Thursday, January 28, 2016

Rapid warming over the Indian Ocean reduces marine productivity

El Niños are caused by the release of accumulated heat in the Pacific Ocean. The current El Niño is so powerful because of the additional heat added by global warming.

Jan. 21, 2016

By Roxy Mathew Koll

Roxy Mathew Koll is a climate scientist at the Indian Institute of Tropical Meteorology in Pune, India, and lead author of the new study, “A reduction in marine primary productivity driven by rapid warming over the tropical Indian Ocean” that was recently published online in Geophysical Research Letters.

Increasing water temperatures in the Indian Ocean are taking a toll on the marine ecosystem, according to our new study.

Almost 90 percent of the extra heat generated by increased greenhouse gases in the atmosphere has been absorbed by the oceans. Among tropical oceans, ocean warming is most prominent in the Indian Ocean. Now, a new study by me and my colleagues suggests rapid warming in the Indian Ocean reduced marine phytoplankton up to 20 percent during the past six decades.

Such a decline in the marine phytoplankton may cascade through the food chain, potentially turning this biologically productive region into an ecological desert. It may also impact food security in the Indian Ocean rim countries and also the global fisheries market.

Almost all life on Earth is directly or indirectly dependent on primary production, whereby organic compounds are produced through photosynthesis.

Marine phytoplankton – microscopic plants in the ocean — generate half of the primary production globally. These phytoplankton sustain the aquatic food web, drive the marine ecosystem, and constrain the global fisheries catch.


“The geopolitical and food security issues also could be important since some of the rim countries like Somalia have been experiencing political instability for some time and a collapse of fisheries in the region could only exacerbate the regional instabilities,” he added.

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