A few weeks ago I had a moan about how the BBC’s flagship nature series Frozen Planet struck me as being a bit content-light. But I’m happy to say I’ve had my confidence restored – thanks to an amazing documentary on BBC4 called After Life: The Strange Science of Decay.
I don’t think I’ve ever seen a single programme that packed in so much fascinating science. Centred around a ‘model home’ filled with food that gradually decayed over 8 weeks, the show touched on insects, bacteria, fungi, slime moulds, military sandwiches, forensic science, and the evolution of life on Earth. And it was all held together by Dr George McGavin, a really charming and down-to-earth presenter who expertly conveyed how exciting and important decay actually is.
I was captivated right from the start – the programme makers had set up a ‘house’ at Edinburgh Zoo, filled with food and all the fungal spores, bacteria, bugs and other organisms necessary to kick-start the process of decay.
We followed the journey of the food from appetising to maggot-ridden, right up to when it had been completely recycled into new plants via the compost heap. Zoo visitors provided fun examples of the human disgust response – not many could force themselves to retrieve a fiver from a beaker of maggots, or resist smelling horrible samples of rotting meat.
Dr McGavin also took the viewers further afield, to the US where he investigated military sandwiches that can fend off decay for up to 2 years (‘Best two-year old sandwich I’ve ever eaten’, said one soldier taste-tester), and to Southampton University where he met a robot controlled by slime mould.
Another highlight was a rather gruesome ‘farm’, where sets of pig carcasses were being studied to understand how human bodies decay over time and under different conditions. Researchers here have learned that decaying bodies deposit charged particles in the soil water, leaving a ‘death signature’ that can be detected years afterwards.
It was a wonderful example of how a seemingly everyday topic can be broadened to encompass some of the biggest themes in science. Dr McGavin met experts who explained how the evolution of fungi that could decompose wood completely changed the prehistoric Earth, making it suitable for all the organisms that exist today by releasing carbon back into ecosystems (but sadly ridding the planet of enormous insects that had flourished in the high oxygen levels).
And some of it was genuinely beautiful – close up shots of fungi growing on food showed how life always begins again, recycling every atom that it can and turning it into new organisms. Dr McGavin followed individual nitrogen atoms from compost into a new radish, and explained how pigs can actually fly once their flesh is converted into flies by hordes of incredibly efficient maggots.
The programme ended with a rather lovely final comment from Dr McGavin – ‘the atoms inside you have been used millions of times before, and they’ll be used millions of times again.’ It was great to see a science documentary that was fun, exciting and informative without resorting to patronising its viewers or calling on the ‘usual suspects’ list of rent-a-quote scientists. It was ambitious but not big-budget, and really fascinating without being overly nerdy or technical. You’ve got two days left to watch it on iPlayer, so stop what you’re doing and enjoy some really excellent science communication. Thank you BBC4!