Diatoms – Incredibly Useful in Life and Death
My algae based wastewater remediation article in the last newsletter fetched some interesting responses. Thanks to all those who responded.
I am going to take up one of them for this week’s article. It has to do with the use of diatoms for wastewater treatment.
Diatoms are at the bottom of the aquatic food web. Thus, they comprise a critical component of the acquatic world.
But even more importantly, diatoms perform a very important service in decreasing atmospheric CO2 levels. Some studies estimate that the diatoms could be abosrbing close to a quarter of the atmospheric CO2. And when they die, the diatoms sink to the bottom of the ocean, carrying and thus sequestering the CO2 along with them. In fact, it is owing to their sinking to the bottom that the diatom deaths are harmless, when compared to the the typical, harmful blooms of algae species such as blue green algae.
In short, diatoms are important, important guys.
For those keen on knowing more about diatoms, here’s a link from Wikipedia – http://en.wikipedia.org/wiki/Diatom
The impetus for this article was provided by Mr M.V.Bhaskar, who assists a company by name Nualgi ( http://nualgi.blogspot.com/ ). Nualgi’s idea is simple: They use diatoms to clean up wastewater, and these diatoms are consumed by zooplankton. These zooplankton are in turn consumed by fish.
So, the logic goes as follows:
Wastewater => Diatoms => Clean Water.
Diatoms => Zooplankton => Fish
The bottomline is, you start with a lake full of sewage water, and end up with a clean lake full of fish.
Sounds too good? Nualgi is making it happen in the city of Bangalore, India. The Nualgi team essentially provides an algal nutrient that results in a large diatom population, and the rest is taken care of by nature.
The Oilgae Team had the opportunity to visit them a few months back and the inventor of Nualgi (=nutrient + algae) Sampath Kumar took time off the entire day to show us around the lakes in which Nualgi was working its magic. You can see more on our visit from here – http://www.oilgae.com/blog/2009/10/nualgi-algae-nutrient-that-cleans.html .
Bhaskar in his mail to me a couple of days back, pointed out a few other advantages with diatoms being used for wastewater treatment:
Diatoms grow very fast. They double in the matter of a few hours
Diatoms give more oxygen than other algae, this is very significant since wastewater treatment requires more oxygen.
Since diatoms are consumed by zooplankton and these by fish, there is no need to harvest them, this reduces the cost of using Diatoms for sewage treatment. Well, this might not be of huge interest to those keen on obtaining biofuels from algal biomass, though.
The diatoms thus are incredibly useful when they are alive, and as mentioned earlier, even in their deaths!
To me, it makes a lot of sense to explore the use diatoms for wastewater remediation. I would like to know if there are any others on this mailing who are using diatoms or have heard of companies using diatoms for wastewater treatment.
For those who wish to contact Nualgi, the following are the co-ordinates: http://www.nualgi.com/
Speaking of diatoms, I came across another interesting piece on them, though not exactly in the context of wastewater treatment – but in the context of low-cost fishmeal. At the CleanTech Forum at San Francisco that ended recently, the company SBAE from Belgium demonstrated its efforts for using diatoms for producing low-cost, high nutrient fishmeal.
The company grows algae in simulated water streams, and uses a new way to harvest algae. It sticks mesh nets into the stream. Diatoms cling and grow on the nets. When it is time to harvest, the company pulls the nets out and harvests it. The net system lets the company circumvent one of the vexing problems of algae: separating the algae from the water. No centrifuges or evaporation systems are needed – you just hoist it out! Ha!
SBAE is targetting – not the biofuel market – but the less demanding market for fish meal for aquaculture. The company says it can produce fishmeal at half the costs of the current products. It does it by mixing the algae with the traditional, hig cost fish meal.
The diatoms continue their impressive march!
Once again, thank you very much for being a subscriber of this newsletter. All the best!
Oilgae – Home of Algae Energy @ www.oilgae.com
Oilgae – Home of Algae Energy @ www.oilgae.com
Diatoms key to evolution of whales
Sydney, Feb 19 (ANI): A new study by scientists has determined that a type of algae called diatoms have been key to the evolution of the diversity of whales.
According to a report by ABC Science, the research was carried out by Felix Marx of the University of Otago in New Zealand and Dr Mark Uhen of George Mason University in the US.
“The fossil record clearly shows that diatoms and whales rose and fell in diversity together,” said Marx, whose research was part of a PhD project under the supervision of Associate Professor Ewan Sordyce.
Marx and Uhen looked at the diversity of dolphins and whales (cetations) in the fossil record dating back 30 million years.
They then compared this with records of climate change and estimates of various food sources in the ocean.
Marx and Uhen measured the abundance of two different types of algae: nanoplankton and diatoms, which are key “primary producers” of the ocean – converting sunlight into food.
They found diatoms were the key to cetation diversity.
“The greater the diversity of diatoms found in the fossil record (a proxy for diatom abundance) the greater the diversity in species of whales and dolphins,” said Marx.
Marx said that the importance of diatoms is linked to their larger size, compared to nanoplankton.
The larger the primary producer, the fewer the links in the food chain between it and the top predator, and less energy is lost on the way.
“This suits a whale,” said Marx.
“You get a relatively large diatom, a krill can come along and eat the diatom and then a whale can come along and eat the krill. So you have two steps in the food chain,” he said.
The findings suggest it will be important for scientists to consider the role of diatoms when modelling the long-term effect of climate change on cetations. (ANI)