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the good dust

Every year a dust storm occurs at the bottom of the Gulf of Eilat that may reduce global warming

Diagram - structure of the Gulf of Eilat. Courtesy of the researchers
Diagram - structure of the Gulf of Eilat. Courtesy of the researchers

One of the ways to assess the level of climate change is to learn about the history of the climate, about its change over the years. Climate change obviously affects humans, but also the oceans (for example causes the sea level to rise and warm). Prof. Adi Torpstein, head of the Department of Oceanography and the Division of Marine Sciences at the Hebrew University, studies climate change through the history of the oceans. He deals with oceanography (a branch of earth science that deals with the study of the oceans and the chemical, physical, geological and biological processes that occur in them) and paleoclimate (the study of past climates). He and his team sail to the oceans, drill cores from the depths of the sea, analyze their chemical and biological composition and prolong the time they sank. This is how they reconstruct the climate of the ocean over millions of years, compare it to the climate of the last 100 years, and even try to predict the future in this area. Is there reason for cautious optimism? It may be so.

What is the question? How do brief events in the oceans, such as dust storms, affect the climate?

The purpose of the latest research by Prof. Torpstein and his team was to examine how short events in the oceans, such as dust storms, affect the climate - a subject that has not been studied until now (usually the study of the climate in the oceans focuses on the chemical and biological composition of the water at a certain time and point and is done in cruises that last several months).

The research, which won a grant from the National Science Foundation, took place in the Gulf of Eilat. The researchers sampled dust that arrives in the area from the Sahara desert using a sampling station where its composition, quantity and origin are measured (using satellites). In addition, they made frequent research cruises in which they sampled the sea water using a system that is placed at depth, and captures the material that sinks into the sea. After that, they analyzed the samples in the laboratory, measured their chemical and biological composition, including the dust particles, and compared them. "These methods are designed to reproduce the climate changes throughout the history of the earth. By examining the composition of the dust on land and at sea, it is possible to distinguish all kinds of particles - and thus, for example, locate its sources (for example from the south or north of the Sahara) and the weather systems," explains Prof. Torpstein.

This is how the researchers discovered that every year (usually in winter), for one to three days, an underwater dust storm takes place at the bottom of the Gulf of Eilat. "Until today we did not know about the existence of this dust storm, during which half of the material that accumulates on the seabed of the Eilat Bay sinks over the course of a year. It has a great contribution to the entire ecosystem there (for example, it produces many nutrients for the animals, which dissolve from the dust) and also to the reduction of the emission of greenhouse gases into the atmosphere and thus to the reduction of global warming," says Prof. Torpstein.

Until recently, researchers did not know about the existence of a dust storm during which half of the material that accumulates on the seabed of the Eilat Bay sinks. It turns out that this phenomenon contributes to the ecosystem in the area.

The ocean is a huge reservoir of carbon dioxide - a greenhouse gas that is known to be the main contributor to global warming. The concentration of this gas on Earth is expected to continue to rise (partly due to transportation and industrial processes for energy production, such as the burning of fossil fuels such as coal, oil and natural gas). Bay of Eilat

Prof. Torpstein says that "the underwater storm we discovered increases the fixation of carbon dioxide on the seabed, so it is less dispersed into the atmosphere, and therefore has a decisive role in climate change." The researchers also examined this finding in relation to the hot temperature of the water in Eilat (which may be the share of the rest of the world's oceans due to global warming) and discovered that it did not interfere with the fixation of carbon dioxide.

"We predict that dust storms will increase in the next 100 years due to desertification processes, which may help fix carbon dioxide at the bottom of the oceans, thus reducing the concentration of greenhouse gases in the atmosphere. It may also be possible to promote solutions in the field of environmental engineering - artificial dispersion of dust - for the purpose of regulating the temperature in the world", Prof. Torpstein concludes.

Life itself:

Prof. Adi Torpstein, 47 years old, married + three (18, 14, 11), lives in the settlement of Beer Ora in the Araba. In his free time he likes to surf, run and ride a bike.

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