Future ‘ocean cities’ need green engineering above and below the waterline



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Artificial islands can cause huge environmental issues for coastlines.
The Forest City Project

Katherine Dafforn, UNSW; Ana Bugnot, UNSW; Eliza Heery, National University of Singapore, and Mariana Mayer-Pinto, UNSW

Population growth has seen skylines creep ever higher and entire cities rise from ocean depths. The latest “ocean city” is the Chinese-developed Forest City project. By 2045, four artificial islands in Malaysia will cover 14km² of ocean (an area larger than 10,000 Olympic swimming pools), and support 700,000 residents.

Often overlooked, however, is the damage that artificial islands can cause to vital seafloor ecosystems. But it doesn’t have to be this way. If proper planning and science are integrated, we can develop the design strategies that will help build the “blue-green” ocean cities of tomorrow.




Read more:
Concrete coastlines: it’s time to tackle our marine ‘urban sprawl’


Colonising the ocean frontier

Ever growing numbers of human-made structures are occupying our oceans. Cities built on artificial islands in the ocean are providing a solution for urban planners trying to manage the population squeeze.

And yet, so-called “ocean sprawl” dates as far back as Ancient Egypt. Over the past few centuries, artificial islands have been built through land reclamation. Land reclamation is the process of creating new land from existing water bodies.

Atlantis, The Palm Hotel in Dubai, United Arab Emirates is built on an entirely artificial island.
Shutterstock

The Netherlands, for instance, has been draining lakes and expanding its coastline to fight the advance of the sea since the 1500s. The Dutch actually built one of the first and largest artificial islands, which is now home to some 400,000 people. Japan’s third-busiest airport, the Kansai International Airport, was built on an artificial island in 1994. China has also been building into the oceans, reclaiming more than 13,000km² of seafloor and an estimated 65% of tidal habitat since the 1950s.

The artificial Eden Island in Mahe, Seychelles.
from http://www.shutterstock.com

Using Google maps, we were able to identify more than 450 artificial islands around the world, including the famous Palm Islands of Dubai. These are often celebrated as engineering marvels, but at what cost to the marine environment?

We can’t ignore what lies beneath

Marine habitats have always been essential for human life in coastal regions. They provide food, building and crafting materials, and less-known services such as coastal protection, nutrient cycling and pollution filtration.

One of the World Map islands in Dubai, United Arab Emirates.
Shutterstock

The creation of artificial islands causes large changes to the seabed by permanently smothering local habitats. In many parts of the world, existing habitats provide the foundation for artificial island construction. For instance, artificial islands in the tropics are often built directly on top of coral reefs. This leads to considerable destruction of already threatened ecosystems.

Land reclamation also impacts nearby habitats that are particularly sensitive to murky waters, such as coral reefs and seagrass beds. In Singapore, land reclamation is associated with coral reef decline due to sedimentation and resulting light reductions. Singapore has lost nearly 45% of the country’s intertidal reef flats and almost 40% of intertidal mudflats.

When the ecological, economic, and social value of marine habitats are considered, artificial islands and ocean sprawl seem to be indulgences that we cannot afford. The effects would be akin to the suburban sprawl of the 20th century. To avoid this cost, we need to address the complexities of the underwater world in urban planning and development.

“Blue urbanism”

In his book Blue Urbanism, Timothy Beatley calls for urban planners to consider and value ocean ecosystems. He argues that we need to recognise the psychological value of human connections to blue space, and extend green practices on land into marine environments. While some artificial island developments such as the Forest City project are touted as “eco-cities”, more could be done both to minimise impacts below the waterline and integrate underwater environments into city life.

Why not combine a “Forest City” with the principles of a “Sponge City”? While native plantings in a forest city could help to reduce air pollution, sponge cities seek to “absorb” and reuse rainwater, thus reducing pollution entering the oceans through stormwater runoff. Around artificial islands, developers could also embrace the water filtration powerhouse of the oceans: active oyster reefs.

The location of future constructions should also be carefully evaluated to ensure the preservation of important marine habitats. Artificial islands have the potential to create fragmented seascapes, but with careful spatial planning and smart designs, they could create corridors for some climate migrants or those threatened species most at risk from habitat loss.

The ConversationDesigns based on ecological principles can reduce the impacts of artificial islands on natural habitats. However, applications of “blue-green” infrastructure remain largely untested at large scales. New designs, building strategies and spatial planning that integrate seascapes and landscapes are an opportunity for both “smarter” cities and experimentation for the development of successful blue-green technologies.

Katherine Dafforn, Senior Research Associate in Marine Ecology, UNSW; Ana Bugnot, Research Associate, UNSW; Eliza Heery, Research Fellow in Marine Ecology, National University of Singapore, and Mariana Mayer-Pinto, Senior Research Associate in marine ecology, UNSW

This article was originally published on The Conversation. Read the original article.

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New coral bleaching outbreak in NT a worrying sign of our warming oceans



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The increasingly bleached coral at Black Point on the Cobourg Peninsula is a worrying sign of what’s to come for other coral reefs in Australia.
Alan Withers, Author provided

Selina Ward, The University of Queensland

An outbreak of coral bleaching has been reported over the summer in Gang Gurak Barlu National Park on the Cobourg Peninsula, 60km northeast of Darwin, homeland of several clans of the Iwaidja-speaking Aboriginal people of Western Arnhem Land.

As no formal monitoring or assessment program is in place for these reefs, it’s impossible to gauge the full severity and extent of the bleaching. However, this video from Black Point on the Cobourg Peninsula contrasts the healthy reef in 2015 and the bleached reef in 2018.

Footage courtesy Alan Withers, music from Kai Engel – Anxiety.

The Northern Territory has unique marine ecosystems which are largely untouched and sit in waters receiving flow from untamed rivers. There are extensive coral reefs with abundant breeding turtle populations, saltwater crocodiles and sharks.

In January this year, the water temperature between the Northern Territory and Papua New Guinea reached what the National Oceanic and Atmospheric Administration (NOAA) calls Alert Level 2 – its highest alert for the risk of bleaching and subsequent coral death.

This is an indication of the duration and intensity of a warming event, measured in “degree heating weeks” – the number of degrees above the average summer maximum temperature, multiplied by the number of weeks. Alert Level 2 indicates at least eight degree heating weeks.

This is not the first time coral bleaching has been seen in the NT. Severe bleaching was recorded in seas off Arnhem Land during the global bleaching event in 2015-16.

Increases in sea surface temperature cause mass bleaching events. The bleached corals have lost most of the single-celled algae, called zooxanthellae, that live and photosynthesise inside the coral cells and provide the corals with most of their energy.

The Great Barrier Reef also suffered severe bleaching in 2016. This resulted in 67% mortality in its northern sections, dwarfing the effects of previous bleaching events in 1998 and 2002.




Read more:
How much coral has died in the Great Barrier Reef’s worst bleaching event?


Bleaching patterns tell a story

The bleaching patterns of these three events were tightly correlated with degree heating weeks within geographic areas, with the 1998 and 2002 events having prominent effects in the southern areas.

In 2016 the highest degree heating weeks were recorded on the northern stretches of the Great Barrier Reef, where the most severe bleaching occurred. Southern areas experienced temperatures close to average, partly due to cooler water from Cyclone Winston.

In 2017 the Great Barrier Reef experienced another bleaching event that affected northern and central areas. This event was particularly disturbing, as it followed 2016 and, unlike 1998, 2002 and 2016, it was not an El Niño year.

It is vital that reefs have time to recover between bleaching events if they are to avoid becoming degraded. For corals that survive being bleached, full recovery takes time. Reproductive output can be reduced for extended periods, resulting in less successful recruitment.

This, often combined with the increased competition from algae and soft corals, means that replacement of corals that do not survive bleaching events can be slow. Even fast-growing corals require 10-15 years to return to their prebleaching size.




Read more:
Will the Great Barrier Reef recover from its worst-ever bleaching?


Recent analysis has shown that the intervals between bleaching events across the globe have decreased substantially since the 1980s. The median period between bleaching events is now six years. One reason for this is that temperatures in La Niña conditions (when we expect lower temperatures) are now higher than those of El Niño conditions in the 1980s.

This is further evidence that if we continue on our current path of rapidly increasing emissions, it is increasingly likely that bleaching events will occur annually later this century, as predicted by coral scientists last century.

Resilience of reefs

The 2016 bleaching event demonstrated that areas with good water quality and controlled fishing were not protected from bleaching during this temperature anomaly. However, local conditions can be vitally important for recovery in previously bleached areas and to maintain healthy populations prior to bleaching events.

Unfortunately, climate change is not only causing higher temperatures but also increased intensity of storm and cyclone damage, sea level rise and ocean acidification. So we need resilient reefs to cope with these additional challenges.

We can increase the resilience of reefs by improving water quality. We can do this by reducing sediment and nitrogen and phosphorus input and other toxins such as coal dust, herbicides and pesticides, alongside regulating fishing pressure and protecting as many areas as possible.

New management approaches urgently needed

The beautiful reefs of the Northern Territory and the Great Barrier Reef need to be protected. If we wish to enjoy Australia’s reefs in future decades, it is vital that we change our management priorities.

State and federal governments need to give these areas the priority they deserve through marine parks and ranger programs, and regulation of potentially harmful activities. Water quality needs to be funded in a serious manner. Industrial developments, such as port expansions, need to be evaluated with protection of reefs as a primary concern.

The ConversationReducing emissions dramatically is crucial to slowing all the climate change effects on reefs. Australia can lead by example by rapidly moving away from fossil fuels and opening no new coal mines.

Selina Ward, Lecturer, School of Biological Sciences, The University of Queensland

This article was originally published on The Conversation. Read the original article.

Our acid oceans will dissolve coral reef sands within decades



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Researchers studied reef sands at Heron Island, Hawaii, Bermuda and Tetiaroa. In this photo, white areas show the predominance of sand on reefs.
Southern Cross University

Bradley Eyre, Southern Cross University

Carbonate sands on coral reefs will start dissolving within about 30 years, on average, as oceans become more acidic, new research published today in Science shows.

Carbonate sands, which accumulate over thousands of years from the breakdown of coral and other reef organisms, are the building material for the frameworks of coral reefs and shallow reef environments like lagoons, reef flats and coral sand cays.

But these sands are sensitive to the chemical make-up of sea water. As oceans absorb carbon dioxide, they acidify – and at a certain point, carbonate sands simply start to dissolve.

The world’s oceans have absorbed around one-third of human-emitted carbon dioxide.

Carbonate sand is vulnerable

For a coral reef to grow or be maintained, the rate of carbonate production (plus any external sediment supply) must be greater than the loss through physical, chemical and biological erosion, transport and dissolution.

It is well known that ocean acidification reduces the amount of carbonate material produced by corals. Our work shows that reefs face a double-whammy: the amount of carbonate material produced will decrease, and the newly produced and stored carbonate sands will also dissolve.

Researchers used benthic chambers (pictured) to test how different levels of seawater acidity affect reef sediments.
Steve Dalton/Southern Cross University

We measured the impact of acidity on carbonate sands by placing underwater chambers over coral reefs sands at Heron Island, Hawaii, Bermuda and Tetiaroa in the Pacific and Atlantic Oceans. Some of the chambers were then acidified to represent future ocean conditions.

The rate at which the sands dissolve was strongly related to the acidity of the overlying seawater, and was ten times more sensitive than coral growth to ocean acidification. In other words, ocean acidification will impact the dissolution of coral reef sands more than the growth of corals.

This probably reflects the corals’ ability to modify their environment and partially adjust to ocean acidification, whereas the dissolution of sands is a geochemical process that cannot adapt.

Sands on all four reefs showed the same response to future ocean acidification, but the impact of ocean acidification on each reef is different due to different starting conditions. Carbonate sands in Hawaii are already dissolving due to ocean acidification, because this coral reef site is already disturbed by pollution from nutrients and organic matter from the land. The input of nutrients stimulates algal growth on the reef.

In contrast, carbonate sands in Tetiaroa are not dissolving under current ocean acidification because this site is almost pristine.

What will this mean for coral reefs?

Our modelling at 22 locations shows that net sand dissolution will vary for each reef. However, by the end of the century all but two reefs across the three ocean basins would on average experience net dissolution of the sands.

A transition to net sand dissolution will result in loss of material for building shallow reef habitats such as reef flats and lagoons and associated coral cays. What we don’t know is whether an entire reef will slowly erode or simply collapse, once the sediments become net dissolving, as the corals will still grow and create reef framework. Although they will most likely just slowly erode.

It may be possible to reduce the impact of ocean acidification on the dissolution of reef sands, by managing the impact of organic matter like algae at local and regional scales. This may provide some hope for some already disturbed reefs, but much more research on this topic is required.

The ConversationUltimately, the only way we can stop the oceans acidifying and the dissolving of coral reefs is concerted action to lower CO₂ emissions.

Bradley Eyre, Professor of Biogeochemistry, Director of the Centre for Coastal Biogeochemistry, Southern Cross University

This article was originally published on The Conversation. Read the original article.

Your drive to the shops makes life pretty noisy for whales



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Living alongside humans gets noisier all the time.
Katrina Burgers/Shutterstock.com

Andrew J. Wright, Fisheries and Oceans Canada

As unlikely as it may seem, your drive to the supermarket is responsible for a lot of noise pollution in our oceans – and a lot of stress to marine life as a result.

Of course, it’s not the specific sound of your car trundling along the street that the fish and whales hear. But many of the products that feature in your weekly shop – from the goods you buy, to the petrol you burn, to your car’s component parts – contribute to marine noise pollution.




Read more:
Noise from offshore oil and gas surveys can affect whales up to 3km away


The fuel

Let’s start with the oil. Before we can drill the oil or turn it into fuel to drive our cars, oil companies have to discover it.

Companies look for oil using high-pressure airguns. These machines are towed across the surface of the ocean, firing off sounds to determine the make-up of sediment layers in the seafloor. These are some of the loudest human-created sounds – researchers working in the middle of the Atlantic Ocean have been able to record the sounds produced from coastal oil surveys.

Rex Virtual Drilling.
Chooywa/wikimedia, CC BY-SA

These sounds are problematic for marine life. Whales and other animals that rely heavily on sound for communicating and finding food are most affected. Hearing is to these animals much the same as vision is to humans. Unusually loud sounds can disturb whales’ behaviour and, if they are close enough, can damage their hearing. There is even some suggestion that the airguns can cause whale strandings, although this is not yet completely certain.

Currently, one-third of all oil comes from offshore sources and this proportion is expected to increase. This can only mean more bad news for our marine life.

The car

What about the metal box that consumes all the oil? Parts for the car are sourced from all over the world and have to be shipped across our oceans. In turn, the raw materials needed to make these parts are usually shipped in from yet more places. The commercial shipping needed for all this represents another problematic source of ocean noise.

The relative density of commercial shipping routes in our oceans.
B.S. Halpern/Wikimedia Commons, CC BY-SA

The contributions of individual ships may seem trivial in comparison to the loud noise from airguns. However, the world merchant fleet includes around 52,000 ships. Collectively, these increase the ambient noise levels in our oceans. In fact, the amount of low-frequency sound in some parts of our oceans has doubled each decade over the past 60 years.

Humans perceive only some of this sound, because of the very low pitches involved. But these sounds are well within the frequency range used by baleen whales. Recent work suggests that this constrains the communication ranges in whales, causing chronic stress and potentially interrupting mating behaviour.

Parts of the ocean are filling up with man-made noise, and that presents many dangers to marine life.
B. Southall/NMFS and NOAA

The groceries

Oh, and most of your groceries are shipped around the world at some point too, as are many other consumer items – including the battery in your hybrid car, if you have one. Around 90% of world trade is carried by commercial ships at some stage. Not all of this ends up in your shopping bag, but a large proportion enters the consumer market at some point.

Certain grocery items, such as fish, originate from the oceans themselves. Like cargo ships, fishing vessels produce noise from their engines and propellers, but they also have noisy fish-finding sonars and winches as well.




Read more:
10 tips for eating locally and cutting the energy used to produce your food


The solutions

The good news is that noise pollution, unlike chemical pollution, dissipates quickly. This means that the future for underwater noise remains bright. If you want to give the whales a break, just drive a little less, or support higher efficiency standards for vehicles. This will not only reduce oil consumption, but also the wear and tear on your car, meaning that fewer replacement parts will need to be shipped in.

Time for a rethink?
Joe Goldberg/flickr, CC BY-SA

You can also buy locally produced items and support the local economy too. That way everyone wins.

The ConversationNo matter how connected we think everything is, the situation is generally even more complicated than we can imagine. So next time you walk to the shops and buy an apple grown in your state, you should allow yourself a moment to feel good about yourself, safe in the knowledge that you have helped to make the oceans a tiny bit quieter.

Andrew J. Wright, Marine Mammal Researcher, Fisheries and Oceans Canada

This article was originally published on The Conversation. Read the original article.

Deposit schemes reduce drink containers in the ocean by 40%



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Uncountable numbers of drink containers end up in the ocean every year.
Shutterstock

Qamar Schuyler, CSIRO; Britta Denise Hardesty, CSIRO, and Chris Wilcox, CSIRO

Plastic waste in the ocean is a global problem; some eight million metric tonnes of plastic ends up in the ocean every year.




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


One possible solution – paying a small amount for returned drink containers – has been consistently opposed by the beverage industry for many years. But for the first time our research, published in Marine Policy, has found that container deposits reduce the amount of beverage containers on the coasts of both the United States and Australia by 40%.

What’s more, the reduction is even more pronounced in areas of lower socio-economic status, where plastic waste is most common.

Plastic not so fantastic

There have been many suggestions for how to reduce marine debris. Some promote reducing plastic packaging, re-purposing plastic debris], or cleaning beaches. There has been a push to get rid of plastic straws, and even Queen Elizabeth II has banned single use plastics from Royal Estates! All of these contribute to the reduction of plastics, and are important options to consider.




Read more:
Pristine paradise to rubbish dump: the same Pacific island, 23 years apart


Legislation and policy are another way to address the problems of plastic pollution. Recent legislation includes plastic bag bans and microbead bans. Economic incentives, such as container deposits, have attracted substantial attention in countries around the world.

Several Australian jusrisdictions, including South Australia, the Northern Territory, and New South Wales), already have container deposit laws, with Western Australia and Queensland set to start in 2019. In the United States, 10 states have implemented container deposit schemes.

But how effective is a cash for containers program? While there is evidence to suggest that container deposits increase return rates and decrease litter, until now there has been no study asking whether they also reduce the sources of debris entering the oceans.

In Australia, we analysed data from litter surveys by Keep South Australia Beautiful, and Keep Australia Beautiful. In the US, we accessed data from the Ocean Conservancy’s International Coastal Cleanup.




Read more:
The future of plastics: reusing the bad and encouraging the good


We compared coastline surveys in states with a container deposit scheme to those without. In both Australia and the US, the proportion of beverage containers in states without a deposit scheme was about 1.6 times higher than their neighbours. Based on estimates of debris loading on US beaches that we conducted previously, if all coastal states in the United States implemented deposit schemes, there would be 6.6 million fewer containers on the shoreline each year.

Keep your lid on

But how do we know that this difference is caused by the deposit scheme? Maybe people in states with container deposit schemes simply drink fewer bottled beverages than people states without them, and so there are fewer containers in the litter stream?

To answer that question, we measured the ratio of lids to containers from the same surveys. Lids are manufactured in equal proportion to containers, and arrive to the consumer on the containers, but do not attract a deposit in either country.

If deposit schemes cause a decrease in containers in the environment, it is unlikely to cause a similar decrease in littered lids. So, if a cashback incentive is responsible for the significantly lower containers on the shorelines, we would expect to see a higher ratio of lids to containers in states with these programs, as compared to states without.

That’s exactly what we found.

We were also interested in whether other factors also influenced the amount of containers in the environment. We tested whether the socio-economic status of the area (as defined by data from the Australian census) was related to more containers in the environment. Generally, we found fewer containers in the environment in wealthier communities. However, the presence of a container deposit reduced the container load more in poorer communities.

This is possibly because a relatively small reward of 10 cents per bottle may make a bigger difference to less affluent people than to more wealthy consumers. This pattern is very positive, as it means that cashback programs have a stronger impact in areas of lower economic advantage, which are also the places with the biggest litter problems.




Read more:
Sustainable shopping: take the ‘litter’ out of glitter


Ultimately, our best hope of addressing the plastic pollution problem will be through a range of approaches. These will include bottom-up grassroots governance, state and federal legislation, and both hard and soft law.

The ConversationAlong with these strategies, we must see a shift in the type of we products use and their design. Both consumers and manufacturers are responsibility for shifting from a make, use, dispose culture to a make, reuse, repurpose, and recycle culture, also known as a circular economy.

Qamar Schuyler, Research Scientist, Oceans and Atmospheres, CSIRO; Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO, and Chris Wilcox, Senior Research Scientist, CSIRO

This article was originally published on The Conversation. Read the original article.

Five active volcanoes on my Asia Pacific ‘Ring of Fire’ watch-list right now


Heather Handley, Macquarie University

In Indonesia, more than 197 million people live within 100km of a volcano, including more than 8.6 million inside a 10km radius.

The country has a record of some of the most deadly volcanic eruptions in history, and right now there are ongoing eruptions at the Agung, Sinabung and Dukono volcanoes. But other volcanoes in the region are active too, including Kadovar in Papua New Guinea, Mayon in the Philippines, and Kusatsu-Shiranesan in Japan.

Although it all seems to be happening at once, it’s normal for the Asia-Pacific region to have frequent earthquake and volcanic activity.

But we still need to keep a close eye on things, and local volcanic authorities are monitoring activity to manage risks and evacuations adequately.




Read more:
Curious Kids: Do most volcanologists die from getting too close to volcanoes?


The Ring of Fire extends around the Pacific Rim in a horseshoe shape.
Earth Observatory of Singapore

These volcanoes are part of the Pacific “Ring of Fire”, a horseshoe-shaped belt of earthquakes and volcanoes that runs for some 40,000km, roughly around the edge of the Pacific Ocean. The Ring stretches from South America, up to North America and across the Bering straight, and down through Japan, the Philippines, Papua New Guinea, Vanuatu and New Zealand. It generates around 90% of the world’s earthquakes and contains 75% of its active volcanoes.

Here are the volcanoes on my Asia-Pacific watch list this week.

Agung, Bali, Indonesia

Mount Agung in Bali has been highly scrutinised for the past few months, largely because of Bali’s popularity as a tourist destination.

After a series of volcanic earthquakes (more than 1,000 per day at its peak), eruptions began on November 21, 2017.




Read more:
Mount Agung continues to rumble with warnings the volcano could still erupt


Since then we’ve seen frequent explosive eruptions emitting gas, steam and volcanic ash reaching thousands of metres above the volcano.

Drones used by the Indonesian Centre for Volcanology and Geological Hazard Mitigation (CVGHM) show an estimated 20 million cubic metres of new lava in the crater, filling roughly one-third of it.

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In the evening of January 19 an explosion of fire (known as a “strombolian” eruption) ejected glowing rocks up to 1km from the crater. The alert level remains at the highest level, with an exclusion zone in place.

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There have been very few issues for tourists visiting Bali so far, apart from a temporary closure of Denpasar airport in late November 2017. However, thousands of Agung’s local residents are still displaced from their homes, with many still stationed in evacuation centres. It remains uncertain when those living closest will be able to return home.

Many evacuated pregnant women have given birth to babies since leaving their homes in places such as the Bumi Sehat’s community health center and birthing clinic in Ubud, which relies on donations to keep running. As a mother of a one-year-old and a three-year-old, I can’t imagine having a newborn baby and not being in the comfort of my own home.




Read more:
Tourists are stuck at the airport, but erupting Mt Agung has a deeper significance for the Balinese


Sinabung, Sumatra, Indonesia

Sinabung volcano awoke in 2010 after a 400-year sleep, and is currently one of the most active volcanoes in Indonesia. It has been pretty much in constant eruption since September 2013, and there are still frequent volcanic earthquakes.

Eruptions have produced ash plumes reaching as high as 11km into the atmosphere, as well as ash fall and lava flows. There have also been volcanic mudflows (“lahars”) and fast-moving, hot flows of gas, ash and rock fragments (“pyroclastic flows”), which have killed 25 people.

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The initial activity in 2010 saw around 30,000 people evacuated. In August last year the Indonesian National Disaster Management Authority (BNPB) reported that there were 7,214 people displaced, and a further 2,863 living in refugee camps. For the locals, life seemingly goes on in the midst of eruptions.

The alert level currently remains at 4 (on a scale of 1-4), with exclusion zones of 3-7km around the volcano.




Read more:
Why do people still live next to an active volcano?


Mayon, Luzon, Philippines

Mayon, around 330km southeast of Manila, is a picture-perfect volcano with its steep-sided conical cone, typical of stratovolcanoes. It is one of the most active volcanoes in the Philippines, with 24 confirmed eruptive periods in the past 100 years. Mayon’s most violent eruption in 1814 killed more than 1,200 people and destroyed several towns.

The recent eruption began on January 13, 2018, and is continuing, with several episodes of dramatic lava fountaining, one lasting 74 minutes.

Eruptions during January 23-29 generated 3-5km-high ash plumes and multiple pyroclastic flows, which travelled more than 5km down drainage channels. The alert is at level 4 (on a scale of 1 to 5) and an 8km danger zone is in place.

Lava flows have currently made their way up to 4.5km down river valleys from the summit crater.

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) estimated on January 27 that the total volume of material deposited from ash fall and pyroclastic flows amounted to 10.5 million cubic metres. Remobilisation of this loose volcanic material by rainfall to form volcanic mudflows is a major concern.

According to news articles, more than 75,000 people have been evacuated, along with the temporary closure of Legazpi airport around 15km away.

Kadovar, Papua New Guinea

Until January 2018, when it began erupting, I hadn’t heard of Kadovar. It’s a 2km-wide, 365m-high emergent summit of a stratovolcano off the coast of Papua New Guinea.

Kadovar island off the coast of PNG is currently an active volcano.
Samaritan Aviation

The volcano had no confirmed historic eruptions before 2018. However, it is possible that William Dampier, a 17th-century pirate and later maritime adventurer, witnessed an eruption at Kadovar during a voyage in search of Terra Australis.

Activity began on January 5, 2018, with rising plumes of ash and steam from the volcano. The island’s inhabitants, some literally living on the crater rim, began evacuating at that time. People were initially taken by boat to neighbouring Blup Blup island but then to the mainland along with other nearby islanders, due to the close proximity of the eruption and logistics of providing people with supplies.

The Rabaul Volcano Observatory reported that activity significantly escalated on January 12, with a large explosive eruption and volcanic rocks ejected to the south. Large amounts of sulfur dioxide have been detected since January 8, and continue to be released along with ash and steam plumes. A lava “dome” has been observed glowing at night.

The impact from the eruption is not just confined to those on Kadovar and nearby islands, with satellite imagery tracking an ash plume from Kadovar travelling over tens of kilometres.

Identified volcanic risks at Kadovar include further potential explosive activity, landslides, and resulting possible tsunamis.

Kusatsu-Shirane, Honshu Japan

On January 23, 2018, an eruption occurred at Kusatsu-Shirane volcano without any prior warning, catching Japan’s Meteorological Agency and volcanic experts, not to mention the skiers on the volcano, by surprise.

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According to agency’s volcanology division, there had been no volcanic activity at the apparent site of the eruption (Kagamiike crater), for about 3,000 years.

The eruption ejected a black plume of ash and larger volcanic material that damaged a gondola and the roof of a mountain lodge.

The ejected volcanic rocks, which landed up to 1km away from the vent, injured several people. A member of the Ground Self-Defence Force who was skiing in a training exercise was killed.

The Japan Meteorological Agency has since analysed the deposits of the eruption and state that there was no new magma erupted on January 23.

Volcanic rocks were ejected from the Kusatsu-Shirane volcano.

Japan has more than 100 active volcanoes, with many monitored 24/7 by Japan’s Meteorological Agency.

Living near volcanoes

Indonesia, the Philippines and Japan have the greatest numbers of people living within 100km of their volcanoes. The populations of small volcanic island nations, such as Tonga and Samoa, almost all live within 100km.

The top 10 countries for population within 100 km of a volcano (left) and the top ten countries (area over 31,415 km²) for percentage of the total population (right).
Sarah Brown and co-authors.

Indonesia has the greatest total population located within 10km (more than 8.6 million), 30km (more than 68 million) and 100km (more than 179 million), and a record of some of the most deadly volcanic eruptions in history.

The eruption of Tambora in 1812-15, was the largest eruption in the last 10,000 years and killed around 100,000 Indonesians (due to the eruption and the ensuing famine). The infamous eruption of Krakatau (Krakatoa) killed an estimated 35,000 people, almost all due to volcanic-generated tsunamis. Volcanic mudflows (lahars) generated by the eruptions of 1586 and 1919 at Kelut (Kelud) in Java took the lives of 10,000 and 5,000 people, respectively.

The ConversationKeeping watch on the world’s volcanoes is a big job for the local volcanic agencies. This is particularly true when volcanoes erupt for the first time in history (Kadovar is a good example) or there were no warning signals before eruption, as at Kusatsu-Shirane.

Heather Handley, Associate Professor in Volcanology and Geochemistry, Macquarie University

This article was originally published on The Conversation. Read the original article.

11 billion pieces of plastic bring disease threat to coral reefs



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A plastic bottle trapped on a coral reef.
Tane Sinclair-Taylor, Author provided

Joleah Lamb, Cornell University

There are more than 11 billion pieces of plastic debris on coral reefs across the Asia-Pacific, according to our new research, which also found that contact with plastic can make corals more than 20 times more susceptible to disease.

In our study, published today in Science, we examined more than 124,000 reef-building corals and found that 89% of corals with trapped plastic had visual signs of disease – a marked increase from the 4% chance of a coral having disease without plastic.

Globally, more than 275 million people live within 30km of coral reefs, relying on them for food, coastal protection, tourism income, and cultural value.

With coral reefs already under pressure from climate change and mass bleaching events, our findings reveal another significant threat to the world’s corals and the ecosystems and livelihoods they support.




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In collaboration with numerous experts and underwater surveyors across Indonesia, Myanmar, Thailand and Australia, we collected data from 159 coral reefs between 2010 and 2014. In so doing, we collected one of the most extensive datasets of coral health in this region and plastic waste levels on coral reefs globally.

There is a huge disparity between global estimates of plastic waste entering the oceans and the amount that washes up on beaches or is found floating on the surface.

Our research provides one of the most comprehensive estimates of plastic waste on the seafloor, and its impact on one of the world’s most important ecosystems.

Plastic litter in a fishing village in Myanmar.
Kathryn Berry

The number of plastic items entangled on the reefs varied immensely among the different regions we surveyed – with the lowest levels found in Australia and the highest in Indonesia.

An estimated 80% of marine plastic debris originates from land. The variation of plastic we observed on reefs during our surveys corresponded to the estimated levels of plastic litter entering the ocean from the nearest coast. One-third of the reefs we surveyed had no derelict plastic waste, however others had up 26 pieces of plastic debris per 100 square metres.

We estimate that there are roughly 11.1 billion plastic items on coral reefs across the Asia-Pacific. What’s more, we forecast that this will increase 40% in the next seven years – equating to an estimated 15.7 billion plastic items by 2025.

This increase is set to happen much faster in developing countries than industrialised ones. According to our projections, between 2010 and 2025 the amount of plastic debris on Australian coral reefs will increase by only about 1%, whereas for Myanmar it will almost double.

How can plastic waste cause disease?

Although the mechanisms are not yet clear, the influence of plastic debris on disease development may differ among the three main global diseases we observed to increase when plastic was present.

Plastic debris can open wounds in coral tissues, potentially letting in pathogens such as Halofolliculina corallasia, the microbe that causes skeletal eroding band disease.

Plastic debris could also introduce pathogens directly. Polyvinyl chloride (PVC) – a very common plastic used in children’s toys, building materials like pipes, and many other products – have been found carrying a family of bacteria called Rhodobacterales, which are associated with a suite of coral diseases.

Similarly, polypropylene – which is used to make bottle caps and toothbrushes – can be colonised by Vibrio, a potential pathogen linked to a globally devastating group of coral diseases known as white syndromes.

Finally, plastic debris overtopping corals can block out light and create low-oxygen conditions that favour the growth of microorganisms linked to black band disease.

Plastic debris floating over corals.
Kathryn Berry

Structurally complex corals are eight times more likely to be affected by plastic, particularly branching and tabular species. This has potentially dire implications for the numerous marine species that shelter under or within these corals, and in turn the fisheries that depend on them.




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Our study shows that reducing the amount of plastic debris entering the ocean can directly prevent disease and death among corals.

The ConversationOnce corals are already infected, it is logistically difficult to treat the resulting diseases. By far the easiest way to tackle the problem is by reducing the amount of mismanaged plastic on land that finds its way into the ocean.

Joleah Lamb, Research fellow, Cornell University

This article was originally published on The Conversation. Read the original article.