Out of the laboratory and into the Amazon
Ben Langford in the Amazon
19 September 2014 by Ben Langford
Working in the field always makes research more challenging, and doing atmospheric science deep in the rainforest is especially tricky. Ben Langford describes how mosquito repellent, gaffer tape and children's balloons helped keep his project on track.
When I was at school, a careers advice software package told me my future lay in golf green keeping, so quite how I ended up as an atmospheric scientist remains something of a mystery. I'm sure to many of you the idea of studying the atmosphere might seem a rather boring career choice, especially when compared to a life tending to the fairways of Great Britain.
Yes, there are hideous equations to solve, chemical formulae to wrestle and endless hours spent in front of a computer but there is something special that makes it all worthwhile - field campaigns!
Getting out into the field lets us probe and test hypotheses by generating new data from which our understanding can evolve. In my field, for example, we know the world's tropical forests are an important influence on both climate and atmospheric chemistry, but our knowledge is limited by a lack of observations. There is still much to learn about the mixture of different chemicals found in these regions, and we need to find out more about how this unique blend of gases and particles moves between the vegetation and the atmosphere.
At school we are all taught how trees take up carbon dioxide and release oxygen as part of photosynthesis. But trees also release many other chemicals, some of which have implications for air quality, rainfall patterns and climate. Knowing why and how they emit these gases, and incorporating the results into models that predict air quality and climate, can help us to fully appreciate the long-term implications of - for example - felling rainforests to make way for oil palm or soya bean plantations. The only way to find these things out is to step out of the laboratory, don our mosquito repellent and venture into the rainforest.
Collecting data in these inaccessible and remote locations is where our crack team of slightly unhinged scientists comes in. We, some might say foolishly, take very expensive analysers, designed never to leave the comfort of an air-conditioned laboratory, and place them in a rainforest with little more than a plastic shed for protection. We then attempt to keep them running for months on end using a generator, seemingly powered by an elderly mouse in a wheel. Having already experienced and embraced such hardships in the rainforests of Borneo, our latest field campaign took us deep into the heart of the Amazon.
Arriving at the National Institute of Amazon Research (INPA) field site after many hours of travel, our first task is to put together the sampling system which will help us find out how quickly particles are emitted from or deposited to the forest. In order for our analyser to sample the air at the interface between the canopy top and atmosphere we need to assemble a long copper tube that will reach to the top of the site's 50m-tall research tower.
The tube has to be metallic because regular plastic tubing carries a static charge, which makes the particles we are trying to measure stick to the walls. Unfortunately, using copper means we are essentially attaching a tall lightning conductor to the front of our instrument in a region where thunderstorms happen daily. A short section of rubber tubing provides a lightning break but quite how effective this is only time will tell - so far, so good.
Science above the treetops
The next challenge is to mount the tubing and an anemometer - an instrument to measure wind speed - to the tower, high above the tree canopy. We need to be a long way up to get away from the disturbed air flow around the treetops. The heat and humidity inside the forest is unbearable at times so climbing up above it, and away from the numerous biting insects, is bliss. The climb is exhausting, but the views from the top, across mile after mile of pristine rainforest, make the effort all worthwhile. There is little time to stop and take in the view, though - the weather in these parts can turn in an instant and the constant threat of lightning lingers in the back of your mind, helping focus your mind on the job in hand.
This initial set-up phase can take anywhere between a week and ten days, and in the sauna of the jungle it is extremely energy sapping. Once completed, you could be forgiven for thinking that we just sit back, relax and watch the data roll in. Sadly, nothing could be further from the truth.
Our days are spent frantically solving problems, surprisingly few of which can't be fixed with either cable ties or gaffer tape, as our instruments cough and splutter in their new and unfamiliar surroundings. For instance, on this campaign our £350,000 aerosol mass spectrometer developed a leak, reducing the state-of-the-art analyser to nothing more than a very expensive table.
This happens now and then, and is easily fixed in the comfort of a laboratory. But out here, in the heart of the Amazon, even the simplest of problems can quickly turn into a showstopper. For us, the only hope of fixing the analyser would be a cylinder of helium, which when sprayed over the fittings of the instrument could help us identify the source of the leak. Of course, in the rainforest helium is in short supply, so it was time to start thinking outside of the box.
On his way into the forest, one of our team had clocked a man peddling balloons to children in the central square of Manaus. Although not ideal, the balloon might just provide enough helium to help pinpoint the leak. Heading back to Manaus that morning, by nightfall he had tracked down the balloon seller and bought a rather fetching SpongeBob SquarePants balloon. The next day he and SpongeBob waited patiently outside their hotel for the jeep to take them back into the rainforest.
Unfortunately, the driver that day didn't speak a word of English, so after some raised eyebrows, the two men set off in silence, with SpongeBob swaying between them in the gentle breeze of the air-con. Little did the driver know, SpongeBob SquarePants was about to rescue a £1·2m research project! Having torn our hair out for days on end trying to locate the leak, with the help of the balloon, a very thin tube and a great deal of patience we eventually managed to get the instrument up and running and our field campaign back on track.
All this goes to show that as well as helping to test scientific theories, field campaigns also test the ingenuity, resolve and sometimes the sanity of those scientists brave enough to venture outside of the laboratory.
Dr Ben Langford is an atmospheric scientist at the Centre for Ecology & Hydrology.