Expressing concern over the low availability of micro-nutrients in seabeds, CSIR-National Institute of Oceanography (NIO) Director Sunil Kumar Singh has said that the situation is affecting the productivity of oceans globally.
Elaborating on the subject, he said the low micro-nutrient levels in ocean water result in low photosynthesis, affecting the growth of phytoplankton, the primary producer that sustain the aquatic foodweb.
“Productivity in 40% of the global oceans including Indian Ocean and a part of Western Arabian Sea is very low, despite the availability of nutrients such as nitrate, phosphates and silicate. However, the situation is comparatively better in the Bay of Bengal,” Mr. Singh told The Hindu.
The CSIR-NIO headquartered in Dona Paula of Goa, in its studies, has found that due to the low availability of micro-nutrients such as dissolved iron and other trace metals such as iron, zinc, cobalt and copper affects the ocean productivity.
“The major source of iron is continental dust and it is deficient in the Antarctic Ocean, resulting in its low productivity,” Mr. Singh told The Hindu.
He further said that there was limited information about the sources and sinks and cycling of these metals, particularly in the Indian Ocean.
“Issues associated with sampling of seawater and measurement of trace metals at low concentration complicate it further. Efforts are on to study the distribution of micro-nutrients in the Indian Ocean. Results suggest that many additional sources of iron are present in hydrothermal vents, subduction zones, continental margins and oxygen deficient regions. Isotopes of these metals are being analysed to contain their sources,” he said.
Research activity of the NIO has helped explore about 150,000 sq km area in the Central Indian Ocean to find about 100 million metric tonne of poly metallic nodules of iron, manganese and nickel.
Mining metals
India has obtained a licence from International Seabed Authority, an inter-governmental body which regulates all minerals (non-living resources), to mine these metals in 18,000 sq km area. “Now, we focus on the development of the required technology to mine these minerals from the seabed below 5000 metres of depth,” Mr. Singh said.
The NIO is also conducting a series of studies to study the changing behaviour of tidal waves, sea erosion and changing weather pattern, he added.