China’s Belt and Road mega-plan may devastate the world’s oceans, or help save them



Shutterstock

Mischa Turschwell, Griffith University; Christopher Brown, Griffith University, and Ryan M. Pearson, Griffith University

China’s signature foreign policy, the Belt and Road initiative, has garnered much attention and controversy. Many have voiced fears about how the huge infrastructure project might expand China’s military and political influence across the world. But the environmental damage potentially wrought by the project has received scant attention.

The policy aims to connect China with Europe, East Africa and the rest of Asia, via a massive network of land and maritime routes. It includes building a series of deepwater ports, dubbed a “string of pearls”, to create secure and efficient sea transport.

All up, the cost of investments associated with the project have been estimated at as much as US$8 trillion. But what about the environmental cost?

Coastal development typically damages habitats and species on land and in the sea. So the Belt and Road plan may irreversibly damage the world’s oceans – but it also offers a chance to better protect them.

A map showing sea and land routes planned under the Belt and Road initiative.
A map showing sea and land routes planned under the Belt and Road initiative.
Shutterstock

Controversial deals

China’s President Xi Jinping announced the Belt and Road initiative in 2013. Since then, China has already helped build and operate at least 42 ports in 34 countries, including in Greece, Sri Lanka and Pakistan. As of October this year, 138 countries had signed onto the plan.

The Victorian government joined in 2018, in a move that stirred political controversy. Those tensions have heightened in recent weeks, as the federal government’s relationship with China deteriorates.




Read more:
Why is there so much furore over China’s Belt and Road Initiative?


Victorian Premier Daniel Andrews recently reiterated his commitment to the deal, saying: “I think a strong relationship and a strong partnership with China is very, very important.”

However, political leaders signing up to the Belt and Road plan must also consider the potential environmental consequences of the project.

Dan Andrews in Beijing
Victorian Premier Daniel Andrews is committed to the Belt and Road initiative.
Twitter

Bigger ports and more ships

As well as ports, the Belt and Road plan involves roads, rail lines, dams, airfields, pipelines, cargo centres and telecommunications systems. Our research has focused specifically on the planned port development and expansion, and increased shipping traffic. We examined how it would affect coastal habitats (such as seagrass, mangroves, and saltmarsh), coral reefs and threatened marine species.

Port construction can impact species and habitats in several ways. For example, developing a site often requires clearing mangroves and other coastal habitats. This can harm animals and release carbon stored by these productive ecosystems, accelerating climate change. Clearing coastal vegetation can also increase run-off of pollution from land into coastal waters.




Read more:
Ships moved more than 11 billion tonnes of our stuff around the globe last year, and it’s killing the climate. This week is a chance to change


Ongoing dredging to maintain shipping channels stirs up sediment from the seafloor. This sediment smothers sensitive habitats such as seagrass and coral and damages wildlife, including fishery species on which many coastal communities depend.

A rise in shipping traffic associated with trade expansion increases the risk to animals being directly struck by vessels. More ships also means a greater risk of shipping accidents, such as the oil spill in Mauritius in July this year.

Seagrass in the Pacific Ocean
Dredging can cause sediment to smother seagrass.
iStock

Ocean habitat destroyed

Our spatial analysis found construction of new ports, and expansion of existing ports, could lead to a loss of coastal marine habitat equivalent in size to 69,500 football fields.

These impacts were proportionally highest in small countries with relatively small coastal areas – places such as Singapore, Togo, Djibouti and Malta – where a considerable share of coastal marine habitat could be degraded or destroyed.

Habitat loss is particularly concerning for small nations where local livelihoods depend on coastal habitats. For example, mangroves, coral reefs, and seagrass protect coasts from storm surges and sea-level rise, and provide nursery habitat for fish and other marine species.

Our analysis also found more than 400 threatened species, including mammals, could be affected by port infrastructure. More than 200 of these are at risk from an increase in shipping traffic and noise pollution from ships. This sound can travel many kilometres and affect the mating, nursing and feeding of species such as dolphins, manatees and whales.

A manatee
Noise pollution from ships can affect threatened species such as manatees.
Shutterstock

But there are opportunities, too

Despite these environmental concerns, the Belt and Road initiative also offers an opportunity to improve biodiversity conservation, and progress towards environmental targets such as the United Nations’ Sustainable Development Goals.

For example, China could implement a broad, consistent environmental framework that ensures individual infrastructure projects are held to the same high standards.

In Australia, legislation helps prevent damage to wildlife from port activities. For example, go-slow zones minimise the likelihood of vessels striking iconic wildlife such as turtles and dugongs. Similarly, protocols for the transport, handling, and export of mineral concentrates and other potentially hazardous materials minimise the risk of pollutants entering waterways.




Read more:
China just stunned the world with its step-up on climate action – and the implications for Australia may be huge


The Belt and Road initiative should require similar environmental protections across all its partner countries, and provide funding to ensure they are enacted.

China has recently sought to boost its environment credentials on the world stage – such as by adopting a target of net-zero carbon emissions by 2060. The global nature of the Belt and Road initiative means China is in a unique position: it can cause widespread damage, or become an international leader on environmental protection.The Conversation

Mischa Turschwell, Research Fellow, Griffith University; Christopher Brown, Senior Lecturer, School of Environment and Science, Griffith University, and Ryan M. Pearson, Research Fellow, Griffith University

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

Gene editing is revealing how corals respond to warming waters. It could transform how we manage our reefs



Mikaela Nordborg/Australian Institute of Marine Science, Author provided

Dimitri Perrin, Queensland University of Technology; Jacob Bradford, Queensland University of Technology; Line K Bay, Australian Institute of Marine Science, and Phillip Cleves, Carnegie Institution for Science

Genetic engineering has already cemented itself as an invaluable tool for studying gene functions in organisms.

Our new study, published in the Proceedings of the National Academy of Sciences, now demonstrates how gene editing can be used to pinpoint genes involved in corals’ ability to withstand heat stress.

A better understanding of such genes will lay the groundwork for experts to predict the natural response of coral populations to climate change. And this could guide efforts to improve coral adaptation, through the selective breeding of naturally heat-tolerant corals.

A threatened national treasure

The Great Barrier Reef is among the world’s most awe-inspiring, unique and economically valuable ecosystems. It spans more than 2,000 kilometres, has more than 600 types of coral, 1,600 types of fish and is of immense cultural significance — especially for Traditional Owners.

But warming ocean waters caused by climate change are leading to the mass bleaching and mortality of corals on the reef, threatening the reef’s long-term survival.




Read more:
The first step to conserving the Great Barrier Reef is understanding what lives there


Many research efforts are focused on how we can prevent the reef’s deterioration by helping it adapt to and recover from the conditions causing it stress.

Understanding the genes and molecular pathways that protect corals from heat stress will be key to achieving these goals.

While hypotheses exist about the roles of particular genes and pathways, rigorous testings of these have been difficult — largely due to a lack of tools to determine gene function in corals.

But over the past decade or so, CRISPR/Cas9 gene editing has emerged as a powerful tool to study gene function in non-model organisms.

CRISPR: a technological marvel

Scientists can use CRISPR to make precise changes to the DNA of a living organisms, by “cutting” its DNA and editing the sequence. This can involve inactivating a specific gene, introducing a new piece of DNA or replacing a piece.

In our 2018 research, we showed it is possible to make precise mutations in the coral genome using CRISPR technology. However, we were unable to determine the functions of our specific target genes.

For our latest research, we used an updated CRISPR method to sufficiently disrupt the Heat Shock Transcription Factor 1, or HSF1, in coral larvae.

Based on this protein-coding gene’s role in model organisms, including closely related sea anemones, we hypothesised it would play an important role in the heat response of corals.

Injection going into coral egg.
We injected CRISPR components into the fertilised eggs of the coral species Acropora millepora to inactivate the HSF1 gene.
Phillip Cleves/Carnegie Institute for Science, CC BY-NC-ND

Past research had also demonstrated HSF1 can influence a large number of heat response genes, acting as a kind of “master switch” to turn them on.

By inactivating this master switch, we expected to see significant changes in the corals’ heat tolerance. Our prediction proved accurate.




Read more:
What is CRISPR, the gene editing technology that won the Chemistry Nobel prize?


What we discovered by injecting coral eggs

We spawned corals at the Australian Institute of Marine Science during the annual mass spawning event in November, 2018.

We then injected CRISPR/Cas9 components into fertilised coral eggs to target the HSF1 gene in the common and widespread staghorn coral Acropora millepora.

_Acropora millepora_ coral colony during a mass spawning event.
Acropora millepora colonies can be found widely on the Great Barrier Reef. They reproduce sexually in ‘mass spawning’ events.
Mikaela Nordborg/Australian Institute of Marine Science, Author provided

We were able to demonstrate a strong effect of HSF1 on corals’ heat tolerance. Specifically, when this gene was mutated using CRISPR (and no longer functional) the corals were more vulnerable to heat stress.

Larvae with knocked-out copies of HSF1 died under heat stress when the water temperature was increased from 27℃ to 34℃. In contrast, larvae with the functional gene survived well in the warmer water.

Let’s understand what we already have

It may be tempting now to focus on using gene-editing tools to engineer heat-resistant strains of corals, to fast-track the Great Barrier Reef’s adaptation to warming waters.

However, genetic engineering should first and foremost be used to increase our knowledge of the fundamental biology of corals and other reef organisms, including their response to heat stress.

Not only will this help us more accurately predict the natural response of coral reefs to a changing climate, it will also shed light on the risks and benefits of new management tools for corals, such as selective breeding.

It is our hope these genetic insights will provide a solid foundation for future reef conservation and management efforts.The Conversation

During mass spawning events, corals release little balls that float to the ocean’s surface in a spectacle resembling an upside-down snowstorm.

Dimitri Perrin, Senior Lecturer, Queensland University of Technology; Jacob Bradford, , Queensland University of Technology; Line K Bay, Principal Research Scientist and Team Leader, Australian Institute of Marine Science, and Phillip Cleves, Principal Investigator, Carnegie Institution for Science

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

Photos from the field: these magnificent whales are adapting to warming water, but how much can they take?



Olaf Meynecke, Author provided

Olaf Meynecke, Griffith University

Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this new series, we’ve invited them to share their unique photos from the field.


The start of November marks the end of the whale season in the Southern Hemisphere. As summer approaches, whales that were breeding along the east and west coasts of Australia, Africa and South America will now swim further south to feed around Antarctica.

This annual cycle of whales coming and going has taken place for at least 10,000 years. But rising ocean temperatures from climate change are challenging this process, and my colleagues and I have already seen signs that humpback whales are changing their feeding, migration and breeding patterns to adapt.




Read more:
Genome and satellite technology reveal recovery rates and impacts of climate change on southern right whales


As krill stocks decline and ocean circulation is set to change more drastically, climate change remains an unprecedented threat to whales. The challenge now is to forecast what will happen next to better protect them.

Losing krill is the biggest threat

I’m part of an international team of researchers trying to learn what the next 100 years might look like for humpback whales in the Southern Hemisphere, and how they’ll adapt to changing ocean conditions.

Whales depend on recurring environmental conditions and oceanographic features, such as temperature, circulation, changing seasons and biogeochemical (nutrient) cycles. In particular, these features influence the availability of krill in the Southern Ocean, their biggest food source.

Whales are particularly sensitive to this because they need enormous amounts of food to develop sufficient fat reserves to migrate, give birth and nurse a calf, as they don’t eat during this time.

In fact, models predict declines in krill from climate change could lead to local extinctions of whales by 2100. This includes Pacific populations of blue, fin and southern right whales, as well as fin and humpback whales in the Atlantic and Indian oceans.




Read more:
Climate change threatens Antarctic krill and the sea life that depends on it


Still, when it comes to their migration and breeding cycles, recent studies have shown humpback whales can adapt with changes in ocean temperature and circulation at a remarkable level.

Whales can adapt to warming water, but at what cost?

In a long term study from the Northern Hemisphere, scientists found the arrival of humpback whales in some feeding grounds shifted by one day per year over a 27-year period in response to small fluctuations in ocean temperatures.

This led to a one-month shift in arrival time, but a big concern is whether they can continue to time their arrival with their prey in the future when the water gets warmer still.

Likewise, in breeding grounds near Hawaii, the number of mother and calf humpback whale sightings dropped by more than 75% between 2013 and 2018. This coincided with persistent warming in the Alaskan feeding grounds these whales had migrated from.

Collecting humpback whale exhale (“whale snot”)

But humpback whales shifting their distribution and behaviour can cause unexpected human encounters, and cause new challenges that weren’t an issue previously.

Research from earlier this year found humpback whales switched to fish as their main prey when the sea surface temperature in the California current system increased in a heatwave. This has been leading to record numbers of entanglements with gear from coastal fisheries.




Read more:
I measure whales with drones to find out if they’re fat enough to breed


And between 2013 and 2016, we documented hundreds of newborn humpback whales in subtropical and temperate shallow bays on the east coast of Australia, 1,000 kilometres further south from their traditional breeding areas off the Great Barrier Reef.

However, since these aren’t designated calving areas, the newborns aren’t well protected from getting tangled in shark nets or colliding with jet skis or cruise ships.

Protecting whales

The Whales and Climate Program is the largest project of its kind, combining hundreds of thousands of humpback whale sightings and advanced modelling techniques. Our aim is to advance whale conservation in response to climate change, and learn how it threatens their recovery after decades of over-exploitation by the whaling industry.

Each whale season between June and October, I sail out to the open ocean. This means I have unique opportunities to see and engage with whales, especially during the breeding season. The following photos show some of our breathtaking encounters, and can remind us of our marine ecosystem’s fragile beauty.

A humpback whale fin

Olaf Meynecke, Author provided
Breaching humpback whale in front of buildings

Olaf Meynecke, Author provided

During one of our boat-based surveys on the Gold Coast, we encountered this acrobatic humpback whale calf, shown in the photos above. We counted 254 breaches in two hours, making it the record holder of most breaches in our 10 years of observation.

To check on whales’ health, we collect and study the air they exhale through their blow hole (“whale snot”), and measure their size at different times of the year. The photo above shows me tagging a whale with CATs suction cup tags, to collect data on short term changes in their movement patterns.

Close up of a humpback whale's mouth

Olaf Meynecke, Author provided

In regions where the whales adapt to ocean changes and, as such, move closer to shore for feeding and shift their breeding grounds, there’s a higher risk of entanglements and other human encounters. This is particularly concerning when they travel outside protected areas.

A newborn humpback whale resting on its mum's head

Olaf Meynecke, Author provided

Look closely and you can see a newborn humpback, just one to three days old, resting on its mother’s head.

In the first days of life, baby humpback whales sink easily and aren’t able to stay on the water surface for long. They need their mothers’ support to stay on the surface to breathe.

Once they’ve gained enough fat from the mothers milk they become positively buoyant (meaning they can float), making it easier for them to breathe.

Photo of a whale underwater

Olaf Meynecke, Author provided

A final note — during one of our land-based whale surveys this year, a keen whale watcher approached us, and we helped him find the whales with our binoculars. I will never forget the joy in his face when he spotted them.

It’s a joy I hope many future generations can experience. To ensure this, we need to understand how we can best protect whales in a changing climate.




Read more:
Photos from the field: capturing the grandeur and heartbreak of Tasmania’s giant trees


The Conversation


Olaf Meynecke, Research Fellow in Marine Science, Griffith University

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

We estimate there are up to 14 million tonnes of microplastics on the seafloor. It’s worse than we thought



Shutterstock

Britta Denise Hardesty, CSIRO; Chris Wilcox, CSIRO, and Justine Barrett, CSIRO

Nowhere, it seems, is immune from plastic pollution: plastic has been reported in the high Arctic oceans, in the sea ice around Antarctica and even in the world’s deepest waters of the Mariana Trench.

But just how bad is the problem? Our new research provides the first global estimate of microplastics on the seafloor — our research suggests there’s a staggering 8-14 million tonnes of it.

This is up to 35 times more than the estimated weight of plastic pollution on the ocean’s surface.

What’s more, plastic production and pollution is expected to increase in coming years, despite increased media, government and scientific attention on how plastic pollution can harm marine ecosystems, wildlife and human health.

These findings are yet another wake-up call. When the plastic we use in our daily lives reaches even the deepest oceans, it’s more urgent than ever to find ways to clean up our mess before it reaches the ocean, or to stop making so much of it in the first place.

Breaking down larger plastic

Our estimate of microplastics on the seafloor is huge, but it’s still a fraction of the amount of plastic dumped into the ocean. Between 4-8 million tonnes of plastic are thought to enter the sea each and every year.




Read more:
Eight million tonnes of plastic are going into the ocean each year


Most of the plastic dumped into the ocean likely ends up on the coasts, not floating around the ocean’s surface or on the seafloor. In fact, three-quarters of the rubbish found along Australia’s coastlines is plastics.

A dead albatross with plastic in its stomach from Midway Atoll
Plastic including toothbrushes, cigarette lighters, bottle caps and other hard plastic fragments are found in the stomachs of many marine species.
Britta Denise Hardesty

The larger pieces of plastic that stay in the ocean can deteriorate and break down from weathering and mechanical forces, such as ocean waves. Eventually, this material turns into microplastics, pieces smaller than 5 millimetres in diameter.

Their tiny size means they can be eaten by a variety of marine wildlife, from plankton to crustaceans and fish. And when microplastics enter the marine food web at low levels, it can move up the food chain as bigger species eat smaller ones.

But the problem isn’t as well documented for microplastics on the seafloor. While plastics, including microplastics, have been found in deep-sea sediments in all ocean basins across the world, samples have been small and scarce. This is where our research comes in.

Collecting samples in the Great Australian Bight

We collected samples using a robotic submarine in a range of sea depths, from 1,655 to 3,062 metres, in the Great Australian Bight, up to 380 kilometres offshore from South Australia. The submarine scooped up 51 samples of sand and sediment from the seafloor and we analysed them in a laboratory.

Sampling of deep sea sediments took place using an underwater robot.
CSIRO, Author provided

We dried the sediment samples, and found between zero and 13.6 plastic particles per gram. This is up to 25 times more microplastics than previous deep-sea studies. And it’s much higher than studies in other regions, including in the Arctic and Indian Oceans.

While our study looked at one general area, we can scale up to calculate a global estimate of microplastics on the seafloor.

Using the estimated size of the entire ocean — 361,132,000 square kilometres — and the average number and size of particles in our sediment samples, we determined the total, global weight as between 8.4 and 14.4 million tonnes. This range takes into account the possible weights of individual microplastics.

How did the plastic get there?

It’s important to note that since our location was remote, far from any urban population centre, this is a conservative estimate. Yet, we were surprised at just how high the microplastic loads were there.

Plastic waste floating in the ocean
Areas with floating rubbish on the ocean’s surface have plastic on the seafloor.
Shutterstock

Few studies have conclusively identified how microplastics travel to their ultimate fate.

Larger pieces of plastic that get broken down to smaller pieces can sink to the seafloor, and ocean currents and the natural movement of sediment along continental shelves can transport them widely.

But not all plastic sinks. A 2016 study suggests interaction with marine organisms is another possible transport method.

Scientists in the US have shown microbial communities, such as bacteria, can inhabit this marine “plastisphere” — a term for the ecosystems that live in plastic environments. The microbes weigh the plastic down so it no longer floats. We also know mussels and other invertebrates may colonise floating plastics, adding weight to make them sink.




Read more:
Plastic pollution creates new oceanic microbe ecosystem


The type of rubbish will also determine whether it gets washed up on the beach or sinks to the seafloor.

For example, in a previous study we found cigarette butts, plastic fragments, bottlecaps and food wrappers are common on land, though rare on the seabed. Meanwhile, we found entangling items such fishing line, ropes and plastic bags are common on the seafloor.

Microplastics at the water's edge
We were surprised at just how high the microplastic loads were in such a remote location.
CSIRO

Interestingly, in our new study we also found the number of plastic fragments on the seafloor was generally higher in areas where there was floating rubbish on the ocean’s surface. This suggests surface “hotspots” may be reflected below.

It’s not clear why just yet, but it could be because of the geology and physical features of the seabed, or because local currents, winds and waves result in accumulating zones on the ocean’s surface and the seabed nearby.

Stop using so much plastic

Knowing how much plastic sinks to the ocean floor is an important addition to our understanding of the plastic pollution crisis. But stemming the rising tide of plastic pollution starts with individuals, communities and governments – we all have a role to play.

Reusing, refusing and recycling are good places to start. Seek alternatives and support programs, such as Clean Up Australia Day, to stop plastic waste from entering our environment in the first place, ensuring it doesn’t then become embedded in our precious oceans.




Read more:
The oceans are full of our plastic – here’s what we can do about it


The Conversation


Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO; Chris Wilcox, Senior Principal Research Scientist, CSIRO, and Justine Barrett, Research assistant, CSIRO

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

The ocean is swimming in plastic and it’s getting worse – we need connected global policies now



Fotos593 / shutterstock

Steve Fletcher, University of Portsmouth and Keiron Philip Roberts, University of Portsmouth

It seems you cannot go a day without reading about the impact of plastic in our oceans, and for good reason. The equivalent of a garbage truck of plastic waste enters the sea every minute, and this increases every day. If we do nothing, by 2040 the amount of plastic entering the ocean will triple from 13 million tonnes this year, to 29 million tonnes in 2040. That is 50kg of waste plastic entering the ocean for every metre of coastline.

Add to that almost all the plastic that has entered the ocean is still there since it takes centuries to break down. It is either buried or broken down into smaller pieces and potentially passes up the food chain creating further problems.

Despite this, plastic has also been a saviour. During the COVID-19 pandemic plastic used in face masks, testing kits, screens and to protecting food has enabled countries to come out of lockdown during and support social distancing. We still need to use these items until sustainable and “COVID safe” alternatives are available. But we also need to look to the future to reduce our dependence on plastic and its impact on the environment. With plastic in the ocean being a global problem, we need global agreements and policies to reverse the plastic tide.




Read more:
Rubbish is piling up and recycling has stalled – waste systems must adapt


Ambitious policies are needed

Environment ministers of the G20 group of the world’s most economically powerful countries and regions met on September 16 to discuss their immediate challenges, with marine plastic pollution a top priority. A key item for discussion was “safeguarding the planet by fostering collective efforts to protect our global commons”. This means working out how we can continue to use the planet’s resources sustainably without harming the environment.

A global analysis of plastics policies over the past two decades found that typical reactions to marine plastic litter were bans or taxes on individual or groups of plastic items within single countries. So far, 43 countries have introduced a ban, tax or levy on plastic bags. Other plastic packaging or single-use plastic products were banned in at least 25 countries, representing a population of almost 2 billion people in 2018.

But plastic waste doesn’t respect land or ocean borders, with mismanaged plastic waste easily migrating from country to country when leaked into the environment. Policies also need to consider the entire plastics life cycle to stand a chance of being effective. For example, the inclusion of easier to recycle plastics in consumer products sounds positive, but their actual recycling rate depends on effective sorting and collection of plastic waste, and appropriate infrastructure being in place.




Read more:
What happens to the plastic you recycle? Researchers lift the lid


Ultimately, a joined up but adaptable set of rules and guidelines are needed so all plastic producers and users can prevent its leakage across all stages of the plastics life cycle.

The G20 has sought to lead action on marine plastic litter through a 2017 Action Plan on Marine Litter which set out areas of concern and possible policy interventions, and through connections to initiatives such as the UN Environment Programme’s Global Partnership on Marine Litter and most recently the Osaka Blue Ocean Vision. The Osaka vision was agreed under the Japanese G20 presidency in 2019 and commits countries to “reduce additional pollution by marine plastic litter to zero by 2050”. Although an agreement led by the G20, it now has the support of 86 countries.

But even with these agreements in place, plastic entering the ocean will still only reduce by 7% by 2040. We need ambitious new agreements as current and emerging policies do not meet the scale of the challenge.

A consensus is forming that the G20 and other global leaders must focus on a systemic change of the plastics economy. This includes focusing on “designing out” plastics, promoting technical and business innovation, immediately scaling up actions known to reduce marine plastic litter, and transitioning to a circular economy in which materials are fully recovered and reused. These actions have the potential to contribute to the G20’s vision of net-zero plastics entering the ocean by 2050, but only if ambitious actions are taken now.The Conversation

Steve Fletcher, Professor of Ocean Policy and Economy, University of Portsmouth and Keiron Philip Roberts, Research Fellow in Clean Carbon Technologies and Resource Management, University of Portsmouth

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

For decades, scientists puzzled over the plastic ‘missing’ from our oceans – but now it’s been found


Britta Denise Hardesty, CSIRO and Chris Wilcox, CSIRO

You’ve probably heard that our oceans have become a plastic soup. But in fact, of all the plastic that enters Earth’s oceans each year, just 1% has been observed floating on the surface. So where is the rest of it?

This “missing” plastic has been a longstanding scientific question. To date, the search has focused on oceanic gyres such as the Great Pacific Garbage Patch, the water column (the part of the ocean between the surface and the sea bed), the bottom of the ocean, and the stomachs of marine wildlife.

But our new research suggests ocean plastic is being transported back onshore and pushed permanently onto land away from the water’s edge, where it often becomes trapped in vegetation.

Of course, plastic has been reported on beaches around the world for decades. But there has been little focus on why and how coastal environments are a sink for marine debris. Our findings have big implications for how we tackle ocean plastic.

New research shows a significant amount of plastic pollution from our oceans ends up back on land, where it gets trapped.

The hunt for marine pollution

Our separate, yet-to-be-published research has found around 90% of marine debris that enters the ocean remains in the “littoral zone” (the area of ocean within 8km of the coast). This new study set out to discover what happens to it.

We collected data on the amount and location of plastic pollution every 100 kilometres around the entire coast of Australia between 2011 and 2016. Debris was recorded at 188 locations along the Australian coastline. Of this, 56% was plastic, followed by glass (17%) and foam (10%).

Data was recorded approximately every 100 kilometres along the coast of Australia. Of the marine debris recorded, more than half was plastic.

The debris was a mix of litter from people and deposition from the ocean. The highest concentrations of plastic pollution were found along coastal backshores – areas towards the inland edge of the beach, where the vegetation begins. The further back from the water’s edge we went, the more debris we found.

The amount of marine debris, and where it ends up, is influenced by onshore wave activity and, to a lesser extent, wind activity. Densely populated areas and those where the coast was easily accessible were hotspots for trapped plastics.




Read more:
Stop shaming and start empowering: advertisers must rethink their plastic waste message


Think about what you see on your beach. Smaller debris is often found near the water’s edge, while larger items such as drink bottles, plastic bags and crisp packets are often found further back from the water, often trapped in vegetation.

We also found more debris near urban areas where rivers and creeks enter the ocean. It could be that our trash is being trapped by waterways before it gets to the sea. We’re finding similar patterns in other countries we’re surveying around the Asia Pacific and beyond.

This pollution kills and maims wildlife when they mistake it for food or get tangled in it. It can damage fragile marine ecosystems by smothering sensitive reefs and transporting invasive species and is potentially a threat to human health if toxins in plastics make their way through the food chain to humans.

It can also become an eyesore, damaging the economy of an area through reduced tourism revenue.

Onshore waves, wind and areas with denser human populations influences where and how much marine debris there is along our coastlines.
CSIRO

Talking rubbish

Our findings highlight the importance of studying the entire width of coastal areas to better understand how much, and where, debris gets trapped, to inform targeted approaches to managing all this waste.

Plastic pollution can be reduced through local changes such as water refill stations, rubbish bins, incentives and awareness campaigns. It can also be reduced through targeted waste management policies to reduce, reuse and recycle plastics. We found container deposit schemes to be a particularly effective incentive in reducing marine pollution.




Read more:
We organised a conference for 570 people without using plastic. Here’s how it went


This discussion is particularly timely. The National Plastics Summit in Canberra last week brought together governments, industry and non-government organisations to identify new solutions to the plastic waste challenge, and discuss how to meet targets under the National Waste Policy Action Plan. Understanding that so much of our debris remains local, and trapped on land, provides real opportunities for successful management of our waste close to the source. This is particularly critical given the waste export ban starting July 1 at the latest.

Plastic in our oceans is increasing. It’s clear from our research that waste management strategies on land must accommodate much larger volumes of pollution than previously estimated. But the best way to keep plastic from our ocean and land is to stop putting it in.

Arianna Olivelli contributed to this article, and the research upon which it was based.




Read more:
Here is a global solution to the plastic waste crisis – and A$443 million to get it started


The Conversation


Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO and Chris Wilcox, Senior Research Scientist, CSIRO

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

Why drought-busting rain depends on the tropical oceans


Andrew King, University of Melbourne; Andy Pitman, UNSW; Anna Ukkola, Australian National University; Ben Henley, University of Melbourne, and Josephine Brown, University of Melbourne

Recent helpful rains dampened fire grounds and gave many farmers a reason to cheer. But much of southeast Australia remains in severe drought.

Australia is no stranger to drought, but the current one stands out when looking at rainfall records over the past 120 years. This drought has been marked by three consecutive extremely dry winters in the Murray-Darling basin, which rank in the driest 10% of winters since 1900.

Despite recent rainfall the southeast of Australia remains in the grip of a multi-year drought.
Bureau of Meteorology

So what’s going on?

There has been much discussion on whether human-caused climate change is to blame. Our new study explores Australian droughts through a different lens.




Read more:
Rain has eased the dry, but more is needed to break the drought


Rather than focusing on what’s causing the dry conditions, we investigated why it’s been such a long time since we had widespread drought-breaking rain. And it’s got a lot to do with how the temperature varies in the Pacific and Indian Ocean.

Our findings suggest that while climate change does contribute to drought, blame can predominately be pointed at the absence of the Pacific Ocean’s La Niña and the negative Indian Ocean Dipole – climate drivers responsible for bringing wetter weather.

Understanding the Indian Ocean Dipole.

What’s the Indian Ocean Dipole?

As you may already know, the Pacific Ocean influences eastern Australia’s climate through El Niño conditions (associated with drier weather) and La Niña conditions (associated with wetter weather).

The lesser known cousin of El Niño and La Niña across the Indian Ocean is called the Indian Ocean Dipole. This refers to the difference in ocean temperature between the eastern and western sides of the Indian Ocean. It modulates winter and springtime rainfall in southeastern Australia.




Read more:
Dipole: the ‘Indian Niño’ that has brought devastating drought to East Africa


When the Indian Ocean Dipole is “negative”, there are warmer ocean temperatures in the east Indian Ocean, and we see more rain over much of Australia. The opposite is true for “positive” Indian Ocean Dipole events, which bring less rain.

The Murray-Darling Basin experiences high rainfall variability, with decade-long droughts common since observations began. The graph shows seasonal rainfall anomalies from a 1961-1990 average with major droughts marked.
Author provided

What does it mean for the drought?

When the drought started to take hold in 2017 and 2018, we didn’t experience an El Niño or strongly positive Indian Ocean Dipole event. These are two dry-weather conditions we might expect to see at the start of a drought.

Rather, conditions in the Pacific and Indian Oceans were near neutral, with little to suggest a drought would develop.

So why are we in severe, prolonged drought?

The problem is we haven’t had either a La Niña or a negative Indian Ocean Dipole event since winter 2016. Our study shows the lack of these events helps explain why eastern Australia is in drought.

For the southeast of Australia in particular, La Niña or negative Indian Ocean Dipole events provide the atmosphere with suitable conditions for persistent and widespread rainfall to occur. So while neither La Niña or a negative Indian Ocean Dipole guarantee heavy rainfall, they do increase the chances.

What about climate change?

While climate drivers are predominately causing this drought, climate change also contributes, though more work is needed to understand what role it specifically plays.

Drought is more complicated and multidimensional than simply “not much rain for a long time”. It can be measured with a raft of metrics beyond rainfall patterns, including metrics that look at humidity levels and evaporation rates.

What we do know is that climate change can exacerbate some of these metrics, which, in turn, can affect drought.




Read more:
Is Australia’s current drought caused by climate change? It’s complicated


Climate change might also influence climate drivers, though right now it’s hard to tell how. A 2015 study suggests that under climate change, La Niña events will become more extreme. Another study from earlier this month suggests climate change is driving more positive Indian Ocean Dipole events, bringing even more drought.

Unfortunately, regional-scale projections from climate models aren’t perfect and we can’t be sure how the ocean patterns that increase the chances of drought-breaking rains will change under global warming. What is clear is there’s a risk they will change, and strongly affect our rainfall.

Putting the drought in context

Long periods when a La Niña or a negative Indian Ocean Dipole event were absent characterised Australia’s past droughts. This includes two periods of more than three years that brought us the Second World War drought and the Millennium drought.

The longer the time without a La Niña or negative Indian Ocean Dipole event, the more likely the Murray-Darling Basin is in drought.

In the above graph, the longer each line continues before stopping, the longer the time since a La Niña or negative Indian Ocean Dipole event occurred. The lower the lines travel, the less rainfall was received in the Murray Darling basin during this period. This lets us compare the current drought to previous droughts.

During the current drought (black line) we see how the rainfall deficit continues for several years, almost identically to how the Millennium drought played out.

But then the deficit increases strongly in late 2019, when we had a strongly positive Indian Ocean Dipole.

So when will this drought break?

This is a hard question to answer. While recent rains have been helpful, we’ve developed a long-term rainfall deficit in the Murray-Darling Basin and elsewhere that will be hard to recover from without either a La Niña or negative Indian Ocean Dipole event.




Read more:
Weather bureau says hottest, driest year on record led to extreme bushfire season


The most recent seasonal forecasts don’t predict either a negative Indian Ocean Dipole or La Niña event forming in the next three months. However, accurate forecasts are difficult at this time of year as we approach the “autumn predictability barrier”.

This means, for the coming months, the drought probably won’t break. After that, it’s anyone’s guess. We can only hope conditions improve.The Conversation

Andrew King, ARC DECRA fellow, University of Melbourne; Andy Pitman, Director of the ARC Centre of Excellence for Climate System Science, UNSW; Anna Ukkola, Research Fellow, Australian National University; Ben Henley, Research Fellow in Climate and Water Resources, University of Melbourne, and Josephine Brown, Lecturer, University of Melbourne

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

Acidic oceans are corroding the tooth-like scales of shark skin



CT scan of a catshark hatchling head. Note the ridged scales.
Rory Cooper, Kyle Martin & Amin Garbout/Natural History Museum London, Author provided

Rory Cooper, University of Sheffield

Shark skin might look perfectly smooth, but inspect it under a microscope and you’ll notice something strange. The entire outer surface of a shark’s body is actually covered in sharp, little scales known as denticles. More remarkable still, these denticles are incredibly similar to human teeth, as they’re also comprised of dentine and enamel-like materials.

Your dentist will no doubt have warned you that acidic drinks like fizzy cola damage your teeth. This is because acid can dissolve the calcium and phosphate in the enamel tooth covering. For the first time, scientists have discovered a similar process acting on the tooth-like scales of sharks in the ocean.




Read more:
How we uncovered the feeding habits of sharks, thanks to plankton ‘post codes’


The carbon dioxide (CO₂) that humans release into the atmosphere doesn’t just heat the planet. As more of it dissolves in the ocean, it’s gradually increasing the acidity of seawater. In the past 200 years, the ocean has absorbed 525 billion tonnes of CO₂ and become 30% more acidic as a result. Now scientists worry that the lower pH is affecting one of the ocean’s top predators.

Denticles have sharp ridges and are arranged in an overlapping pattern, similar to chainmail.
Rory Cooper, Author provided

An unwelcome sea change

Over hundreds of millions of years, the denticles that make up shark skin have evolved to allow sharks to thrive in different environments. Different species have distinct denticle shapes and patterns that enable a range of remarkable functions. I’ve spent the last four years attempting to understand how the development of these scales is genetically controlled in shark embryos, and how their intricate details give each species an edge.

Denticles have highly specialised ridges which help reduce drag by up to 10%, allowing sharks to swim further and faster while using less energy. This works in a similar fashion to the ridges in the hulls of speed boats, which help the vessel move more efficiently through the water. In fact, these scales are so effective at reducing drag that scientists and engineers have long tried to create shark skin-inspired materials for boats and aircraft that can help them travel further on less fuel.

A catshark embryo about 80 days after fertilisation.
Rory Cooper, Kyle Martin & Amin Garbout/Natural History Museum London, Author provided

The patterning of denticles also works as a defensive armour, which protects sharks from their environment and from other predators. Some female sharks – such as the small-spotted catshark – have even developed a region of enlarged denticles which provide protection from a male shark’s bites during mating.

The changing chemistry of the ocean has been linked to coral bleaching, but its effect on other marine animals is less clear. To address this, researchers exposed puffadder shysharks – a species found off the coast of South Africa – to different levels of acidity in aquariums, and used a high-resolution imaging technique to examine the effect of acid exposure on their skin. After just nine weeks, they found that increased water acidity had weakened the surfaces of their denticles.

The puffadder shyshark (Haploblepharus edwardsii) is a slow moving species that lives on the sea floor.
Derekkeats/Wikipedia, CC BY-SA

Corrosion and weakening of the denticle surface could degrade the highly specialised drag-reducing ridges, affecting the ability of these sharks to swim and hunt. Many shark species are top-level predators, so if they’re not able to hunt as effectively, this might have an unpredictable impact on the population size of their prey and other animals in the complex marine environment. Some species of shark need to swim constantly to keep oxygen-rich water flowing over their gills and to expel CO₂ – another process which might be hindered by increased drag.




Read more:
Sharks: one in four habitats in remote open ocean threatened by longline fishing


Sharks belong to an ancient group of vertebrates known as the cartilaginous fishes, which split from the bony fishes – a lineage that later gave rise to humans – roughly 450 million years ago. Sharks, and other cartilaginous fish like rays, arose long before the dinosaurs, and have outlived multiple mass extinction events. But the rate of change in the marine environment over the last few centuries is an unprecedented challenge. These ancient predators may struggle to adapt to the fastest known change in ocean chemistry in the last 50 million years.The Conversation

Rory Cooper, PhD Researcher in Evolutionary Developmental Biology, University of Sheffield

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

Fish larvae float across national borders, binding the world’s oceans in a single network


Larval black sea bass, an important commercial species along the US Atlantic coast.
NOAA Fisheries/Ehren Habeck

Nandini Ramesh, University of California, Berkeley; James Rising, London School of Economics and Political Science, and Kimberly Oremus, University of Delaware

Fish populations are declining around the world, and many countries are trying to conserve them by regulating their fishing industries. However, controlling fishing locally may not do enough to strengthen fish populations. Often one nation’s fish stocks depend on the spawning grounds of a neighboring country, where fish release eggs and sperm into the water and larvae hatch from fertilized eggs.

We do research on oceans, climate and fisheries. In a recent study, we showed that global fisheries are even more tightly connected than previously understood. The world’s coastal marine fisheries form a single network, thanks to the drift of larvae along ocean currents.

This suggests that country-by-country fishery management may be fundamentally insufficient. If a fish species that provides food to one country should decline, the amount of fish spawn, or eggs and larvae, riding the ocean currents from there to other countries would also decline dramatically, resulting in further loss of fish elsewhere.

Many countries live with this risk, although they may not realize it. To manage fisheries effectively, nations must understand where the fish in their territories originate.

Ocean currents affect the speed at which fish eggs and larvae drift and vary through the year. This map shows surface current speeds for January: yellow = fastest, dark blue = slowest. Each country’s territory is highlighted with red dots during the month of maximum spawning activity in that country. In each territory, a different number of species spawn in each month of the year. The red dots appear in the month during which the largest number of species spawn in that territory.

Crossing national borders

Fish don’t recognize political boundaries, and regularly travel internationally. Scientists have tracked adult fish movements using electronic tags, and have shown that a few species migrate over long distances.

Countries and territories have negotiated agreements to ensure sustainable sharing of migratory fish. One such agreement joins several nations in the Western and Central Pacific Fisheries Commission to ensure that the territories fish cross share them sustainably.

But fish eggs and larvae are much harder to follow. Many species lay eggs in large numbers that float near the ocean surface. When they hatch, larvae measure a few millimeters long and continue to drift as plankton until they grow large enough to swim. During these stages of the life cycle, ocean currents sweep fish spawn across international boundaries.

Simulating the journeys of eggs and larvae

Like weather on land, the pattern of ocean currents varies with the seasons and can be predicted. These currents are typically sluggish, traveling about an inch per second, or less than 0.1 miles per hour.

There are a few exceptions: Currents along the eastern coasts of continents, like the Gulf Stream in North America or the Kuroshio in Asia, and along the equator can be significantly faster, reaching speeds of 2 miles per hour. Even a gentle current of 0.1 miles per hour can carry spawn 40 miles over a month, and some species can float for several months.

Government and academic scientists use a vast network of satellites, moored instruments and floating buoys to monitor these surface flows. Using this information, we performed a computer simulation of where drifting particles would be carried over time. Scientists have used this type of simulation to study the spread of marine plastic pollution and predict where debris from plane crashes at sea could have washed ashore.

Different fish species spawn in different seasons, and a single species may spawn in several months at different locations. We matched the seasons and locations of spawning for over 700 species with ocean current data, and simulated where their spawn would drift. Then, using records of where those species have been fished, and information about how suitable conditions are for each species in different regions, we deduced what fraction of the fish caught in each country arrived from other countries because of ocean currents.

A small-world network

Scientists and policymakers can learn a lot by studying these international connections. Each species that floats across international boundaries during its plankton stage represents a linkage between countries. These linkages span the world in a dense, interconnected network.

Each color represents a region in the network of fish larvae connections. This map shows the strongest 467 connections among a total of 2,059 that the authors modeled.
Nandini Ramesh, James Rising and Kimberly Oremus, CC BY-ND

At a global level, this network of connections has an important property: It is a small-world network. Small-world networks connect regions that are far apart to each other by just a few steps along the network. The concept is rooted in social scientist Stanley Milgram’s 1960s experiments with social networks, which found that it was possible for a letter to reach almost any total stranger by passing through six or fewer hands. Milgram’s work was popularized in the 1990 play “Six Degrees of Separation.”

Among fisheries, the world seems even smaller: We found that the average number of degrees of separation among fisheries is five. This means that local problems can become global risks.

For example, imagine that a fishery collapses in the middle of the Mediterranean. If the population in one spawning region collapses, it could quickly put pressure on neighboring fisheries dependent upon it. If fishers in those neighboring countries overfish the remaining population or shift to other species, the disturbance can grow. Within just a few years, a fisheries disturbance could travel around the world.

We assessed how countries would be affected in terms of food security, employment and gross domestic product if they were to lose access to fish spawn from other territories. The most affected countries cluster in the Caribbean, the western Pacific, Northern Europe and West Africa. These hotspots correspond to the network’s most clustered areas, because the effects of these flows of fish spawn are most pronounced where many coastal countries lie in close proximity.

International flows of fish eggs and larvae affect countries’ total catch, food security, jobs and economies.
Nandini Ramesh, James Rising and Kimberly Oremus, CC BY-ND

Thinking globally about fisheries

Because the world’s fisheries are so interconnected, only international cooperation that takes flows of fish spawn into account can effectively manage them. Aside from egg and larvae connections, fisheries are linked by movements of adult fish and through agreements among countries allowing them to fish in each other’s waters.

All of this suggests that fishery management is best conducted at a large, international scale. Proposals for doing this include defining Large Marine Ecosystems to be jointly managed and creating networks of Marine Protected Areas that safeguard a variety of critical habitats. Ideas like these, and careful study of interdependence between national fisheries, are crucial to sustainable use of the oceans’ living resources.

[ Expertise in your inbox. Sign up for The Conversation’s newsletter and get a digest of academic takes on today’s news, every day. ]The Conversation

Nandini Ramesh, Postdoctoral Researcher in Earth and Planetary Science, University of California, Berkeley; James Rising, Assistant Professorial Research Fellow, London School of Economics and Political Science, and Kimberly Oremus, Assistant Professor of Marine Policy, University of Delaware

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

Acid oceans are shrinking plankton, fuelling faster climate change



Researchers investigated how acidic oceans affect plankton in Prydz Bay, East Antarctica.
Daniel A. Nielsen, Author provided

Katherina Petrou, University of Technology Sydney and Daniel Nielsen, University of Technology Sydney

Increasingly acidic oceans are putting algae at risk, threatening the foundation of the entire marine food web.

Our research into the effects of CO₂-induced changes to microscopic ocean algae – called phytoplankton – was published today in Nature Climate Change. It has uncovered a previously unrecognised threat from ocean acidification.

In our study we discovered increased seawater acidity reduced Antarctic phytoplanktons’ ability to build strong cell walls, making them smaller and less effective at storing carbon. At current rates of seawater acidification, we could see this effect before the end of the century.




Read more:
Ocean acidification is already harming the Great Barrier Reef’s growth


What is ocean acidification?

Carbon dioxide emissions are not just altering our atmosphere. More than 40% of CO₂ emitted by people is absorbed by our oceans.

While reducing the CO₂ in our atmosphere is generally a good thing, the ugly consequence is this process makes seawater more acidic. Just as placing a tooth in a jar of cola will (eventually) dissolve it, increasingly acidic seawater has a devastating effect on organisms that build their bodies out of calcium, like corals and shellfish.

Many studies to date have therefore taken the perfectly logical step of studying the effects of seawater acidification on these “calcifying” creatures. However, we wanted to know if other, non-calcifying, species are at risk.

Diatoms in our oceans

Phytoplankton use photosynthesis to turn carbon in the atmosphere into carbon in their bodies. We looked at diatoms, a key group of phytoplankton responsible for 40% of this process in the ocean. Not only do they remove huge amounts of carbon, they also fuel entire marine food webs.

Diatoms use dissolved silica to build the walls of their cells. These dense, glass-like structures mean diatoms sink more quickly than other phytoplankton and therefore increase the transfer of carbon to the sea floor where it may be stored for millennia.

Diatoms are microscopic plant plankton that collectively remove huge amounts of carbon from the atmosphere.
Alyce M. Hancock, Author provided

This makes diatoms major players in the global carbon cycle. That’s why our team decided to look at how climate-change-driven ocean acidification might affect this process.

We exposed a natural Antarctic phytoplankton community to increasing levels of acidity. We then measured the rate at which the whole community used dissolved silica to build their cells, as well as the rates of individual species within the community.

More acid means less silicone

The more acidic the seawater, the more the diatom communities were made up of smaller species, reducing the total amount of silica they produced. Less silica means the diatoms aren’t heavy enough to sink quickly, reducing the rate at which they float down to the sea bed, safely storing carbon away from the atmosphere.

On examining individual cells, we found many of the species were highly sensitive to increased acidity, reducing their individual silicification rates by 35-80%. These results revealed not only are communities changing, but species that remain in the community are building less-dense cell walls.

Most alarming, many of the species were affected at ocean pH levels predicted for the end of this century, adding to a growing body of evidence showing significant ecological implications of climate change will take effect much sooner than previously anticipated.

Marine diversity is in decline

These losses in silica production could have far reaching consequences for the biology and chemistry of our oceans.

Many species affected are also an important component of the diet of the Antarctic krill, which is central to the Antarctic marine food web.

Fewer diatoms sinking to the ocean floor mean significant changes in silicon cycling and carbon burial. In a time when carbon drawn down by our ocean is crucial to helping sustain our atmospheric systems, any loss from this process will exacerbate CO₂ pollution.

Our new research adds yet another group of organisms to the list of climate change casualties. It emphasises the urgent need to reduce our dependency on fossil fuels.




Read more:
Our acid oceans will dissolve coral reef sands within decades


The only course of action to prevent catastrophic climate change is to stop emitting CO₂. We need to cut our emissions soon, if we hope to keep our oceans from becoming too acidic to sustain healthy marine ecosystems.The Conversation

Katherina Petrou, Senior Lecturer in Phytoplankton Ecophysiology, University of Technology Sydney and Daniel Nielsen, Casual Academic, University of Technology Sydney

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