If you didn’t know, most white sand you see on some beaches around the world, has at some point in time, passed through a fish called the parrot fish. It’s an amazing ecological role the parrot fish plays.
An interestingly similar ecological role is served by a marine animal with a very leathery skin called the sea cucumber. Professor Ove Hoegh-Guldberg explains why these organisms have such an important role in the marine environment.
Basically, while scavenging for algae or minute aquatic animals, sea cucumbers ingest a lot of sand. As it passes through their bodies, the digestive system increases the pH of the sand, making it more basic. When this comes out, the sand is clean and turned basic. This way it plays a chief role in countering the negative effects of ocean acidification.
It also helps coral reefs survive by supplying them with calcium carbonate (a by product of its digestion process) and helping them maintain a net inflow of calcium carbonate.
The ammonia that comes out also makes the bed more fertile, making it much more suitable for coral reefs to grow.
Watch these underwater vacuum cleaners in action below.
Things absorbing water from the air is nothing new. Hygroscopic substances – or substances which have ability to attract and hold water molecules from the surrounding environment – have always been around. Coffee powder for instance is one great example – leave the dry coffee powder in the open and it will turn into a mushy matter within hours. Thanks to the moisture present in the air that it absorbs.
Hygroscopy in Nature
In the nature too, hygroscopy – the ability to extract water from thin air – has some peculiar functions. One fantastic example is the seed of the needle-and-Thread grass. This seed, with the help of a hygroscopic awn attached to it, can twist and untwist the screw like structure by releasing and absorbing moisture from the air. This way, it is able to dig its way into the ground. But that’s just one of the many examples of how hygroscopy is all around us. Here’s another one…
Thorny devil – an Australian lizard – lives in the arid scrubland and desert that covers most of central Australia. It has a hard time finding water in this dry place. So, blessed by the evolutionary forces of nature, the lizard has developed tiny hygroscopic channels between the spines on its back. These channels, working in tandem with a capillary action mechanism, are able to draw water from the air. Then their precise design makes the water move into the mouth of the lizard. Fascinating!
Although not exactly using hygroscopy, the Namib desert beetle, also does something similar – drawing water from thin air. Unlike the hygroscopic grooves of the thorny devil’s back, the desert dwelling beetle has developed some patterns on its hard wings which help it in drawing water from the air. These patterns include an array of hydrophobic and hydrophilic materials which are able to trap water from the foggy morning air and are able to channel it to the beetle’s mouth.
The Nanotube Sponge Mat
This particular beetle’s hard wings with magical patterns on it, intrigued a couple of researchers. They took cue from this natural material and were able to create an artificial mat which could absorb water from the air.
Although we do have commercial Atmospheric Water Generators (AWG) which can harvest water from the air and supply drinking water, the sad thing is that these things run on electricity. This new mat that was fabricated recently, using an array of carbon nano tubes sandwiched between hydrophilic and hydrophobic layers, doesn’t need any electricity to extract water.
This mat they’ve fabricated is smaller than your thumbnail, but it still works, and is able to extract about 1/4th of it’s weigh in water within a few hours. The researchers are working on it to make it more efficient. [more information] [Original Paper]
A couple of years back a US based startup, NBD Nano, was inclined on developing a water bottle based on the same Namib desert beetle principle. The much touted water bottle, they said, would be able to fill itself! I’m not sure where their project is headed today, but an auto-filling water bottle sure would be a product just too cool to not own by every kid at school!
Needless to say, it would probably make a huge difference by lowering greatly the number of people who don’t find clean drinking water every day – Just for the record, about 1/7th of the world population didn’t have access to clean water today.
It’s Christmas! On this happy day let’s take a minute to look at what the major part of the world is facing today.
The present situation might not look as bad, but the truth is that we are running out of fresh water. To give you an idea about how much water is actually there on earth, this image of the whole world’s water compared with the size of earth is, in my view, the best thing that could prove it to you.
Fresh water in all the lakes and rivers on the whole planet is represented by the tiniest dot. Yes, there is a third water sphere in the picture. You might have to squint to find it. So, that is the amount of fresh water we have here on earth.
War for water: If this image isn’t much of a proof that fresh water is scarce, probably this will do the trick:
Countries consider fresh water a very precious resource. Several countries all around the world are fighting with their neighbors for this blue gold. Two good examples of that – [India starts water war] and [This]
Today, economically and technologically backward countries require good cost-effective methods to purify water. Scientists are doing a tremendous amount of work in this area and coming out with innovative methods to deal with the problem. Also, it is one great idea for taking up as a science fair project by students. One such recent research regarding this caught my attention.
The fruit peel method
Note: If you are wondering why have I written fruit when we are dealing with a tomato here, this might come as a shock to you that Tomato is actually a fruit. And BTW:
Knowledge is knowing that a tomato is a fruit. Wisdom is knowing that a tomato doesn’t belong in a fruit salad. – Miles Kingston
Mr Ramakrishna Mallampati, under the guidance of Associate Professor Suresh Valiyaveettil of the Department of Chemistry at the NUS Faculty of Science, have discovered a new way of purifying water which is both innovative and cost effective. Moreover, it uses the waste product of a fruit, its peel, for something good. They hope that their new technology will comes as a boon to the people living in areas where a water treatment plant cannot be set up.
According to their research, a tomato’s peel, under certain conditions, can remove dissolved organic and inorganic chemicals, dyes and pesticides. Additionally, an apple’s peel was also found to have these wonderful properties. Apple’s peel loaded with Zirconium were found to be effective in removing phosphate, arsenate, arsenite, and chromate anions. This is the first time ever someone has used to remove two different kinds of pollutants using two different kinds of peels. Notably, all their processes can be scaled up for large scale applications.
I hope that this new discovery will come as a respite to all the poor nations where people die everyday due to the unavailability of drinking water – due to diseases.