Two-thirds of the world’s oceans fall outside national jurisdictions – they belong to no one and everyone.
These international waters, known as the high seas, harbour a plethora of natural resources and millions of unique marine species.
According to a 2019 global assessment report on biodiversity and ecosystem services, 66% of the world’s oceans are experiencing detrimental and increasing cumulative impacts from human activities.
In the high seas, human activities are regulated by a patchwork of international legal agreements under the 1982 UN Convention on the Law of the Sea (UNCLOS). But this piecemeal approach is failing to safeguard the ecosystems we depend on.
A decade ago, world leaders updated an earlier pledge to establish a network of marine protected areas (MPAs) with a mandate to protect 10% of the world’s oceans by 2020.
But MPAs cover only 7.66% of the ocean across the globe. Most protected sites are in national waters where it’s easy to implement and manage protection under the provision of a single country.
In the more remote areas of the high seas, only 1.18% of marine ecosystems have been gifted sanctuary.
The Southern Ocean accounts for a large portion of this meagre percentage, hosting two MPAs. The South Orkney Islands southern shelf MPA covers 94,000 square kilometres, while the Ross Sea region MPA stretches across more than 2 million square kilometres, making it the largest in the world.
The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is responsible for this achievement. Unlike other international fisheries management bodies, the commission’s legal convention allows for the closing of marine areas for conservation purposes.
A comparable mandate for MPAs in other areas of the high seas has been nowhere in sight — until now.
In 2017, the UN started negotiations towards a new comprehensive international treaty for the high seas. The treaty aims to improve the conservation and sustainable use of marine organisms in areas beyond national jurisdiction. It would also implement a global legal mechanism to establish MPAs in international waters.
This innovative international agreement provides an opportunity to work across institutional boundaries towards comprehensive high seas governance and protection. It is crucial to use lessons drawn from existing high seas marine protection initiatives, such as those in the Southern Ocean, to inform the treaty’s development.
The final round of treaty negotiations is pending, delayed by the COVID-19 pandemic, and significant detail within the treaty’s draft text remains undeveloped and open for further debate.
CCAMLR comprises 26 member states (including the European Union) and meets annually to make conservation-based decisions by unanimous consensus. In 2002, the commission committed to establishing a representative network of MPAs in Antarctica in alignment with globally agreed targets for the world’s oceans.
The two established MPAs in the high seas are far from an ecologically representative network of protection. In October 2020, the commission continued negotiations for three additional MPAs, which would meet the 10% target for the Southern Ocean, if agreed.
But not a single proposal was agreed. For one of the proposals, the East Antarctic MPA, this marks the eighth year of failed negotiations.
CCAMLR’s progress towards its commitment for a representative MPA network may have ground to a halt, but the commission has gained invaluable knowledge about the challenges in establishing MPAs in international waters. CCAMLR has demonstrated that with an effective convention and legal framework, MPAs in the high seas are possible.
The commission understands the extent to which robust scientific information must inform MPA proposals and how to navigate inevitable trade-offs between conservation and economic interests. Such knowledge is important for the UN treaty process.
As the high seas treaty moves closer to adoption, it stands to outpace the commission regarding progress towards improved marine conservation. Already, researchers have identified high-priority areas for protection in the high seas, including in Antarctica.
Many species cross the Southern Ocean boundary into other regions. This makes it even more important for CCAMLR to integrate its management across regional fisheries organisations – and the new treaty could facilitate this engagement.
But the window of time is closing with only one round of negotiation left for the UN treaty. Research tells us Antarctic decision-makers need to use the opportunity to ensure the treaty supports marine protection commitments.
Stronger Antarctic leadership is urgently needed to safeguard the Southern Ocean — and beyond.
In 2018, a map named after an oceanographer went viral.
The so-called Spilhaus projection, in which Earth is viewed from above the South Pole, was designed to show the connected nature of the ocean basins.
It is a perspective that comes naturally to those who live in the ocean-dominated southern hemisphere.
The Southern Ocean, also called the Antarctic Ocean (or even the Austral ocean), is like no other and best described in superlatives.
Let’s first look at the Southern Ocean’s capacity to store excess heat and carbon. The world’s oceans take up more than 90% of the excess heat generated by the burning of fossil fuels and a third of the additional carbon dioxide.
The Southern Ocean, south of 30°S, is estimated to store about 75% of this global oceanic uptake of excess heat and about 35% of the global uptake of excess carbon from the atmosphere. It is the primary storage of heat and carbon for the planet.
The Southern Ocean connects all major ocean basins, except the Arctic. The link is the Antarctic Circumpolar Current (ACC) – the largest ocean current on the planet. It carries more than 100 times the flow of all the rivers on Earth and transports enough water to fill Lake Ontario in just a few hours.
A combination of strong winds and a nearly uninterrupted passage around Antarctica give the ACC its strong flows and speed.
The Roaring Forties, Furious Fifties and Screaming Sixties are all popular names for the strong westerly winds that blow, nearly uninterrupted, across the Southern Ocean, creating equally impressive waves. This results in a massively energetic – and hard to measure – ocean surface.
But the heat and carbon exchanges across this complicated interface are globally important, and oceanographers have designed tools specifically for this challenging environment.
To really comprehend the Southern Ocean, one must think in three dimensions. Waters with different properties mix both horizontally and vertically in eddies.
Relatively warm subtropical water is mixed south, deep cool water from the North Atlantic rises back up toward the surface and colder polar water masses mix northward and sink back down.
This complex interplay is guided by the wind and by the shape of the seafloor.
To the north, there are only three major constrictions: the 850km-wide Drake Passage, and the submarine Kerguelan and Campbell Plateaus. To the south, the ACC butts up against Antarctica.
Here the ocean plays another crucial role in the global climate system by bringing relatively warm — and warming — Circumpolar Deep Water into contact with the ice fringing Antarctica.
The annual cycle of sea ice growing and melting around Antarctica is one of the defining rhythms of our planet and an important facet of the Southern Ocean. The two polar regions couldn’t be more different in this regard.
The Arctic is a small, deep ocean surrounded by land with only narrow exits. The Antarctic is a large landmass with a continental shelf surrounded by ocean. Each year, 15 million square kilometres of sea ice advance and retreat in these waters.
In contrast to the clear and dramatic changes in the north, the rhythm of Antarctic sea ice has followed less obvious patterns. In the face of a warming ocean, it was actually slowly expanding northward until around 2016, when it suddenly started to contract.
Looking at the annual cycle of Antarctic sea ice, one might think it simply grows and melts in place as things get cold and warmer through the year. But in truth, much of the sea ice production happens in polynya – sea ice factories near the coast where cold and fast Antarctic winds both create and blow away new sea ice as fast as it appears.
This process brings us back to global ocean circulation. When the new ice grows, the salt from the freezing sea water gets squeezed out and mixes with the seawater below, creating colder and saltier seawater that sinks to the seafloor and drains northward.
Polynya are in effect a metro stop on a global transport system that sees water sinking at the poles, flowing north to be mixed upwards in a cycle lasting close to 1,000 years.
Computer simulations have shown how the ice shelves at Antarctica’s fringe have waxed and waned over past millennia.
Because these floating extensions of the ice sheet interact directly with the ocean, they make the ice sheet sensitive to climate. Ocean warming and changes in the source of the water coming into contact with an ice shelf can cause it – and in turn the whole ice sheet – to change.
But not all ice shelves will respond to warming in the same way. Some ocean cavities are cold and slowly evolving. Others are actually described as hot – in polar terms – because of their interaction with Circumpolar Deep Water. The latter are changing rapidly right now.
We can observe many cryosphere processes from space, but to truly understand how far the ocean reaches beneath the ice we have to go hundreds of metres beneath the ice surface.
Making climate predictions requires an understanding of detailed processes that happen on short timescales, such as tidal cycles, in parts of the planet we are only beginning to explore.
How do we sample something so big and so stormy? With robots.
Satellites have been observing the ocean surface since the 1980s. This technology can measure properties such as temperature and ocean surface height, and even be used to estimate biological productivity. But satellites can’t see beneath the surface.
When the game-changing Argo programme started in the 1990s, it revolutionised earth science by building a network of drifting ocean sentinels measuring temperature and salinity down to a depth of two kilometres.
The research vessel Kaharoa holds the record for the most deployments of Argo probes in the Southern Ocean, including its most recent storm-tossed, COVID-19-impacted voyage south of Australia and into the Indian Ocean.
The Argo program is only the start of a new era of ocean observation. Deep Argo probes dive to depths of 6km to detect how far down ocean warming is penetrating.
Earth hasn’t always looked as it does today. At times in the planet’s past, the Southern Ocean didn’t even exist. Continents and ocean basins were in different positions and the climate system operated very differently.
From the narrow view of human evolution, the Southern Ocean has been a stable component of a climate system and subject to relatively benign glacial oscillations. But glacial cycles play out over tens of thousands of years.
We are imposing a very rapid climate transient. The nearly three centuries since the start of the industrial revolution is shorter than the blink of an eye in geological context.
Future changes in the short (say by 2050) and long (by 2300) term are difficult to project. While the physics are relatively clear about what will happen, predicting when it will happen is more challenging.
Simulation tools that get the ocean, atmosphere and ice processes right are only starting to include ice shelf cavities and ocean eddies. The most recent synthesis of climate models shows progress in the simulated workings of the Southern Ocean. But sea ice remains a challenge to simulate well.
This is the frontier: a global research community working to connect data with rapidly improving computer models to better understand how this unique ocean operates.
At first glance, Antarctica seems an inhospitable and almost barren environment of ice and snow, speckled with occasional seabirds and seals.
But diving beneath the surface reveals an ocean bursting with life and complex ecosystems, from single-celled algae and tiny spineless creatures to the well-known top predators: penguins, seals and whales.
The Southern Ocean is home to more than 9,000 known marine species — and expeditions and studies keep revealing more.
It’s not easy to study life in the Southern Ocean. Waves can be more than 20 metres high, and icebergs and sea ice lurk among them.
The water temperature is often sub-zero – freshwater freezes at 0℃, but saltwater freezes at closer to -2℃. Although scuba diving is possible, a lot of research on life in the Southern Ocean is done through remote sampling.
Marine scientists use robotic tools such as remotely operated underwater vehicles to look at and collect samples, and grabs and dredges to bring up bottom-dwelling organisms. We take genetic samples from marine mammals by shooting tiny biopsy tubes (like needles), attached to a cord for retrieval, into the animal’s flesh from a distance.
We can glean wider information on diversity from environmental DNA (eDNA). Traces of organisms are filtered from samples of water and analysed using genetic tools that can usually identify what sorts of species are or were present.
Every expedition reveals new species – some of which are potentially commercially valuable, and all of which are important parts of the Southern Ocean ecosystem. Our knowledge of the diversity of the region is growing rapidly.
Nonetheless, the Southern Ocean is vast, and much of it remains either unsampled or undersampled.
In the Southern Ocean, primary producers (organisms at the start of the food chain) range from single-celled algae – such as diatoms with intricately detailed shells made of silica – through to large macroalgae like kelp.
Kelp and other large seaweeds generally only survive where icebergs don’t often scrape the seafloor. Diatoms are diverse, and some species thrive on the underside of sea ice.
Ice algae form an important food source for krill, small crustaceans that are a critical part of Southern Ocean food webs.
Astonishingly, the cold Southern Ocean is also home to hot hydrothermal vent systems. These communities, which include huge densities of crustaceans and echinoderms, get their energy from chemicals that seep out of Earth’s crust, rather than from the Sun.
Antarctic invertebrates make up more than 90% of the species in the Southern Ocean. More than 50% are unique to this ocean.
These invertebrates are often much larger than their relatives in more northern, warmer waters. This phenomenon is know as “polar gigantism” and is found across many groups, with giant sea spiders, huge sponges and scale worms the size of a forearm.
Nobody is quite sure why Antarctic invertebrates grow so large, but it may be related to high oxygen levels, slow growth rates or the absence of key predatory groups such as sharks and brachyuran crabs.
In the marine food chain, Antarctic krill swim between the algal primary producers and the iconic top predators we always associate with Antarctica.
Baleen whales get much of their energy from great gulps of swarming krill (10,000–30,000 individual animals per cubic metre), and the pink streaks in penguin and seal poo show they are also keen on these tasty crustaceans.
Fish and cephalopods (squid and octopus) thrive in the Southern Ocean, providing food for deep-diving marine mammals such as elephant seals. Some fish species are so well adapted to the oxygen-rich cold waters they no longer produce red blood cells but instead produce antifreeze proteins in their blood to help them survive in the subzero waters.
Arguably the most voracious predators in the Southern Ocean are humans.
Antarctica might be remote, but in the 200 or so years since its discovery, the seas around Antarctica have been heavily exploited by people.
First came the sealers, then the whalers, driving species to the brink of extinction. Even penguins were harvested for their oil.
More recently, fish and krill (which is fished for food or dietary supplements) have been the main targets, and populations of some species have declined sharply as a consequence.
When more indirect impacts like ocean warming and acidification combine with fishing, this can lead to declining populations of krill, which in turn leads to reduced numbers of top predators such as whales.
Fishing in the Southern Ocean can be hard to regulate because these waters do not belong to any one nation. To help manage the impact of fisheries, quotas that limit catches are now managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).
This international body is also working to establish more marine protected areas.
Without these efforts to manage catches, critical parts of the food web (such as krill) could be exploited to such an extent that ecosystems could collapse.
More than 21,000 tourists and scientists visit Antarctica each year, potentially bringing pollution, diseases and invasive species. To manage human impacts on Antarctic ecosystems, and to help with political negotiations, the Antarctic Treaty came into force on June 23, 1961.
The treaty regulates all activity south of 60°S and includes an environmental protection protocol.
The impacts of global climate change and ocean acidification are nonetheless evident in the Southern Ocean, with warming ocean temperatures, reduction in sea ice and collapsing ice shelves.
Increasingly, research is showing that even the distant Southern Ocean is not truly cut off from the rest of the world, with warming, plastic pollution and non-native species making their way to Antarctic waters from beyond the mighty polar front.
Rafts of floating seaweeds from outside the Antarctic, some carrying animal passengers, are able to cross the Southern Ocean and reach Antarctic shores. At the moment, they don’t seem able to survive the extreme climate of Antarctica, but that could change with warming.
New species moving in and setting up shop will put a lot of pressure on Antarctica’s unique plants and animals.
It’s not all doom and gloom, though. Over the several decades since the Antarctic Treaty came into force, we’ve seen that nations can work together to help resolve challenges facing the Antarctic. One example is the establishment of Antarctic Marine Protected Areas (MPAs).
This level of international cooperation should give us hope not just for the future of the Southern Ocean, but also for other key challenges the world faces.
This story is part of our Oceans 21 series
Five profiles open our series on the global ocean, delving into ancient Indian Ocean trade networks, Pacific plastic pollution, Arctic light and life, Atlantic fisheries and the Southern Ocean’s impact on global climate. All brought to you from The Conversation’s international network.
Ceridwen Fraser, Associate professor, University of Otago; Christina Hulbe, Professor and Dean of the School of Surveying (glaciology specialisation), University of Otago; Craig Stevens, Associate Professor in Ocean Physics, National Institute of Water and Atmospheric Research, and Huw Griffiths, Marine Biogeographer, British Antarctic Survey
Jodie L. Rummer, James Cook University; Bridie JM Allan, University of Otago; Charitha Pattiaratchi, University of Western Australia; Ian A. Bouyoucos, James Cook University; Irfan Yulianto, IPB University, and Mirjam van der Mheen, University of Western Australia
The Pacific Ocean is the deepest, largest ocean on Earth, covering about a third of the globe’s surface. An ocean that vast may seem invincible. Yet across its reach – from Antarctica in the south to the Arctic in the north, and from Asia to Australia to the Americas – the Pacific Ocean’s delicate ecology is under threat.
In most cases, human activity is to blame. We have systematically pillaged the Pacific of fish. We have used it as a rubbish tip – garbage has been found even in the deepest point on Earth, in the Mariana Trench 11,000 metres below sea level.
And as we pump carbon dioxide into the atmosphere, the Pacific, like other oceans, is becoming more acidic. It means fish are losing their sense of sight and smell, and sea organisms are struggling to build their shells.
Oceans produce most of the oxygen we breathe. They regulate the weather, provide food, and give an income to millions of people. They are places of fun and recreation, solace and spiritual connection. So, healthy, vibrant oceans benefit us all. And by better understanding the threats to the precious Pacific, we can start the long road to protecting it.
This article is part of the Oceans 21 series
The series opens with five profiles delving into ancient Indian Ocean trade networks, Pacific plastic pollution, Arctic light and life, Atlantic fisheries and the Southern Ocean’s impact on global climate. It’s brought to you by The Conversation’s international network.
The problem of ocean plastic was scientifically recognised in the 1960s after two scientists saw albatross carcasses littering the beaches of the northwest Hawaiian Islands in the northern Pacific. Almost three in four albatross chicks, who died before they could fledge, had plastic in their stomachs.
Now, plastic debris is found in all major marine habitats around the world, in sizes ranging from nanometers to meters. A small portion of this accumulates into giant floating “garbage patches”, and the Pacific Ocean is famously home to the largest of them all.
Most plastic debris from land is transported into the ocean through rivers. Just 20 rivers contribute two-thirds of the global plastic input into the sea, and ten of these discharge into the northern Pacific Ocean. Each year, for example, the Yangtze River in China – which flows through Shanghai – sends about 1.5 million metric tonnes of debris into the Pacific’s Yellow Sea.
Plastic debris in the oceans presents innumerable hazards for marine life. Animals can get tangled in debris such as discarded fishing nets, causing them to be injured or drown.
Some organisms, such as microscopic algae and invertebrates, can also hitch a ride on floating debris, travelling large distances across the oceans. This means they can be dispersed out of their natural range, and can colonise other regions as invasive species.
And of course, wildlife can be badly harmed by ingesting debris, such as microplastics less than five millimetres in size. This plastic can obstruct an animal’s mouth or accumulate in its stomach. Often, the animal dies a slow, painful death.
Seabirds, in particular, often mistake floating plastics for food. A 2019 study found there was a 20% chance seabirds would die after ingesting a single item, rising to 100% after consuming 93 items.
Plastic is extremely durable, and can float vast distances across the ocean. In 2011, 5 million tonnes of debris entered the Pacific during the Japan tsunami. Some crossed the entire ocean basin, ending up on North American coastlines.
And since floating plastics in the open ocean are transported mainly by ocean surface currents and winds, plastic debris accumulates on island coastlines along their path. Kamilo Beach, on the south-eastern tip of Hawaii’s Big Island, is considered one of the world’s worst for plastic pollution. Up to 20 tonnes of debris wash onto the beach each year.
Similarly, on uninhabited Henderson Island, part of the Pitcairn Island chain in the south Pacific, 18 tonnes of plastic have accumulated on a beach just 2.5km long. Several thousand pieces of plastic wash up each day.
Plastic waste can have different fates in the ocean: some sink, some wash up on beaches and some float on the ocean surface, transported by currents, wind and waves.
Around 1% of plastic waste accumulates in five subtropical “garbage patches” in the open ocean. They’re formed as a result of ocean circulation, driven by the changing wind fields and the Earth’s rotation.
There are two subtropical garbage patches in the Pacific: one in the northern and one in the southern hemisphere.
The northern accumulation region is separated into an eastern patch between California and Hawaii, and a western patch, which extends eastwards from Japan.
First discovered by Captain Charles Moore in the early 2000s, the eastern patch is better known as the Great Pacific Garbage Patch because it’s the largest by both size (around 1.6 million square kilometers) and amount of plastic. By weight, this garbage patch can hold more than 100 kilograms per square kilometre.
The garbage patch in the southern Pacific is located off Valparaiso, Chile, extending to the west. It has lower concentrations compared to its giant counterpart in the northeast.
Discarded fishing nets make up around 45% of the total plastic weight in the Great Pacific Garbage Patch. Waste from the 2011 Japan tsunami is also a major contributor, making up an estimated 20% of the patch.
With time, larger plastic debris degrades into microplastics. Microplastics form only 8% of the total weight of plastic waste in the Great Pacific Garbage Patch, but make up 94% of the estimated 1.8 trillion pieces of plastic there. In high concentrations, they can make the water “cloudy”.
Each year, up to 15 million tonnes of plastic waste are estimated to make their way into the ocean from coastlines and rivers. This amount is expected to double by 2025 as plastic production continues to increase.
We must act urgently to stem the flow. This includes developing plans to collect and remove the plastics and, vitally, stop producing so much in the first place.
As the largest and deepest sea on Earth, the Pacific supports some of the world’s biggest fisheries. For thousands of years, people have relied on these fisheries for their food and livelihoods.
But, around the world, including in the Pacific, fishing operations are depleting fish populations faster than they can recover. This overfishing is considered one of the most serious threats to the world’s oceans.
Humans take about 80 million tonnes of wildlife from the sea each year. In 2019, the world’s leading scientists said of all threats to marine biodiversity over the past 50 years, fishing has caused the most harm. They said 33% of fish species were overexploited, 60% were being fished to the maximum level, and just 7% were underfished.
The decline in fish populations is not just a problem for humans. Fish play an important role in marine ecosystems and are a crucial link in the ocean’s complex food webs.
Overfishing happens when humans extract fish resources beyond the maximum level, known as the “maximum sustainable yield”. Fishing beyond this causes global fish stocks to decline, disrupts food chains, degrades habitats, and creates food scarcity for humans.
The Pacific Ocean is home to huge tuna fisheries, which provide almost 65% of the global tuna catch each year. But the long-term survival of many tuna populations is at risk.
For example, a study released in 2013 found numbers of bluefin tuna – a prized fish used to make sushi – had declined by more than 96% in the Northern Pacific Ocean.
Along Canada’s west coast, Pacific salmon populations have declined rapidly since the early 1990s, partly due to overfishing. And Japan was recently heavily criticised for a proposal to increase quotas on Pacific bluefin tuna, a species reportedly at just 4.5% of its historic population size.
Experts say overfishing is also a problem in Australia. For example, research in 2018 showed large fish species were rapidly declining around the nation due to excessive fishing pressure. In areas open to fishing, exploited populations fell by an average of 33% in the decade to 2015.
There are many reasons why overfishing occurs and why it is goes unchecked. The evidence points to:
poverty among fishers in developing nations
weak compliance with fishing regulations due to shortfalls in local government capacity.
Let’s take Indonesia as an example. Indonesia lies between the Pacific and Indian oceans and is the world’s third-biggest producer of wild-capture ﬁsh after China and Peru. Some 60% of the catch is made by small-scale ﬁshers. Many hail from poor coastal communities.
Overfishing was first reported in Indonesia in the 1970s. It prompted a presidential decree in 1980, banning trawling off the islands of Java and Sumatra. But overfishing continued into the 1990s, and it persists today. Target species include reef fishes, lobster, prawn, crab, and squid.
Indonesia’s experience shows how there is no easy fix to the overfishing problem. In 2017, the Indonesian government issued a decree that was supposed to keep fishing to a sustainable level – 12.5 million tonnes per year. Yet, in may places, the practice continued – largely because the rules were not clear and local enforcement was inadequate.
Implementation was complicated by the fact that almost all Indonesia’s smaller fishing boats come under the control of provincial governments. This reveals the need for better cooperation between levels of government in cracking down on overfishing.
To prevent overfishing, governments should address the issue of poverty and poor education in small fishing communities. This may involve finding them a new source of income. For example in the town of Oslob in the Philippines, former fishermen and women have turned to tourism – feeding whale sharks tiny amounts of krill to draw them closer to shore so tourists can snorkel or dive with them.
Tackling overfishing in the Pacific will also require cooperation among nations to monitor fishing practices and enforce the rules.
And the world’s network of marine protected areas should be expanded and strengthened to conserve marine life. Currently, less than 3% of the world’s oceans are highly protected “no take” zones. In Australia, many marine reserves are small and located in areas of little value to commercial fishers.
The collapse of fisheries around the world shows just how vulnerable our marine life is. It’s clear that humans are exploiting the oceans beyond sustainable levels. Billions of people rely on seafood for protein and for their livelihoods. But by allowing overfishing to continue, we harm not just the oceans, but ourselves.
The tropical and subtropical waters of the Pacific Ocean are home to more than 75% of the world’s coral reefs. These include the Great Barrier Reef and more remote reefs in the Coral Triangle, such as those in Indonesia and Papua New Guinea.
Coral reefs are bearing the brunt of climate change. We hear a lot about how coral bleaching is damaging coral ecosystems. But another insidious process, ocean acidification, is also threatening reef survival.
Ocean acidification particularly affects shallow waters, and the subarctic Pacific region is particularly vulnerable.
Coral reefs cover less than 0.5% of Earth’s surface, but house an estimated 25% of all marine species. Due to ocean acidification and other threats, these incredibly diverse “underwater rainforests” are among the most threatened ecosystems on the planet.
Ocean acidification involves a decrease in the pH of seawater as it absorbs carbon dioxide (CO₂) from the atmosphere.
Oceans absorb up to 30% of atmospheric CO₂, setting off a chemical reaction in which concentrations of carbonate ions fall, and hydrogen ion concentrations increase. That change makes the seawater more acidic.
Since the Industrial Revolution, ocean pH has decreased by 0.1 units. This may not seem like much, but it actually means the oceans are now about 28% more acidic than since the mid-1800s. And the Intergovernmental Panel on Climate Change (IPCC) says the rate of acidification is accelerating.
Carbonate ions are the building blocks for coral structures and organisms that build shells. So a fall in the concentrations of carbonate ions can spell bad news for marine life.
In more acidic waters, molluscs have been shown to have trouble making and repairing their shells. They also exhibit impaired growth, metabolism, reproduction, immune function, and altered behaviours. For example, researchers exposed sea hares (a type of sea slug) in French Polynesia to simulated ocean acidification and found they had less foraging success and made poorer decisions.
Ocean acidification is also a problem for the fishes. Many studies have revealed elevated CO₂ can disrupt their sense of smell, vision and hearing. It can also impair survival traits, such as a fish’s ability to learn, avoid predators, and select suitable habitat.
Of the seven oceans, the Pacific and Indian Oceans have been acidifying at the fastest rates since 1991. This suggests their marine life may also be more vulnerable.
However, ocean acidification does not affect all marine species in the same way, and the effects can vary over the organism’s lifetime. So, more research to predict the future winners and losers is crucial.
This can be done by identifying inherited traits that can increase an organism’s survival and reproductive success under more acidic conditions. Winner populations may start to adapt, while loser populations should be targets for conservation and management.
One such winner may be the epaulette shark, a shallow water reef species endemic to the Great Barrier Reef. Research suggests simulated ocean acidification conditions do not impact early growth, development, and survival of embryos and neonates, nor do they affect foraging behaviours or metabolic performance of adults.
But ocean acidification is also likely to create losers on the Great Barrier Reef. For example, researchers studying the orange clownfish – a species made famous by Disney’s animated Nemo character – found they suffered multiple sensory impairments under simulated ocean acidification conditions. These ranged from difficulties smelling and hearing their way home, to distinguishing friend from foe.
More than half a billion people depend on coral reefs for food, income, and protection from storms and coastal erosion. Reefs provide jobs – such as in tourism and fishing – and places for recreation. Globally, coral reefs represent an industry worth US$11.9 trillion per year. And importantly, they’re a place of deep cultural and spiritual connection for Indigenous people around the world.
Ocean acidification is not the only threat to coral reefs. Under climate change, the rate of ocean warming has doubled since the 1990s. The Great Barrier Reef, for example, has warmed by 0.8℃ since the Industrial Revolution. Over the past five years this has caused devastating back-to-back coral bleaching events. The effects of warmer seas are magnified by ocean acidification.
Cutting greenhouse gas emissions must become a global mission. COVID-19 has slowed our movements across the planet, showing it’s possible to radically slash our production of CO₂. If the world meets the most ambitious goals of the Paris Agreement and keeps global temperature increases below 1.5℃, the Pacific will experience far less severe decreases in oceanic pH.
We will, however, have to curb emissions by a lot more – 45% over the next decade – to keep global warming below 1.5℃. This would give some hope that coral reefs in the Pacific, and worldwide, are not completely lost.
Clearly, the decisions we make today will affect what our oceans look like tomorrow.
Jodie L. Rummer, Associate Professor & Principal Research Fellow, James Cook University; Bridie JM Allan, Lecturer/researcher, University of Otago; Charitha Pattiaratchi, Professor of Coastal Oceanography, University of Western Australia; Ian A. Bouyoucos, Postdoctoral fellow, James Cook University; Irfan Yulianto, Lecturer of Fisheries Resources Utilization, IPB University, and Mirjam van der Mheen, Fellow, University of Western Australia
Killer whales are icons of the northeastern Pacific Ocean. They are intimately associated with the region’s natural history and First Nations communities. They are apex predators, with females living as long as 100 years old, and recognized a sentinels of ecosystem health — and some populations are currently threatened with extinction.
There are three major types of killer whales in the region: the “resident” populations that feed mainly on salmon, the “transients” that prey on other marine mammals like seals and sea lions, and the “offshores” that transit along the continental shelf, eating fish and sharks.
In the 1990s, an abrupt decline in the fish-eating southern resident population dropped to 75 whales from 98, prompting both Canada and the United States to list them as endangered.
Since then, southern resident killer whales, whose range extends from the waters off the southeast Alaska and the coast of British Columbia to California, have not recovered — only 74 remain today. Because killer whale strandings are rare, scientists have been uncertain about the causes of killer whale mortality and how additional deaths might be prevented in the future.
As a pathologist and wildlife veterinarian, and with the help of countless biologists and veterinarians, we have carried out in-depth investigations into why killer whales in this region strand and died. If we don’t know what is causing killer whale deaths, we are not able to prevent the ones that are human-caused.
Human activities have been implicated in the decline and lack of recovery of the southern resident killer whale population, including ship noise and strikes, contaminants, reduced prey abundance and past capture of these animals for aquariums.
Only three per cent and 20 per cent of the northern and southern resident killer whales, respectively, that died between 1925 and 2011 were even found and available for a post-mortem exam. And in most cases, only cursory or incomplete post-mortem exams can be done, generating a limited amount of information.
To figure out why these killer whales are dying — and what it means for the health of individual animals and the population as a whole — we reviewed the post-mortem records of 53 animals that became stranded in the eastern Pacific Ocean and Hawaii between 2004 and 2013. We identified the cause of death in 22 animals, and gained important insight from nine other animals where the cause of death could not be determined.
Human-caused injuries were found in nearly every age group of whales, including adults, sub-adults and calves. Some had ingested fishing hooks, but evidence of blunt-force trauma, consistent with ship and propeller strikes, was more common.
This is the first study to document the lesions and forensic evidence of lethal trauma from ship and propeller strikes.
In recent years governments have focused on limiting vessel noise and disturbance. This study reinforces the need for this, showing that in addition to noise and disturbance, vessel strikes are an important cause of death in killer whales.
We also developed a body condition index to evaluate the animals’ nutritional health — were they eating enough salmon, for example — to see what role food might play in the sickness and death of stranded animals. Observations of free-ranging killer whales from boats and by unmanned aerial drones have documented sub-optimal body condition or generalized emaciation in many southern resident killer whales.
In this study, we found that longer and therefore older animals tend to have thicker blubber. Our study also found that those animals that died from blunt-force trauma had a better body condition — they were in good health before death. Those that died from infections or nutritional causes were more likely to be in worse body condition.
This new body condition index can help scientists better understand the health of killer whales, and gives us a tool to evaluate their health regardless of their age, reproductive status and health condition.
Our team, working with numerous collaborators including the National Marine Mammal Foundation, is building a health database of the killer whales living in the northeastern Pacific Ocean so that their health can be tracked over time. This centralized database will let stranding response programs, regional and national government agencies and First Nations communities collaborate with field biologists, research scientists and veterinarians.
Ultimately, the information about the health of these killer whales must be conveyed to the public and policy-makers to ensure that the appropriate legislation is enacted to reverse the downward trend in the health and survival of these killer whales. We should now be able to assess future efforts and gain a better understanding of the impact of ongoing human activities, such as fishing, boating and shipping.
Stephen Raverty, Adjunct professor, Veterinary Pathology, University of British Columbia and Joseph K. Gaydos, Wildlife Veterinarian and Science Director, The SeaDoc Society, University of California, Davis
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.
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.
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.
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.
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.
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.
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.
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.
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
The mysterious bigfin squid has been spotted in Australia’s waters for the first time. My colleagues and I from the CSIRO and Museums Victoria detail the encounters in our new research, published today in Public Library of Sciences ONE.
There have only been about a dozen bigfin squid sightings worldwide over the past two decades. Ours happened more than two kilometres below the ocean’s surface in the Great Australian Bight, off the coast of South Australia.
For many people, the phrase “deep-sea squid” may conjure up images of the giant squid, Architeuthis dux, or krakens with huge tentacles swimming in inky black water.
But there are dozens, if not hundreds, of other species of deep-sea squid and octopus (both members of the class Cephalopoda) that are just as mysterious.
For years, one of the only ways to sample the deep sea was to trawl the sea floor with nets. This often damaged the soft bodies of deep-sea organisms beyond recognition. These mangled specimens are then difficult to identify and reveal little to nothing about the creatures.
Fortunately, newer technologies such as remotely-operated vehicles (ROVs) equipped with high-definition cameras are letting scientists see species as they’ve never seen before — offering deeper insight into their shapes, colours and behaviours in the wild.
The enigmatic bigfin squid, Magnapinna, is one case in point. When scientists first described the species in 1998, all they had to go by were some damaged specimens from Hawaii.
The most distinctive feature of these specimens were the large fins (at the very top of the body), which gave the squid its name. Years later, scientists exploring the deep Gulf of Mexico with ROVs realised they had come across Magnapinna in the wild.
They discovered that in addition to its distinctive fins, its arms had incredibly long filaments on the tips, making the bigfin squid unlike any other encountered.
These delicate filaments, which are mostly broken off in collected specimens, give Magnapinna an estimated total length of up to seven meters!
But despite deep-sea ROV surveys becoming more common, Magnapinna has remained elusive.
The handful of sightings have been as far apart as the Central Pacific, North and South Atlantic, Gulf of Mexico and Indian Ocean. This suggests a worldwide distribution.
Yet, the big fin squid had never been seen in Australian waters. That is, until recently, when our team took part in a major research project to better understand the biology and geology of the Great Australian Bight, through the Great Australian Bight Deepwater Marine Program.
On the CSIRO’s research vessel Investigator and charter vessel REM Etive, we surveyed as deep as five kilometres below the water’s surface. Using nets, ROVs and other camera equipment, we recorded hundreds of hours of video footage and uncovered thousands of species.
On one dive, as we watched the video feed from cameras far below us, a wispy shape emerged from the gloom. With large undulating fins, a small torpedo-shaped body and long stringy limbs, it was unmistakably Magnapinna. We yelled and brought the ROV to a halt to get a better look.
The meeting lasted about three minutes. During this time we managed to use parallel laser pointers to measure the squid’s length — about 1.8 meters — before it swam away into darkness.
In total, we recorded five encounters with Magnapinna in the Great Australian Bight. Based on the animals’ measurements, we believe we recorded five different individuals: the most Magnapinna ever filmed in one place.
Most previous records have been of single Magnapinna, but our five squid were all found clustered close to each other. This might mean they like the habitat where they were found, but we’ll need more sightings to be sure.
The footage we captured has offered new information about Magnapinna’s ecology, behaviour and anatomy.
Previously, Magnapinna has been seen many meters off the sea floor in an upright posture, with arms held wide and filaments draping down. We’re not sure what the specific function of this behaviour is. It might be a way to find prey — akin to dangling sticky, sucker-covered fishing lines.
On our voyage, we saw the squid in a horizontal version of this pose, just centimetres off the sea floor, with its arms and filaments streaming behind. Again, we don’t know whether this behaviour is for travelling, avoiding predators or another method of searching for prey.
One near-miss with a camera gave us a very closeup image of Magnapinna which showed filaments that appeared to be coiled like springs. This may be a means for Magnapinna to retract its filaments when needed, perhaps if it wanted to avoid damage, or reel in something it caught.
Until now, only one other cephalopod, the vampire squid (Vampyroteuthis infernalis), has been known to coil its filamentous appendages this way.
We have learned more about the mysterious bigfin squid. But until we have more sightings, or even an intact specimen, questions will remain.
One thing we do know is ROV surveying has great potential to enhance our understanding of deep-sea animals. With so much of the ocean around Australia yet to be explored, who knows what we’ll see coming out of the gloom next time?
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The Japanese government recently announced plans to release into the sea more than 1 million tonnes of radioactive water from the severely damaged Fukushima Daiichi nuclear plant.
The move has sparked global outrage, including from UN Special Rapporteur Baskut Tuncak who recently wrote,
I urge the Japanese government to think twice about its legacy: as a true champion of human rights and the environment, or not.
Alongside our Nobel Peace Prize-winning work promoting nuclear disarmament, we have worked for decades to minimise the health harms of nuclear technology, including site visits to Fukushima since 2011. We’ve concluded Japan’s plan is unsafe, and not based on evidence.
Japan isn’t the only country with a nuclear waste problem. The Australian government wants to send nuclear waste to a site in regional South Australia — a risky plan that has been widely criticised.
In 2011, a massive earthquake and tsunami resulted in the meltdown of four large nuclear reactors, and extensive damage to the reactor containment structures and the buildings which house them.
Water must be poured on top of the damaged reactors to keep them cool, but in the process, it becomes highly contaminated. Every day, 170 tonnes of highly contaminated water are added to storage on site.
If radioactive material leaks into the sea, ocean currents can disperse it widely. The radioactivity from Fukushima has already caused widespread contamination of fish caught off the coast, and was even detected in tuna caught off California.
Ionising radiation harms all organisms, causing genetic damage, developmental abnormalities, tumours and reduced fertility and fitness. For tens of kilometres along the coast from the damaged nuclear plant, the diversity and number of organisms have been depleted.
Of particular concern are long-lived radioisotopes (unstable chemical elements) and those which concentrate up the food chain, such as cesium-137 and strontium-90. This can lead to fish being thousands of times more radioactive than the water they swim in.
In recent years, a water purification system — known as advanced liquid processing — has been used to treat the contaminated water accumulating in Fukushima to try to reduce the 62 most important contaminating radioisotopes.
But it hasn’t been very effective. To date, 72% of the treated water exceeds the regulatory standards. Some treated water has been shown to be almost 20,000 times higher than what’s allowed.
The cherry trees of Fukushima
One important radioisotope not removed in this process is tritium — a radioactive form of hydrogen with a half-life of 12.3 years. This means it takes 12.3 years for half of the radioisotope to decay.
Tritium is a carcinogenic byproduct of nuclear reactors and reprocessing plants, and is routinely released both into the water and air.
The Japanese government and the reactor operator plan to meet regulatory limits for tritium by diluting contaminated water. But this does not reduce the overall amount of radioactivity released into the environment.
The Japanese Citizens Commission for Nuclear Energy is an independent organisation of engineers and researchers. It says once water is treated to reduce all significant isotopes other than tritium, it should be stored in 10,000-tonne tanks on land.
If the water was stored for 120 years, tritium levels would decay to less than 1,000th of the starting amount, and levels of other radioisotopes would also reduce. This is a relatively short and manageable period of time, in terms of nuclear waste.
Then, the water could be safely released into the ocean.
Australians currently face our own nuclear waste problems, stemming from our nuclear reactors and rapidly expanding nuclear medicine export business, which produces radioisotopes for medical diagnosis, some treatments, scientific and industrial purposes.
This is what happens at our national nuclear facility at Lucas Heights in Sydney. The vast majority of Australia’s nuclear waste is stored on-site in a dedicated facility, managed by those with the best expertise, and monitored 24/7 by the Australian Federal Police.
But the Australian government plans to change this. It wants to transport and temporarily store nuclear waste at a facility at Kimba, in regional South Australia, for an indeterminate period. We believe the Kimba plan involves unnecessary multiple handling, and shifts the nuclear waste problem onto future generations.
The infrastructure, staff and expertise to manage and monitor radioactive materials in Lucas Heights were developed over decades, with all the resources and emergency services of Australia’s largest city. These capacities cannot be quickly or easily replicated in the remote rural location of Kimba. What’s more, transporting the waste raises the risk of theft and accident.
And in recent months, the CEO of regulator ARPANSA told a senate inquiry there is capacity to store nuclear waste at Lucas Heights for several more decades. This means there’s ample time to properly plan final disposal of the waste.
The Conversation contacted Resources Minister Keith Pitt who insisted the Kimba site will consolidate waste from more than 100 places into a “safe, purpose-built, state-of-the-art facility”. He said a separate, permanent disposal facility will be established for intermediate level waste in a few decades’ time.
Pitt said the government continues to seek involvement of Traditional Owners. He also said the Kimba community voted in favour of the plan. However, the voting process was criticised on a number of grounds, including that it excluded landowners living relatively close to the site, and entirely excluded Barngarla people.
Both Australia and Japan should look to nations such as Finland, which deals with nuclear waste more responsibly and has studied potential sites for decades. It plans to spend 3.5 billion euros (A$5.8 billion) on a deep geological disposal site.
Intermediate level nuclear waste like that planned to be moved to Kimba contains extremely hazardous materials that must be strictly isolated from people and the environment for at least 10,000 years.
We should take the time needed for an open, inclusive and evidence-based planning process, rather than a quick fix that avoidably contaminates our shared environment and creates more problems than it solves.
It only kicks the can down the road for future generations, and does not constitute responsible radioactive waste management.
The following are additional comments provided by Resources Minister Keith Pitt in response to issues raised in this article (comments added after publication):
(The Kimba plan) will consolidate waste into a single, safe, purpose-built, state-of-the-art facility. It is international best practice and good common sense to do this.
Key indicators which showed the broad community support in Kimba included 62 per cent support in the local community ballot, and 100 per cent support from direct neighbours to the proposed site.
In assessing community support, the government also considered submissions received from across the country and the results of Barngarla Determination Aboriginal Corporation’s own vote.
The vast majority of Australia’s radioactive waste stream is associated with nuclear medicine production that, on average, two in three Australians will benefit from during their lifetime.
The facility will create a new, safe industry for the Kimba community, including 45 jobs in security, operations, administration and environmental monitoring.
Tilman Ruff, Associate Professor, Education and Learning Unit, Nossal Institute for Global Health, School of Population and Global Health, University of Melbourne and Margaret Beavis, Tutor Principles of Clinical Practice Melbourne Medical School