Shifting Desert Winds Could Turn Arabian Fisheries Barren

ABU DHABI—Fish stocks in the Arabian Sea feed millions of people, both in the Arab world and beyond, but new research from New York University in Abu Dhabi has revealed the sustainability of these fisheries is looking precarious thanks to climate change.

The research, published in the journal Geophysical Research Letters, shows that much of the productivity in these fisheries is dependent on nutrients in desert dust blown out to sea from the Arabian Peninsula. These nutrients are then used by organisms at the bottom of the food chain, which the fish feed on.

The scientists behind the work also say that it’s a finely tuned balance. Should the wind patterns driving this nutrient dump alter—either increasing or decreasing the nutrient concentration—it could drastically reduce the productivity of phytoplankton at the bottom of the food chain and therefore reduce fish catches.

“Turns out dust is really important,” says Zouhair Lachkar, a senior scientist at the Center for Prototype Climate Modeling at New York University in Abu Dhabi. “Who would have thought it. We usually don’t like dust storms here, but they serve a purpose.”

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Lachkar and his colleagues used data such as wind direction to estimate the amount of dust blown into the Arabian Sea. To gauge the productivity of the bottom of the food chain, they combined a number of different types of data including satellite imagery and measures of water salinity, oxygen levels and temperature.

With that information, the scientists created a computer model to look at what happens to bio-productivity under a few different theoretical scenarios. “We compared no dust with most dust,” Lachkar says.

Previously, researchers had thought the Arabian Sea owed its bountiful fish stocks to upwelling currents, which bring nutrients from the seabed up to the surface layers where they can be consumed by organisms. “Our analysis shows that’s only half true,” says Lachkar. “The other contributor is dust, mainly iron particles in the dust. In areas where there is no desert dust deposition, the ecosystem was half as productive.”

While knowing more about dust is interesting enough, jokes Lachkar, the significance of the study’s findings becomes clear when you learn that wind patterns are widely expected to change in the coming years and decades. According to Lachkar’s computer model, that could mean fish stocks drastically reduce, which could mean millions of people from India and Pakistan to Yemen and Oman need to look for an alternative food source in the future.

The predicted wind change is directly linked to climate change, says Muchamad Al Azhar, an ocean modeler at the Plymouth Marine Laboratory in the United Kingdom.

“Rising sea levels create a difference in pressure between the land and ocean, which will cause a change in wind patterns,” says Al Azhar, who collaborated with Lachkar on the dust project. “Of course, it’s always debatable whether this will happen, but most computer models are predicting a different wind pattern, which I would say means it’s more likely to happen than not.”

“It depends on the time scale you’re looking at,” explains Al Azhar. “In the short term [of up to 50 years] you might even see a positive impact. If the wind change means more iron and nutrients coming into the ocean, you’ll obviously get more productivity. But in the longer term [of 50 to 100 years] you’ll suffer a negative feedback cycle because more productivity means more oxygen consumption, and since the whole ecosystem depends on oxygen to survive—you can see the problem.”

If the wind pattern changes mean a decrease in dust reaching the sea, then the decrease in productivity is likely to be observed sooner rather than later. So far, however, the data show that oxygen levels are already falling, says Lachkar, which would seem to suggest that the Arabia Sea is heading in the direction of the first scenario where the ecological damage would play out in the longer term.

“We’d like to emphasize that this ocean needs more attention,” says Lachkar. “It’s close to India with really large populations that eat a lot of fish. The west coast of India is likely to be the most at risk of adverse conditions.”

Whatever happens, this is just one more example of research showing how climate change is set to affect the Arab region. Other research has shown that wildfires are expected to increase in the Levant (See a related article: “As Lebanon’s Forests Burn, Researchers Seek Solutions”) and dwindling water supplies are likely to be a region-wide problem (See a related article: “New Data Show Water Scarcity Is Increasing in the Arab World, Stirring Discussion.”)

Researchers like Lachkar hope their data can help policy makers to make informed decisions to mitigate the impacts of the coming environmental changes.