From rocket launches to a crashing space station, we’re in for a huge year in space

Rocket Lab successfully launched its Electron rocket from the company’s complex on the Māhia Peninsula in New Zealand.
Rocket Lab

Brad E Tucker, Australian National University

A Blood Moon, a trip to the Moon and back for two explorers, a space station crashing to Earth and the launch of a new mission to find planets around other stars: these are just some of the exciting things to watch in space in 2018.

Elon Musk’s Space X also plans to launch one of the new Falcon Heavy rockets, the largest since the manned Moon landings.

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The next Full Moon brings a lunar eclipse, but is it a Super Blood Blue Moon as well? That depends…

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The Blood Moon comes from the lunar eclipse on Wednesday night, which is also being claimed as a Blue Super Full Moon (or is it?)

A Blood Moon – when the Moon turns red during a total lunar eclipse. The red comes from the sunrise and sunset here on Earth, continuing out into space and lighting up the Moon.
NASA

All of Australia, plus most of Asia and the Pacific region, will be treated to this spectacular lunar event on January 31. If you miss it, don’t worry, you’ll get another total lunar eclipse on the night of July 27 and early morning hours of July 28.

Unlike a Solar eclipse, you do not need any special equipment to see a lunar eclipse and it is safe to look at with your eyes.

Speaking of solar eclipses, Tasmania and southern parts of Victoria and South Australia will be treated to a partial Solar Eclipse on July 13.

Goodbye Kepler, thanks for the Exoplanets!

The Kepler Space telescope was launched nearly nine years ago and has changed our view of the cosmos and our place in it, but its mission is coming to an end this year.

Kepler has confirmed around 2,500 exoplanets (planets orbiting other stars), with thousands more potential planets. It discovered the first Earth-like planet in a habitable zone , an area where water could exist as a liquid.

An artistic impression of NASA’s planet-hunting Kepler space telescope.
NASA Ames/JPL-Caltech/T Pyle

Kepler also showed that rocky, potentially Earth-like and/or habitable planets are common with potentially tens of billions (yes, billions with a b) existing in our galaxy alone.

After a failure of two reaction wheels (the things that help it point) in 2013, a new mission, K2, was conceived. It was able to keep stable by using a combination of short thruster firings and using the Sun to steer it like a sail.

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Google’s artificial intelligence finds two new exoplanets missed by human eyes

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Kepler continued its exoplanet-finding quest, along with discoveries such as shockwaves from exploding stars and even picking up sound waves deep in the heart of stars (a technique called asteroseismology).

But this extra thruster firing is causing Kepler to use up its fuel, and it is due to run out sometime this year, which will cause NASA to put it into hibernation.

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Where one missions ends, a new one begins. The Transiting Exoplanet Survey Satellite (TESS), is set to be launched between March and June, aboard a SpaceX Falcon 9 rocket. If the stars align, we might even have overlap between these two exoplanet-discovering machines.

A conceptual image of TESS in space and its targets – planets orbiting other stars.
NASA

Rockets, rockets and more rockets

The privatisation of space continued this year with the US-based Rocket Labs having its first successful launch, from a site across the Tasman in New Zealand.

SpaceX also had its first static test of the new Falcon 9 Heavy, the largest rocket since the Saturn V that took US astronauts to the Moon.

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The Falcon 9 Heavy is scheduled for a first launch in early February where it will carry one of Musk’s Tesla Roadsters. We may even see an appearance of the company’s Dragon 2 that will carry humans into space this year. SpaceX has already announced that two people have paid to go on a tour around the Moon.

It’s not just private companies exploring space, with China aiming for 40 launches in 2018 alone.

Exploring the small things in our Solar System

The Moon is on the radar for both India and China. India’s Chandrayaan-2 is set to land on the Moon in March, while China’s Chang’e 4 will be its second lunar rover, set to land on the far side of the Moon at the end of 2018. First it will have to launch a special communication satellite, slated for June, to a position called L2, or a special point related to the Earth-Moon system that will allow for communications with Earth and the far side of the Moon.

While it is a bit early for New Year’s Eve 2018, NASA already has big plans. New Horizons, the probe that flew by Pluto in 2015 is set to swing past its second icy world, 2014 MU 69, on December 31. Little is known about 2014 MU 69, which is around 6.5 billion km from the Sun, other than the fact that it might be two objects instead of one and that it needs a better name.

Hubble Space Telescope Wide Field Camera 3 discovery images of 2014 MU69. Positions are shown by the green circles.
NASA, ESA, SwRI, JHU/APL, and the New Horizons KBO Search Team

Asteroids are not forgotten in all of this space exploration. Japan’s Hayabusa-2 is set to arrive at asteroid 162173 Ryugu. It’s a new version of Hayabusa, which surveyed the asteroid 25143 Itokawa and took samples before returning back to Earth, landing near Woomera, South Australia in 2010.

Likewise, NASA’s OSIRIS-REx will arrive at the asteroid Bennu where it will extend an arm to drill down into the asteroid, and return with samples, in what is the next step towards an asteroid mining future.

An artist impression of OSIRIS-REx extending its arm down to the asteroid Bennu.
NASA

A falling space station

If you were around in 1979 and happened to be in Western Australia, you might have a unique souvenir – part of the US space station Skylab, which re-entered and crashed outside Esperance, WA.

If you’ve seen the 2013 movie Gravity (and a spoiler alert for those who haven’t!) you might remember the final scene in which Sandra Bullock’s character returns home by hijacking Tiangong-1, the Chinese space station. She returns safely, but the same can’t be said for Tiangong-1.

Well in March, we are set for a clash of sci-fi against reality when Tiangong-1 comes back down to Earth.

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Looking up a century ago, a vision of the future of space exploration

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You can track its progress but in short, somewhere between +43 and -43 latitude (or half the Earth), it will re-enter and break apart. Currently, the likely potential (land) areas are around Central and South America, Northern Africa and the Mediterranean, and indeed Western Australia.

Like Skylab, there are likely to be large pieces that survive re-entry. Hopefully you are lucky to be in a position to see it with your eyes, but not so close that it lands on your house, as it’s unlikely to be covered by your insurance policy.

So that’s a summary of some of the things we’re expecting to happen this year. But as with all science, I’m just as excited for those discoveries that we do not know about that will happen in 2018.

Brad E Tucker, Astronomer and outreach officer, Australian National University

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

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Climate scientists explore hidden ocean beneath Antarctica’s largest ice shelf

The team used hot-water drilling gear to melt a hole through Antarctica’s Ross Ice Shelf to explore the ocean below.
Christina Hulbe, CC BY-ND

Craig Stevens and Christina Hulbe

Antarctica’s Ross Ice Shelf is the world’s largest floating slab of ice: it’s about the size of Spain, and nearly a kilometre thick.

The ocean beneath, roughly the volume of the North Sea, is one of the most important but least understood parts of the climate system.

We are part of the multi-disciplinary Aotearoa New Zealand Ross Ice Shelf programme team, and have melted a hole through hundreds of metres of ice to explore this ocean and the ice shelf’s vulnerability to climate change. Our measurements show that this hidden ocean is warming and freshening – but in ways we weren’t expecting.

Instruments travelling 360m down a bore hole, from the snow-covered surface of the Ross Ice Shelf through to the ocean below the ice. After splash-down at about 60m, they move through the bubble-rich upper ice and down into the dark bubble-free lower reaches of the ice – passing embedded sediment that left the coast line centuries ago.

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Antarctic glacier’s unstable past reveals danger of future melting

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A hidden conveyor belt

All major ice shelves are found around the coast of Antarctica. These massive pieces of ice hold back the land-locked ice sheets that, if freed to melt into the ocean, would raise sea levels and change the face of our world.

An ice shelf is a massive lid of ice that forms when glaciers flow off the land and merge as they float out over the coastal ocean. Shelves lose ice by either breaking off icebergs or by melting from below. We can see big icebergs from satellites – it is the melting that is hidden.

Because the water flowing underneath the Ross Ice Shelf is cold (minus 1.9C), it is called a “cold cavity”. If it warms, the future of the shelf and the ice upstream could change dramatically. Yet this hidden ocean is excluded from all present models of future climate.

This satellite map shows the camp site on the Ross Ice Shelf, Antarctica.
Ross Ice Shelf Programme, CC BY-ND

There has only been one set of measurements of this ocean, made by an international team in the late 1970s. The team made repeated attempts, using several types of drills, over the course of five years. With this experience and newer, cleaner, technology, we were able to complete our work in a single season.

Our basic understanding is that seawater circulates through the cavity by flowing in at the sea bed as relatively warm, salty water. It eventually finds its way to the shore – except of course this is a shoreline under as much as 800 metres of ice. There it starts melting the shelf from beneath and flows across the shelf underside back towards the open ocean.

Peering through a hole in the ice

The New Zealand team – including hot water drillers, glaciologists, biologists, seismologists, oceanographers – worked from November through to January, supported by tracked vehicles and, when ever the notorious local weather permitted, Twin Otter aircraft.

As with all polar oceanography, getting to the ocean is often the most difficult part. In this case, we faced the complex task of melting a bore hole, only 25 centimetres in diameter, through hundreds of metres of ice.

A team of ice drillers from Victoria University of Wellington used hot water and a drilling system developed at Victoria to melt a hole through hundreds of metres of ice.
Craig Stevens, CC BY-ND

But once the instruments are lowered more than 300m down the bore hole, it becomes the easiest oceanography in the world. You don’t get seasick and there is little bio-fouling to corrupt measurements. There is, however, plenty of ice that can freeze up your instruments or freeze the hole shut.

A moving world

Our camp in the middle of the ice shelf served as a base for this science, but everything was moving. The ocean is slowly circulating, perhaps renewing every few years. The ice is moving too, at around 1.6 metres each day where we were camped. The whole plate of ice is shifting under its own weight, stretching inexorably toward the ocean fringe of the shelf where it breaks off as sometimes massive icebergs. The floating plate is also bobbing up and down with the daily tides.

The team at work, preparing a mooring.
Christina Hulbe, CC BY-ND

Things also move vertically through the shelf. As the layer stretches toward the front, it thins. But the shelf can also thicken as new snow piles up on top, or as ocean water freezes onto the bottom. Or it might thin where wind scours away surface snow or relatively warm ocean water melts it from below.

When you add it all up, every particle in the shelf is moving. Indeed, our camp was not so far (about 160km) from where Robert Falcon Scott and his two team members were entombed more than a century ago during their return from the South Pole. Their bodies are now making their way down through the ice and out to the coast.

What the future might hold

If the ocean beneath the ice warms, what does this mean for the Ross Ice Shelf, the massive ice sheet that it holds back, and future sea level? We took detailed temperature and salinity data to understand how the ocean circulates within the cavity. We can use this data to test and improve computer simulations and to assess if the underside of the ice is melting or actually refreezing and growing.

Our new data indicate an ocean warming compared to the measurements taken during the 1970s, especially deeper down. As well as this, the ocean has become less salty. Both are in keeping with what we know about the open oceans around Antarctica.

We also discovered that the underside of the ice was rather more complex than we thought. It was covered in ice crystals – something we see in sea ice near ice shelves. But there was not a massive layer of crystals as seen in the smaller, but very thick, Amery Ice Shelf.

Instead the underside of the ice held clear signatures of sediment, likely incorporated into the ice as the glaciers forming the shelf separated from the coast centuries earlier. The ice crystals must be temporary.

None of this is included in present models of the climate system. Neither the effect of the warm, saline water draining into the cavity, nor the very cold surface waters flowing out, the ice crystals affecting heat transfer to the ice, or the ocean mixing at the ice fronts.

It is not clear if these hidden waters play a significant role in how the world’s oceans work, but it is certain that they affect the ice shelf above. The longevity of ice shelves and their buttressing of Antarctica’s massive ice sheets is of paramount concern.

Craig Stevens, Associate Professor in Ocean Physics and Christina Hulbe, Professor and Dean of the School of Surveying (glaciology specialisation)

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

Space Fence

The next Full Moon brings a lunar eclipse, but is it a Super Blood Blue Moon as well? That depends…

Changing colours of the Moon during a total lunar eclipse, Mt Buffalo National Park, June 16, 2011.
Phil Hart, Author provided

Tanya Hill, Museums Victoria

A total lunar eclipse will occur on Wednesday, January 31, and Australia is in the perfect position to see it. But it’s also being called many other lunar things, from a Blood Moon to a Blue Moon and a Super Moon.

So what is really going to happen on the night?

This is the first time in three years that we have the chance to see a total lunar eclipse from Australia, and the Moon will spend just over three hours passing through Earth’s shadow.

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Explainer: what is a lunar eclipse?

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The great thing about lunar eclipses is that they are lovely to watch and no special equipment is needed to see the events unfold.

From light to dark

At first we’ll see the Full Moon begin to darken. For Wednesday’s lunar eclipse the shadow will approach from the bottom-right, leaving the top part of the Moon in sunlight.

It takes an hour before the Earth’s shadow crosses the Moon entirely and once the Moon is completely engulfed the period known as totality begins.

The steady progression of an eclipse as the Moon drifts into the Earth’s shadow, June 16, 2011.
Phil Hart, Author provided

Totality brings its own surprise. The Earth’s shadow is not completely black, but has a reddish hue. This has led many cultures, including some Indigenous Australian communities, to describe a lunar eclipse as a Blood Moon.

Sunlight still manages to reach the Moon but it must first pass through Earth’s atmosphere. This both reddens the light (by scattering away the shorter wavelengths or blue light) and also bends the path of the light, directing it into the shadow.

This week’s lunar eclipse is a fairly deep one and totality will last just over an hour. Thereafter, the Moon will begin to emerge from the shadows, and it will be another hour before we see the brilliance of the Full Moon once more.

How I can see it?

The eclipse can be seen by the entire night side of the globe and everyone will experience the event at precisely the same moment. What affects the eclipse timings are local time zones.

For Western Australia, the eclipse occurs in the early evening, within an hour after sunset. The Moon will be low to the eastern horizon at the start of the eclipse but will move higher in the sky and towards the northeast as the eclipse progresses.

For the rest of Australia, the eclipse occurs two to three hours after sunset. The eclipse will begin with the Moon in the northeast and climbing towards the north.

Check in with your local planetarium or amateur astronomy group, as many organisations are hosting eclipse events so that you can share the occasion with others.

But if the weather doesn’t cooperate in your local area, you can also follow the eclipse via live streaming by Slooh, the Virtual Telescope, or timeanddate.com.

A lunar eclipse over San Francisco Bay in 2014 (note the moons have been enlarged slightly for clarity).
John ‘K’/flickr, CC BY-NC-ND

Super Blood Blue Moon

It seems these days that it’s not enough to be treated to a beautiful natural phenomenon like a total lunar eclipse. Instead, I’ve been hearing a lot of hype surrounding this eclipse and the numerous names applied.

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Five reasons India, China and other nations plan to travel to the Moon

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It’s true that lunar eclipses can only occur around the time of Full Moon. That’s when the Sun is on one side of the Earth, while the Moon is located on Earth’s opposite side.

Most of the time the Full Moon sits above or below Earth’s shadow and the Moon remains flooded with sunlight. But twice a year, the three bodies fall into line so that Earth casts its shadow on the Moon.

As well as being a Full Moon, eclipses can also be described as a Blood Moon because of the Moon’s reddish appearance, as mentioned previously.

But the descriptions of Super Moon and Blue Moon may not be quite what they seem.

Look to the sky … it’s a Super Moon!

I’ve written before about the Super Moon sensation and it’s a term that has only taken off in the past seven years.

Back in March 2011, NASA published an article describing a “super full moon”. The precise time of Full Moon that month occurred 59 minutes before perigee, that is, the Moon’s closest approach to Earth as it travels along its elliptical orbit.

As quoted in the article:

The full Moon of March 19th [2011] occurs less than one hour from perigee – a near-perfect coincidence that happens only every 18 years or so.

It must have seemed a worthwhile curiosity to report on at the time.

Seven years later and the Super Moon craze is now a bit out of hand, with some claiming three Super Moons a year depending on the chosen definition.

As a Super Moon this lunar eclipse is definitely on the outer limits, with the Full Moon occurring 27 hours after perigee and at a distance of more than 360,000km (calculated in the usual way from the centre of Earth to the centre of the Moon).

Considering that it’s also quite difficult to tell the difference in both size and brightness between a regular Full Moon and a Super Moon, this one is really pushing the limits of credibility.

Once in a Blue Moon

According to Philip Hiscock, a folklorist at the Memorial University, USA (now retired), the classic saying “once in a blue moon” is more than 400 years old. It originated as something so absurd it could never actually happen, similar to saying “when pigs fly”.

But it is possible on rare occasions for the Moon to turn blue.

Intense volcanic activity or smoky forest fires can fill Earth’s atmosphere with dust particles that are slightly larger than usual. As a result, red light is scattered away, giving everything a blue tinge, including the Moon (normally the atmosphere scatters blue light, hence why the sky is blue).

When Krakatoa erupted in 1883 the Moon turned blue for a couple of years.
flydime/Wikipedia

But when it comes to this lunar eclipse, it’s not the colour of the Moon but a quirk of our timekeeping that is in play.

What a difference a day makes

A Full Moon occurs every 29.5 days, but our months are longer (excluding February). This mismatch of timing means that every couple of years there comes a month with two Full Moons.

In recent times, a Blue Moon has referred to the second full moon of a calendar month. For most of the world, this lunar eclipse is occurring during a Blue Moon, except for Australia’s eastern states of New South Wales, Victoria, Tasmania and the Australian Capital Territory.

Those states follow daylight saving, which pushes the Full Moon into the following day and out of the month of January (the actual time of Full Moon is 12:26am AEDT, February 1). This leaves January with only one Full Moon for those states and territory.

A lunar eclipse begins in Virginia, USA, December 21, 2010.
Flickr/NASA/Bill Ingalls

But there’s more. This modern definition of Blue Moon arose only 30 years ago.

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Read more:
Stars that vary in brightness shine in the oral traditions of Aboriginal Australians

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The original definition is as follows: if four Full Moons occur between an equinox and a solstice (for example, in the three months between a spring equinox and a summer solstice) then the third Full Moon should be called a Blue Moon.

This ensured that the proper names of the Full Moons (common in North America, such as the Harvest Moon) were correct relative to the equinoxes and solstices.

But regardless of the exact flavour of this lunar eclipse, what’s certainly true is that we are part of a grand universe, and Wednesday night is the perfect reminder of that.

Tanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria

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

Chile’s New National Parks

The link below is to an article that reports on the creation of massive new national parks in Chile.

For more visit:
https://www.theguardian.com/environment/2018/jan/29/chile-creates-five-national-parks-in-patagonia

Greenland and Climate Change

Climate Change Denial Persists

South Africa should sort out the bad from the really bad on its invasive species list

Managing trout is a contentious issue with conflicting views about whether they pose a risk, or are beneficial.
Shutterstock

Tsungai Zengeya, South African National Biodiversity Institute

This article is the third in a series The Conversation Africa is running on invasive species.

Alien species have been introduced to Africa for a variety of reasons. They provide food, raw materials for industry, ornamental plants, recreation in the form of sport fishing, hunting and pets. Some that are highly valued have been moved around widely. And in some areas they now form prominent components of societies and ecosystems like the domestic cat for example.

Many alien species bring considerable benefits. But some have become invasive, causing a loss of biodiversity, changes to ecosystems, economic losses and, in some cases, even affecting people’s health.

The shrub Prosopis or mesquite is an example. It was introduced to South Africa to provide fodder, firewood and shade in arid parts of the country. But it’s also a major water user. And two trout species (S. trutta and O. mykiss) are used for recreational angling and commercial aquaculture. But they’ve also been implicated in having a negative effect on the environment.

Managing invasive species is therefore critical. In South Africa the movement and use of 552 listed invasive species are managed under the Biodiversity Act and regulations attached to it. But not all the species on the list are equally harmful. Several may in fact be relatively harmless.

All the listed species under these regulations require management. Given that the capacity is limited, regulations should arguably focus on priority species because not all are necessarily harmful to the extent that would justify spending large amounts of time and effort on keeping them under control.

The question then is: are there some species that could be removed from the list? In our recent study we set out to answer this question by classifying species as inconsequential, beneficial, destructive or conflict generating species. This was done by assessing the relative degree of benefit they brought and their negative effects.

Beneficial and harmful species

The classification was done by using a simple scoring system. It had two categories for the negatives (ecological and socio-economic) and two for the benefits (economic and intrinsic).

1. Inconsequential species: these make up 55% of the species listed under the act and in the regulations. They were associated with relatively low costs and low benefits to society. Species in this group had limited distribution or no known impact and were largely introduced as ornamentals or pets. Some examples include the eastern grey squirrel (Sciurus carolinensis), European perch (Perca fluviatilis), and the Père David’s Deer (Elaphurus davidianus).

2. Destructive species: these make up 29% of the list. They don’t bring substantial benefits to society or the environment, but they have a highly negative impact. Many were introduced accidentally and are regarded largely as pests and weeds. Examples include invasive rodents like the black rat (Rattus rattus) which causes damage to infrastructure and transmission of zoonotic diseases and pitch canker (Fusarium circinatum) a growing threat to pine plantations and forests worldwide.

The jacaranda is an iconic tree species in the city of Pretoria where it’s regarded as part of the identity.
Shutterstock

1. Beneficial species: they make up 10% of the list and have clear social or environmental benefits. For example the jacaranda (Jacaranda mimosifolia) is an iconic tree species in the city of Pretoria where the species is regarded as part of the identity and “sense of place” of the city. Active management is not necessary or should only be done in particular cases.

2. Conflict-generating organisms: these can be either beneficial or destructive, depending on one’s perspective or what value is placed on them. They make up only 6% of the list. There’s huge disagreement about whether these species should be controlled, or how they should be controlled. Examples include woody plants introduced for forestry, erosion control, sand dune stabilisation, agriculture and as ornamentals. Acacias and pines are examples. Animal examples include species like the Himalayan tahr which was introduced to the Table Mountain National Park. The goat has been the focus of eradication attempts, despite strong opposition. It also includes species introduced for aquaculture like maroon and brown trout. Managing trout has been highly contentious with conflicting views about whether they pose a risk, or deliver a benefit. This has led to them being listed and delisted. The trout fraternity refuse to acknowledge that trout are invasive species and highlight the lack of scientific evidence of the risks they pose.

Finding common ground

We need to keep sight of the fact that there is general agreement on 94% of listed species. By identifying the small number that are generating the greatest tension, it’s more likely discussions can be held to reach common ground on regulation.

Most countries in Africa don’t have invasive species regulations. But there’s growing recognition that they’re needed. South Africa offers useful lessons on how this could be done.

The control of species listed under the country’s biodiversity act is compulsory. This means that plans to manage them have to be drawn up and implemented. But this doesn’t seem sensible given that not all are equally harmful and resources are limited. Our study suggests that some of the species currently regulated could be removed from the list.

Countries wanting to set up a system of managing invasive species could start by classifying a prospective list of candidates. Policymakers could then quickly bring out legislation against the most damaging and destructive ones. At the same time, discussions could be had on the ones that generate conflict with the aim of reaching consensus.

This would allow managers and regulators to focus on the most destructive species – as well as those that are at the centre of fierce disagreement.

Tsungai Zengeya, Researcher at the South African National Biodiversity Institute, South African National Biodiversity Institute

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

11 billion pieces of plastic bring disease threat to coral reefs

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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This South Pacific island of rubbish shows why we need to quit our plastic habit

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

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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.

Once 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.

Alien animals and plants are on the rise in Africa, exacting a growing toll

The larger grain borer beetle attacks crops like maize and cassava, threatening food security.
Shutterstock

Katelyn Faulkner, University of Pretoria; Brett Hurley, University of Pretoria, and Mark Robertson, University of Pretoria

This article is the first in a series The Conversation Africa is running on invasive species.

Let’s say you’re travelling from Uganda to South Africa for business. You finally arrive at your hotel after a long day and decide to change before dinner. You unlock and unzip your luggage, but there’s something in your bag that you didn’t pack. As you reach for a clean shirt, a moth flies out. Did that come with you all the way from Uganda? It’ll be fine, right? Surely, something so small won’t cause any harm.

Species are intentionally or accidentally transported by humans between continents to regions where they are not native. With the help of humans or by natural means like flight, these alien species can also spread within continents.

Their spread within continents can be rapid, affecting both the ecology as well as societies and the economy. Unfortunately, it’s really challenging to prevent species from spreading. Given the vast amount of people and goods that are transported between and around continents they can easily be moved across oceans as well as between countries.

The spread of alien species within Africa is increasing. Since 2000 more alien insect pests of eucalyptus trees have spread to other African countries from South Africa, than have been introduced to these African countries from other continents. To manage the spread of these alien species countries need to co-operate, communicate and share information and skills..

The spread of alien species

Many alien plants and animals have been introduced to Africa from other regions and then have spread from country to country, often having devastating effects.

Take the larger grain borer beetle, (Prostephanus truncatus) which is thought to have arrived on the continent in imported grain from Mexico and central America. The beetle was introduced to Tanzania before 1984, Togo before 1981 and Guinea before 1987. It then spread across the continent and within 20 years could be found further south in South Africa.

The beetle attacks crops such as maize and cassava, threatening food security and the livelihoods of the poor. Infestations often destroy maize that’s been stored by farmers, forcing them to buy maize as well as lose income they could have earned from selling any excess.

But alien species don’t just arrive from abroad. Many that are native to parts of Africa have also spread to countries on the continent where they are not native.

An example is the fish commonly known as the Mozambique tilapia (Oreochromis mossambicus) which is native to rivers on the east coast of southern Africa. Fishermen have transported the Mozambique tilapia to other areas and it is now found in river systems in southern and western South Africa and Namibia.

The Mozambique tilapia is a popular species for fishing but it can pose a threat to native fish and has been responsible for the disappearance of native species in some regions.

The spread of alien species within Africa is by no means a new thing. For instance, the bur clover (Medicago polymorpha), a plant from northern Africa, might have been accidentally transported by humans to South Africa as early as 760 AD.

A high and increasing threat

Recently a number of alien species have spread extremely rapidly across the continent, posing a particularly high threat to food security and livelihoods.

The fall armyworm, native to the Americas, was first recorded in west and central Africa in early 2016 and then in South Africa in January 2017.
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One is a caterpillar known as the fall armyworm (Spodoptera frugiperda). The species, native to the Americas, was first recorded in west and central Africa in early 2016 and then in South Africa in January 2017.

The moths of the armyworm are strong fliers and the species may have spread through flight to South Africa from other African countries. Although the species attacks a wide range of crops, it poses a particularly serious threat to grain farmers. It is extremely difficult to manage.

Another example is a wasp known as the bluegum chalcid (Leptocybe invasa), which is native to Australia. In 2000 it was detected in Israel and shortly afterwards it was reported in Uganda and Kenya. From there it spread rapidly to many African countries including Zimbabwe, Mozambique, and Tanzania and was finally detected in South Africa in 2007. The insect probably reached Israel on live plant material and spread into Africa the same way, or was carried by people travelling between countries.

The wasp causes swelling or growths on eucalyptus trees, which can lead to decreased growth and tree death. As eucalyptus trees are an important source of income and fuel, this species could have an impact on the livelihoods of locals in these countries.

Preventing the introduction and spread

Once a species is introduced to one African country it’s highly likely it will spread to others on the continent because borders checks are weak.

The introduction and spread of species could be reduced if countries introduced biosecurity systems. These are used extensively in countries like Australia and New Zealand and involve using technology to check for alien species when people and goods enter a country. In Australia this involves inspecting goods, vehicles and luggage before they enter the country.

But even these systems aren’t a guarantee that species won’t spread. African countries would need to work together and share information and skills. This would also allow countries to prepare for the arrival of species, and to draw up plans to reduce their impact.

This is a tall order. But as a country’s defence against alien species introductions is only as strong as that of its neighbours, such action would benefit all of the countries involved.

Katelyn Faulkner, Postdoctoral research fellow, University of Pretoria; Brett Hurley, Senior Lecturer Zoology and Entomology, University of Pretoria, and Mark Robertson, Associate Professor Zoology & Entomology, University of Pretoria

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