Scientific research doesn’t usually mean being strapped in a harness by the open paratroop doors of a Vietnam-war-era Hercules plane. But that’s the situation I found myself in several years ago, the result of which has just been published in the journal Marine Biodiversity.
As part of the Ocean Cleanup’s Aerial Expedition, I was coordinating a visual survey team assessing the largest accumulation of ocean plastic in the world: the Great Pacific Garbage Patch.
When the aircraft’s doors opened in front of me over the Pacific Ocean for the first time, my heart jumped into my throat. Not because I was looking 400m straight down to the wild sea below as it passed at 260km per hour, but because of what I saw.
This was one of the most remote regions of the Pacific Ocean, and the amount of floating plastic nets, ropes, containers and who-knows-what below was mind-boggling.
However, it wasn’t just debris down there. For the first time, we found proof of whales and dolphins in the Great Pacific Garbage Patch, which means it’s highly likely they are eating or getting tangled in the huge amount of plastic in the area.
The Great Pacific Garbage Patch is said to be the largest accumulation of ocean plastic in the world. It is located between Hawaii and California, where huge ocean currents meet to form the North Pacific subtropical gyre. An estimated 80,000 tonnes of plastic are floating in the Great Pacific Garbage Patch.
Our overall project was overseen and led by The Ocean Cleanup’s founder Boyan Slat and then-chief scientist Julia Reisser. We conducted two visual survey flights, each taking an entire day to travel from San Francisco’s Moffett Airfield, survey for around two hours, and travel home. Along with our visual observations, the aircraft was fitted with a range of sensors, including a short-wave infrared imager, a Lidar system (which uses the pulse from lasers to map objects on land or at sea), and a high-resolution camera.
Both visual and technical surveys found whales and dolphins, including sperm and beaked whales and their young calves. This is the first direct evidence of whales and dolphins in the heart of the Great Pacific Garbage Patch.
Plastics in the ocean are a growing problem for marine life. Many species can mistake plastics for food, consume them accidentally along with their prey or simply eat fish that have themselves eaten plastic.
Both beaked and sperm whales have been recently found with heavy plastic loads in their stomachs. In the Philippines, a dying beaked whale was found with 40kg of plastic in its stomach, and in Indonesia, a dead sperm whale washed ashore with 115 drinking cups, 25 plastic bags, plastic bottles, two flip-flops, and more than 1,000 pieces of string in its stomach.
The most common debris we were able to identify by eye was discarded or lost fishing nets, often called “ghost nets”. Ghost nets can drift in the ocean for years, trapping animals and causing injuries, starvation and death.
Whales and dolphins are often found snared in debris. Earlier this year, a young sperm whale almost died after spending three years tangled in a rope from a fishing net.
During our observation we saw young calves with their mothers. Calves are especially vulnerable to becoming trapped. With the wide range of ocean plastics in the garbage patch, it is highly likely animals in the area ingest and become tangled in it.
It’s believed the amount of plastics in the ocean could triple over the next decade. It is clear the problem of plastic pollution has no political or geographic boundaries.
The most devastating effects fall on communities in poverty. New research shows the Great Pacific Garbage Patch is rapidly growing, posing a greater threat to wildlife. It reinforces the global movement to reduce, recycle and remove plastics from the environment.
But to really tackle this problem we need creative solutions at every level of society, from communities to industries to governments and international organisations.
To take one possibility, what if we invested in fast-growing, sustainably cultivated bamboo to replace millions of single-use plastics? It could be produced by the very countries most affected by this crisis: poorer and developing nations.
It is only one of many opportunities to dramatically reduce plastic waste, improve the health of our environments and people, and to help communities most susceptible to plastic pollution.
Tropical tuna are one of the few wild animals we still hunt in large numbers, but finding them in the vast Pacific ocean can be tremendously difficult. However, fishers have long known that tuna are attracted to, and will aggregate around, floating objects such as logs.
In the past, people used bamboo rafts to attract tuna, fishing them while they were gathered underneath. Today, the modern equivalent – called fish aggregating devices, or FADs – usually contain high-tech equipment that tell fishers where they are and how many fish have accumulated nearby.
It’s estimated that between 30,000 and 65,000 man-made FADs are deployed annually and drift through the Western and Central Pacific Ocean to be fished on by industrial fishers. Pacific island countries are reporting a growing number of FADs washing up on their beaches, damaging coral reefs and potentially altering the distribution of tuna.
Our research in two papers, one of which was published today in Scientific Reports, looks for the first time at where ocean currents take these FADs and where they wash up on coastlines in the Pacific.
We do not fully understand why some fish and other marine creatures aggregate around floating objects, but they are a source of attraction for many species. FADs are commonly made of a raft with 30-80m of old ropes or nets hanging below. Modern FADs are attached to high-tech buoys with solar-powered electronics.
The buoys record a FAD’s position as it drifts slowly across the Pacific, scanning the water below to measure tuna numbers with echo-sounders and transmitting this valuable information to fishing vessels by satellite.
Throughout their lifetimes FADs may be exchanged between vessels, recovered and redeployed, or fished and simply left to drift with their buoy to further aggregate tuna. Fishers may then abandon them and remotely deactivate the buoys’ satellite transmission when the FAD leaves the fishing area.
The Western and Pacific Ocean provides around 55% of the worlds’ 5 million tonne catch of tropical tuna, and is the main source of skipjack, yellowfin and bigeye tuna worth some US$6 billion annually.
Fishing licence fees can provide up to 98% of government revenue for some Pacific Island countries and territories. These countries balance the need to sustainably manage and harvest one of the only renewable resources they have, while often having a limited capacity to fish at an industrial scale themselves.
FADs help stabilise catch rates and make fishing fleets more profitable, which in turn generate revenue for these nations.
However, they are not without problems. Catches around FADs tend to include more bycatch species, such as sharks and turtles, as well as smaller immature tuna.
The abandonment or loss of FADs adds to the growing mass of marine debris floating in the ocean, and they increasingly damage coral as they are dragged and get caught on reefs.
Perhaps most importantly, we don’t know how the distribution of FADs affects fishing effort in the region. Given that each fleet and fishing company has their own strategy for using FADs, understanding how the total number of FADs drifting in one area increases the catch of tuna is crucial for sustainably managing these valuable species.
Our research, published in Environmental Research Communications and Scientific Reports, used a regional FAD tracking program and fishing data submitted by Pacific countries, in combination with numerical ocean models and simulations of virtual FADs, to work out how FADs travel on ocean currents during and after their use.
In general, FADs are first deployed by fishers in the eastern and central Pacific. They then drift west with the prevailing currents into the core industrial tropical tuna fishing zones along the equator.
We found equatorial countries such as Kiribati have a high number of FADs moving through their waters, with a significant amount washing up on their shores. Our research showed these high numbers are primarily due to the locations in which FADs are deployed by fishing companies.
In contrast, Tuvalu, which is situated on the edge of the equatorial current divergence zone, also sees a high density of FADs and beaching. But this appears to be an area that generally aggregates FADs regardless of where they are deployed.
Unsurprisingly, many FADs end up beaching in countries at the western edge of the core fishing grounds, having drifted from different areas of the Pacific as far away as Ecuador. This concentration in the west means reefs along the edge of the Solomon Islands and Papua New Guinea are particularly vulnerable, with currents apparently forcing FADs towards these coasts more than other countries in the region.
Overall, our studies estimate that between 1,500 and 2,200 FADs drifting through the Western and Central Pacific Ocean wash up on beaches each year. This is likely to be an underestimate, as the tracking devices on many FADs are remotely deactivated as they leave fishing zones.
Using computer simulations, we also found that a significant number of FADs are deployed in the eastern Pacific Ocean, left to drift so they have time to aggregate tuna, and subsequently fished on in the Western and Central Pacific Ocean. This complicates matters as the eastern Pacific is managed by an entirely different fishery Commission with its own set of fisheries management strategies and programmes.
Growing human populations and climate change are increasing pressure on small island nations. FAD fishing is very important to their economic and food security, allowing access to the wealth of the ocean’s abundance.
We need to safeguard these resources, with effective management around the number and location of FAD deployments, more research on their impact on tuna and bycatch populations, the use of biodegradable FADs, or effective recovery programs to remove old FADs from the ocean at the end of their slow journeys across the Pacific.
Joe Scutt Phillips, Senior Fisheries Scientists (Tuna Behavioural Ecology), Secretariat of the Pacific Community; Alex Sen Gupta, Senior Lecturer, School of Biological, Earth and Environmental Sciences, UNSW; Graham Pilling, Principal Fisheries Scientist, Secretariat of the Pacific Community, and Lauriane Escalle, Fisheries Scientist, Secretariat of the Pacific Community
Climate change is rapidly changing the oceans, driving coral reefs around the world to breaking point. Widely publicised marine heatwaves aren’t the only threat corals are facing: the seas are increasingly acidic, have less oxygen in them, and are gradually warming as a whole.
Each of these problems reduces coral growth and fitness, making it harder for reefs to recover from sudden events such as massive heatwaves.
Our research, published today in Marine Ecology Progress Series, investigates corals on the Great Barrier Reef that are surprisingly good at surviving in increasingly hostile waters. Finding out how these “super corals” can live in extreme environments may help us unlock the secret of coral resilience helping to save our iconic reefs.
The central cause of these problems is climate change, so the central solution is reducing carbon emissions. Unfortunately, this is not happening rapidly enough to help coral reefs, so scientists also need to explore more immediate conservation options.
To that end, many researchers have been looking at coral that manages to grow in typically hostile conditions, such as around tide pools and intertidal reef zones, trying to unlock how they become so resilient.
These extreme coral habitats are not only natural laboratories, they house a stockpile of extremely tolerant “super corals”.
“Super coral” generally refers to species that can survive both extreme conditions and rapid changes in their environment. But “super” is not a very precise term!
Our previous research quantified these traits so other ecologists can more easily use super coral in conservation. There are a few things that need to be established to determine whether a coral is “super”:
What hazard can the coral survive? For example, can it deal with high temperature, or acidic water?
How long did the hazard last? Was it a short heatwave, or a long-term stressor such as ocean warming?
Did the coral survive because of a quality such as genetic adaption, or was it tucked away in a particularly safe spot?
How much area does the coral cover? Is it a small pocket of resilience, or a whole reef?
Is the coral trading off other important qualities to survive in hazardous conditions?
Is the coral super enough to survive the changes coming down the line? Is it likely to cope with future climate change?
If a coral ticks multiple boxes in this list, it’s a very robust species. Not only will it cope well in our changing oceans, we can also potentially distribute these super corals along vulnerable reefs.
We discovered mangrove lagoons near coral reefs can often house corals living in very extreme conditions – specifically, warm, more acidic and low oxygen seawater.
Previously we have reported corals living in extreme mangroves of the Seychelles, Indonesia, New Caledonia – and in our current study living on the Great Barrier Reef. We report diverse coral populations surviving in conditions more hostile than is predicted over the next 100 years of climate change.
Importantly, while some of these sites only have isolated populations, other areas have actively building reef frameworks.
Particularly significant were the two mangrove lagoons on the Great Barrier Reef. They housed 34 coral species, living in more acidic water with very little oxygen. Temperatures varied widely, over 7℃ in the period we studied – and included periods of very high temperatures that are known to cause stress in other corals.
While coral cover was often low and the rate at which they build their skeleton was reduced, there were established coral colonies capable of surviving in these conditions.
The success of these corals reflect their ability to adapt to daily or weekly conditions, and also their flexible relationship with various symbiotic micro-algae that provide the coral with essential resources.
While we are still in the early phases of understanding exactly how these corals can aid conservation, extreme mangrove coral populations hold a reservoir of stress-hardened corals. Notably the geographic size of these mangrove locations are small, but they have a disproportionately high conservation value for reef systems.
However, identification of these pockets of extremely tolerant corals also challenge our understanding of coral resilience, and of the rate and extent with which coral species can resist stress.
Emma F Camp, DECRA & UTS Chancellor’s Research Fellow, Climate Change Cluster, Future Reefs Research Programe, University of Technology Sydney and David Suggett, Associate Professor in Marine Biology, University of Technology Sydney
Increasingly acidic oceans are putting algae at risk, threatening the foundation of the entire marine food web.
Our research into the effects of CO₂-induced changes to microscopic ocean algae – called phytoplankton – was published today in Nature Climate Change. It has uncovered a previously unrecognised threat from ocean acidification.
In our study we discovered increased seawater acidity reduced Antarctic phytoplanktons’ ability to build strong cell walls, making them smaller and less effective at storing carbon. At current rates of seawater acidification, we could see this effect before the end of the century.
Carbon dioxide emissions are not just altering our atmosphere. More than 40% of CO₂ emitted by people is absorbed by our oceans.
While reducing the CO₂ in our atmosphere is generally a good thing, the ugly consequence is this process makes seawater more acidic. Just as placing a tooth in a jar of cola will (eventually) dissolve it, increasingly acidic seawater has a devastating effect on organisms that build their bodies out of calcium, like corals and shellfish.
Many studies to date have therefore taken the perfectly logical step of studying the effects of seawater acidification on these “calcifying” creatures. However, we wanted to know if other, non-calcifying, species are at risk.
Phytoplankton use photosynthesis to turn carbon in the atmosphere into carbon in their bodies. We looked at diatoms, a key group of phytoplankton responsible for 40% of this process in the ocean. Not only do they remove huge amounts of carbon, they also fuel entire marine food webs.
Diatoms use dissolved silica to build the walls of their cells. These dense, glass-like structures mean diatoms sink more quickly than other phytoplankton and therefore increase the transfer of carbon to the sea floor where it may be stored for millennia.
This makes diatoms major players in the global carbon cycle. That’s why our team decided to look at how climate-change-driven ocean acidification might affect this process.
We exposed a natural Antarctic phytoplankton community to increasing levels of acidity. We then measured the rate at which the whole community used dissolved silica to build their cells, as well as the rates of individual species within the community.
The more acidic the seawater, the more the diatom communities were made up of smaller species, reducing the total amount of silica they produced. Less silica means the diatoms aren’t heavy enough to sink quickly, reducing the rate at which they float down to the sea bed, safely storing carbon away from the atmosphere.
On examining individual cells, we found many of the species were highly sensitive to increased acidity, reducing their individual silicification rates by 35-80%. These results revealed not only are communities changing, but species that remain in the community are building less-dense cell walls.
Most alarming, many of the species were affected at ocean pH levels predicted for the end of this century, adding to a growing body of evidence showing significant ecological implications of climate change will take effect much sooner than previously anticipated.
These losses in silica production could have far reaching consequences for the biology and chemistry of our oceans.
Many species affected are also an important component of the diet of the Antarctic krill, which is central to the Antarctic marine food web.
Fewer diatoms sinking to the ocean floor mean significant changes in silicon cycling and carbon burial. In a time when carbon drawn down by our ocean is crucial to helping sustain our atmospheric systems, any loss from this process will exacerbate CO₂ pollution.
Our new research adds yet another group of organisms to the list of climate change casualties. It emphasises the urgent need to reduce our dependency on fossil fuels.
The only course of action to prevent catastrophic climate change is to stop emitting CO₂. We need to cut our emissions soon, if we hope to keep our oceans from becoming too acidic to sustain healthy marine ecosystems.
The rise in sea levels is not the only way climate change will affect the coasts. Our research, published today in Nature Climate Change, found a warming planet will also alter ocean waves along more than 50% of the world’s coastlines.
If the climate warms by more than 2℃ beyond pre-industrial levels, southern Australia is likely to see longer, more southerly waves that could alter the stability of the coastline.
Scientists look at the way waves have shaped our coasts – forming beaches, spits, lagoons and sea caves – to work out how the coast looked in the past. This is our guide to understanding past sea levels.
But often this research assumes that while sea levels might change, wave conditions have stayed the same. This same assumption is used when considering how climate change will influence future coastlines – future sea-level rise is considered, but the effect of future change on waves, which shape the coastline, is overlooked.
Waves are generated by surface winds. Our changing climate will drive changes in wind patterns around the globe (and in turn alter rain patterns, for example by changing El Niño and La Niña patterns). Similarly, these changes in winds will alter global ocean wave conditions.
Curious Kids: why are there waves?
Further to these “weather-driven” changes in waves, sea level rise can change how waves travel from deep to shallow water, as can other changes in coastal depths, such as affected reef systems.
Recent research analysed 33 years of wind and wave records from satellite measurements, and found average wind speeds have risen by 1.5 metres per second, and wave heights are up by 30cm – an 8% and 5% increase, respectively, over this relatively short historical record.
These changes were most pronounced in the Southern Ocean, which is important as waves generated in the Southern Ocean travel into all ocean basins as long swells, as far north as the latitude of San Francisco.
Given these historical changes in ocean wave conditions, we were interested in how projected future changes in atmospheric circulation, in a warmer climate, would alter wave conditions around the world.
As part of the Coordinated Ocean Wave Climate Project, ten research organisations combined to look at a range of different global wave models in a variety of future climate scenarios, to determine how waves might change in the future.
While we identified some differences between different studies, we found if the 2℃ Paris agreement target is kept, changes in wave patterns are likely to stay inside natural climate variability.
However in a business-as-usual climate, where warming continues in line with current trends, the models agreed we’re likely to see significant changes in wave conditions along 50% of the world’s coasts. These changes varied by region.
Less than 5% of the global coastline is at risk of seeing increasing wave heights. These include the southern coasts of Australia, and segments of the Pacific coast of South and Central America.
On the other hand decreases in wave heights, forecast for about 15% of the world’s coasts, can also alter coastal systems.
But describing waves by height only is the equivalent of describing an orchestra simply by the volume at which it plays.
Some areas will see the height of waves remain the same, but their length or frequency change. This can result in more force exerted on the coast (or coastal infrastructure), perhaps seeing waves run further up a beach and increasing wave-driven flooding.
Similarly, waves travelling from a slightly altered direction (suggested to occur over 20% of global coasts) can change how much sand they shunt along the coast – important considerations for how the coast might respond. Infrastructure built on the coast, or offshore, is sensitive to these many characteristics of waves.
While each of these wave characteristics is important on its own, our research identified that about 40% of the world’s coastlines are likely to see changes in wave height, period and direction happening simultaneously.
While some readers may see intense waves offering some benefit to their next surf holiday, there are much greater implications for our coastal and offshore environments. Flooding from rising sea levels could cost US$14 trillion worldwide annually by 2100 if we miss the target of 2℃ warming.
How coastlines respond to future climate change will be a response to a complex interplay of many processes, many of which respond to variable and changing climate. To focus on sea level rise alone, and overlooking the role waves play in shaping our coasts, is a simplification which has great potential to be costly.
The authors would like to acknowledge the contribution of Xiaolan Wang, Senior Research Scientist at Environment and Climate Change, Canada, to this article.
Mark Hemer, Principal Research Scientist, Oceans and Atmosphere, CSIRO; Ian Young, Kernot Professor of Engineering, University of Melbourne; Joao Morim Nascimento, PhD Candidate, Griffith University, and Nobuhito Mori, Professor, Kyoto University
The Pacific Islands Forum meeting in Tuvalu this week has ended in open division over climate change. Australia ensured its official communique watered down commitments to respond to climate change, gaining a hollow victory.
Traditionally, communiques capture the consensus reached at the meeting. In this case, the division on display between Australia and the Pacific meant the only commitment is to commission yet another report into what action needs to be taken.
The cost of Australia’s victory is likely to be great, as it questions the sincerity of Prime Minister Scott Morrison’s commitment to “step up” engagement in the Pacific.
Australia’s stance on climate change has become untenable in the Pacific. The inability to meet Pacific Island expectations will erode Australia’s influence and leadership credentials in the region, and provide opportunities for other countries to grow influence in the region.
When Morrison arrived in Tuvalu, he was met with an uncompromising mood. In fact, the text of an official communique was only finished after 12 hours of pointed negotiations.
While the “need for urgent, immediate actions on the threats and challenges of climate change”, is acknowledged, the Pacific was looking for action, not words.
What’s more, the document reaffirmed that “strong political leadership to advance climate change action” was needed, but leadership from Australia was sorely missing. It led Tuvaluan Prime Minister Enele Sopoaga to note:
I think we can say we should’ve done more work for our people.
Presumably, he would have hoped Australia could be convinced to take more climate action.
In an unprecedented show of dissent, smaller Pacific Island countries produced the alternative Kainaki II Declaration. It captures the mood of the Pacific in relation to the existential threat posed by climate change, and the need to act decisively now to ensure their survival.
And it details the commitments needed to effectively address the threat of climate change. It’s clear nothing short of transformational change is needed to ensure their survival, and there is rising frustration in Australia’s repeated delays to take effective action.
Australia hasn’t endorsed the alternative declaration and Canberra has signalled once and for all that compromise on climate change is not possible. This is not what Pacific leaders hoped for and will come at a diplomatic cost to Australia.
Conflict had already begun brewing in the lead up to the Pacific Islands Forum. The Pacific Islands Development Forum – the brainchild of the Fijian government, which sought a forum to engage with Pacific Island Nations without the influence of Australia and New Zealand – released the the Nadi Bay Declaration in July this year.
This declaration called on coal producing countries like Australia to cease all production within a decade.
But it’s clear Canberra believes compromise of this sort on climate change would undermine Australia’s economic growth and this is the key stumbling block to Australia answering its Pacific critics with action.
As Sopoaga said to Morrison:
You are concerned about saving your economy in Australia […] I am concerned about saving my people in Tuvalu.
And a day before the meeting, Canberra announced half a billion dollars to tackle climate change in the region. But it received a lukewarm reception from the Pacific.
The message is clear: Canberra cannot buy off the Pacific. In part, this is because Pacific Island countries have new options, especially from China, which has offered Pacific island countries concessional loans.
As tension built at the Pacific Island Forum meeting, New Zealand Foreign Minister Winston Peters argued there was a double standard with respect to the treatment of China on climate change.
China is the world’s largest emitter of climate change gasses, but if there is a double standard it’s of Australia’s making.
Australia purports to be part of the Pacific family that can speak and act to protect the interests of Pacific Island countries in the face of China’s “insidious” attempts to gain influence through “debt trap” diplomacy. This is where unsustainable loans are offered with the aim of gaining political advantage.
But countering Chinese influence in the Pacific is Australia’s prime security interest, and is a secondary issue for the Pacific.
But unlike Australia, China has never claimed the moral high ground and provides an attractive alternative partner, so it will likely gain ground in the battle for influence in the Pacific.
For the Pacific Island Forum itself, open dissent is a very un-Pacific outcome. Open dissent highlights the strains in the region’s premier intergovernmental organisation.
Australia and (to a lesser extent) New Zealand’s dominance has often been a source of criticism, but growing confidence among Pacific leaders has changed diplomatic dynamics forever.
This new pacific diplomacy has led Pacific leaders to more steadfastly identify their security interests. And for them, the need to respond to climate change is non-negotiable.
If winning the geopolitical contest with China in Pacific is Canberra’s priority, then far greater creativity will be needed as meeting the Pacific half way on climate change is a prerequisite for success.