Science Feature

A ready-mix solution to global warming

K. S. Jayaraman

doi:10.1038/nindia.2012.115 Published online 31 July 2012

The European Iron Fertilization Experiment (EIFEX) recently reported that dumping iron in the ocean stimulates algal blooms which capture atmospheric carbon-dioxide and deposit the carbon in deep waters when they die1. This has come as welcome news to Thothathri Sampath Kumar, Bangalore-based inventor and founder of 'NuAlgi Nanobiotech'.

"The most encouraging fact is the confirmation that the algal bloom that capture the carbon are dominated by diatoms," he told Nature India.

A centric diatom (above) and a star diatom (below).

Diatoms are a group of algae that grow in any sun-lit, wet place on Earth. "Because of their abundance in marine plankton, diatoms probably account for as much as 20% of global photosynthetic fixation of carbon, making them more productive than all the world's tropical rainforests," says David Mann, Principal Research Scientist at the Royal Botanic Garden in Edinburgh.

The reason for Kumar's elation at the EIFEX's finding is understandable. Eight years ago he invented 'NuAlgi' which he claimed causes a copious bloom of diatoms in any type of water within 15 minutes of its addition. "NuAlgi (U.S.patent 7585898) could be an alternative to iron sulphate used in ocean fertilization experiments like EIFEX," says Kumar. Iron sulphate can cause bloom of any organism including harmful algae whereas NuAlgi triggers the growth of only diatoms and not any other algae, he says. "So there need not be any fear of producing toxic algal blooms or depletion of oxygen levels. On the contrary NuAlgi increases the level of dissolved Oxygen."

NuAlgi is a mix of all the micronutrients required by diatoms in the form of nano particles. Silica, which the diatoms require to build their outer shell, is the main constituent of NuAlgi while iron constitutes only 1%. "It is inexpensive and can be mass produced and is being used for the past seven years in many lakes and fish ponds in southern India to promote diatom blooms. It is also marketed in USA, China and Vietnam," says Mallimadugula Bhaskar, Kumar's collaborator.

NuAlgi collaborators Sampath Kumar (left) & M. Bhaskar.

While the oxygen released by the diatoms keeps the lakes clean, the diatoms are consumed by zooplanktons that in turn are food for fishes. Based on studies so far, Bhaskar estimates that when used for ocean fertilization one gram of iron in 100 grams of NuAlgi can capture at least 5000 grams of carbon which is 80% more than what was achieved with iron sulphate in EIFEX.

Syed Naqvi, distinguished scientist at the National Institute of Oceanography in Goa is sceptical. "To say that NuAlgi will work in ocean because it does so in lakes is a misconception," he told Nature India.

However, impressed by the claims, David Karl, director of Hawaii University's Center for Microbial Oceanography Research and Education has taken some NuAlgi for testing. "Our scientists are currently at sea aboard Kilo Moana conducting experiments that are all relevant to the issues raised recently except that our field site is the low nutrient, low chlorophyll region of the North Pacific called the North Pacific Gyre," Karl said in an email interview.

"We are conducting a series of experiments with NuAlgi to determine whether or not it can be used to select for the growth of diatoms and which species are favoured. If our initial shipboard experiments are successful we will explore the use of NuAlgi to stimulate large-scale, export events by this mechanism perhaps including an open ocean trial of this hypothesis in summer 2013 or later."

Kumar says while carbon sequestration to mitigate climate change is one of the goals, he would first like to promote NuAlgi's use to revive fresh water eutrophic lakes and the 530 aquatic "dead zones" (lacking oxygen) worldwide. The project to revive the Baltic Sea Dead Zone — the world's largest dead zone — reportedly would require around 100 pumping stations to transport oxygen deep underwater. "NuAlgi may provide an alternative to this as well as to Western Australia's $3.4 million plan for setting up pumping systems to breathe life into the dying Swan River," he says.


References

  1. Smetacek, V. et al. Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. Nature 487, 313-319 doi: 10.1038/nature11229 (2012) | Article | PubMed |