The scientists sampled the seawater with specially designed metal-free sampling gears. Credit: GEOTRACES India
Researchers have discovered very high concentrations of dissolved iron in the sub-surface water from hydrothermal vents in the southern Arabian Sea1. These vents can also be a hotspot for other metals.
The team, at the CSIR-National Institute of Oceanography in Goa, India, identified that continental shelf or slope sediment in the Arabian Sea is also a major source of dissolved iron, while atmospheric soluble iron dust flux plays a secondary role.
Microalgae and other marine plants use iron in photosynthesis that converts carbon dioxide to organic carbon.
These findings suggest that seeding the iron-deficient waters of the Arabian Sea with an ample amount of iron could help algae and plants to speed up photosynthesis, sequestering atmospheric carbon dioxide as organic carbon. This would reduce atmospheric carbon dioxide, a greenhouse gas that contributes to global warming, the researchers say.
Scientists, led by Sunil Kumar Singh, sampled the seawater with specially designed metal-free sampling gears and processed the samples in a metal-free laboratory onboard a research vessel.
The researchers found that in the sunlit region of the Arabian Sea the integrated dissolved iron is two times higher than that of the subtropical Indian Ocean, and that free-floating microalgae largely contribute to higher primary production of food for this ecosystem.
However, a large part of the Arabian Sea in the south and northwest is iron-deficient, resulting in lower biological production. Seeding these regions with iron may increase productivity, boosting fish production, the researchers note.
