Christian M. 10 min read

Coastal protection using marshy blobs?

Climate change is bringing a plethora of challenges, amongst them sea-level rise and stronger, more frequent storms. Inevitably, we’ll need to protect the coastal areas from flooding and erosion, and building a giant wall to enclose the sea isn’t feasible. So what if we told you that a team in the U.S. is using an interconnected network of floating blobs to do so? Meet the ‘Emerald Tutu’.


Attack on the coast 🔱

This may sound like hyperbole, but coastal cities are under attack by Poseidon.

This has always been the case, but our love of living beside the ocean while pumping greenhouse gasses only worsens it.

40% of the global population now lives within 100km of the coast, many of which live right on the seaside. Sitting ducks at the mercy of the ocean’s mood.

Much of the world lives on the coast. (Credit: Rekacewicz, 2006)

And to top this off, sea levels are expected to rise by 0.3 meters by 2050, while the frequency and strength of hurricanes and storms are increasing.

Living next to the sea is quietly turning grim, and unless something is done (unlikely at this rate), places like New York, London and  Tokyo will just become Posiedon’s punching bag.

Erosion will eat away at valuable properties, aquifers will turn salty, and winter flooding will become the new normal.

Coastal solutions 🌊

Still, we’ve always been fighting back against Poseidon’s mood swings.

Over the last century, we’ve become fixated on doing so by building gargantuan barriers to protect the built-up coastal environment.

Could a colossal seawall protect the coast last longer with some help? (Credit:

We’ve built colossal armour stone breakwaters and vast concrete walls to shield us from sea surges, often effectively.

The stronger and bigger our shields, the safer we feel, thinking that the iterative nature of sea surges in the climate change era will simply be solved by maintaining these shields.

But what many fail to understand is that surrounding the coasts with concrete walls is simply not feasible, and unless we start thinking outside the box, we’ll fail.

Boston’s coastal defences 🛡️

Before we begin banging on about marshy blobs, let’s look at Boston: a US coastal city in its prime.

For the last few hundred years, Boston has been at the mercy of any Atlantic storm that deviated northwards from its usual express route across the Atlantic into North-west Europe.

City engineers have kept the city relatively safe from harm by building extensive sea walls and tide gates, but many believe they are inadequate.

Waves battering a Boston sea well. (Credit: The Scope)

On top of this, Boston’s urban growth has led to the demise of its marshland which used to naturally absorb storms like a sponge, making matters worse.

Not enough greens 🥦

Aerial view of a densely-built downtown Boston. (Credit: TimeOut)

Besides dealing with the ocean, coastal cities have to deal with their internal problems that come from humans living together.

Everyone loves parks and natural spaces to relax in, but we haven’t built enough of them.

Also, people love safe cycling lanes and an efficient public transportation system.

But as usual, we have fallen prey to the tragedy of the commons and, instead, have filled our urban public spaces with busy roads to suffocate in and malls to over-consume.

Boston’s Emerald Necklace 📿

Boston’s Emerald Necklace is a 1,000-acre interconnected park system that traverses part of the city centre in a necklace shape, providing both areas for leisure and safe cycle lanes.

This network of parks, parkways and waterways was initially envisaged to surround the city by landscape architect Fred Olmsted during the 19th century, but it was never entirely completed.

Boston’s necklace-shape network of green spaces. (Credit: Boston Emerald Necklace)

What Olmsted didn’t know was that his legacy was going to be an inspiration for innovating the coastal protection sector by giving his old-fashioned necklace a ‘tutu’ spin.

The Emerald Tutu 🩰

A network of interconnected marshy modules to serve Boston in more ways than one. (Credit: Emerald Tutu)

Fortunately, Boston is full of very smart people with a vested interest in the city’s well-being, such as the progressive team behind Emerald Tutu.

The stellar lineup of four has taken Boston as their testing ground for a new way in which to dampen Poseidon’s blows, all while restoring marshland, giving city-dwellers carbon-negative public spaces at a discounted rate, and subtly building infrastructure with progressive values (i.e. coasts will be wearing a tutu!)

In more technical terms, the aim of the project is five-fold:

  • Dampen the strength of storm swells in any coastal area.
  • Provide habitat for local coastal ecosystems to thrive.
  • Create new public spaces in coastal urban areas.
  • Absorb carbon dioxide and toxic pollutants from the atmosphere and sea.
  • Introduce progressive social values in landscaping.

In plain sight, it’s just a mesh of floating pods.

The Emerald Tutu is an NSF-funded conceptualised network of interconnected artificial marshes that float on the harbour area of East Boston.

Each module is man-made but designed to be easy to colonise by local marshland species and create a series of inter-connected ecosystem pods.

As the ecosystem on each module develops, it will gain the capacity to harbour more species, remove pollutants and CO2 from water and air and gain the ability to absorb wave energy.

At maturity, these floating blobs can also serve as foundations for public spaces usable by the public to enjoy nature and create green transport corridors.

A visual model of a floating walkway across the Emerald Tutu, as conceptualised for Boston. (Credit: Emerald Tutu)

It’s such a simple solution that it looks like it was designed at the back of a napkin, but there is some severe rationale and testing behind this progressive innovation.

Let’s see this in more detail:

>Soft and living > Hard and dead 🥊

While man-made materials degrade over time, living organisms tend to consolidate and self-renew, and while man-made materials need to be manufactured, locally available species just occur.

Field testing of an inconspicuous Emerald ‘blob’ as it acquires biomass over the summer. (Credit: Emerald Tutu)

The Emerald Tutu inherits the anti-fragile properties of the living ecosystems it hosts without the need to be hard and rigid.

The living biomass within the modules gives it the ability to absorb excess water and reduce wave energy through its internal softness and surface roughness. At the same time, the mesh arrangement works to attenuate the swells like an anechoic chamber.

Even the strongest bones need soft tissue to protect them. Even the strongest coastal walls need a Tutu to protect them.

Simple > Complicated 😌

Mathematicians will often agree that the simplest solution is the most elegant, just like a ballerina’s Tutu.

This solution is like this too. No moving parts, sensors or unrequired tech. Just a simple, cost-efficient, multi-purpose structure that looks, feels and works effectively.

Like the hexagonal arrangement of the network that splits the forces applied to the system efficiently.

The hexagonal arrangement lets it absorb Poseidon’s wrath effectively (Credit: Emerald Tutu)

Or the use of ubiquitous, recyclable and durable material that is brilliant at hosting marshland seeds to unchain the rapid development of an ecosystem.

Modular > Colossal 🏰

We’ve all loved legos at one point in our lives and dreamed of a world made of legos.

You can connect them or disconnect them at a whim, scale the model up or down as your imagination sees fit, all with little consequence.

Anchored modules can be added or removed with little effort by a diver equipped with some tools. (Credit: Emerald Tutu)

The Tutu’s marshy modules are like living legos: just a regular array of replaceable, scalable blobs that are really good at hosting local seaweeds while greatly reducing the energy from storm swells.

If the situation is worse than predicted, just add some more blobs. If it turns out that climate change is a hoax, just take some out, no dramas at low cost.

Well studied > Speculative 🧪

Computer model of the Emerald Tutu showing its ability to reduce swell strength (Credit: Emerald Tutu)

Our blog covers a plethora of novel solutions, many of which have some serious marketing material that makes it easy to over-hype. and become subject to much speculation.

But the reality is that only a small portion of these start-ups ever make it even to the mock-up phase as they were mainly smoke and mirrors.

But the Emerald Tutu has some very serious science behind it, and the team have made sure to give this robustness some visibility by dedicating an entire section of their website to their experimentation process and outcomes.

And this is the kind of stuff that funding agencies and venture capitalists look for when providing capital to unproven solutions.

So what now? 🤯

As you may have noticed by now, the team have been hard at work making sure the Tutu is ready and battle-tested for any show the sea decides to put on. And this goes for any sea.

The tutu is flexible enough to fit into any coastal setting. Simply adjust the floater size and the spacing between each module and the network of mushy blobs is ready to endure any type of sea swell, all while enhancing habitats and cleaning the ocean and air.

There is a chance that many of the world’s coastal areas will start acquiring a tutu. (Credit: Newsweek)

Can you imagine Rio de Janeiro or London wearing a Tutu for the benefit of all? The future is progressive, and the less resistance we put into changing, the more likely we are to make it out of climate catastrophe.


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