Wave power and seaweed

Let's try a little case study and see how a product used biomimicry for its design. The company BioPower Systems developed a solution called bioWAVE(TM) in order to harness power from waves and tides to produce electricity. 

Multiple deployed bioWAVE(TM) units. Author: BioPower Systems Pty Ltd License: CC-BY-SA

bioWAVE(TM) is intended for use at 40-45m depth and is anchored to the sea floor. The bulky parts you can see on the picture are floats which allow the structure to move back and forth with the current. As the waves make the surface move up and down, the current under the surface has a back and forth movement which the floats follow. That oscillation is mechanical energy which is converted to electric energy via a hydraulic system. The movement is used to put fluids under pressure, that pressure is used to spin a generator which then produces electricity. Just for a scale, one bioWAVE(TM) unit should produce 250kW, an average wind turbine produces 5MW.

Now we've all seen (if not experienced) how mighty the sea can be: tremendous forces are at play and you gotta have a bit of respect for that if you intend to survive in such an environment. So BioPower Systems who wanted to harness the power from ocean swells had to find a way to make their units robust enough for these operating conditions and they turned to Nature to find solutions.

Bull KELP. CREDIT: LOST COAST

Their champion: the bull kelp! Not very sexy, i agree, walking on kelp on the beach is not very tempting except for kids maybe... Anyway, bull kelp is very good at withstanding strong water movements. Here are a few interesting strategies the bull kelp uses and that inspired the bioWAVE(TM)'s design:

  • Strong root-like system called holdfast. The holdfasts are not called roots because they don't go deep in the ground but rather stay close to the surface creating many anchor points that redistribute vertical and lateral forces.

  • Buoyancy: the kelp has gas filled bladders that float and keep the kelp upright. From the bladders emerge blades that need to be close to the surface to absorb sunlight for photosynthesis.
  • Kelp moves with the currents rather than resisting them. That way it can withstand very strong currents.

The three strategies mentioned above were reused in bioWAVE(TM) design as follows:

  • Holdfast-like anchor system allows it to not drill deep in the ground, minimising cost and damage to the seafloor.
  • Floats allow for buoyancy and movement with the sub surface currents.
  • Flexibility of the kelp reproduced by using a swivel and pivot system allows the structure to rotate in the direction of the current. It also can lay down close to the seafloor when the current gets too strong, minimising the forces seen by the structure and the risk for damaging and 'uprooting' it

This post is based on an assignment i got in the Essentials of Biomimicry course and the feedback from instructor Zeynep Ahron.

Rooted Like a Mangrove Tree

Imagine you’re paddling in the mangrove in Costa Rica. Your kayak make its way through tight muddy channels between rows of tall mangrove trees. Above you the trees spread their leafy branches shading you from the sun but keeping the moisture under their leaves. At your sides, a complex network of roots emerges from the waters, making a nice habitat for thousands of crabs and barnacles. Below you, the brown salty waters move slowly in a direction imposed by the tide. Fresh water from the streams, loaded with sediments, come down the mountain and blend with the salty water of the sea here in the mangrove.

The mangrove is a forest, but it’s also the name of the trees that compose it. The most popular one, the red mangrove, is a stilt root tree. The roots are interconnected tubular arcs that help stabilising the tree directly by the channels. About half the network of roots is in the ground, and the other is in the sea, conquering new ground!

The red mangrove has many fascinating strategies. It is constantly exposed to the tides, halfway between salty waters and fresh waters, the ground it sits on is basically mud. The mangrove is very resilient in this very dynamic environment.

Let’s focus on the intricate root system and the fact that it creates new ground. You see, those many roots diving into the water slow the stream down. Because of that, the sediments get more time to sink to the ground. So the mangrove slows down the flow and helps stabilising the ground. Now that’s an interesting feature. Think coastal zones, or terrain exposed to landslides. Could we take inspiration from the mangrove roots to stabilise the ground and constructions on those terrains? We keep putting everything on straight cylindrical pillars in unstable zones. What if we used interconnected arched structures? What if the cross section was elliptic? What if the cross sections came in different sizes? Would it help to match the ‘pillar’ density with the one of the roots of mangrove trees? 

What about ‘mangrove-root-ish' pontoons or coastal houses supports? Bjørvika is sinking, could a mangrove type of structure slow the process down or even stop it?

What do you think? Any cool application ideas?

The Leaf's Network

Here's a cool experiment. It's gonna be tricky for you to do at home but just imagine for a second:

You take a leaf with its stem and make a hole in the center vein of the leaf. Then inject some fluorescent liquid and watch it spread in the leaf. Intuitively you would assume that all the veins upstream from the hole won't be filled with the fluorescent liquid. And surprise! The whole leaf becomes fluorescent despite the hole!


Take a close look at a tree leaf next time you have one in hand and observe the veins on the leaf. At first sight it seems they replicate a tree structure, but then looking closely you'll see they form actually loops!

My friend Astrid DesLandes shared this study by Eleni Katifori et al with us at the Nature's Genius workshop we attended. You might wanna have a look at least at the pictures in that paper if nothing else, and maybe download the short time lapse of the experiment, it's really beautiful!

So the leaf has ways to keep it's whole surface supplied with water and get the sugars produced by photosynthesis back to the tree despite damages in its vein network. Small damages are not killing it. With all the insects feeding on them, it was a pretty important property to evolve!

Astrid was explaining that replicating the properties of the network of veins in leaves could be very useful in urban areas. Think road blocked because of an accident. How cool would it be to still get home without loosing too much time stuck in the traffic jam generated by the accident? For that you're gonna need loops, many of them, and no one way streets. Now of course implementing this in the existing urban networks bight be tricky because many traffic arteries cannot be re-dimensioned. But still, improving that by following the leaf's strategies could definitely help!

Now this can serve in any type of network really, not only urban, obviously. Computer networks, snail mail, logistics,... Any other thoughts on that?

And by the way, if you want to learn more about how leaves function, here is a really nice animation:


Getting fatter thanks to bubbles...

image1.JPG

When you’re as big as whale, you gotta get in a lot of calories to keep that body functioning. Let’s have a look at the humpback whale’s strategy to get fat. Humpbacks are the whales you most often see on videos as they like jumping, they have those large, easily identifiable fins.

So some humpback whales have come up with a pretty effective way of fishing. They manage to concentrate their prey in a confined area so they can eat more in a single mouthful. They hunt in groups of maybe 5-6 individuals. They got one doing the job and the rest are free loaders, i would assume thy take turns though…

The humpbacks like schools of fish. The whale doing the job goes swimming a little deeper than the school, and makes a spiral trajectory around it while blowing bubbles through its blow hole. Now those bubble ascending to the surface look like a net to the fish. The humpback tightens its turn around the school so it foolishly gathers at the center of the bubble net. Scared, the fish move towards the surface in an attempt to escape what they sense could be a predator. And that’s their mistake: the freeloader whales swim up in the bubble net with their huge mouth open and have a feast.

What’s useful in that technique? Well, the Instituto Politecnico de Leiria got inspired and is developing a system that would make use of this bubble net strategy. That allows them to catch the fish without a physical net. No net = no fish damaged! Now if you bring the live fish on board you can scan which ones you need, release the bycatch and the ones with eggs, keeping only what you effectively need! If that becomes a standard in the fishing industry, that would reduce drastically the waste while letting the fish regenerate!

Other ideas?

Also check out:

AskNature.org

Instituto Politecnico de Leiria's project 

What the heck is this blog about???

Culture! It's like jam they say, the less you have of it, the more you spread it... Well, this is about getting more jam in stock, so that we don't get short of any when we need it. Ok, i mean, i want to build some biomimicry culture: showing good biomimicry cases so that when we have a challenge, we have material to inspire us for solutions!

In my experience it's hard to find a blog that makes biomimicry both fun and easy to understand and i want to fill that gap. 

I intend to introduce to you, in a casual way, various examples of biomimicry. I'll be taking either a specific challenge and exploring what solution Nature offers to solve it, or a fascinating organism and analysing what challenges it solves and how.

I'll do my best to keep most of the geeky scientific jargon out, but don't worry, i'll always put a few links in the posts so you can dig into the more technical aspects if you wish!

This is intended to serve YOU! Serve US all actually! I'm a life-long learner and possess by no means the absolute truth about all the organisms i'll be discussing here! So i welcome any comments on the posts that contribute to the content. That also means skepticism and criticism if you have any, it makes for a healthy discussion! And don't hesitate to suggest new topics you want me to write about!

Hope you'll enjoy reading those posts and don't hesitate to give me feedback so i can improve their quality!