and rocks and seaweed. The bottom of the wave slows down, and soon, the top of the wave is going faster than the bottom part of the wave, so the top spills forward and topples over in a big splash.

This wave is breaking over the top of the surfer because the top half of the wave is travelling faster than the bottom half.
Flickr/Duncan Rawlinson – Duncan.co – @thelastminute, CC BY

Waves can travel a long way

Scientists who study the ocean (called oceanographers) have measured waves created in the Southern Ocean, and seen them travel all the way across the Pacific Ocean and break on the beaches of North America more than a week later.

Try counting the seconds between waves breaking on the beach. If the time between waves is 10 seconds or more, the waves have come from a long way away. If the waves were created nearby, the time between waves will be short, perhaps five seconds or fewer.

Sometimes when we look at the sea we might see different waves (some big, some small) all happening at the same time. These waves were created at different places, perhaps by different storms, but ended up in the same spot at the same time.

Freak waves

During big storms, waves can get very big. If big waves from two different storms meet together, that can create enormous waves that we call “freak waves”. The largest waves measured are around 25 metres high (that’s five giraffes standing on top of each other!) and they can tip over ships.




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Curious Kids: How do plastic bags harm our environment and sea life?


Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au


CC BY-ND

Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.The Conversation

Mark Hemer, Senior Research Scientist, Oceans and Atmosphere, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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‘Bright white skeletons’: some Western Australian reefs have the lowest coral cover on record


Corals at Scott Reef in 2012, and at the same site during the 2016 mass bleaching.
James Gilmour/AIMS

James Paton Gilmour, Australian Institute of Marine Science and Rebecca Green, University of Western Australia

Diving on the remote coral reefs in the north of Western Australia during the world’s worst bleaching event in 2016, the first thing I noticed was the heat. It was like diving into a warm bath, with surface temperatures of 34⁰C.

Then I noticed the expanse of bleached colonies. Their bright white skeletons were visible through the translucent tissue following the loss of the algae with which they share a biological relationship. The coral skeletons had not yet eroded and collapsed, a grim reminder of what it looked like just a few months before.

I spent the past 15 years documenting the recovery of these reefs following the first global coral bleaching event in 1998, only to see them devastated again in the third global bleaching event in 2016.




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Western Australia’s coral reefs are in trouble: we mustn’t ignore them


The WA coral reefs may not be as well known as the Great Barrier Reef, but they’re just as large and diverse. And they too have been affected by cyclones and coral bleaching. Our recent study found many WA reefs now have the lowest coral cover on record.

When my colleague, Rebecca Green, witnessed that mass bleaching for the first time, she asked me how long it would take the reefs to recover.

“Probably not in my lifetime” was my reply – an abrupt but accurate reply considering the previous rate of recovery, future increases in ocean temperatures … and my age.

The worst mass bleaching on record

A similar scene is playing out around the world as researchers document the decline of ecosystems they have spent a lifetime studying.

Our study, published in the journal Coral Reefs, is the first to establish a long-term history of changes in coral cover across eight reef systems, and to document the effects of the 2016 mass bleaching event at 401 sites across WA.




Read more:
The third global bleaching event took its toll on Western Australia’s super-corals


Given the vast expanse of WA coral reefs, our assessment included data from several monitoring programs and researchers from 19 institutions.

These reefs exist in some of the most remote and inaccessible parts of the
world, so our study also relied on important observations of coral bleaching from regional managers, tourist operators and Bardi Jawi Indigenous Rangers in the Kimberley.

Our aim was to establish the effects of climate change on coral reefs along Western Australia’s vast coastline and their current condition.

The heat stress in 2016 was the worst on record, causing mass bleaching and large reductions in coral cover at Christmas Island, Ashmore Reef and Scott Reef. This was also the first time mass bleaching was recorded in the southern parts of the inshore Kimberley region, including in the long oral history of Indigenous Australians who have managed this sea-country for thousands of years.

The mass bleaching events we documented were triggered by a global increase in temperature of 1⁰C above pre-industrial levels, whereas temperatures are predicted to rise by 1.5⁰C between 2030 and 2052.

In that scenario, the reefs that have bleached badly will unlikely have the capacity to fully recover, and mass bleaching will occur at the reefs that have so far escaped the worst impacts.




Read more:
The world’s coral reefs are in trouble, but don’t give up on them yet


The future of WA’s coral reefs is uncertain, but until carbon emissions can be reduced, coral bleaching will continue to increase.

Surviving coral reef refuges must be protected

The extreme El Niño conditions in 2016 severely affected the northern reefs, and a similar pattern was seen in the long-term records.

The more southern reefs were affected by extreme La Niña conditions – most significantly by a heatwave in 2011 that caused coral bleaching, impacted fisheries and devastated other marine and terrestrial ecosystems.

Since 2010, all of WA’s reefs systems have bleached at least once.

Frequent bleaching and cyclone damage have stalled the recovery of reefs at Shark Bay, Ningaloo and at the Montebello and Barrow Islands. And coral cover at Scott Reef, Ashmore Reef and at Christmas Island is low following the 2016 mass bleaching.

In fact, average coral cover at most (75%) reef systems is at or near the lowest on record. But not all WA reefs have been affected equally.

In 2016 there was little (around 10%) bleaching recorded at the northern inshore Kimberley Reefs, at the Cocos Keeling Islands, and at the Rowley Shoals. Coral cover and diversity at these reefs remain high.

And during mass bleaching there were patches of reef that were less affected by heat stress.

These patches of reef will hopefully escape the worst impacts and retain moderate coral cover and diversity as the world warms, acting as refuges. There are also corals that have adapted to survive in parts of the reef where temperatures are naturally hotter.

Some reefs across WA will persist, thanks to these refuges from heat stress, their ability to adapt and to expand their range. These refuges must be protected from any additional stress, such as poor water quality and overfishing.




Read more:
Even the super-corals of Australia’s Kimberley are not immune to climate change


In any case, the longer it takes to curb carbon emissions and other pressures to coral reefs, the greater the loss will be.

Coral reefs support critical food stocks for fisheries around the world and provide a significant contribution to Australia’s Blue Economy, worth an estimated A$68.1 billion.

We are handing environmental uncertainty to the next generation of scientists, and we must better articulate to everyone that their dependence on nature is the most fundamental of all the scientific concepts we explore.The Conversation

James Paton Gilmour, Research Scientist: Coral Ecology, Australian Institute of Marine Science and Rebecca Green, Postdoctoral research associate, University of Western Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

From sharks in seagrass to manatees in mangroves, we’ve found large marine species in some surprising places


Michael Sievers, Griffith University; Rod Connolly, Griffith University, and Tom Rayner, Griffith University

When we think of mangrove forests, seagrass meadows and saltmarshes, we don’t immediately think of shark habitats. But the first global review of links between large marine animals (megafauna) and coastal wetlands is challenging this view – and how we might respond to the biodiversity crisis.

Mangrove forests, seagrass meadows and saltmarshes support rich biodiversity, underpin the livelihoods of more than a billion people worldwide, store carbon, and protect us from extreme weather events.

Mangrove forests, seagrass meadows and saltmarshes are the three key vegetated habitats found in coastal wetlands.
Tom Rayner/www.shutterstock.com

We know marine megafauna also use these habitats to live, feed and breed. Green turtles and manatees, for instance, are known to eat seagrass, and dolphins hunt in mangroves.

But new associations are also being discovered. The bonnethead shark – a close relative of hammerheads – was recently found to eat and digest seagrass.




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The problem is that we’re losing these important places. And until now, we’ve underestimated how important they are for large, charismatic and ecologically important marine animals.

Counting wetland megafauna

Today our review of the connections between marine megafauna and vegetated coastal wetlands was published in the journal Trends in Ecology and Evolution. As it turns out, far more megafauna species use coastal wetlands than we thought.


Author provided/The Conversation, CC BY-ND

Before our review, the number of marine megafauna species known to use these habitats was 110, according to the International Union for Conservation of Nature (IUCN) Red List, which assesses species’ conservation status.

We identified another 64 species from 340 published studies, bringing the total number to 174 species. This means 13% of all marine megafauna use vegetated coastal wetlands.

We predominantly documented these habitat associations by electronic tracking, direct observation or from analysing stomach contents or chemical tracers in animal tissues.

Less commonly, acoustic recordings and animal-borne video studies – strapping a camera on the back of turtle, for instance – were used.

Deepening our understanding of how species use their habitats

In recent weeks, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) released a damming assessment of humanity’s stewardship of the natural world. Up to 1 million species were reported to be facing extinction within decades.




Read more:
‘Revolutionary change’ needed to stop unprecedented global extinction crisis


We need to dramatically change how we relate to and engage with species and their habitats, if we are to fix this problem.

But the question is, how can we make global change real, relevant and feasible at local and regional scales? And, as the international community rises to this challenge, what information is needed to support such efforts?

Our study suggests a critical first step to addressing the global biodiversity crisis is to deepen our understanding of links between species and their habitats. We also need to elevate how the evidence is used to both assess extinction risk and prioritise, plan and deliver conservation actions.

A juvenile lemon shark swimming in mangroves. More than half of the world’s coastal wetlands have been lost.
Shutterstock

More than half of all coastal wetlands have been lost globally and the rest are at risk from a range of serious threats, including deforestation. There is an urgent need to limit and reverse the loss of coastal wetlands to stop biodiversity loss, protect communities and tackle climate change.

Targeting places where high rates of mangrove loss intersect with threatened megafauna could lead to more efficient and effective conservation outcomes. Southeast Asia, Mexico and northern Brazil are such places.

In Southeast Asia, for example, the world’s largest mangrove forest is losing trees at a rate far exceeding global averages, largely due to aquaculture and agriculture. This is threatening the critically endangered green sawfish, which relies on these mangrove habitats.

Habitats should always be considered in assessments

The IUCN Red List assesses the extinction risk for almost 100,000 species. It provides comprehensive information on global conservation statuses, combining information on population sizes, trends and threats.

The wealth of data collected during species’ assessments, including habitat associations of threatened species, is one of the Red List’s most valuable features.

But our study shows many known associations are yet to be included. And for more than half of the assessments for marine megafauna, habitat change is yet to be listed as a threat.

‘Proportion species’ refers to all species within key taxonomic groups that are associated with coastal wetlands.
Author supplied

This is concerning because assessments that overlook habitat associations or lack sufficient detail, may not allow conservation resources be directed at the most effective recovery measures.

But it’s also important to note habitat associations have varying strengths and degrees of supporting evidence. For example, a population of animals shown to consume substantial amounts of seagrass is clearly a stronger ecological link than an individual simply being observed above seagrass.

The data on habitat associations must be strengthened in species assessments.
Shutterstock

In our paper, we propose a simple framework to address these issues, by clarifying habitat associations in conservation assessments. Ideally, these assessments would include the following:

  • list all habitat types the species is known to associate with
  • indicate the type of association (occurrence, grazing, foraging or breeding)
  • cite the source of supporting evidence
  • provide an estimate of the level of habitat dependence.

Data for decision making

Habitat loss is accelerating a global extinction crisis, but the importance of coastal habitats to marine megafauna has been significantly undervalued in assessments of extinction risk.

We need to strive to protect remaining coastal wetland habitats, not only for their ecological role, but also for their economic, social and cultural values to humans. We can do this by strengthening how we use existing scientific data on habitat associations in species assessments and conservation planning.The Conversation

Michael Sievers, Research Fellow, Global Wetlands Project, Australia Rivers Institute, Griffith University; Rod Connolly, Professor in Marine Science, Griffith University, and Tom Rayner, Science Communicator, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How we used CRISPR to narrow in on a possible antidote to box jellyfish venom



File 20190430 136800 u6bay2.jpg?ixlib=rb 1.1
Venom from box jellyfish causes extreme pain and tissue damage. Massive exposure can cause death.
from www.shutterstock.com

Greg Neely, University of Sydney

Warm Australian waters are home to the box jellyfish (Chironex fleckeri), which is considered to be one of the most venomous animals on the planet.

Box jellyfish stings lead to excruciating pain lasting days, tissue death and scarring at the site of the sting, and with significant exposure, death within minutes. While most jellyfish stings do not lead to death, pain and scarring is quite common.




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Despite its potent ability to cause pain and death, to date we’ve had very little understanding of how this deadly venom works. This makes it very difficult to understand how it can cause so much pain – and how to develop medicines to block venom actions.

Published today, our new research has uncovered a potential antidote for box jellyfish venom. By working with humans cells and the gene-editing tool CRISPR, we identified a common, cheap drug that is already on the market and which could be a candidate for treating box jellyfish stings.

Flipping all the switches

This work began in 2012, when we set out to determine what it was about box jellyfish venom molecules that made them so effective in causing pain and damage.

The venom didn’t seem to work through the known pathways that cause cell death. So we used CRISPR genome editing technologies in human cells grown in the laboratory. This let us systematically turn off each gene in the human genome, and test to see which of these is needed for the jellyfish venom to kill the cells.




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It’s kind of like flipping all the switches in a house, trying to figure out which one turns off the kitchen lights, but at the whole genome level. We actually didn’t even know if it would be possible to find single genes that when turned off could block the venom action.

But luckily, we were successful. While normal human cells exposed to venom die in the laboratory within five minutes, we identified gene-edited cells that could last for two weeks continually exposed to venom.

Putting the evidence together

Then using new DNA sequencing technologies (that allow us to identify CRISPR guide RNAs targeting specific genes), we identified which human genes had been switched off in our genome editing experiments.

By putting the evidence together, we worked out which genes the box jellyfish venom needs to target in order to kill human cells in the lab.

One we identified is a calcium transporter molecule called ATP2B1, and is present on the surface of cells.

We tested a drug that we know targets this gene. If we added the drug before the venom, we could block cell death, but if we added the drug after the venom, it didn’t have any effect.

So this helped us understand more about how the venom works – and maybe even how it causes pain. We are still looking at this particular pathway in more detail, but at the moment it doesn’t seem promising for a therapy.




Read more:
Going to the beach this Easter? Here are four ways we’re not being properly protected from jellyfish


Stopping cell death

Next we looked at the pathways involved in how box jellyfish venom kills cells.

We found four of the top ten genes required for venom action were all part of a pathway that makes cholesterol in cells.

Since cholesterol has been heavily studied over the last 30 years, there are already drugs available that target lots of different steps in cholesterol regulation. We focused on drugs that could bind to cholesterol and remove it quickly, basically acting like a cholesterol sponge.

We found these drugs could completely block the box jelly fish venom’s ability to kill human cells in the lab if added before venom exposure. We also found there is a 15-minute window after venom exposure where if we add this cholesterol sponge, it still blocks venom action.

This was exciting, as the capacity to have effect after the venom means the drug could work as a treatment in the case of being stung by a box jellyfish.

So far our additional studies show that these same drugs can block pain, tissue death and scarring associated with a mouse model of box jellyfish stings.

Moving towards a human treatment

The really cool thing about this work is that the potential box jellyfish antidote we found is in a family of drugs called cyclodextrins. These are known to be safe for us in humans, and are cheap and stable.

So now we are trying to work with the state or national government, or first responders, to see if we can move this venom antidote forward for human use.

As well as developing a topical application at the site of a sting, we also aim to develop this idea as a potential treatment for cardiac injection in the emergency room in the case of very severe box jellyfish sting cases.The Conversation

Greg Neely, Associate Professor , University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Going to the beach this Easter? Here are four ways we’re not being properly protected from jellyfish



File 20190312 86717 1gbl6mw.jpg?ixlib=rb 1.1
Thousands of Queensland beachgoers have been stung by bluebottle jellyfish in recent months.
Shutterstock

Lynda Crowley-Cyr, University of Southern Queensland and Lisa-ann Gershwin, CSIRO

The Easter long weekend marks the last opportunity this year for many Australians to go to the beach as the weather cools down. And for some, particularly in Queensland, it means dodging bluebottle tentacles on the sand.

In just over a month this summer, bluebottles stung more than 22,000 people across Queensland, largely at beaches in the southeast. At least eight of these stings required hospitalisation.

To make matters worse, there were more than twice the number of Irukandji jellyfish stings in Queensland than is typically reported for this time of the season. Irukandjis – relatives of the lethal box jellyfish – cause “Irukandji syndrome”, a life-threatening illness.




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Venomous jellyfish can lurk beneath Australia’s picturesque beaches, including in the Whitsundays. Better public awareness is vital.
alexmgn/Shutterstock

There have also been widespread reports that Irukandjis have been migrating southwards. Many reports have assumed there is a southward migration linked to climate change. But Australia’s jellyfish problem is far more complex. Despite the media hype, there exists no evidence that any tropical Irukandji species has migrated, or is migrating, south.

In addition, many people find it surprising to learn there are Irukandji species native to southern waters. Many cases of Irukandji syndrome have been recorded in Moreton Bay (since 1893), New South Wales (since 1905), and even as far south as Queenscliff, near Geelong (in 1998).

So amid the misinformation, pain and misery, why is this jellyfish problem not more effectively managed?




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What is being done to manage jellyfish risks?

In North Queensland, coastal councils have grappled with jellyfish risk for decades.

At popular beaches in the Cairns, Townsville, and Whitsunday regions, visitors are offered protection in the form of lifeguard patrols and stinger nets. Beaches are also peppered with marine stinger warning signs.

But these strategies are not as effective as intended. Stinger nets, for instance, protect people against the larger, deadlier box jellyfish, but not against the tiny Irukandji.

There’s a lack of public awareness about many aspects of stinger safety. For example, that Irukandji can enter the nets; that Irukandji may be encountered on the reefs and islands as well as in many types of weather conditions; and that both Irukandjis and box jellies are typically very difficult to spot in the water.

To make matters worse, visitors, especially international tourists, are completely unaware of these types of hazards at all. This was confirmed in a recently published study that found marine stinger warning signs are not effectively communicating the true risk.

These signs comply with the requirements established by Standards Australia, but do not fully meet research-based design guidelines for effective warning signage.

The high number of stings that continue to occur at patrolled beaches highlights the need for a redesign.




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Reef operators share a similar problem.

Workplace Health and Safety legislation requires businesses for recreational water activities to do all they reasonably can to protect their staff and customers from health and safety risks.

Jellyfish risk management is only mentioned in the Code of Practice applying to diving and snorkelling businesses. But jellyfish stings continue to be widely reported, raising questions about the effectiveness of this law and its applicability to businesses for other water activities like jet skiing, kayaking, and resort watersports.

Can jellyfish risk management improve?

Absolutely! But only with more data and communication about the risks of jellyfish.

A newly established independent Marine Stinger Authority, based in Cairns, will be well positioned to provide all coastal councils, government and tourism organisations, and the wider public with updated research, information and consultation on jellyfish risks in Australia.




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Why your tourist brain may try to drown you


A warning sign at a Queensland beach.
Shutterstock

It’s a good start, and all current strategies provide a level of protection, but there is room for improvement. We have identified the following points as the highest priority:

1. a national reporting system

A national reporting system to capture real-time data about stings. This would inform coastal councils, tourism operators and other stakeholders so they can better protect the public and meet their duty of care.

Such a system has been partially developed by CSIRO, but this has ceased. We are seeking funding to resume development and implementation of this critical public safety tool.

2. improved warning signage

Modification of jellyfish warning signs should be consistent with research-based design guidelines.

Effective signs should, among other things: be noticeable and include a signal-word panel with “WARNING” in appropriate size and coulours to alert of the hazard; be easy to read, including by international visitors; include a well-designed pictogram indicating scale of hazardous jellyfish; and include hazard information, its consequences and how to avoid it.

Any modifications would also need to be monitored to ensure the signs are properly understood where deployed.

3. an updated Code of Practice

The Work Health and Safety Code of Practice should be amended to include all businesses for recreational water activities and make jellyfish risk management mandatory.

4. safety messaging research

More research is needed to better understand the effectiveness of jellyfish management strategies, taking into account the diverse cultural expectations and
languages of visitors at different destinations.

For this Easter break, here a few safety tips for beachgoers:

  • plan ahead and be aware of local conditions

  • don’t touch bluebottles or other jellyfish (they can still sting out of the water)

  • wear stinger protective clothing like a full body lycra suit (a “rashy”) or neoprene wet suit (especially in tropical areas)

  • pack a bottle of vinegar in your beach bag, boat or boot of the car

  • get local advice on recent stings (from lifeguards or tour operators).The Conversation

Lynda Crowley-Cyr, Associae Professsor of Law, University of Southern Queensland and Lisa-ann Gershwin, Research scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

There’s no ‘garbage patch’ in the Southern Indian Ocean, so where does all the rubbish go?


File 20190401 177175 1wvztzj.jpg?ixlib=rb 1.1
Plastic waste on a remote beach in Sri Lanka.
Author provided

Mirjam van der Mheen, University of Western Australia; Charitha Pattiaratchi, University of Western Australia, and Erik van Sebille, Utrecht University

Great areas of our rubbish are known to form in parts of the Pacific and Atlantic oceans. But no such “garbage patch” has been found in the Southern Indian Ocean.

Our research – published recently in Journal of Geophysical Research: Oceans – looked at why that’s the case, and what happens to the rubbish that gets dumped in this particular area.

Every year, up to 15 million tonnes of plastic waste is estimated to make its way into the ocean through coastlines (about 12.5 million tonnes) and rivers (about 2.5 million tonnes). This amount is expected to double by 2025.




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Some of this waste sinks in the ocean, some is washed up on beaches, and some floats on the ocean surface, transported by currents.

The garbage patches

As plastic materials are extremely durable, floating plastic waste can travel great distances in the ocean. Some floating plastics collect in the centre of subtropical circulating currents known as gyres, between 20 to 40 degrees north and south, to create these garbage patches.

The Great Pacific Garbage Patch.
National Oceanic and Atmospheric Administration

Here, the ocean currents converge at the centre of the gyre and sink. But the floating plastic material remains at the surface, allowing it to concentrate in these regions.

The best known of these garbage patches is the Great Pacific Garbage Patch, which contains about 80,000 tonnes of plastic waste. As the National Oceanic and Atmospheric Administration points out, the “patches” are not actually clumped collections of easy-to-see debris, but concentrations of litter (mostly small pieces of floating plastic).

Similar, but smaller, patches exist in the North and South Atlantic Oceans and the South Pacific Ocean. In total, it is estimated that only 1% of all plastic waste that enters the ocean is trapped in the garbage patches. It is still a mystery what happens to the remaining 99% of plastic waste that has entered the ocean.

Rubbish in the Indian Ocean

Even less is known about what happens to plastic in the Indian Ocean, although it receives the largest input of plastic material globally.

For example, it has been estimated that up to 90% of the global riverine input of plastic waste originates from Asia. The input of plastics to the Southern Indian Ocean is mainly through Indonesia. The Australian contribution is small.

The major sources of riverine input of plastic material into the Indian Ocean.
The Ocean Cleanup, CC BY-NC-ND

The Indian Ocean has many unique characteristics compared with the other ocean basins. The most striking factor is the presence of the Asian continental landmass, which results in the absence of a northern ocean basin and generates monsoon winds.

As a result of the former, there is no gyre in the Northern Indian Ocean, and so there is no garbage patch. The latter results in reversing ocean surface currents.

The Indian and Pacific Oceans are connected through the Indonesian Archipelago, which allows for warmer, less salty water to be transported from the Pacific to the Indian via a phenomenon called the Indonesian Throughflow (see graphic, below).

Schematic currents and location of a leaky garbage patch in the southern Indian Ocean: Indonesian Throughflow (ITF), Leeuwin Current (LC), South Indian Counter Current (SICC), Agulhas Current (AC).
Author provided

This connection also results in the formation of the Leeuwin Current, a poleward (towards the South Pole) current that flows alongside Australia’s west coast.

As a result, the Southern Indian Ocean has poleward currents on both eastern and western margins of the ocean basin.

Also, the South Indian Counter Current flows eastwards across the entire width of the Southern Indian Ocean, through the centre of the subtropical gyre, from the southern tip of Madagascar to Australia.

The African continent ends at around 35 degrees south, which provides a connection between the southern Indian and Atlantic Oceans.

How to follow that rubbish

In contrast to other ocean basins, the Indian Ocean is under-sampled, with only a few measurements of plastic material available. As technology to remotely track plastics does not yet exist, we need to use indirect ways to determine the fate of plastic in the Indian Ocean.

We used information from more than 22,000 satellite-tracked surface drifting buoys that have been released all over the world’s oceans since 1979. This allowed us to simulate pathways of plastic waste globally, with an emphasis on the Indian Ocean.

Global simulated concentration of floating waste after 50 years.
Mirjam van der Mheen, Author provided

We found that unique characteristics of the Southern Indian Ocean transport floating plastics towards the ocean’s western side, where it leaks past South Africa into the South Atlantic Ocean.

Because of the Asian monsoon system, the southeast trade winds in the Southern Indian Ocean are stronger than the trade winds in the Pacific and Atlantic Oceans. These strong winds push floating plastic material further to the west in the Southern Indian Ocean than they do in the other oceans.

So the rubbish goes where?

This allows the floating plastic to leak more readily from the Southern Indian Ocean into the South Atlantic Ocean. All these factors contribute to an ill-defined garbage patch in the Southern Indian Ocean.

Simulated concentration of floating waste over 50 years in the Indian Ocean.

In the Northern Indian Ocean our simulations showed there may be an accumulation of waste in the Bay of Bengal.




Read more:
‘Missing plastic’ in the oceans can be found below the surface


It is also likely that floating plastics will ultimately end up on beaches all around the Indian Ocean, transported by the reversing monsoon winds and currents. Which beaches will be most heavily affected is still unclear, and will probably depend on the monsoon season.

Our study shows that the atmospheric and oceanic attributes of the Indian Ocean are different to other ocean basins and that there may not be a concentrated garbage patch. Therefore the mystery of all the missing plastic is even greater in the Indian Ocean.The Conversation

Mirjam van der Mheen, PhD Candidate in Oceanography, University of Western Australia; Charitha Pattiaratchi, Professor of Coastal Oceanography, University of Western Australia, and Erik van Sebille, Associate Professor in Oceanography and Climate Change, Utrecht University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Squid team finds high species diversity off Kermadec Islands, part of stalled marine reserve proposal



File 20190308 150693 xpab44.jpg?ixlib=rb 1.1
This squid belongs to one of the families (Histioteuthidae) that is highly diverse but was not previously recorded from the Kermadecs.
Richard Young, CC BY-SA

Kat Bolstad, Auckland University of Technology and Heather Braid, Auckland University of Technology

Squids and octopuses could be considered the “parrots of the ocean”. Some are smart, and many have complex behaviours. And, of course, they have strange, bird-like beaks.

They are the subject of ancient myths and legends about sea monsters, but they do not live for decades. In fact, their high intelligence and short lifespan represent an unusual paradox.

In our latest research we have discovered several new species that have never been reported from New Zealand waters. Our study almost doubles the known diversity for the Kermadec region, north of New Zealand, which is part of the proposed, but stalled, Kermadec–Rangitāhua ocean sanctuary.




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More than we bargained for

Collectively, squids and octopuses are known as cephalopods, because their limbs attach directly to their head (cephalus). Our team studies cephalopods in our part of the world – the waters between Antarctica and the most northern reaches of New Zealand, the Kermadec Islands – as well as further afield.

Our first inkling of an impressive regional diversity came as we began to open boxes of frozen cephalopod samples at the National Institute for Water and Atmospheric Research (NIWA). These animals had been collected during a deep-sea survey voyage to the Kermadec Islands to better understand the region’s marine biodiversity. Members of the AUT Lab for Cephalopod Ecology and Systematics (ALCES), also known as the “squid lab”, had come to identify and examine them.

As we gently defrosted each specimen, we marvelled at their perfect suckers, iridescent eyes, and shining light organs. We noticed that many species were rare among New Zealand collections. There were some familiar faces, but also some we had only rarely or never encountered before in our local waters. Some were known from neighbouring regions; others, we suspected, might be entirely new to science.

We examined them, photographed each one, took small samples of muscle tissue for DNA analysis, and preserved them for additional work in the future. Then we set about systematically comparing our observations with what had previously been reported in New Zealand waters. And we were in for a surprise.

Doubling known diversity

Among the 150 cephalopod specimens that were collected, we identified 43 species, including 13 species that had not been previously found anywhere in New Zealand waters. Three entire orders – the taxonomic rank above family, which is the level at which, for example, egg-laying mammals split off from all other living mammals – had not been reported from this region: “Bobtail squids” (sepiolids), “comb-fin squids” (genus Chtenopteryx, order Bathyteuthoidea), and myopsid squids (coastal squids with eyes covered by a cornea).

We extracted DNA and obtained sequences for the species that had been seen for the first time in New Zealand waters. This allows us to compare them with individuals from other regions of the world. These included the strange tubercle-covered “glass” (cranchiid) squid Cranchia scabra, and the little “ram’s horn squid” Spirula spirula.

Examples of squid specimens collected recently from the Kermadec Islands Ridge: A) Histioteuthis miranda, B) Heteroteuthis sp. ‘KER’ (likely new to science), C) Chtenopteryx sp. ‘KER1’ (likely new to science), D) Leachia sp. (likely new to science), E) Pyroteuthis serrata, F) Enoploteuthis semilineata. Scale bars: 5mm.
Images by Rob Stewart/Keren Spong, CC BY-ND

Five species appear likely new to science, across a number of families with colourful common names such as “strawberry” and “fire” squids (Histioteuthidae and Pyroteuthidae, respectively). These individuals were genetically distinct from all other specimens that had been previously identified and sequenced (by us or others). Their physical appearances will now need to be compared in detail with other similar-looking species in order to fully evaluate their taxonomic status.

In total, 28 of the species we encountered had not previously been reported in the Kermadecs. This brings the total number of species in the region to at least 70. Of these, half are not known to occur elsewhere in New Zealand waters.

Kermadec–Rangitāhua Ocean Sanctuary

The Kermadec Islands, north-north-east of New Zealand, represent a diverse and nearly pristine environment. The region includes (among other habitats) a chain of seamounts and the second-deepest ocean trench in the world.

Currently, the Kermadec Islands region is on a tentative list of UNESCO World Heritage Sites. A small proportion of the area is already protected by an existing marine reserve, which extends 12 nautical miles around each of five islands and pinnacles.

This map shows New Zealand’s Exclusive Economic Zone (EEZ) in light grey, the existing Kermadec Islands marine reserve in dark grey, and the proposed Kermadec–Rangitāhua Ocean Sanctuary outlined in black.
Heather Braid, Kat Bolstad, CC BY-ND

The proposed Kermadec–Rangitāhua Ocean Sanctuary would extend the protection to 200 nautical miles and protect 15% of New Zealand’s ocean environment. It would be among the world’s largest marine protected areas.




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We strongly support the establishment of the proposed sanctuary, especially since most of the cephalopod taxa newly reported by this research are deep-sea species whose habitat is not protected by the existing marine reserve.

Although the creation of the sanctuary is supported by most political parties, New Zealand First, which is part of the government coalition, opposes it. So does the fishing industry because fishing would be banned. It is possible that the sanctuary might be created with a lower level of protection than originally proposed (with some fishing still permitted), but the government has reached an impasse.

If the Kermadec–Rangitāhua ocean sanctuary were to be established, it would protect habitats that are used by over half of the known squid and octopus biodiversity in New Zealand waters, including 34 species that have so far only been reported from the Kermadec region.The Conversation

Kat Bolstad, Senior Lecturer, Auckland University of Technology and Heather Braid, Postdoctoral Research Fellow, Auckland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.