HU Scientists Discover Novel Method to Measure CO2 in Oceans

 

An aerial photo of a coral reef. Researchers developed a new tool to quantify the effect of ocean acidification on calcifying organisms. (Photo: Boaz Lazar, Hebrew University)

November 20, 2014: Following a 5,000 km long ocean survey, research published in the Proceedings of the National Academy of Sciences presents a new way to measure how the acidification of water is affecting marine ecosystems over an entire oceanic basin.

As a result of man-made emissions, the content of CO2 in the atmosphere and oceans has increased dramatically during recent decades. In the ocean, the accumulating CO2 is gradually acidifying the surface waters, making it harder for shelled organisms like corals and certain open sea plankton to build their calcium carbonate skeletons.

This process of CO2 acidification has been studied in recent years, because of its impact on marine ecosystems. However, obtaining an accurate measurement of CO2 is difficult over large areas because of the all of the variables involved.To get a clearer picture of how ocean acidification is affecting large marine areas, a group of Israeli researchers studied a 5,000 km long strip of ocean, from Eilat to the Seychelles crossing the Red Sea, the Gulf of Aden and the Western Indian Ocean.

The group was led by Profs. Boaz Lazar and Jonathan Erez along with Prof. Amitai Katz and Ph.D. student Zvi Steiner , all from the Fredy and Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem, together with professors from around Israel.

This process of CO2 acidification has been studied in recent years, because of its impact on marine ecosystems. However, obtaining an accurate measurement of CO2 is difficult over large areas because of the all of the variables involved. To get a clearer picture of how ocean acidification is affecting large marine areas, a group of Israeli researchers studied a 5,000 km long strip of ocean, from Eilat to the Seychelles crossing the Red Sea, the Gulf of Aden and the Western Indian Ocean.

The researchers developed a new method to assess the overall calcification rates of coral reefs and pelagic (open sea) plankton over a whole oceanic basin, based on variations in surface water chemistry. The group estimated that pelagic plankton precipitate 80% of the Red Sea calcium carbonate, and coral reefs precipitate about 20%. This data is a crucial milestone in tracking the anthropogenic activity originating from human actions, because it provides an objective baseline measurement.

Monitoring the variations in coral and plankton growth rates every few years can provide essential information regarding rates of environmental change in tropical and subtropical seas like the Red Sea, Caribbean and South China Sea.

The research was published in PNAS (Proceedings of the National Academy of Sciences of the United States of America) as ”Basin scale estimates of pelagic and coral reef calcification in the Red Sea and Western Indian Ocean”. The research was supported by the Israel Science Foundation, the Bill and Melinda Gates Foundation and the Israeli Ministry of Science and Technology.