Planet Earth Summer 2013

www.planetearth.nerc.ac.uk

Summer 2013

sea

Under the

Flash flood predictions • Antarctic moss banks • Algae blooms • Super-eruptions

About us The Natural Environment Research Council (NERC) is the UK’s main agency for funding research, training and knowledge exchange in environmental science. Our work tackles some of the most urgent and fascinating environmental issues we face, including climate change, natural hazards and sustainability.

NERC is a non-departmental public body. Much of our funding comes from the Department for Business, Innovation and Skills but we work independently of government. Our projects range from ‘blue-skies’ research to long-term, multi-million-pound strategic programmes, coordinated by universities and our own research centres:

NERC research covers the globe, from the deepest ocean trenches to the outer atmosphere, and our scientists work on everything from plankton to glaciers, volcanoes and air pollution – often alongside other UK and international researchers, policy-makers and businesses.

British Antarctic Survey British Geological Survey Centre for Ecology & Hydrology National Oceanography Centre National Centre for Atmospheric Science National Centre for Earth Observation

Contact us To give us your feedback or to subscribe email: requests@nerc.ac.uk or write to us at Planet Earth Editors, NERC, Polaris House, North Star Avenue, Swindon SN2 1EU. NERC-funded researchers should contact: editors@nerc.ac.uk

Planet Earth is NERC’s quarterly magazine, aimed at anyone interested in environmental science. It covers all aspects of NERC-funded work and most of the features are written by the researchers themselves.

Editors Adele Rackley, 01793 411604 admp@nerc.ac.uk Tom Marshall, 01793 442593 thrs@nerc.ac.uk Science writers Tamera Jones, Harriet Jarlett, Alex Peel, Alison Smith, Valerie Nadeau Design and production Candy Sorrell, 01793 411518 cmso@nerc.ac.uk ISSN: 1479-2605

Front cover: Map of the ocean floor. NOAA/NGDC

2

PLANET EARTH Summer 2013

For the latest environmental science news, features, blogs and the fortnightly Planet Earth Podcast, visit our website Planet Earth Online at www.planetearth.nerc.ac.uk.

Not all of the work described in Planet Earth has been peer-reviewed. The views expressed are those of individual authors and not necessarily shared by NERC. We welcome readers’ feedback on any aspect of the magazine or website and are happy to hear from NERC-funded scientists who want to write for Planet Earth. Please bear in mind that we rarely accept unsolicited articles, so contact the editors first to discuss your ideas.

In this issue Summer 2013 12 Rain, brains and climate

17

change

Medical methods meet monsoon modelling.

14 Super-eruptions –

not quite so super?

Little and often for Yellowstone.

17 Competition skills bloom into eco-business

From science to seed balls.

18 The last stand?

How genetic science could help save Britain’s ash trees.

20 The heart of the matter

Understanding clouds from the inside.

COVER STORY 22 Under the sea

Drilling kilometres beneath the seabed for insight into earthquakes and tsunamis.

24 Unlocking the secrets of

27 Planning for biodiversity

A different kind of climate record.

Antarctic moss banks

26 Health of Iceland’s glaciers

failing fast

New study highlights speed of glacier retreat.

in Westminster

Communicating science to Parliament.

28 Repelling invaders

How to safeguard the unique wildlife of the Galapagos.

30 All choked up

Low or high tech – two ways to deal with freshwater algal blooms.

28

24 PLANET EARTH Summer 2013

3

www.planetearth.nerc.ac.uk

News Editorial A

fter Spring’s food-themed edition, Summer’s Planet Earth returns to covering a typically diverse range of NERC-funded environmental science research. Our main goal in commissioning features is to demonstrate that diversity and give readers an insight into the working lives of our researchers.

Some of them work in an office or lab, some in difficult or downright hostile corners of the planet, and for others it means studying some little-understood aspect of places you wouldn’t be surprised to see in a travel brochure. You’ll find examples of all three approaches in these pages.

But driving all this research is the desire to make a difference – to improve people’s everyday lives, whether that’s by finding out more about the effects of environmental change, by protecting people and infrastructure from natural hazards, or by discovering better ways to manage our resources.

The key to realising these benefits is sharing ideas across science disciplines and working with people in business, policy and NGOs to get the most out of environmental knowledge and data.

So among other things, in this edition an ecologist describes her work advising Westminster on how the planning system should take account of biodiversity, and two environmental scientists tell us about how a NERC-funded competition gave them the skills to set up their own business.

We hear from a researcher who took MRI techniques from the medical world and used them to reduce inconsistencies in climate models, with potential benefits not just for science but for the millions of people around the world whose livelihoods rely on knowing when it’s going to rain.

And in the 60th anniversary year of Watson and Crick’s description of the double-helix structure of DNA, we hear from scientists who are decoding the ash tree’s genome to help halt the fungal disease that threatens 80 million of these iconic trees in the UK alone.

The Editors

Half of 2009 Tamiflu prescriptions weren’t taken

A

round half the antiviral drug Tamiflu prescribed during the 2009 H1N1 swine flu pandemic was never used, new research shows.

Scientists looked at consumption of the drug within two populations, 208,000 people in Oxford and 6,000 people in nearby Benson, by analysing the sewage

4

PLANET EARTH Summer 2013

they produced over 24 hours. The Tamiflu people use ends up flushed down the toilet, so analysing waste is a fast, cheap way to tell how much has been taken.

An estimated 600,000 courses of Tamiflu went unused over the course of the pandemic, costing the public some £7.8 million. This suggests government plans to respond to flu pandemics could be improved.

The 2009 swine flu turned out not to be as deadly as had been feared, but if it had been more serious, would people still have failed to take Tamiflu they’d been prescribed? If so, they’d have been endangering both themselves and others.

‘The UK government’s plan ended up working well, but in a severe epidemic or

pandemic people who get Tamiflu and then don’t use it are taking it from those who really need it,’ says Dr Andrew Singer, a chemical ecologist at NERC’s Centre for Ecology & Hydrology and member of the UK government’s Scientific Pandemic Influenza Advisory Committee, who led the research. He thinks more cooperation between medical and environmental researchers is needed to let us understand these problems and respond more effectively.

Singer suggests we need more research on why people get hold of medicine and then don’t take it, to help create better public-awareness campaigns to deal with the problem. The study, published in PLOS ONE, also involved scientists from Uppsala, Linnaeus and Umeå Universities in Sweden and the University of South Bohemia in the Czech Republic.

Daily updated news @ www.planetearth.nerc.ac.uk

Climate change threatens corn crops

A

warming world is putting crops at risk, according to scientists who studied how the weather affects French maize yields.

If climate-change projections are right, we’ll need to improve yields per acre by

up to 12 per cent between 2016 and 2035 just to maintain today’s total production.

This is a real threat to our food supply in the coming decades. It turns out that maize yields drop significantly for every day when temperatures climb over around

32°C, and that heat stress has been as important an influence on maize yield as variation in rainfall since the turn of the century.

Over the past 50 years, the average number of days over this dangerous threshold has already risen from around three a year to more than five, and this is predicted to climb to around ten over the next two decades. In some major farming areas it could reach 15.

‘It’s a serious risk to food security,’ says Dr Ed Hawkins of NERC’s National Centre for Atmospheric Science and the University of Reading, who led the Global Change Biology study. ‘Crop yields increased fourfold since the 1960s, largely due to better technology such as pesticides and fertilisers, but this improvement has slowed in recent decades and the current rate of increase in technology may not be enough to maintain current production levels.’ Better farming methods and new crop varieties will help, but there’s no guarantee we can meet the target.

mySoil app updated T

he British Geological Survey and Centre for Ecology & Hydrology have updated their popular mySoil iPhone app, extending its coverage from Britain to the whole EU. mySoil is for anyone interested in the ground beneath their feet. Just entering your postcode or finding your location with GPS brings up an interactive map with copious information about the local soil’s pH, texture, depth, organic matter content and a host of other properties.

Since it was launched last year, it’s proved popular with everyone from farmers and allotment gardeners to planners and environmentalists.

As well as introducing a unified continent-wide soil map, the free app also

includes lots of new information, including data on average UK soil temperatures from the Met Office and Europe-wide information on soil texture, depth, parent material and habitat from the EU’s Joint Research Centre.

The app doesn’t just deliver information to users; it also enables citizen science by letting them upload data about, and pictures of, the soils and vegetation habitats near them, in order to build up a community-produced collection of soil information and fill gaps in existing datasets.

Download the app from www.bgs.ac.uk/mysoil

PLANET EARTH Summer 2013

5

www.planetearth.nerc.ac.uk

News Sharp rise in summer melt on Antarctic Peninsula

SUMMER MELTING AT THE ICE-CORE SITE TODAY IS NOW AT A HIGHER LEVEL THAN AT ANY OTHER TIME OVER THE LAST 1000 YEARS Dr Nerilie Abram British Antarctic Survey

6

PLANET EARTH Summer 2013

S

ummer melting on the Antarctic Peninsula has intensified almost tenfold in the past 600 years and mostly in the past 50 years, according to a Nature Geoscience study. It’s now greater than at any other time in the last millennium.

This is the first research to show the sensitivity of summer melt on the peninsula to rising temperatures in the 20th century. It helps scientists understand the causes of environmental change in Antarctica, and could help improve predictions of the continent’s contribution to sea-level rise.

Dr Nerilie Abram of the Australian National University and NERC’s British Antarctic Survey led the study. ‘This new icecore record shows that even small changes in temperature can result in large increases in the amount of melting in places where summer temperatures are near to zero,’ she says. ‘This has important implications for ice stability and sea-level rise in a warming climate.’

The team investigated an ice core taken in 2008 from James Ross Island, near the northern tip of the peninsula. They examined visible layers in it, created by the annual thawing and refreezing of summer snow, and compared these with a temperature record that had already been constructed for the same core.

‘We found that the coolest conditions on the Antarctic Peninsula and the lowest amount of summer melt occurred around 600 years ago,’ Abram says. ‘At that time temperatures were around 1.6°C lower than those recorded in the late 20th century and the amount of annual snowfall that melted and refroze was about half a per cent. Today, we see almost ten times as much of the annual snowfall melting each year.’

Daily updated news @ www.planetearth.nerc.ac.uk

Soil mites evolve in Skin-eating a few generations amphibian found

A

changing environment can make animals evolve much faster than we’d ever thought possible, scientists have found.

New conditions caused major genetic shifts in soil mites within just 15 generations. This doubled the age at which they reached adulthood and had a major effect on population size.

The findings challenge the assumption that evolution happens only over centuries or millennia. They could have implications in areas from pest control to fisheries management.

‘We found that populations evolve rapidly in response to environmental change and population management,’ says Professor Tim Benton of the University of Leeds, one of the authors of the Ecology Letters paper. ‘This can have major consequences such as reducing harvesting yields or saving a population heading for extinction.’

The group collected wild mites and put them in glass tubes, dividing them into three groups. From the first group they removed 40 per cent of adults each week; from the second, the same proportion of juvenile mites. The third group went unmodified.

Initially it seemed the change of scene would lead to extinction; all groups quickly declined by around half. But after about six generations, all started growing again. It turned out that the tube environment selected for late-maturing mites that produced more eggs.

‘Removing the adults caused them to remain as juveniles even longer because the genetics were responding to the high chance that they were going to die as soon as they matured,’ explains lead author Dr Tom Cameron of Umeå University in Sweden. ‘When they did eventually mature, they were so enormous that they could lay all of their eggs very quickly.’ Maturing late would normally be a disadvantage, but in this hyper-competitive environment it became helpful.

S

cientists have discovered a new species of caecilian – a worm-like amphibian – whose young peel off and eat their mother’s skin.

The species, named Microcaecilia dermatophaga, is the first new caecilian discovered in French Guiana for 150 years, and is one of only four species whose young are known to feed in this way.

‘What we’ve found is another species that’s a skin-feeder, but most importantly, it’s another species that’s quite distantly related to other skin-feeders we’ve found, meaning that skin-feeding is probably an ancestral characteristic for caecilians,’ says Dr Emma Sherratt from Harvard University, who discovered them during her PhD while working at the Natural History Museum, London.

Caecilians (pronounced siss-ee-leean) are amphibians, like frogs or toads, but are often mistaken for worms or snakes because they have no legs.

Little is known about these strange creatures, which have existed since before the dinosaurs. They live only in the moist tropics and most species live underground, so they are difficult to study.

Their colour ranges from pink to dark grey and they have ring-like ridges along their bodies, adding to their worm-like appearance. But unlike worms, caecilians have large mouths and sharp teeth that they use to eat invertebrates like worms and termites. Their eyes are covered by bone, so they are nearly blind and only see in black and white, but tentacles on the front of their heads detect soil chemicals, giving them a ‘sixth sense’.

To feed their young, females grow an extra fatty layer of skin, which their young then scrape off and eat. To help them, they have specialised teeth adapted to the job, which are eventually replaced by pointier adult teeth.

This research appears in PLOS ONE.

in brief . . .

➤ Work out your nitrogen footprint Most people have heard of carbon footprints, but nitrogen ones? Not so much. Nitrogen pollution’s a real problem, though, doing serious harm to air and water quality. In the long term the way we’re disturbing the nitrogen cycle could have enormous implications for life on Earth. Scientists at the universities of Lancaster, Oxford and Virginia have created a web-based tool to let people in the UK work out how much nitrogen pollution they’re causing, and what they could do to improve the situation with changes in diet or lifestyle. The tool was developed with funds from NERC’s Macronutrient Cycles programme; check it out at www.n-print.org/sites/n-print.org/files/ footprint_java/index.html#/home.

➤ Ocean Business breaks records In April NERC’s National Oceanography Centre hosted Ocean Business 2013 – Europe’s biggest showcase for marine technology, knowledge exchange, training and careers. The show, the fourth in a row, was a great success, attracting more than 4000 visitors over three days – almost a third up on last year. Over 300 companies from 27 countries exhibited their wares, and delegates also had the chance to attend conferences and workshops on topical subjects like the so-called Blue Economy.

➤ New Science into Policy booklet NERC has launched a new edition of its Science into Policy publication, designed to help scientists understand the relevance of their science to policy-makers, to identify opportunities to influence the policy-making process and to communicate their science as effectively as possible. The booklet explains key aspects of how policy gets made, directs researchers to valuable information resources and provides case studies of successful policy engagement – it’s part of NERC’s efforts to make sure that the research it funds and the expertise of the scientists it supports bring the greatest possible benefits to society. Download it for free at www.nerc. ac.uk/publications/corporate/policy.asp.

PLANET PLANETEARTH EARTH Summer Summer2013 2013 7

www.planetearth.nerc.ac.uk

News Chris Connolly

Pesticides disrupt bee learning P

esticides can affect the brain function of important pollinators even at low concentrations.

A paper in Nature Communications found that neonicotinoid and organophosphate pesticides disturb the function of the learning centre in honeybees’ brains.

‘These pesticides, at field-relevant concentrations, cause hyperactivity very quickly,’ says Dr Chris Connolly of the University of Dundee, one of the study’s authors. ‘The prediction is that the bee cannot learn efficiently.’

‘You would expect all higher-order functions to be affected, so that’s their ability to learn, communicate and navigate,’ he adds. ‘Bees are social insects and their efficiency relies on the fact that they share information. They must be able to share information on new food sources and hive sites and they must be able to learn new food sources.’

8

PLANET EARTH Summer 2013

THE REAL QUESTION IS: HOW DID WE GET INTO THIS DEVASTATING POSITION IN THE FIRST PLACE? WE HAVE TO FIND A WAY TO SUSTAINABLY INTERACT WITH OUR ENVIRONMENT TO FEED OURSELVES. Dr Chris Connolly University of Dundee

Because the two pesticides affect the same part of the brain in the same way, using them together makes the problem even worse.

The news came shortly before the EU decided to restrict the use of neonicotinoid pesticides, after a controversial vote in which 15 countries supported a ban but others, including the UK, argued there wasn’t sufficient evidence to support such a move.

The team worked with an intact half of a honeybee brain. Previous studies had looked at disconnected brain cells in controlled conditions using a process known as cell culture but, according to Connolly, those studies were not getting the full picture and needed far more pesticide to get the same effect.

The study was funded by NERC, Defra, BBSRC, the Scottish Government and the Wellcome Trust under the Insect Pollinators Initiative.

Daily updated news @ www.planetearth.nerc.ac.uk

European fisheries flip with long-term ocean cycle

ere Island Arctic camel on Ellesm Illustration of the high 3.5 million years ago. ut abo , iod per rm wa during the Pliocene

A

Julius Csotonyi

New technique proves camels once lived in the high Arctic A

new way of identifying fossils has shown that ancient camels roamed the high Arctic Circle.

The breakthrough came from Dr Mike Buckley, a NERC research fellow at Manchester University. It uses the collagen in fossils to build a unique profile of the proteins in the bone. This fingerprint means even small fragments of bone whose DNA has long since decomposed can be identified.

The technique caught the eye of palaeontologists in Canada, in particular Professor Natalia Rybczynski, who led the study. They had excavated a site on Ellesmere Island, but returned only bits of bone too small to yield any information.

Buckley suspected the bone fragments were from mammals but was surprised to find the bones’ collagen fingerprint was closest to that of a camel. Meanwhile Rybczynski’s team were examining the bones’ shape, concluding they fit together to make a tibia – albeit a very big one; 30 per cent bigger than those of modern camels.

By combining the two insights, the researchers decided the fossil came from something close to Paracamelus, the oldest known camel ancestor, never before found so far north.

The camel lived in a time of global warming around 3.5 million years ago, in a forested Arctic around 14-22°C warmer than today but still subject to harsh winters and months of complete darkness. This may have given the camels an edge in moving out; features like wide, flat feet and a hump that now help it survive in deserts could have arisen in equally extreme but much colder conditions.

sudden switch from herring to sardines in the English Channel in the 1930s stemmed from a long-term ocean cycle called the Atlantic Multidecadal Oscillation (AMO), international research shows.

The AMO is a 60- to 80-year cycle between warm and cold sea surface temperatures in the North Atlantic. There were warm periods from 1860 to 1890 and 1930 to 1960; the current one started in 1995.

The PLOS ONE study compared data on sea-surface temperatures with measurements of ocean plankton levels since 1948, and historical records of sardine egg abundance and herring catches dating back to the 16th century. It shows the AMO was the second most important factor influencing the distribution of plankton in the North Atlantic, after man-made global warming.

Its effects on herring, sardine and other fish are also dramatic.

During the 1930-1960 warm period, the weight of herring spawning in Norwegian seas increased tendfold, while the herring fishery in the English Channel collapsed and was replaced a few years later by sardines. The Channel represents the boundary between sardines, which prefer warm water, and cold-loving herring. In warm periods, the boundary shifts northwards, and in cool periods it retreats south.

At the same time, the cod fishery extended northwards by 1000km along the coast of Greenland. During the subsequent cool period in the 1970s, the herring population in the Norwegian Sea fell from 16 million tonnes to just 50,000, but since the start of the next warming period in the 1990s it has recovered to 1960 levels.

PLANET EARTH Summer 2013

9

www.planetearth.nerc.ac.uk

News More severe and widespread UK droughts projected

D

roughts are projected to be more severe and affect more of the UK in the coming century.

That’s according to a new paper, whose findings have consequences for how water is managed, particularly in southeast England.

‘If you have small, localised droughts, that’s not so important from a watermanagement point of view, because most utilities can move water in from another place,’ says author Professor Mark New of the University of Oxford. ‘But if a drought affects a whole region like the southeast of England, then you’ve got a more significant problem.’

The team analysed regional climate data from the Met Office’s Hadley Centre, concluding that droughts will get more severe in the UK, particularly in the winter and later in the century. They are also increasingly likely to affect more than one region at a time.

‘It’s the southern water resource regions

that need to think about shared risks,’ New explains. ‘They will increasingly have to think about how their resource scarcity problems link to adjacent regions as well as their own.

It’s all very well borrowing from your neighbour if they’ve got something to lend, but if your neighbours are broke as well, then it becomes a bit of a problem.’

New and his team will now investigate long-term options to address the problem. These include controversial dam projects and systems to move water long distances, as well as softer options aimed at cutting demand.

Their work appears in Water Resources Management.

Pollution slows reef growth

F

ine particles produced by burning fossil fuels are slowing coral reef growth, say scientists.

New research in Nature Geoscience establishes the first clear link between the speed at which corals grow and pollution by humans.

When these fine particles – known as aerosols – are released into the atmosphere by either volcanic eruptions or burning coal, they reflect incoming sunlight and shade the Earth. This process is known as ‘global dimming’. An international team found that it stops necessary sunlight reaching the coral and cools the surrounding waters, slowing coral growth.

‘Coral grows by producing calcium carbonate skeletons, contributing to a process called reef accretion,’ explains Lester Kwiatkowski, a PhD student from Exeter University who led the research. ‘Since the reef structure is continually being broken down by storms and other factors there’s an important balance between secreting calcium carbonate and losing it.’

Lower sea-surface temperatures and limited sunlight for photosynthesis could mean corals can’t produce enough calcium carbonate to maintain this balance, so that reefs dwindle away.

10

PLANET EARTH Summer 2013

Daily updated news @ www.planetearth.nerc.ac.uk

Salt makes chalk cliffs collapse

Scientists pay tribute to climate-change pioneer, 75 years on

Brian Harris / Alamy

I

S

alt plays a greater role in undermining chalk cliffs than previously thought, say scientists.

Until recently, such collapses were blamed on waves eroding cliff bases, or chalk weakening as it became waterlogged. But in Brighton in 2001 a cliff behind a sea wall that protected it from these processes started collapsing, and scientists questioned why.

‘These cliffs behind the sea walls have been stable for 60 to 70 years so we wanted to know why they are now collapsing,’ says Dr James Lawrence, now at the University of Leeds, the lead author of the Geomorphology study. ‘We realised that over that time large amounts of salt had penetrated the pores of the cliff and was degrading the chalk.’

Lawrence and a team of researchers from the University of Brighton and the British Geological Survey tested chalk

samples from British and French cliffs.

They then compared them with chalk from an inland quarry with no exposure to salt. Examining both with an electron microscope revealed the coastal chalk had large salt crystals, left behind when seawater splashes onto the cliffs and then evaporates.

‘When we tested the coastal samples’ strength against the quarry samples they were between 20 and 55 per cent weaker,’ explains Lawrence. When the team then exposed the quarry rock to salt in the lab, they were shocked to see it had quickly become just as weak as the coastal cliff samples. This shows that salt is a major factor in chalk cliff collapses, and with rising sea and more storm surges predicted as a result of climate change, these may become more common in future.

n April this year, scientists celebrated the 75th anniversary of a vital breakthrough in grasping how our actions affect the climate.

Global warming didn’t become widely known until at least the 1980s, but the first research showing that Earth’s climate is getting warmer was published in 1938 by a British amateur scientist, Guy Stewart Callendar, who demonstrated that the planet had warmed by about 0.3°C over the last 50 years and suggested CO2 could be partly to blame.

Dr Ed Hawkins of the National Centre for Atmospheric Science at the University of Reading and Professor Phil Jones of the University of East Anglia reanalysed Callendar’s results, publishing the results as a paper in the Quarterly Journal of the Royal Meteorological Society – the same publication the original study appeared in.

In Callendar’s day, few scientists believed humans could change a system as vast and complex as the Earth’s climate, and his paper didn’t get the recognition it deserved. The new study tries to set the record straight, drawing attention to a true pioneer in the field.

‘In hindsight, Callendar’s contribution was fundamental,’ says Hawkins. ‘He is still relatively unknown, but in the history of climate science his paper is a classic.

He was the first scientist to discover that the planet had warmed by analysing temperature measurements from around the globe, and suggested that this warming was partly related to man-made carbon dioxide emissions.’

Hawkins and Jones show that Callendar’s estimates for the amount of warming have stood up remarkably well, especially considering the limited data he was working with and the fact that he had to do all his calculations by hand. Despite these handicaps, he managed to measure terrestrial temperature change to within modern estimates of uncertainty. Not bad for someone who spent his days as a steam engineer.

PLANET EARTH Summer 2013

11

Rain, brains and climate change Comparing the results of different climate models is harder than you’d think; Adam Levy describes how he’s tackling the problem with techniques developed to analyse medical images.

12

PLANET EARTH Summer 2013

F

ive years ago, I spent half an hour in an MRI scanner trying to obey instructions not to look away from the huge crosshairs filling my vision. Many thoughts ran through my head as I lay there.

Mostly, I wondered whether the scientists could tell each time I cheated at their test by glancing away, and if this would jeopardise my payment. I did not lend a thought to how the images of my brain would be analysed, and it certainly did not occur to me that in five short years I’d be using the very same techniques to help predict climate change.

When I started my doctorate in 2011, one of the first things I learned about climate science was just how difficult it is.

Although it’s relatively straightforward to demonstrate that increased carbon dioxide will increase the Earth’s temperature, understanding how this will affect different regions at different times of the year is much harder.

Climate scientists now use incredibly complex, physics-based computer models to try to simulate the climate under different scenarios. These allow us to visualise and understand the climate change we’ve seen over the past century, and help us predict the changes that we might see in the future.

Frustratingly, though, these models have always struggled to simulate rainfall.

Changes in rain patterns will have a huge impact on agriculture, potentially threatening the livelihoods and lives of millions of the world’s poorest people. Yet when we compare the results of different climate models, not only do they disagree on how climate change will affect future rainfall in different regions of the world – they even struggle to simulate present-day rainfall.

It’s possible that disagreement between the models is partly caused by each model simulating weather features in different locations. For example, if two models agree that a monsoon will become wetter

in future years, but they always predict it in different places from each other, then comparisons will imply they disagree.

This is a bit like trying to compare two photos taken of the same scene, but from different viewpoints – even though they represent the same thing, if you put one on top of the other, the images won’t line up.

The purpose of my work is to find a way to get all the climate features in all the models lined up before we compare them… and this is where the brain scans come in.

Warped imagery After scanning my brain, the scientists compared the images to the brain scans of other individuals, so they could understand what effects the experiment was having on me. To do this, they first needed to align the 3D images from the scans so that all the anatomical features overlapped.

Medical image-analysis researchers do this by using image-manipulation tools, which distort (or ‘warp’) an image of one patient’s brain so that its features line up with those of another patient. Imagine our photos from different viewpoints are printed on rubber sheets – to get them to line up better, we can stretch and squash them, but only within reason. We don’t want to fold or tear an image, as then we’ll be losing parts of the scene it captured.

In just the same way, when we’re comparing climate models, we want to get the climate features to overlap. Regardless of the original application, the idea makes good sense – in both fields we want to compare features, but have to make sure that they’re correctly lined up first.

To test out the potential of this technique, I started by looking at 14 stateof-the-art climate models’ simulations of the present day. I applied the medical imaging software in such a way that it could adjust the climate simulations instead of brain images. Each model’s simulation was warped to get its rainfall features – the patterns where rain fell – to line up better with the observed patterns. In other words, the models’ simulations end up looking more like what actually happened.

I then applied the same warps to the models’ predictions of future rainfall under an extreme climate-change scenario. If the technique worked, the rainfall features in the predictions would be better lined up, and so there would be a reduction in disagreement between the models.

Calculating something like this is one of those moments when your heart stops as a scientist. I ran through the code that compares the models before and after

IPCC

TO GET IMAGES TO LINE UP BETTER, WE CAN STRETCH AND SQUASH THEM – BUT ONLY WITHIN REASON. applying my technique and waited for two numbers to pop up on my computer screen.

If the second number was smaller, then the idea had worked. If not, I was going to have to think of another idea for my thesis.

The numbers appeared. I breathed a sigh of relief, and then quickly plugged the numbers into my calculator. I’d managed to remove 15 per cent of the disagreement between climate models by using software originally designed for looking at images of people’s brains. Not only that, but in some areas this improvement was much higher, more than halving the disagreement.

Now that I’ve shown that these tools can help improve our predictions, the next step is to develop a version of the software that is designed from the get-go to look at rainfall. The medical software is not set up to deal with warping images on the surface of a sphere, and so there are limitations in applying it to global rainfall. Once I’ve corrected this, and dealt with some other shortcomings, I should be able to achieve bigger improvements in the agreement between models.

I’ll then apply the software to a broad range of emissions scenarios, which could provide a much clearer understanding of how rainfall will change. My hope is that these results will help inform policy and adaptation to avoid some of the worst consequences of global warming.

MORE INFORMATION Adam Levy is a doctoral student in the Atmospheric Physics department of the University of Oxford.

Email: levy@atm.ox.ac.uk

PLANET EARTH Summer 2013

13

14

PLANET EARTH Summer 2013

Grand Prismatic Spring, Yellowstone National Park, Wyoming.

David Mencin, distributed by EGU under a Creative Commons Licence.

Super-eruptions – not quite so super?

It turns out that one of the deadliest hazards the Earth can throw at us may happen more often than we thought. Darren Mark and Ben Ellis report on how their work in Yellowstone could radically change our understanding of these events, with implications not just for those living nearby but also for the global climate.

T

he largest explosive volcanic events, known as ‘super-eruptions’, are one of the greatest geological threats to mankind. Globally, millions of people live in regions that could be devastated by the eruption of a super-volcano – for example, Yellowstone in North America, Campi Flegrei in southern Italy, and Toba in Indonesia.

These eruptions can produce hundreds or even thousands of cubic kilometres of magma over days or weeks.

Yet their most widespread effects don’t come from locally-devastating pyroclastic flows of superheated gas and rock, but from ash clouds that can circle the globe. Sulphur injected into the stratosphere oxidises to form small droplets of sulphuric acid. These stop sunlight reaching the planet’s surface, cooling the climate.

For example, the most recent super-eruption of the Quaternary Period – the one we are in at present – was the eruption of the Young Toba Tuff (YTT), which occurred around 75,000 years ago in what is now Indonesia. It has been suggested as one of the most significant events in the course of human evolution, leading to cataclysmic changes in terrestrial ecosystems and nearly wiping our species out. Yet not all scientists agree. To prove or disprove the theory, we need to know the exact order of events around the supereruption, as well as precisely how – and how quickly – ecosystems responded.

We can test these relationships with high-precision geochronology. The ash ejected during super-eruptions comprises silica-glass shards and mineral crystals from the fragmented magma, as well as pieces of the volcano itself. We can harvest the different mineral crystals that were growing in the magma before the eruption from the volcanic deposits, and date some of them to reveal the age of the eruption.

High-precision dating techniques are now transforming our view of super-eruptions.

These rely on accurately measuring the relative amounts of two different forms of the same element – known as isotopes – in a sample of rock. Some isotopes decay into others at a constant rate, so if we know how much of each was there at the start and can measure what is there now, we can learn how long ago the rocks were created.

These methods are getting more precise all the time. This improvement comes from new technological developments in mass spectrometry, the technique we use to measure minerals’ isotopic composition; from refinements to the known rates at which different isotopes decay; and from other changes in our approaches to dating of rocks and minerals.

This isn’t just a matter of adding another decimal place to a number; it lets us dissect the geological record at the highest level of detail, and accurately sequence the Earth’s history.

PLANET EARTH Summer 2013

15

Little and often?

With these new tools at our disposal, we wanted to test our understanding of super-eruptions by studying one of the largest examples of recent geological times – Yellowstone, a volcano synonymous with the term. The Yellowstone Caldera is well known for three huge eruptions, at around 2.1, 1.3 and 0.6 million years ago.

These episodes were punctuated by long periods of relative peace, during which lava flowed out episodically rather than being hurled explosively into the air. The largest and oldest of the three major explosive events was the Huckleberry Ridge Tuff (HRT), which erupted a volume of rock approximately 2,500 times larger than the recent Eyjafjallajökull eruption in Iceland – a relatively small event that nevertheless caused chaos in the skies across the Atlantic and Europe.

The HRT has three component parts, known as members A, B and C. They contain a superficially similar mixture of minerals, but they have some subtle yet important differences. Initial mapping in the late 1960s discriminated between the three members on the basis of differences in texture, such as the size and proportions of the crystals, proposing that each erupted

emerged at the same time, but member C appeared at least 6,000 years later.

Member C accounts for around 12 per cent of the HRT’s total volume, and although the eruption of Members A and B is still big enough to count as a super-eruption (estimated at around 2200km3 of rock), the volume of Member C alone, an estimated 290km3, is around 300 times larger than all the material ejected by the 1980 eruption of Mount St Helens.

The study raises the possibility that many ancient ‘super-eruptions’ may actually have been many separate events that happened across timescales that are short in geological terms, although still very long by everyday standards.

If this is right, it is a paradigm-shifting hypothesis. It implies that although each volcanic event was smaller than we have thought until now, super-eruptions may have happened more often. As well as the hazard potential of more frequent supereruptions, we have little idea what impact several large eruptions occurring over a short period would have on the global climate, yet this is an extremely important question.

Our research is now focusing on the younger Yellowstone super-eruptions,

MANY ANCIENT ‘SUPER-ERUPTIONS’ MAY ACTUALLY HAVE BEEN MANY SEPARATE EVENTS.

MORE INFORMATION Dr Darren Mark is a post-doctoral research fellow and manager of the NERC Argon Isotope Facility, based at the Scottish Universities Environmental Research Centre. Dr Ben Ellis is a postdoctoral researcher at ETH Zurich.

Email: d.mark@suerc.gla.ac.uk.

16

PLANET EARTH Summer 2013

from a different place. Having reviewed this literature in detail, we were intrigued by this idea. We wondered – was it possible that each member also erupted at a different time?

We started out by analysing the chemical and isotopic composition of hundreds of crystals of sanidine, quartz, augite and fayalitic olivine from the HRT deposits.

Data showed that whereas members A and B were similar, member C was chemically different, suggesting it crystallised under different conditions.

These results added fuel to our fire, and we began a campaign to date each member as precisely as possible. We harvested potassium feldspar from each member, and analysed single crystals using a method known as argon-argon dating at the NERC Argon Isotope Facility. This technique relies on the known decay rate of a naturally occurring isotope of potassium; we measure the relative quantities of this isotope and its decay product to calculate exactly how long ago it was erupted.

Our results showed members A and B

assessing the super-eruption deposits of Toba, and reexamining Campi Flegrei and Mount Vesuvius, infamous for the destruction of Pompeii in 79AD. We have found multiple layers of volcanic ash that can be correlated to the YTT, but that are separated by varying amounts of sediment in deep ocean cores. This suggests there may have been multiple eruptions of Toba around 75,000 years ago. Pilot data from all study sites show similarities with our results from Yellowstone, suggesting these other supereruption deposits are also made up of smaller eruptions over time.

As a result, the most important question we have to resolve is ‘how long does it take to generate voluminous super-eruptionsized batches of magma?’ This may be the primary control on how quickly one supervolcano eruption can follow another.

With the potential possibility that some super-eruptions could be resolved into smaller, discrete events we wonder whether in times to come, super-eruptions will not be quite so super?

If you’ve ever wanted to create a bit of wildflower garden in your outside space but been put off by having to find and nurture the right seeds, then the perfect solution is now available – thanks to a competition through which NERC helps environmental scientists take their skills out of the lab and into business.

Competition skills bloom into eco-business T he solution in question is the seed ball, made and marketed by scientists Anna Evely and Emily Lambert.

The pair knew they wanted to start a company when they met as PhD students at the University of Aberdeen. The catalyst for their aspirations was Environment YES, an annual competition which provides all entrants with training and advice on how to run a business.

Together with two other researchers, Evely and Lambert took part in 2010, and the experience gave them the knowledge and confidence to put their ideas into action.

‘There was just so much to learn,’ says Lambert. ‘We all had different business roles which made us appreciate that you can’t just do it by yourself, you need to draw on the skills of other people around you. I think it’s made us more collaborative in our approach to building the business, and more open to other people’s ideas.’

Evely and Lambert went on to found Project Maya, a sustainability training academy. The seed balls, which come in several wildflower mixes, are Project Maya’s latest initiative. Their

creators hope they will raise funds for sustainability projects as well as improving biodiversity in our backyards.

‘Seed balls in some form have been used throughout history,’ says Lambert. ‘Ours are based on the design of a Japanese natural farming innovator and monk, Masanobu Fukuoka. Fukuoka showed that two people working a few weeks a year could produce high crop yields from seed balls without ploughing, weeding or the need for pesticides and fertiliser.’

‘Gardens are one of the most important havens for wildlife,’ explains Evely. ‘The total land in UK gardens covers an area larger than all our designated national nature reserves combined – yet the flowers we plant in them often have no pollen and nectar and so are unsuitable for bees and butterflies. Seed balls are a really easy way to make our gardens buzz with life.’

Each marble-sized ball is a mini-ecosystem of wildflower seeds mixed with clay, peat-free compost and chilli powder. At around 1cm in diameter the balls are super easy to scatter and once that hard work is done the rest is taken care of.

The dried clay protects the seeds from hungry ants, mice and birds and allows them to germinate once enough rain has soaked through the clay. The nutrients and minerals in the balls give the seeds the best possible start, and the chilli powder? Well that continues to deter predators as the seed ball slowly breaks down and the seeds sprout.

MORE INFORMATION Environment YES is run by NERC in collaboration with the Nottingham University Business School: www.nerc.ac.uk/funding/available/schemes/yes/ www.seedball.co.uk

Project Maya

www.mayaproject.org

PLANET EARTH Summer 2013

17

The last stand?

Few people will have missed the news that Britain’s 80 million ash trees are under threat from an apparently unstoppable fungal disease, Chalara.

But there is a glimmer of hope. Richard Hollingham talks to Richard Buggs from Queen Mary University of London, and Jo Clark, from the Earth Trust, to find out how decoding the ash’s genetic sequence could help save these important trees.

ONE OF THE REALLY ENCOURAGING THINGS IS THIS HAS SHOWN US HOW MUCH THE PUBLIC CARES ABOUT WOODLANDS.

18

PLANET EARTH Summer 2013

Jo Clark being interviewed by Richard Hollingham.

which we then have to piece together like the reads of DNA. In this case we have to put all the DNA bases together like a big jigsaw puzzle in the computer to find the whole genome code of the ash tree.

Richard Hollingham: How does the DNA sequence help you understand which trees are going to be resistant to the disease?

Jo Clark: We’re in Paradise Wood, the research woodland of the Earth Trust. Set up about 20 years ago it’s the largest collection of genetic broadleaf trials in the country, dedicated to improving the quality of some of our most important timber trees.

Richard Hollingham: Where we are right now the trees are really quite small and stubby.

Jo Clark: Yes, that’s partly because we’re in a bit of a frost pocket here so it’s not ideal for planting trees. But also these are a special line of ash trees that have been cross-bred with themselves, which has an impact on their growth.

Richard Buggs: For me to sequence a genome it is really important that these are inbred trees. Normally trees have one genome copy from mum and one from dad and they can be quite different so it can be hard to untangle the two to sequence the genome. But a plant that is the product of self-pollination has the same mum and dad which makes assembling the genome much more efficient and gives us really good results.

Richard Hollingham: Jo, I mentioned that alarming statistic of 80 million trees likely to be affected by ash dieback, but how important are ash trees?

Jo Clark: Ash is one of our most important trees, it’s the third most common tree and the second most widely planted broadleaf tree. A lot of British biodiversity depends on the structure of our broadleaf woodland and ash is a very important component of that.

It’s also very important for timber – it’s quite elastic, quite good at absorbing impact so it’s used in things like flooring and door frames. Morgan cars are still made from ash trees – it’s widely used.

Richard Hollingham: So, Richard, what are you actually going to do?

Shutterstock.com

Richard Buggs: Today I’ll be collecting a sample from the ash and taking that back to my lab where PhD student Yasmin Zoren will extract the DNA from the bark. We send that DNA to Eurofins in Germany and they’ll send back a whole load of short reads [of the chemical structure] covering the genome 155 times over. We then put that all together, using high-performance computers to assemble the actual genome sequence.

Sequencing a genome is a bit like building up a picture of an unexplored island. All we know is how big the island is; to find out what the interior’s like we might take lots of small aerial photos

Richard Buggs: The genes for resistance aren’t just going to pop out of the genome as soon as we sequence it, we’ll have to find them. We’ll do that by looking at lots of trees to find ones that are resistant, then genotyping them – not the whole genome but enough of it to pick out the genes associated with resistance or susceptibility to ash dieback.

Jo Clark: The underlying genetics is of paramount importance, whether you’re trying to produce robust populations to combat climate change, or to resist a novel disease like this fungus, Chalara. The genetics is what underpins all our research work to produce productive timber trees for the future.

Richard Hollingham: Richard, how long is this going to take?

Richard Buggs: Sequencing the genome should take less than a year – we should be releasing a draft assembly of the ash genome very quickly. Technologies have moved on really fast in the last five years and this is now quite a routine thing to do.

Richard Hollingham: And, Jo, how soon do you expect to be able to use this information?

Jo Clark: Once we have individuals that are likely to be resistant we have very good techniques for grafting them onto a rootstock; then you can be producing seeds perhaps in five years’ time. The public can help by identifying trees they think are resistant, and letting researchers know on the Future Trees Trust website. Those are the ones we would like Richard to be screening to see if they are resistant and we can breed from them.

Richard Buggs: This is obviously a huge natural disaster for Britain but one of the really encouraging things is this has shown us how much the public cares about woodlands. And within the scientific community I have seen a huge enthusiasm to get involved with trying to combat this problem. People with different research skills are coming together and saying, look, here is something that I can bring to the table, let me work on this. We’re all looking to collaborate to combat this together as a scientific community within Britain.

MORE INFORMATION This Q&A is adapted from the Planet Earth Podcast, 5 February 2013.

The full podcast and transcript are on Planet Earth Online: http://planetearth.nerc.ac.uk/multimedia/story.aspx?id=1354 Future Trees Trust: www.futuretrees.org The Earth Trust: www.earthtrust.org.uk Richard Buggs, QMUL: www.sbcs.qmul.ac.uk/staff/richardbuggs.html

PLANET EARTH Summer 2013

19

The heart of the matter Helping to improve our predictions of flash flooding means unpicking everything that’s happening inside a convective cloud – from the inside. Alan Blyth and colleagues describe a project that will use the best-equipped aircraft – and the strongeststomached scientists – to do just that.

20

PLANET EARTH Summer 2013

The aircraft equipped with some of the most sophisticated research instruments in the world.

C

onvective clouds are designed to produce heavy rain, and we have all experienced how well they do it.

When you’re driving, in particular, it can seem like the heavens suddenly open then just as suddenly the deluge stops. But if it keeps raining in one place, or is particularly heavy (or both), there’s a good chance of a flash flood. These can develop quickly over a small area, as we saw in 2012 in Devon when Clovelly’s main street turned into a fast-flowing river.

Our ability to forecast where heavy showers are going to form, and to a lesser extent when, has greatly improved over the last few years. But we’ve made less progress on predicting how much rain is going to fall. To do this we need to understand in much more detail the physical processes in a cloud’s complete life cycle.

We know that clouds can form along lines where warm and moist air converges, when the atmosphere is unstable and will allow warm air to rise. We know that cloud drops are formed by water vapour condensing around minute particles in the air (aerosol) and collisions between

IMAGINE PLUMMETING AT EIGHT METRES PER SECOND THEN BEING SWEPT STRAIGHT BACK UP AT TWICE THE SPEED.

JoeFox / Alamy

these cloud drops can create raindrops. We also know that ice particles are produced in the cloud and cloud drops freeze onto those particles which then melt to form raindrops. And we know that strong and persistent updraughts of warm air can cause heavy rain, and that new clouds building up behind older ones can make heavy rain last longer.

But these are just the basics. We still don’t know exactly how ice particles are produced in the cloud, or the detailed physical processes responsible for turning them into rain, particularly heavy rain.

Strange as it seems, the tiny cloud drops in the heart of a growing cumulus cloud do not freeze at 0°C as water does on the ground. The cloud drops remain liquid – albeit supercooled – until they encounter an ice nucleus to freeze around; but these nuclei are few and far between at altitudes of five or six kilometres. We also need to know how fast these crystals grow as more

supercooled cloud drops bump into them and freeze – a process known as riming.

One reason it has proved so difficult to answer these questions is that a convective cloud is a hostile place and techniques like radar, which probe the clouds remotely, can only tell us so much. To get to the heart of the matter you have to fly right into the cloud.

Imagine being suddenly caught up in the air movements inside the cloud, plummeting at eight metres per second then being swept straight back up at twice the speed. Imagine trying to study particles the size of a pin-tip from an aircraft travelling at 200mph. Imagine that aircraft being battered by raindrops at this speed.

And as if that wasn’t challenging enough, you have to take your measurements at just the right time in the life of the cloud to understand how ice particles form and grow.

This is what scientists in a new project called COPE (COnvective Precipitation Experiment) will be doing over south-west England this summer. For the first time, we will study the formation and growth of the particles that lead to rain while also learning about the larger-scale air motions in and around the clouds themselves. By better understanding the processes that control rainfall intensity we can improve the way these processes are represented in our forecast models – and improve the forecasts.

COPE will call on the NERC/Met Office Facility for Airborne Atmospheric Measurements, whose aircraft is equipped with some of the most sophisticated research instruments in the world – instruments that can distinguish between liquid and solid particles at 200mph. One goal of the project is to find these needles in the haystack – the first few ice crystals that form in amongst the hundreds of cloud droplets per cubic centimetre of cloud.

Another research aircraft, from the USA, will use unique on-board Doppler cloud radar and lidar (which uses light waves rather than radio waves). The radar can measure the properties of the small precipitation particles just as they are forming, as well as air movements inside the cloud. The lidar will tell us about air being brought into the cloud from outside, which can kill off the cloud but under some circumstances can actually set the whole rain process going.

When the size of the precipitation particles makes the cloud too dangerous for the aircraft, the new sophisticated

NCAS radar on the ground will take over.

Met Office radars and other instruments run by NERC at a Cornish base will tell us about, among other things, the larger-scale development of precipitation, properties of the aerosols in the clouds and the movement, relative humidity and temperature of the air below them.

That is only part of the story of course: all this information will only help our predictions if our models are up to the job.

COPE will use several different models to help interpret the data from the field campaign. The Met Office will use the information to test and improve one of their models, which can warn of potentially dangerous weather down to areas of just 1.5km2.

COPE is a good example of collaborative science, with different organisations pooling their resources and expertise to improve weather forecasts and give the best advice to policy-makers and the insurance industry.

The impacts of this research will be significant, not least because the estimated bill for the 2007 floods in the UK was £3 billion. But the benefit to society of improved flood forecasts goes beyond money; if they can give people and businesses enough time to act before the flood arrives it will prevent misery and heartache too.

MORE INFORMATION Professor Alan Blyth is director of weather science (part of NERC’s National Centre for Atmospheric Science – NCAS) at the University of Leeds.

Email: a.m.blyth@leeds.ac.uk Phil Brown is cloud physics research manager at the UK Met Office; Professor Tom Choularton is head of the Centre for Atmospheric Science, University of Manchester; Professor Chris Collier is head of strategic partnerships at NCAS; and Humphrey Lean manages mesoscale modelling research at the Met Office.

COPE is a collaboration between NERC, the Met Office, UK universities and international partners. www.ncas.ac.uk/index.php/en/ introduction-to-cope

PLANET EARTH Summer 2013

21

Dean Wilson recently returned from a research cruise off Japan, carrying out deep-sea drilling to gather rock samples and sensor data on the geology beneath the seabed. The results will give us a better understanding of the risk of earthquakes and tsunamis. He describes life aboard the good ship Chikyu.

Under the A

sea

head of my first trip to Japan, my head was full of childhood images of futuristic robots and high-speed trains. Tokyo didn’t disappoint. In the two days I had on dry land, I experienced delicious food, friendly people and the crazy juxtaposition of tranquil shrines in the midst of a busy city. It was a whirlwind experience.

The next morning, I found myself on a small passenger helicopter with a handful of other scientists heading out over the Philippine Sea, to a drop in the ocean about 100km south of Japan. Thirty minutes later I caught my first glimpse of the deep-sea drilling vessel Chikyu, essentially a mobile drilling platform.

It casts an unmistakable silhouette against the enormous expanse of the ocean.

The growing image of the giant ship was stupendous. With its 70m derrick (drilling rig) standing proudly to attention in the centre of the vessel, it looked like a giant Tetris block sent down from the heavens!

The Chikyu would be my home, office and lab for the next seven weeks. Suddenly a wave of emotions washed over me: I was excited, nervous and a little hysterical – what was I doing here?

About ten months earlier, I applied to sail on the Integrated Ocean Drilling Program’s (IODP) Expedition 338, a seagoing science mission to understand what causes large earthquakes and the generation of tsunami waves. Here’s what I thought when reading the advert: ‘WANTED: team of specialist scientists needed for intrepid exploration of the Earth below the sea.

Seven weeks of hard but rewarding work

22

PLANET EARTH Summer 2013

out on the ocean waves. Beards optional!’

As a full-time researcher in marine geophysics, I spend most of my days sitting at a computer, so I really relish the opportunity to escape from the office and get some first-hand experience of collecting the data that is so crucial to my work.

Expedition 338 is part of a larger project aimed at learning more about how and why earthquakes and tsunamis occur.

The IODP explores the geology below the seafloor to study Earth processes that evolve over time, ultimately causing violent, unpredictable natural disasters. The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) is a complex ocean drilling project that is being conducted over several years (2007 to present) with multiple expeditions and scientists from all

over the world.

NanTroSEIZE is the first attempt to drill, sample, and instrument the earthquake-causing or ‘seismogenic’ portion of the Earth’s crust, where violent, large-scale quakes have occurred repeatedly throughout history. The Nankai Trough is one of the most seismically active zones on the planet, and our sensors and sample data are expected to yield insights into the processes responsible for earthquakes and tsunamis, with implications for disaster planning and early warning systems.

Ice cream, ping-pong and borehole geophysics Daily life onboard Chikyu was easy going. Meals are provided every six hours, washing is done within four and cabins

CHIKYU CAN STAY IN EXACTLY THE SAME POSITION FOR MONTHS ON END AND DRILL A STAGGERING 7KM BELOW THE SEAFLOOR.

NOAA/NGDC

JAMSTEC/CDEX

are cleaned regularly.

Everything is run to ensure that the ship’s crew, drilling engineers and scientists can work around the clock. The scientists have a daily meeting, with an operation and logistics update, science presentations, as well as moraleboosting items like choosing logo designs and planning the Christmas party – strictly no alcohol allowed though.

After several weeks, ‘Chikyu Time’ sets in, where days feel like weeks and every day is Groundhog Day. There are, however, plenty of things to break up the routine – ice cream twice a week, ping-pong tournaments, film screenings and even a sauna and hot tub.

Chikyu is an amazing machine. Using its six computer-controlled thrusters, the 210m, 57,000-tonne vessel can stay in exactly the same position for months at a time in all but the most challenging conditions. (For comparison, the Eiffel Tower weighs about 10,000 tonnes.) It can drill a staggering 7km below the seafloor, in water up to 2.5km deep. If the drill pipe that extends from the ship to the seafloor were as thick as a straw, it would be 100m long.

During Expedition 338, we drilled 12 holes into different parts of the seabed.

They reached up to 2km below the seabed, and targeted different features identified from seafloor maps and images of the subsurface. At some holes we recovered rock samples (cores), while at others we measured geophysical properties, including electrical conductivity and acoustic velocity, from within the borehole while drilling. The holes were 12” (30cm) across – the size of a regular pizza – and we recovered the cores from inside the hollow drill barrel, known as the string, using a method akin to coring an apple.

In the end the recovered core is pulled up inside a core liner that’s about the same size as a household drainpipe. After this, the cores get split in two lengthways. One

half is described and measured on board, with samples taken for later work, while the second half is archived. This involved categorising the sediments and rocks based on their mineralogy, elemental composition and grain size to understand where they came from – for example, from submarine river deposits or volcanic ash layers.

Fossils and magnetic minerals can be used to understand the age of the material, and structures within it are analysed to understand how the rocks have been deformed since they were deposited.

My job was to interpret the geophysical data that were collected whilst drilling holes where no core samples were taken.

This involved spending lots of time analysing curves and images for patterns and relating this information to what we already knew about the subsurface geology from the cores recovered at nearby holes. Once I’d analysed the data, key observations were compiled into reports that will eventually be used as an expedition reference volume for the whole scientific community.

Chikyu was also recently involved in IODP’s Japan Trench Fast Drilling Project (JFAST), to understand the very large fault slip that occurred in the shallow subseafloor during the 2011 Tohoku earthquake. (A fault slip is when two sections of the earth’s crust that were previously locked together by friction suddenly slide over each other.) This large slip of 30 to 50 metres was the main source of the devastating tsunami that caused so much damage and loss of life along the northeast coast of Honshu.

Understanding the Tohoku earthquake and tsunami has obvious benefits in

evaluating the hazards at other subduction zones around the world. At these zones, the vast tectonic plates of the Earth’s crust are gradually sliding past each other, one beneath the other along the largest faults on Earth. Friction between the plates makes them grip together, building up energy, until they suddenly slip, releasing the stored energy in an earthquake. Obtaining a piece of the fault that moved tens of metres during the earthquake will provide meaningful new geological information.

Scientists have never seen samples of a fault that has moved so far during a recent subduction zone earthquake.

Although Expedition 338 ended in January, there is still a great deal of work to be done. Our tasks include reports, meetings, post-cruise research, scientific publications and wider public outreach activities. Expeditions are expensive, but the rare data and samples we collected will be worked on for many years to come.

When new techniques are developed or new theories need to be tested, the researchers of the future will be able to build on the work we did on the cruise to better understand the secrets of the Earth.

MORE INFORMATION Dr Dean J Wilson is a marine geophysicist at the University of Southampton.

Email: d.j.wilson@soton.ac.uk Expedition 338 daily reports: www.jamstec.go.jp/Chikyu/eng/ Expedition/NantroSEIZE/exp338_dr.html Integrated Ocean Drilling Program (IODP): www.iodp.org

PLANET EARTH Summer 2013

23

Jessica Royles holding a core sample.

Unlocking the secrets of

Antarctic moss banks You might expect research on Antarctica’s past climate to involve drilling and analysing ice cores. But the warmer, more vegetated parts of the Antarctic Peninsula offer very different kinds of evidence. Matt Amesbury and Jessica Royles explain more, through the eyes of their recent field season down south.

A

s we approach Green Island, the primary target for our recently completed field season, the waters turn uncharted.

Not many people come this way. The first recorded landing was in 1903 and since then the island has remained relatively untouched.

HMS Protector, the Royal Navy ship that is supporting our work in the Antarctic Peninsula, nudges cautiously forward. The James Caird IV, the ship’s smaller survey vessel, is out ahead, plotting a safe course through the multitude of icebergs that cluster around the island, scraping and clattering against each other with ominous low rumbles. Eventually, the ship can go no further and we are dispatched, via the rope ladder that drops some five metres from the main deck to the choppy sea, into another small boat to attempt a landing.

This landing has been a long time coming. Last year when we had completed most of the fieldwork for our project, supported through NERC’s Antarctic Funding Initiative, Green Island was surrounded by impenetrable frozen pack ice and could not be accessed. It is the last piece in the puzzle; the final hole to be plugged in a north–south transect of moss bank samples that stretches over almost ten degrees of latitude, or more than 1000km.

24

PLANET EARTH Summer 2013

The Antarctic Peninsula is one of the most rapidly-warming parts of the planet, with temperature rises of 3°C recorded in some locations since the 1950s. But this warming record lacks a longer-term perspective over centuries to millennia. That is what we aim to provide.

The official landing spot on the more exposed north coast, highlighted in the island’s management plan – Green Island is an Antarctic Specially Protected Area due to the unusual richness and fragility of its vegetation – is inaccessible, awash with floating ice fragments and blocked by an unworkable cross-current.

indispensable British Antarctic Survey field assistant Ashly Fusiarski, we make it. Here, the hard work begins; first we must move 500kg of kit away from the rocky shore to safety and establish our campsite. Then we can explore the moss banks.

Gathering moss Over much of Antarctica, very little grows.

There are a multitude of mosses and lichens, but just two species of higher plants. On the Antarctic Peninsula, summer brings just enough warmth and water to enable the mosses we are studying to grow by a couple of millimetres or so, before they are

IT IS NOW OR NEVER, AND THE SUCCESS OF OUR FIVE-WEEK TRIP HANGS IN THE BALANCE. As an icy wind bites through our many layers, we search for an alternative. The Captain comes over the radio to say that if we can’t land now, then unfortunately the ship’s schedule won’t permit another attempt. It is now or never and the success of our five-week trip, focused entirely on this one place, this one moment, hangs precariously in the balance.

Fortunately, due to the skill and persistence of the boat crew and our

frozen again during the long, cold, dark winter months. The following summer the snow melts and the moss grows another few millimetres. When this sequence continues long enough, moss banks begin to form.

In some places this very slow accumulation has continued for thousands of years. The deepest moss banks in the region, almost three metres deep and 5000 years old, are found on Elephant Island, perhaps best known for its part in

Our campsite on Green Island.

A moss bank on Green Island.

Shackleton’s Endurance expedition of 1916. On Green Island, as we discover after an extensive survey, the moss banks are about a metre in depth, suggesting an age of roughly 1500 years.

Antarctic moss banks are ideal archives for research into past climate. The plant material in them is well preserved through freezing in permafrost, so it can be dated easily using radiocarbon dating, and is dominated by just one or two species; at Green Island the banks turn out to be almost entirely made up of the moss Polytrichum strictum. Despite slow growth rates, low levels of decomposition mean we can develop records with about one sample per decade – pretty high resolution for this type of study.

So why is it so important to put recent climate change on the Antarctic Peninsula into a longer-term context? Broadly speaking, Antarctica is an important part of the Earth system, both influencing and responding to global ocean and atmospheric circulation. The Antarctic ice sheet also plays a major role in sealevel change, so understanding changes in the continent’s climate and biosphere is critical for predicting future global change.

The recent rapid warming on the Antarctic Peninsula has been associated with falling sea-ice extent, ice-shelf collapse, glacier retreat and changes to ecosystems on land and sea. Much still remains to be understood about the causes and context of these changes, which are not well captured in current global climate models. Discovering more about the patterns of past natural climate variability in the region covered by our sites will help answer these questions.

We stay four days on Green Island, often working in such wet and windy conditions that we’re happy just to return to the tent to dry out and warm up each evening. In the end we collect two priceless cores as well as a range of surface moss and water samples and climate data. Since the moss banks are frozen solid from 30cm down, we have to use a modified permafrost corer to extract our

precious cargo.

Analysis of the surface samples will provide vital understanding of the modern processes taking place in the moss banks, which gives us the context we need to interpret our proxy climate data from the core samples. Added to the cores collected last year, our work in the field is now complete. All that remains is the decidedly less glamorous lab work.

MORE INFORMATION Matt Amesbury and Jessica Royles are postdoctoral researchers at the Universities of Exeter and Cambridge/British Antarctic Survey respectively. The project’s other members are Dan Charman of the University of Exeter, Dominic Hodgson and Pete Convey of BAS and Howard Griffiths of the University of Cambridge.

Email: m.j.amesbury@exeter.ac.uk.

PLANET EARTH Summer 2013

25

Health of Iceland’s glaciers failing fast

26

PLANET EARTH Summer 2013

All images BGS

B

ritish Geological Survey scientists have shown that the very rapid retreat of Iceland’s glaciers over the last decade – unprecedented in 80 years of measurements – is largely due to warmer summers. They focused on the Virkisjökull– Falljökull glacier in the southeast of the country, finding that since 2007 its front has moved back nearly 200m – an extraordinary 40 metres a year. They are concerned that warmer conditions in summer have taken it beyond a vital tipping point.

The researchers have used information from laser-scanning techniques and an array of time-lapse cameras to build a 3D model of the glacier at the end of every summer since 2009, accurate to the nearest centimetre.

This will give them a baseline against which to measure future changes.

Planning for biodiversity in Westminster Ecologist Laura Harrison describes her time advising Parliament on how far the English planning system is considering wildlife.

W

hen asked to picture an ecologist, many people imagine someone with wild hair, striding through the undergrowth with notebook, hand lens and possibly a large butterfly net. This is probably how I’ve appeared (minus the butterfly net) during fieldwork for my NERCfunded PhD on a British plant that’s invasive in North America. Few people probably picture an ecologist pacing the corridors of Westminster in a suit. Yet this is exactly where I found myself when I undertook a NERC three-month policy fellowship at the Parliamentary Office of Science and Technology (POST).

POST provides MPs and Lords with independent, balanced and accessible analysis of science and technology issues. Its main publications are four-page briefings (POSTnotes) that are researched and written by a staff of scientific advisers and postgraduates on fellowships funded by research councils and learned societies.

Having solved my minor wardrobe crisis, I turned my attention to my POSTnote topic – how the English planning system takes biodiversity into account. Government is simplifying the planning process. The policy is still that proposed developments should not be approved if they harm biodiversity significantly. Some will need an Ecological Impact Assessment, which identifies the likely direct and indirect harm to wildlife. This should be first avoided, perhaps by altering plans, and then mitigated where it occurs, for example by replacing destroyed bat roosts.

Any remaining damage should be compensated for, usually by creating new habitat or improving existing habitat elsewhere. There is a growing emphasis on increasing overall biodiversity, rather than just avoiding its loss.

But while interviewing academics, ecological consultants and developers, I started picking up a worrying lack of information on how far development harms biodiversity in England. This is partly because of limited monitoring of the impacts of particular developments and the effectiveness of mitigation techniques. There is also a lack of research into improved techniques for avoiding and dealing with biodiversity loss.

Research and interviewees pointed to a skills shortage among some ecological consultants and

a lack of resources and expertise available to Local Authorities. This means they generally consider only a few species with high legal protection, such as bats, rather than looking at biodiversity more generally – even though Local Authorities have a legal duty to do so.

My briefing reported on these issues. It also explained a new way of calculating the compensation for biodiversity loss to be provided off site. This ‘Biodiversity Offsetting’ is now being piloted on a voluntary basis for developers in six areas of England.

Some conservationists highlight its potential for obtaining more compensation than currently occurs and also for pooling compensation from multiple small developments into larger restoration areas of more benefit to wildlife. Others fear that Biodiversity Offsetting might be used to justify environmentallydamaging development.

My fellowship has had an impact beyond the briefing itself. Speaking with people from outside my field and producing work that will be so widely read has been a huge boost to my confidence. The rigorous review process and hours spent poring over my wording are also bearing fruit now I am completing my thesis.

Since returning to Leeds, I’ve been involved in new science communication and policy training events for academics. Both scientists and politicians are sometimes accused of not understanding each other’s work and role. Yet in my experience both communities really do want to engage with each other. NERC schemes such as the Parliamentary fellowships and shadowing opportunities make a valuable contribution in helping them do this. I’m grateful for my chance to play a small part in translating science into debate and policy.

MORE INFORMATION Laura Harrison is working on a PhD in ecology at the University of Leeds. Email: bgyljh@leeds.ac.uk. Dr Jonny Wentworth is the Environment Adviser at POST and co-author of the POSTnote.

POSTnote 429: Biodiversity & Planning Decisions: www.parliament.uk/briefing-papers/POST-PN-429.pdf

PLANET EARTH Summer 2013

27

invaders The unique wildlife of the Galapagos is under threat.

Tom Marshall talked to Ken Collins of the University of Southampton to find out why, and what researchers and conservationists are doing about it.

The lionfish.

28

PLANET EARTH Summer 2013

Eric Isselée/istockphoto.com

Repelling

T

he Galapagos Islands form a giant natural experiment on how organisms respond to an isolated environment.

The incredible range of unique plants and animals that live there inspired Darwin’s theory of evolution, and thousands still come each year to see the likes of giant tortoises and aquatic iguanas.

But this natural cornucopia is in danger.

Growing tourist numbers are a welcome boost to the locals’ incomes, but put serious pressure on the very wildlife they come to see. And invasive species are proliferating, threatening to overwhelm natives that have evolved over millions of years with few predators and little competition or disease.

Dr Ken Collins, a marine scientist at the University of Southampton, based at the National Oceanography Centre in the same city, has been visiting the islands regularly since the mid-1980s, and between 1997 and 2000 played a central part in setting up the Galapagos Marine Management Plan. He’s now leading a project funded by the UK government’s Darwin Initiative, aimed at preserving the islands’ marine biodiversity.

We’ve learned the hard way that the island environments need protection even from seemingly innocuous arrivals. Goats have been one particularly unwelcome guest. Back in the age of sail, when protecting native wildlife got no consideration at all, whalers and other ships were in the habit of dropping a few of them off when they passed by, with the idea that they’d breed and provide a welcome source of fresh meat at the next visit.

The goats didn’t just breed; they set about the islands’ vegetation like a swarm of locusts, and defied repeated efforts to bring them under control. They’ve only recently been eradicated at last from a few islands, after a long and costly campaign involving marksmen in helicopters.

‘The Galapagos are the land of reptiles and birds, not of mammals,’ Collins says. ‘All the mammals we’ve introduced have caused huge problems – not just goats but rats, cats, pigs and donkeys.’

Other threats are subtler. The islands are a largely barren volcanic landscape; most of the food for 25,000 residents and 200,000 visitors each year arrives on cargo ships, and we’ve only recently realised these were bringing mosquitoes in their holds, lured onboard from the tropical swamps of Ecuador by their bright white deck lights. Some of these arrivals carried diseases like malaria and dengue fever, or other infections that threaten the survival of unique local bird populations.

Just changing from normal filament lightbulbs to orange sodium lights – invisible to insects – has largely solved that problem,

Ken Collins

Ken Collins with marine iguana.

along with fumigating plane and ship holds.

But many more remain – some blatant and some more insidious.

Early settlers didn’t confine themselves to mammalian imports; they also planted vegetation they thought would be helpful.

Examples of out-of-control plants include Chinchona trees, intended to provide quinine to combat the malaria spread by those mosquitoes, castor oil plants and the humble blackberry bush. This infiltrated much of the countryside, spreading along roadside verges and covering whole fields in a riot of brambles. Goats can be herded or culled from a distance; blackberries have to be killed one sturdy bush at a time.

But changes in the underwater environment are much harder to spot, and are increasingly the focus of conservationists’ concern. Collins and his team helped carry out the first underwater surveys of the islands’ main ports.

At present the picture’s mixed. There are a few worrying signs, but with vigilance it should be possible to stop the waters round the islands suffering the same fate as has befallen many other places, particularly busy ports. Southampton’s docks have been receiving hitchhikers from all over the world for more than a century, clinging to the bottoms of ships or carried in ballast tanks. Its original ecosystem is now barely recognisable.

‘We get shipments from all over the world, and as a result our underwater environment is now completely alien,’ Collins says. The whole seabed of Southampton Water and the Solent is covered in American slipper limpets, invasive sea squirts and the long fronds of Japanese seaweed. ‘We want to stop anything like that happening in the

Diving survey team at work in Galapagos.

Galapagos,’ he adds. ‘We’ve learned it’s a lot easier to stop something coming in than to eradicate it once it’s established.’

The situation is nowhere near that bad around the islands, but there’s cause for concern. Two new kinds of algae that have caused problems elsewhere have already been spotted in the Galapagos Marine Reserve, a world heritage site. The rampantly aggressive white coral Carijoa racemosa has already been reported off the coast of Ecuador, and it wouldn’t be surprising if it reached the islands.

In the longer term, the lionfish could be an even bigger problem. A native of the Indian Ocean, it has a voracious appetite and can eat its way through whole fish populations at amazing speed – an individual can eat 20 small wrasse in half an hour, its stomach stretching to 30 times its normal volume if necessary. It’s already rampaged through the entire Caribbean in just a decade since its accidental introduction, and there’s no reason it couldn’t make it through the Panama Canal and ultimately reach the Galapagos.

The long-term monitoring and surveillance programmes Collins and his team have put in place should provide early warning of such invaders, allowing conservationists to tackle problems while they can still be solved. They’ll also provide a baseline so we can understand changes as they happen.

Overfishing is causing serious damage around the islands too. Collins has been working with locals to get them to understand that conservation is in their interests too. ‘Most fisheries management is reactive – it’s only after a serious problem has appeared that people start to do

something about it, and by that time it can be too late,’ he says. ‘We want to talk to fishermen before that happens and engage them with our monitoring programmes so that we can manage these resources sustainably.’

Fishermen are just trying to make a living, and it’s often much more effective to show them the consequences of their actions directly – for example, that the sea cucumbers they depend on are in trouble and that they should go easy for a while – than simply to lecture them about it. On their latest trip to the islands, the team also talked to the Ecuadorian navy and civilian maritime authorities about how they can contribute.

The damage averted by these marine conservation efforts may not be as obvious as that caused by invasive species on land, but Collins thinks it’s just as worthwhile; the islands’ underwater life is as unique as its terrestrial and avian inhabitants. ‘Bigger fish like sharks can swim to and from the islands, but smaller ones mostly can’t and so the few that make it there evolve into new species,’ he says. ‘So there’s fantastic diversity under water, just like on land.’

MORE INFORMATION Darwin Initiative: www.darwin.defra.gov.uk.

The Galapagos project is led by the Charles Darwin Foundation and University of Southampton, along with the Galapagos National Park Service, the Navy’s Oceanographic Institute, National Direction of Aquatic Spaces, Ecuadorian Agency for Quality Assurance and the University of Dundee.

PLANET EARTH Summer 2013

29

Marek Pawluczuk/istockphoto.com

Algal blooms mean trouble for the water industry and pondowners alike. But they’re on the increase as more pollution reaches our fresh water. Jonathan Newman explains two techniques to keep them under control.

All choked up

I

t may be toxic blue-green cyanobacteria, or masses of floating filamentous algae, but too much of it can block sluices, pumps and weirs and deprive pond-life of oxygen. Algae bloom, which means they grow rapidly, when there are lots of nutrients in their environment, usually phosphates. Blooms are getting bigger and more frequent in the UK as more and more nutrients reach our watercourses, principally from fertilizers washing out of agricultural soils and into our rivers and lakes. This has led to algae becoming the dominant group of aquatic plants almost everywhere in the UK, and especially in static water like reservoirs, gravel pits, lakes and ponds.

They might be easy enough to remove from a garden pond, but to UK water companies they represent a major and increasing cost.

It’s not a new problem – in fact research into controlling algae has been under way since the 1950s. The first government guidance on managing aquatic vegetation, published in 1958, lists chemical treatments using copper sulphate, chlorination, sodium arsenate and 2,3-Dichloronapthoquinone.

Common sense and the European Plant Protection Products Directive of 1991 have since combined to stop more chemicals

30

PLANET EARTH Summer 2013

being thrown at the problem. It’s a positive move but the problem of algae growth in water industry sites, recreational lakes and our own garden ponds remains. So can we find a way to tackle algal blooms that doesn’t add to the chemical burden in our waters?

Barley straw has been known as an effective and sustainable treatment for years, but the reasons why it works remained something of a mystery. I have researched the anti-algal properties of all types of straw – lavender straw, organic and non-organic straw, brown and white rotted wood and rice straw – with experiments in canals, lakes, reservoirs and laboratories. All of them proved effective against algae to some degree – but why?

As the straw decomposes, microbes set to work on lignin, a chemical found in the cell walls of the straw. Analysis at the Centre for Ecology & Hydrology (CEH) found that this microbial action released more than 800 compounds from the straw, most of which had some anti-algal effect.

We needed to find out which compounds were most important, and exactly how they affected the algae.

Research in South American rivers

had already established a link between organic compounds called polyphenols and the amount of hydrogen peroxide in the water. Absorbing light causes these compounds to decompose, and as they do so they produce hydrogen peroxide. We knew hydrogen peroxide is toxic to algae at very low levels, and when we took a closer look at our barley straw we found that background hydrogen peroxide levels in the water increased by 30 per cent as the straw decomposed. So it looks like the magic ingredients in the decomposing straw are the polyphenolic compounds.

Another proven way of controlling algae is with low-frequency, low-power ultrasound. It’s not exactly a new technique – it was developed by the Marconi company in about 1912, to protect the hulls of submarines from fouling by marine algae. Ultrasound is still a very new technique in the commercial world and is being tested by water companies, with other industries starting to look at it too.

But we still don’t understand the science behind the process, and CEH is running a small research project to try to find out.

We know that ultrasound affects biological systems in various ways. For

example, resonating sound waves disrupt gas pockets, or vesicles, in blue-green algae – but this does not explain the effects on other algal groups. Other theories relate to the well-understood mechanisms of ‘ultrasonically induced cavitation’, which often causes pitting on brass propellers.

The damage is caused by the collapse of small gas bubbles, which produces very high pressures and temperatures and releases light – a process called sonoluminescence – as well as nitrate and hydroxyl radicals. But generating these radicals takes more power than the equipment currently used for algae control can probably generate, so the answer must lie elsewhere. In fact, we have again found increased levels of hydrogen peroxide in algae exposed to ultrasound, so there appears to be a common factor involved in these two very different methods. It seems that if you need to control algae, hydrogen peroxide is the key.

But chemistry aside, the important point is that all this research has led to a practical solution becoming available for gardeners and water companies alike, and you will find barley straw – if not yet a handy ultrasound device – in most aquatic garden centres today.

MORE INFORMATION Jonathan Newman is head of the Aquatic Plant Management Group at CEH Wallingford, and author of an information sheet on the use of barley straw: www.ceh.ac.uk/sci_programmes/ documents/BarleyStrawtocontrolalgae.pdf Email: jone@ceh.ac.uk

PLANET EARTH Summer 2013

31

Back issues

Available as downloads from http://planetearth.nerc.ac.uk

Natural Environment Research Council, Polaris House, North Star Avenue, Swindon, SN2 1EU, UK. Tel: 01793 411500

www.nerc.ac.uk