Mechanical Beach Cleaning: Friend or Foe?

Read time: 10 mins

Recently, there has been a new surge of attention towards business ventures aimed at cleaning up our beaches. I first came across the machines on twitter, where a marine conservation biologist retweeted one onto my timeline, captioning it: “What fresh hell is this? Lots of things live in sand”. After some research, I discovered that these machines, though varying in style, all work pretty much the same way: upturning sand for insertion into some form of vibrating table or other filtration system to collect litter, debris and micro-plastics (Other methods are emerging: e.g. Hoola One, trialled in 2019 to separate plastic from sand via buoyancy). Some of these machines are vehicles which can be driven in order to clean large stretches of beach; others are hand rotated trommel screens, requiring good Samaritans to shovel polluted sand in for separation.

While before and after photos confirm without a doubt that these machines are highly effective in removing plastic pollution, the problem is that lots of things do live in sand. Believe it or not, the beach is not just an empty substrate home to the odd bird or crab – it’s teeming with microscopic life. Meiofauna is what we call these microscopic invertebrates, and they’re very important nutritionally to a variety of animals that couldn’t survive without them. Even though we can’t see them with the naked eye, there are lots of different types that live in our sandy beaches. Laymen may think, ‘what’s the big deal, surely something so tiny can’t matter that much?’, but actually these organisms play an important role as a trophic link between bacteria and larger fauna, and generally speaking bacterial production is stimulated and mineralization of organic material is enhanced when they’re present. Basically, they’re an integral part of beach ecosystems, so let’s try not to get rid of them. And here’s where the problem lies – these cleaning machines aimed at collecting finer micro-plastics aren’t taking into account the jumble of important microscopic creatures that will be snatched up too. To better explain it, let’s look at the actual measurements: firstly, micro-plastics are defined as being under 5mm in size. A grain of sand can measure between 0.02 – 2mm. Meiofauna often measure between 0.5 – 2mm: see the image below for some measurements of common microscopic beach creatures. Machines targeting micro-plastics generally sieve the sand down to 2mm, and on advanced models right down to 0mm. Some don’t sieve the sand at all – instead vacuuming everything up in order to collect the truly microscopic plastic pieces.

Some characteristic meiofauna genera found in sandy beaches (reproduced from Brown and McLachlan 1990 by Elsevier Science)

We live in a world of largeness, so wrapping our heads around the fact that we exist on a spectrum, at the other end of which are living organisms of such indescribably tiny scale is, frankly, unfathomable to most. Yet it is a fact nonetheless, and our actions often have repercussions beyond what we know. Microscopic creatures aren’t the only potential casualties from these pollution cleaning machines, either: a range of other, slightly larger creatures live in beaches, too – many of whom you already know about. Burrowing crabs, beach hoppers, beetles, clams, blood worms and lugworms are just a few of the many other kinds of life in the sand. Mechanical beach grooming has a range of detrimental impacts, as beach ecosystems are fragile and even the slightest man-made alteration can have significant effects. For example, though it may look untidy and smell bad, the ‘strandline’ (what we call the area of permanent accumulation of debris from the ocean onto the beach) is actually an important and unique fringe habitat colonised by invertebrates from both marine and terrestrial ecosystems. Despite sometimes having a disagreeable smell and being yucky to walk through (for us humans), this part of the beach is vital to sustaining life and is only an inconvenience to people for aesthetic reasons. Removing this beach ‘wrack’ (organic materials like seaweed, shells, dead sea urchins or sponges, algae, plants, driftwood etc) removes habitat and food for swarms of insects, larvae, amphipods etc – and so too valuable food sources for fish and birds. As human beings, we have a bad habit of assuming we are entitled to slice, divide and chop away at the natural world until it fits with our aesthetic desires. Perhaps instead of remoulding beaches to please people who are peeved they have to endure the smell of a normal, natural beach and walk through it’s slimy carpet to paddle in the sea, we could accept them as they are – and be grateful they exist at all.

Mechanical cleaning doesn’t just remove our litter, it also removes the strandline and up to 150mm of the top sand, depending on the type (eg mechanical raking is at the deeper end). Strandline meiofauna won’t recover quickly if this type of beach cleaning becomes reality: deeper or repeated cleanings will certainly result in much slower recolonisation rates. A 2014 report summarised: “Where mechanical beach cleaning occurs, strandline populations are obliterated; all life stages are affected with in situ mortality. The food is removed, microhabitats are destroyed and any shore food web obliterated. Potentially valuable food for birds is also removed”.

Some mechanical beach cleaning ventures do come from greener pastures, though, as I discovered when I reached out to one such company gaining popularity in the UK – Nurdle. A not-for-profit venture whose creators have BSc’s in Conservation Biology and Environmental Science, I was pleasantly surprised to discover how academically informed the venture was. Having consulted with “Natural England, beach owners, the Natural Trust, Cornwall and Devon Councils, beach cleaning orgs and others”, Nurdle informed me they have also been working with a top professor to minimise accidental damage to the ecosystem, and explained the collection process. The micro-plastic collection first conducts an impact assessment using random sampling and quadrating to highlight vulnerable and endangered organisms: based on this, the beach either passes or fails, and cleaning can either go ahead or not. If it gets the green light, the mechanical cleaning is then conducted only at the high tide mark of the day and limited to twice a year for the same beach to avoid over-cleaning. The vacuum doesn’t turn over sand, is designed with light-sensitive organisms in mind, and doesn’t collect larger than 40mm to avoid seaweed etc. The collection is then laid on a tarpaulin, where as many invertebrates and organic material are returned as possible. The machines are not autonomous, so the driver can avoid areas and never cleans an entire beach – using science to target areas of accumulation only. Finally, Nurdle informed me that when their new upgraded design is finished (which will include “an inbuilt winnower and static charge for the polystyrene and nano plastics”), they will be uploading free, accessible and downloadable blueprints so “people can tackle the problem over the world and look to provide blueprints for other methods to either prevent or recover ocean plastic”. As well as this, they plan to release informative videos – to ensure businesses seeking to build or buy similar machines are aware of the steps necessary to avoid adverse effects to beach ecosystems.

So; mechanical beach cleaning, though a dangerous venture, appears to have significant potential – if designed and implemented correctly, rather than commissioned by councils for solely aesthetic purposes or business owners seeking to make profit without consulting relevant experts. Perhaps if enough attention is given to life on the beach too small to see, mechanical cleaning will become standardised to Nurdle’s level of care, and intensive raking will become a thing of the past. William Blake said it best when he wrote Auguries of Innocence, reminding us that the world exists beyond our egos: and that other things alive in nature are also important, especially those lives we deem smaller and so more insignificant than our own.

To see a World in a Grain of Sand
And a Heaven in a Wild Flower
Hold Infinity in the palm of your hand
And Eternity in an hour
A Robin Red Breast in a Cage
Puts all Heaven in a Rage
A Dove house filld with Doves & Pigeons
Shudders Hell thr' all its regions
A dog starvd at his Masters Gate
Predicts the ruin of the State
A Horse misusd upon the Road
Calls to Heaven for Human blood
Each outcry of the hunted Hare
A fibre from the Brain does tear 

- Extract from Auguries of Innocence, William Blake
 


https://www.sciencedirect.com/science/article/pii/B9780123744739002125
https://www.researchgate.net/publication/225565510_Loss_of_Coastal_Strand_Habitat_in_Southern_California_The_Role_of_Beach_Grooming
https://hypertextbook.com/facts/2000/IlanaPrice.shtml
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/meiofauna
https://nurdle.org.uk/
https://www.theswimguide.org/2016/08/24/beach-grooming/
https://www.academia.edu/23290028/The_response_of_macrofauna_communities_and_shorebirds_to_macrophyte_wrack_subsidies_on_exposed_sandy_beaches_of_southern_California

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