'Nanominerals' drive Earth's physical, chemical, and biological processes

Washington, Mar 21 : A new study states that tiny particles of minerals i.e. mineral nanoparticles, influence earth systems from ocean to atmosphere to biosphere.

And this knowledge may soon enable the scientists to devise new ways of understanding Earth's workings, thanks to the ubiquitous nature of these nanominerals found in oceans and rivers, atmosphere and soils, and in living cells.

The study, by a team of researchers from seven universities and led by Michael Hochella of the Virginia Polytechnic Institute and State University in Blacksburg, Va, has stated that Earth's physical, chemical, and biological processes are influenced or driven by the properties of these 'nanominerals'.

The scientists said that the mechanism followed by these infinitesimally small minerals, may influence Earth's systems is more complex than previously thought

"This is an excellent summary of the relevance of natural nanoparticles in the Earth system. It shows that there is much to be learned about the role of nanominerals, and points to the need for future research," said Enriqueta Barrera, program director in NSF's Division of Earth Sciences.

It is known that minerals have a vast range of physical and chemical properties owing to a wide range of composition and structure, including particle size. Each mineral has a set of specific physical and chemical properties.

However, there is one critical difference in case of Nanominerals-a range of physical and chemical properties, depending on their size and shape.

"This difference changes our view of the diversity and complexity of minerals, and how they influence Earth systems," said Hochella.

According to Hochella, the role of nanominerals is far-reaching. Nanominerals are widely distributed throughout the atmosphere, oceans, surface and underground waters, and soils, and in most living organisms, even within proteins.

Nanoparticles play an important role in the lives of ocean-dwelling phytoplankton, which remove carbon dioxide from the atmosphere. Phytoplankton growth is limited by iron availability. Iron in the ocean is mae up of nanocolloids, nanominerals, and mineral nanoparticles, supplied by rivers, glaciers and deposition from the atmosphere. Nanoscale reactions leading to the formation of phytoplankton biominerals, such as calcium carbonate, are important influences on oceanic and global carbon cycling.

On land, nanometer-scale hematite catalyzes the oxidation of manganese, leading to rapid formation of minerals that absorb heavy metals in water and soils. The rate of oxidation is increased when nanoparticles are present.

On the contrary, harmful heavy metals may disperse widely, due to nanominerals. While researching at the Clark Fork River Superfund Complex in Montana, Hochella discovered a nanomineral involved in the movement of lead, arsenic, copper, and zinc through hundred of miles of Clark River drainage basin.

Nanominerals can also move radioactive substances. Research at one of the most contaminated nuclear sites in the world, a nuclear waste reprocessing plant in Mayak, Russian, has revealed that plutonium travels in local groundwater, carried by mineral nanoparticles.

Mineral nanoparticles impact heating and cooling in the atmosphere. Such particles act as water droplet growth centres, which lead to cloud formation. The size and density of droplets influences solar radiation and cloud longevity, which in turn influence average global temperatures.

"The biogeochemical and ecological impact of natural and synthetic nanomaterials is one of the fastest growing areas of research, with not only vital scientific, but also large environmental, economic, and political consequences," concluded the authors.

The details of the study are published in a paper titled "Nanominerals, Mineral Nanoparticles, and Earth Systems" in the latest issue of the journal Science.

ANI