Egyptian Algae Bloom Likely Caused Israeli Desalination Plant Shutdowns

Most of Israel's desalination plants were temporarily shut down in recent days due to a significant increase in water turbidity in the Mediterranean Sea. Initial investigations by researchers at the National Institute of Oceanography and Limnology suggest the turbidity stems from a microalgae bloom originating from the Nile Delta in Egypt. Five plants were affected: Ashkelon, Ashdod, Sorek A, Sorek B, and Palmahim. The Sorek plants have since resumed operations, with Ashdod and Palmahim expected to return to service shortly. The Hadera and Eilat plants remained operational.

As a consequence of the shutdowns, irrigation of agricultural fields in southern Israel and watering of public gardens were halted. Energy and Infrastructure Minister Eli Cohen stated that Israel's water economy is robust and that measures were taken to ensure continuous water supply despite the disruptions. Experts noted that the extremely small size of these algae allows them to bypass the intake filters of the desalination facilities.

Algae blooms are natural phenomena influenced by weather, sea currents, and organic matter. However, pinpointing the exact cause and timing of specific blooms can be challenging. Researchers have collected algae samples from areas like Ashkelon and Palmahim for genetic sequencing to identify the species and determine if they produce toxins. Satellite imagery has revealed extensive blooms in the Nile Delta region, and prevailing currents are believed to be carrying these blooms, along with sediment, towards Israel's southern coast.

Alon Zask, CEO of the Israel Oceanographic and Limnological Research Institute, explained that the pattern of the southernmost plant in Ashkelon being the first affected is consistent with currents carrying materials from the Nile. He added that different desalination plants draw water from varying depths, which could influence the spread. Experts are monitoring satellite data and conducting field studies to better understand the algae and their origin.

To prevent future occurrences, experts recommend maximizing desalination output during normal periods and preserving natural sources like the Sea of Galilee and aquifers as emergency reserves. Professor David Katz from the University of Haifa highlighted that while algae and sediment from the Nile Delta are common, the current bloom is unusually large. He also pointed to untreated sewage in Gaza as a contributing factor to water turbidity. Katz advised maintaining vigilance through satellite monitoring and prioritizing desalination when possible, relying on reserves during crises. A new desalination plant planned for the Western Galilee is expected to enhance geographical security.