These underwater photos show Norfolk Island reef life still thrives, from vibrant blue flatworms to soft pink corals



A big coral bommie in the lagoon at Norfolk Island.
John Turbull , Author provided

John Turnbull, UNSW

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.


Two weeks ago, I found myself hitting the water on Norfolk Island, complete with a survey reel, slate and camera.

Norfolk Island is a small volcanic outcrop located between New Caledonia and New Zealand, 1,400 kilometres east of Australia’s Gold Coast. It’s surrounded by coral reefs, with a shallow lagoon on the south side that looks out on two smaller islands: Nepean and Phillip.

The island is picturesque, but like marine environments the world over, Norfolk Marine Park is subject to pressures from climate change, fishing pressure, habitat change and pollution.

I was diving in the marine park as a volunteer for Reef Life Survey, a citizen science program where trained SCUBA divers survey marine biodiversity in rocky and coral reefs around the world. We first surveyed Norfolk Island in 2009, then again in 2013, with an eight year hiatus before our return this month.

While the scientific analysis of our data is yet to be done, we can make anecdotal observations to compare this year’s findings with prior records and photographs. This time, our surveys turned up several new sightings and observations.

A wrinkly orange nudibranch nestled in algae
A red-ringed nudibranch (Ardeadoris rubroannulata). This beautiful little mollusc was a couple of centimetres long, nestled on the side of a wall covered in colourful algae. I had to look twice to notice it, but recognised it as a species I had seen before in Sydney. It had previously only been recorded in the Coral Sea, the east coast of Australia and Lord Howe island, so it was nice to get a record of it even further east in the Pacific.
John Turnbull, Author provided

What we saw

Diving under the waves in Norfolk Marine Park takes you into a world of crackling, popping reef sounds through clear blue water, with darting tropical fish, a tapestry of algae and hard and soft corals in pink, green, brown and red.

In these surveys we record fish species including their size and abundance, invertebrates such as urchins and sea stars, and habitat such as coral cover. This allows us to track changes in marine life using standardised scientific methods.

Emily Bay is a sheltered swimming beach at the eastern end of the lagoon, great for snorkelling too thanks to the diverse corals just below the surface.
John Turbull, Author provided
An orange fish near a mound of orange coral
Banded parma are quite territorial — they charge you as you approach their turf. This one is guarding what it regards as its own personal coral clump.
John Turbull, Author provided

Given recent major marine heatwaves and bleaching events in Australia, we were pleased to see healthy corals on many of our survey sites on Norfolk. We even felt there had been increases in coral cover at some sites.

This may be due to Norfolk’s location. The island is further south than most Australian coral reefs, which means it has cooler seas, and it’s surrounded by deeper water. I’m a marine ecologist involved in soft coral monitoring at the University of NSW, so I particularly noticed the wonderful diversity and size of soft corals.

Healthy brown coral garden
This photo shows the structure corals provide for fish and other animals to shelter in. They are the foundation for the whole tropical marine community. The corals here are a healthy brown — which comes from the symbiotic algae in their tissues – with no signs of bleaching.
John Turbull, Author provided
Soft pink coral
The soft corals on Norfolk Island are some of the largest I’ve seen. Their structure is made up of soft tissue, often inflated by water pressure, rather than hard skeleton.
John Turbull, Author provided
Close-up of white, wrinkly coral
Hard corals come in a diversity of shapes and sizes, including this massive form growing on the side of rock wall.
John Turbull, Author provided

I noticed generally low numbers of large fish such as morwong and sharks on our survey sites. Some classes of invertebrate were also rare on this year’s surveys, particularly sea shell animals like tritons and whelks.

Urchins, on the other hand, were common, particularly the red urchin. Some sites also had numerous black long-spined urchins and large sea lamingtons.

These invertebrate observations follow patterns we see in eastern and southern Australia, where there are declines in the numbers of many invertebrate species, and increases in urchin barrens — regions where urchin populations grow unchecked.

The expansion of urchin barrens can threaten biodiversity in a region, as large numbers of a single species of urchin can out-compete multiple species of other invertebrates, over-graze algae and reduce habitat suitable for fish.

Red urchin beside coral
The abundant red urchin competes for space with other invertebrates, such as this one encrusting hard coral.
John Turbull, Author provided
Fat, black and white urchins beneath a coral mound
Lamingtons are an Australian cake (although there are claims they were invented in NZ!) and I love this descriptive common name for the Tripneustes gratilla urchin. The sea lamingtons on Norfolk appear particularly fat and happy, as they cluster in sheltered grooves during the day to avoid predators. They can also be different colours — I’ve seen them on the east coast of Australia in orange and cream, even with stripes.
John Turbull, Author provided
Two spindly shrimp beneath coral
A pair of banded cleaner shrimp, which grow to 9cm long. They advertise their fish cleaning services with their distinct banding and white antennae.
John Turbull, Author provided

A highlight of any survey dive is when you find an animal you suspect may not have been recorded at a location before, and I had several of those on this trip.

I recorded first sightings for Reef Life Survey of blue mao mao, convict surgeonfish, the blue band glidergoby, sergeant major (a damselfish), chestnut blenny, Susan’s flatworm, red-ringed nudibranch, fine-net peristernia and an undescribed weedfish.

While some of these sightings are yet to be confirmed by specialists, they gave a buzz of excitement each night as we searched the records to confirm our suspicions of a new find.

A school of large blu fish
This big school of drummer circled us for several minutes on our first survey dive at Nepean Island. If you look closely you can see one of the fish is different, in the top right. This is one of a few blue mao mao circulating in the school – and a first sighting for Reef Life Survey at Norfolk. You might also notice another species in the school, the darker spotted sawtail down the bottom of the photo.
John Turbull, Author provided
A vibrant blue ribbon-like worm with an orange stripe
Susan’s flatworm is a colourful invertebrate listed as living only in the Indian Ocean and Indonesia. This sighting from Norfolk Island is a new record in the Pacific Ocean. When I first saw this little worm at the end of a survey, I wondered if it was anything special. Just as well I took the photo anyway!
John Turbull, Author provided

Recruiting the locals

Other highlights for me included the warm welcome we received from the local community on Norfolk and the great turnout we had at our community seminar. Everyone I spoke to was supportive and encouraging when they heard we were on the island as volunteers doing surveys, and several people expressed interest in getting involved.

This is great news, as the best outcome is for local people to be trained to conduct their own local surveys.

An underwater SCUBA selfie
Tyson, Sal, Jamie, Toni and me taking an underwater selfie on the west side of Phillip Island, 10 metres below the surface. It’s harder than on land, with your fins off the ground, everyone moving and bubbles to deal with.
John Turbull, Author provided

Ideally we will return for comprehensive surveys of our 17 sites every two years or so, allowing us to plot trends over time. Only then can we hope to understand what is really happening in our marine environment, and make evidence-based conservation decisions. Having a skilled local team would make this easier and more likely to happen.

In any case, our 2021 surveys in Norfolk Marine Park, conducted by our team of five dedicated volunteers and supported by many others, give us one more essential point in time in the Norfolk series, and gave me some great memories to boot.

You can view my full photo album from the Norfolk Island survey here.




Read more:
Photos from the field: zooming in on Australia’s hidden world of exquisite mites, snails and beetles


The Conversation


John Turnbull, Postdoctoral research associate, UNSW

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

Think all your plastic is being recycled? New research shows it can end up in the ocean


Shutterstock

Monique Retamal, University of Technology Sydney; Elsa Dominish, University of Technology Sydney; Nick Florin, University of Technology Sydney, and Rachael Wakefield-Rann, University of Technology Sydney

We all know it’s wrong to toss your rubbish into the ocean or another natural place. But it might surprise you to learn some plastic waste ends up in the environment, even when we thought it was being recycled.

Our study, published today, investigated how the global plastic waste trade contributes to marine pollution.

We found plastic waste most commonly leaks into the environment at the country to which it’s shipped. Plastics which are of low value to recyclers, such as lids and polystyrene foam containers, are most likely to end up polluting the environment.

The export of unsorted plastic waste from Australia is being phased out – and this will help address the problem. But there’s a long way to go before our plastic is recycled in a way that does not harm nature.

Man puts items in bins
Research shows plastic meant for recycling often ends up elsewhere.
Shutterstock

Know your plastics

Plastic waste collected for recycling is often sold for reprocessing in Asia. There, the plastics are sorted, washed, chopped, melted and turned into flakes or pellets. These can be sold to manufacturers to create new products.

The global recycled plastics market is dominated by two major plastic types:

  • polyethylene terephthalate (PET), which in 2017 comprised 55% of the recyclable plastics market. It’s used in beverage bottles and takeaway food containers and features a “1” on the packaging

  • high-density polyethylene (HDPE), which comprises about 33% of the recyclable plastics market. HDPE is used to create pipes and packaging such as milk and shampoo bottles, and is identified by a “2”.

The next two most commonly traded types of plastics, each with 4% of the market, are:

  • polypropylene or “5”, used in containers for yoghurt and spreads

  • low-density polyethylene known as “4”, used in clear plastic films on packaging.

The remaining plastic types comprise polyvinyl chloride (3), polystyrene (6), other mixed plastics (7), unmarked plastics and “composites”. Composite plastic packaging is made from several materials not easily separated, such as long-life milk containers with layers of foil, plastic and paper.

This final group of plastics is not generally sought after as a raw material in manufacturing, so has little value to recyclers.




Read more:
China’s recycling ‘ban’ throws Australia into a very messy waste crisis


Symbols on PET plastic item
Items made from PET plastic resin are marked with a ‘1’.
Shutterstock

Shifting plastic tides

China banned the import of plastic waste in January 2018 to prevent the receipt of low-value plastics and to stimulate the domestic recycling industry.

Following the bans, the global plastic waste trade shifted towards Southeast Asian nations such as Vietnam, Thailand, Malaysia, and Indonesia. The largest exporters of waste plastics in 2019 were Europe, Japan and the US. Australia exported plastics primarily to Malaysia and Indonesia.

Australia’s waste export ban recently became law. From July this year, only plastics sorted into single resin types can be exported; mixed plastic bales cannot. From July next year, plastics must be sorted, cleaned and turned into flakes or pellets to be exported.

This may help address the problem of recyclables becoming marine pollution. But it will require a significant expansion of Australian plastic reprocessing capacity.

Map showing the import and export map of plastic waste globally.
Map showing the import and export map of plastic waste globally.
Authors provided

What we found

Our study was funded by the federal Department of Agriculture, Water and the Environment. It involved interviews with trade experts, consultants, academics, NGOs and recyclers (in Australia, India, Indonesia, Japan, Malaysia, Vietnam and Thailand) and an extensive review of existing research.

We found when it comes to the international plastic trade, plastics most often leak into the environment at the destination country, rather than at the country of origin or in transit. Low-value or “residual” plastics – those left over after more valuable plastic is recovered for recycling – are most likely to end up as pollution. So how does this happen?

In Southeast Asia, often only registered recyclers are allowed to import plastic waste. But due to high volumes, registered recyclers typically on-sell plastic bales to informal processors.

Interviewees said when plastic types were considered low value, informal processors frequently dumped them at uncontrolled landfills or into waterways. Sometimes the waste is burned.

Plastics stockpiled outdoors can be blown into the environment, including the ocean. Burning the plastic releases toxic smoke, causing harm to human health and the environment.

Interviewees also said when informal processing facilities wash plastics, small pieces end up in wastewater, which is discharged directly into waterways, and ultimately, the ocean.

However, interviewees from Southeast Asia said their own domestic waste management was a greater source of ocean pollution.

Birds fly over landfill site
Plastic waste meant for recycling can end up in overseas landfill, before it blows into the ocean.
Anupam Nath/AP

A market failure

The price of many recycled plastics has crashed in recent years due to oversupply, import restrictions and falling oil prices, (amplified by the COVID-19 pandemic). However clean bales of PET and HDPE are still in demand.

In Australia, material recovery facilities currently sort PET and HDPE into separate bales. But small contaminants of other materials (such as caps and plastic labels) remain, making it harder to recycle into high quality new products.

Before the price of many recycled plastics dropped, Australia baled and traded all other resin types together as “mixed plastics”. But the price for mixed plastics has fallen to zero and they’re now largely stockpiled or landfilled in Australia.

Several Australian facilities are, however, investing in technology to sort polypropylene so it can be recovered for recycling.

Shampoo bottles in supermarket
High-density polyethylene items such as shampoo bottles comprise a large share of the plastic waste market.
Shutterstock

Doing plastics differently

Exporting countries can help reduce the flow of plastics to the ocean by better managing trade practices. This might include:

  • improving collection and sorting in export countries

  • checking destination processing and monitoring

  • checking plastic shipments at export and import

  • improving accountability for shipments.

But this won’t be enough. The complexities involved in the global recycling trade mean we must rethink packaging design. That means using fewer low-value plastic and composites, or better yet, replacing single-use plastic packaging with reusable options.


The authors would like to acknowledge research contributions from Asia Pacific Waste Consultants (APWC) – Dr Amardeep Wander, Jack Whelan and Anne Prince, as well as Phil Manners at CIE.




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Here’s what happens to our plastic recycling when it goes offshore


The Conversation


Monique Retamal, Research Principal, Institute for Sustainable Futures, University of Technology Sydney; Elsa Dominish, Senior Research Consultant, Institute for Sustainable Futures, University of Technology Sydney; Nick Florin, Research Director, Institute for Sustainable Futures, University of Technology Sydney, and Rachael Wakefield-Rann, Research Consultant, Institute for Sustainable Futures, University of Technology Sydney

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

Plastic in the ocean kills more threatened albatrosses than we thought


Lauren Roman, Author provided

Richelle Butcher, Massey University; Britta Denise Hardesty, CSIRO, and Lauren Roman, CSIRO

Plastic in the ocean can be deadly for marine wildlife and seabirds around the globe, but our latest study shows single-use plastics are a bigger threat to endangered albatrosses in the southern hemisphere than we previously thought.

You may have heard of the Great Pacific garbage patch in the northern Pacific, but plastic pollution in the southern hemisphere’s oceans has increased by orders of magnitude in recent years.

We examined the causes of death of 107 albatrosses received by wildlife hospitals and pathology services in Australia and New Zealand and found ocean plastic is an underestimated threat.

Plastic drink bottles, disposable utensils and balloons are among the most deadly items.

Albatrosses are some the world’s most imperiled seabirds, with 73% of species threatened with extinction. Most species live in the southern hemisphere.

We estimate plastic ingestion causes up to 17.5% of near-shore albatross deaths in the southern hemisphere and should be considered a substantial threat to albatross populations.




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These are the plastic items that most kill whales, dolphins, turtles and seabirds


Magnificent ocean wanderers

Albatrosses spend their entire lives at sea and can live for more than 70 years. They return to land only to reunite with their mate and raise a single chick during the warmer months.

Although the world’s largest flying birds are rarely seen from land, human activities are driving nearly three quarters of albatross species to extinction.

An albatross flying across the ocean.
The great albatrosses are the largest flying birds in the world, circumnavigating the southern oceans in search of food.
Lauren Roman, Author provided

Each year, thousands of albatrosses are caught as unintended bycatch and killed by fishing boats. Introduced rats and mice eat their chicks alive on remote islands and the ocean where they spend their lives is becoming increasingly warmer and filled with plastic.

Young Laysan albatrosses with their bellies full of plastic are not just a tragic tale from the remote northern Pacific. Albatrosses are dying from plastic in the southern oceans, too.

When a Royal albatross recently died in care at Wildbase Hospital after eating a plastic bottle, it was not an isolated incident.

Single-use plastics hit albatrosses close to home

A veterinarian treating a light-mantled albatross
Veterinarian Baukje Lenting treating a light-mantled albatross at The Nest Te Kōhanga at Wellington Zoo.
Wellington Zoo, Author provided

Eighteen of the world’s 22 albatross species live in the southern hemisphere, where plastic is currently considered a lesser threat. But the amount of discarded plastic is increasing every year, mostly leaked from towns and cities and accumulating near the shore.

Single-use items make up most of the trash found on coastlines around the world. Seven of the ten most common items — drink bottles, food wrappers and grocery bags — are made of plastic.

When albatrosses are found struggling near the shore in New Zealand, they are delivered to wildlife hospitals such as Wildbase Hospital and The Nest Te Kōhanga. A recent spate of plastic-linked deaths spurred us to dig a little deeper into the risk of plastic pollution to these magnificent ocean wanderers.

A thousand cuts: plastic and other threats

Of the 107 albatrosses of 12 species we examined, plastic was the cause of death in half of the birds that had ingested it. In the cases we examined, plastic deaths were more common than fisheries-related deaths or oiling.

We compared these cases with data on plastic ingestion and fishery interaction rates from other studies. Based on our findings, we used statistical methods to estimate how many albatrosses were likely to eat plastic and might die from ingesting it, and how these figures compared to other major threats such as fisheries bycatch.

We found that in the near-shore areas of Australia and New Zealand, the ingestion of plastic is likely to cause about 3.4% of albatross deaths. In more polluted near-shore areas, such as those off Brazil, we estimate plastic ingestion causes 17.5% of all albatross deaths.




Read more:
Plastic poses biggest threat to seabirds in New Zealand waters, where more breed than elsewhere


Because albatrosses are highly migratory, even those birds that live in less polluted areas are at risk as they wander the global ocean, travelling to polluted waters. Our results suggest the ingestion of plastic is at least of equivalent concern as long-line fishing in near-shore areas.

For threatened and declining albatross species, these rates of additional mortality are a serious concern and could result in further population losses.

Deadly junk food for marine life

Balloon fragments found in the stomach on an endangered albatross
The remains of two balloons in the stomach of an endangered grey-headed albatross.
Lauren Roman, Author provided

Not all types of plastic are equally deadly when eaten. Albatrosses can regurgitate many of the indigestible items they eat.

Soft plastic and rubber items (such as latex balloons), in particular, can be deadly for marine animals because they often become trapped in the gut and cause fatal blockages, leading to a long, slow death by starvation. Plastic is difficult to see with common scanning techniques, and gut blockages often remain undetected.

A plastic bottle found in the stomach of an albatross
A 500ml plastic bottle and balloon fragments were found in the stomach of a southern royal albatross which died in care at Wildbase Hospital.
Stuart Hunter, Author provided

Albatrosses like to eat squid, and inexperienced young birds are especially prone to mistaking balloons and other plastic for food, with potentially lethal consequences.

We recommend that wildlife hospitals, carers and biologists consider gastric obstruction when sick albatrosses are presented. Our publication includes a checklist to help in the detection of gastric blockages.

Global cooperation to reduce leakage of plastic items into the ocean — such as the Basel Convention and the recommendations by the High Level Panel for a Sustainable Ocean Economy — are first steps towards preventing unnecessary deaths of marine animals.




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We need a legally binding treaty to make plastic pollution history


Stronger adherence to multilateral agreements, such as the Agreement on the Conservation of Albatrosses and Petrels which aims to reduce the impact of activities known to kill albatrosses, would help prevent the decline of breeding populations to unsustainably low levels.

If populations fall to critically endangered levels, intensive remediation including the expansion of chick and nest protection programmes, invasive species eradication and seabird translocations, may be required to prevent species extinction.


We would like to acknowledge our New Zealand and Australian colleagues who contributed to this research project. Veterinarians Baukje Lenting and Phil Kowalski care for injured seabirds and other wildlife at The Nest Te Kōhanga at Wellington Zoo. Veterinarian Megan Jolly cares for injured wildlife at Wildbase Hospital and vet pathologist Stuart Hunter provides a nationwide wildlife pathology service at Wildbase pathology at Massey University. David Stewart conducts threatened species research and monitoring at the Queensland state government’s Department of Environment and Science.The Conversation

Richelle Butcher, Veterinary Resident at Wildbase, Massey University; Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO, and Lauren Roman, Postdoctoral Researcher, Oceans and Atmosphere, CSIRO

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

Marine protection falls short of the 2020 target to safeguard 10% of the world’s oceans. A UN treaty and lessons from Antarctica could help



John B. Weller, Author provided

Natasha Blaize Gardiner, University of Canterbury and Cassandra Brooks, University of Colorado Boulder

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.

But they are being damaged irretrievably. Research shows unsustainable fisheries are one of the greatest threats to marine biodiversity in the high seas.

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.




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Empty pledges

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.

Weddell seal pup and mother
Currently, the world’s largest marine protected area is in the Ross Sea region off Antarctica.
Natasha Gardiner, CC BY-ND

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.




Read more:
An ocean like no other: the Southern Ocean’s ecological richness and significance for global climate


A new ocean treaty

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.

Lessons from Southern Ocean management

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.

Fisheries interests from a select few nations, combined with complex geopolitics, are thwarting progress towards marine protection in the Antarctic.

Map of marine protected areas around Antarctica.
CCAMLR’s two established MPAs (in grey) are the South Orkney Islands southern shelf MPA and the Ross Sea region MPA. Three proposed MPAs (hashed) include the East Antarctic, Domain 1 and Weddell Sea proposals.
C. Brooks, CC BY-ND

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.




Read more:
Why are talks over an East Antarctic marine park still deadlocked?


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.The Conversation

Natasha Blaize Gardiner, PhD Candidate, University of Canterbury and Cassandra Brooks, Assistant Professor Environmental Studies, University of Colorado Boulder

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

An ocean like no other: the Southern Ocean’s ecological richness and significance for global climate



Shutterstock/CherylRamalho

Ceridwen Fraser, University of Otago; Christina Hulbe, University of Otago; Craig Stevens, National Institute of Water and Atmospheric Research, and Huw Griffiths, British Antarctic Survey

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.

Map of the world's oceans
The Spilhaus map depicts the world’s oceans as a single body of water.
Spilhaus ArcGIS project, CC BY-ND

The Southern Ocean, also called the Antarctic Ocean (or even the Austral ocean), is like no other and best described in superlatives.

Storing heat and carbon

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.

Southern Ocean, with open ocean and sea ice
The Southern Ocean is our planet’s primary storage of heat and carbon.
Crag Stevens, Author provided

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.




Read more:
Explainer: how the Antarctic Circumpolar Current helps keep Antarctica frozen


Mixing global currents

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.

Ship crossing the Southern Ocean
Strong westerly winds and the circumpolar current create massive waves in the Southern Ocean.
Craig Stevens, Author provided

But the heat and carbon exchanges across this complicated interface are globally important, and oceanographers have designed tools specifically for this challenging environment.

Ocean currents with different properties mix, rise and sink.
Craig Stevens, Author provided

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.

Annual thaw and freeze of sea ice

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.

sea ice around Antarctica
The annual freezing and thawing of sea ice around Antarctica is the world’s largest seasonal change.
Shutterstock/Maxim Tupikov

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.




Read more:
Why Antarctica’s sea ice cover is so low (and no, it’s not just about climate change)


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.

Not all ice shelves respond the same

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.

Riiser Larsen Ice Shelf, in Antarctica
Floating ice shelves act like a buttress to hold back Antarctica’s massive ice sheet.
Shutterstock/sirtravelalot

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.




Read more:
What an ocean hidden under Antarctic ice reveals about our planet’s future climate


Observing the Screaming Sixties

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.

Marine scientist deploying an ocean probe
Argo probes measure salinity and temperature as they drift with currents in the Southern Ocean.
NIWA/Daniel Jones, Author provided

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.

The past and future Southern Ocean

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.

Calving ice shelf in Antarctica
Antarctica’s ice is changing as global temperatures rise.
Shutterstock/Bernhard Staehli

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.




Read more:
60 days in Iceberg Alley, drilling for marine sediment to decipher Earth’s climate 3 million years ago


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.

Life in a sub-zero ocean

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.

Ship battling high waves
The RV Polarstern battles through a storm in the Southern Ocean.
Huw Griffiths, Author provided

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.




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


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.

Down at the bottom of the food chain

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.

Algae growing on the underside of sea ice in Antarctica.
Algae growing on the underside of sea ice.
Andrew Thurber, Author provided

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.

Antarctic krill
Antarctic krill is a key species in the Antarctic marine ecosystem.
British Antarctic Survey, Author provided

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.

An Antarctic hydrothermal vent on the East Scotia Ridge. The image was taken by a remotely operated vehicle during the ChEsSO expedition.
ChEsSO/NERC, Author provided

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.

A selection of invertebrates commonly found by scientists diving at Rothera Station, Antarctica.
A selection of invertebrates commonly found by scientists diving at Rothera Station, Antarctica.
British Antarctic Survey, Author provided

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.

Colourful creatures that live on the seafloor.
Marine invertebrates on the seafloor off the Antarctic coast.
Alfred Wegener Institute, OFOBS team, Author provided

Higher up in the food chain

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.

Chinstrap penguins on Deception Island
Chinstrap penguins on Deception Island. Many penguins pooh in pink, because their diet is rich in krill.
Michelle LaRue, Author provided

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.

Minke whale in Antarctic waters
Many whale species depend on Antarctic ecosystems for summer feeding and migrate to warmer, lower latitudes for winter breeding. But Antarctic minke whales are resident all year round.
Huw Griffiths, Author provided

Protecting marine environments

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.

An abandoned whaling station.
An abandoned whaling station.
Ceridwen Fraser, Author provided

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.




Read more:
Humans are encroaching on Antarctica’s last wild places, threatening its fragile biodiversity


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.

Graphic showing how people affect ecosystems in the Southern Ocean
Humans are changing Southern Ocean ecosystems in many ways, both directly (purple-blue arrows) and indirectly (red arrows).
From: Chown et al (2015) The changing form of Antarctic biodiversity. Nature, 522: 431-438, CC BY-ND

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.

Changing environments mean changing ecosystems

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.

Ocean off the Antarctic coast
Antarctic ocean waters are warming dramatically.
Ceridwen Fraser, Author provided

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.

Seals and seaweed on a southern beach.
Southern bull kelp does not grow in the Antarctic, but it floats well and recent research has shown that it can drift to Antarctica, travelling tens of thousands of kilometres across the Southern Ocean.
Author provided

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.

Adélie penguins rest and breed on land, but go to sea to forage for food.
Michelle LaRue, Author provided

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.The Conversation

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

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

It might be the world’s biggest ocean, but the mighty Pacific is in peril



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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 ocean plastic scourge

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.

A wildlife killer

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.




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


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.

A turtle tangled in a fishing net
Discarded fishing nets, or ‘ghost nets’ can entangle animals like turtles.
Shutterstock

A scourge on small island nations

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.

Kamilo Beach is referred to as the world’s dirtiest.

Subtropical garbage patches

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.

Locations of the five subtropical garbage patches.
van der Mheen et al. (2019)

Our ocean garbage shame

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.




Read more:
Whales and dolphins found in the Great Pacific Garbage Patch for the first time


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.

Divers releasing a whale shark from a fishing net.

Fisheries on the verge of collapse

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.

A school of fish
Overfishing is stripping the Pacific Ocean of marine life.
Shutterstock

Not plenty of fish in the sea

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.

Developing countries, including Indonesia and China, are major overfishers, but so too are developing nations.




Read more:
When hurricanes temporarily halt fishing, marine food webs recover quickly


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.

A plate of sushi
Stocks of fish used to make sushi have declined in number.
Shutterstock

So what’s driving overfishing?

There are many reasons why overfishing occurs and why it is goes unchecked. The evidence points to:




Read more:
The race to fish: how fishing subsidies are emptying our oceans


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.

Man checks fishing haul
Globally, compliance and enforcement of fishing limits is often poor.
Shutterstock

What else can we do?

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.

fish in a net
Providing fishers with an alternative income can help prevent overfishing.
Shutterstock



Read more:
Poor Filipino fishermen are making millions protecting whale sharks


The threat of acidic oceans

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.

A chemical reaction

Ocean acidification involves a decrease in the pH of seawater as it absorbs carbon dioxide (CO₂) from the atmosphere.

Each year, humans emit 35 billion tonnes of CO₂ through activities such as burning of fossil fuels and deforestation.

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.

An industrial city from the air
Each year, humans emit 35 billion tonnes of CO₂.
Shutterstock

Why is ocean acidification harmful?

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.

Such impairment appears to be the result of changes in neurological, physiological, and molecular functions in fish brains.

A sea hare
Sea hares exposed to acidification made poorer decisions.
Shutterstock

Predicting the winners and losers

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.




Read more:
Acid oceans are shrinking plankton, fuelling faster climate change


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.

A clownfish
Clownfish struggled to tell friend from foe when exposed to ocean acidification.
Shutterstock

It’s not too late

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.




Read more:
Coronavirus is a ‘sliding doors’ moment. What we do now could change Earth’s trajectory


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.The Conversation

The Pacific Ocean off the Taiwan coast
Our decisions today will determine the fate of tomorrow’s oceans.
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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

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

Pacific killer whales are dying — new research shows why



A female killer whale leaps from the water in Puget Sound near Seattle.
(AP Photo/Elaine Thompson)

Stephen Raverty, University of British Columbia and Joseph K. Gaydos, University of California, Davis

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.

A dead killer whale lies on her side in shallow water.
Emaciated female killer whale from Hawaii.
(NOAA/NMFS/PIRO), CC BY

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.

We can do better

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.

A dead killer whale lies on a beach
The 18-year-old male southern resident killer whale, J34, stranded near Sechelt, B.C., on Dec. 21, 2016. Post-mortem examination suggested he died from trauma consistent with vessel strike.
(Paul Cottrell/Fisheries and Oceans Canada), Author provided

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.

Direct human impact

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.The Conversation

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

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

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



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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.
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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.




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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.
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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.




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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.




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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.