Algae Bloom Halts Israel's Desalination Plants; Gaza Sewage Suspected

Most of Israel's desalination plants have been forced to halt operations due to a massive bloom of cyanobacteria, identified as belonging to the Synechococcus genus. While the specific species is still under investigation by the Israel Oceanographic and Limnological Research Institute, officials from the Ministry of Energy and the Water Authority stated on Friday, September 4, that the water supply system remains stable, with reservoirs expected to be refilled over the weekend. However, experts express concern that the situation is more severe than authorities are portraying.

The Ashdod and Ashkelon plants are completely shut down, while Sorek B and Palmahim are operating at reduced capacity. Sorek A ceased operations after only a few hours. The Hadera plant is currently unaffected, but there are fears the bloom could spread north. The Eilat plant continues to operate normally.

Dr. Ruti Kaplan-Levi of the Kinneret Limnological Laboratory explained that the cyanobacteria are microscopic, measuring two microns, and are common in the Mediterranean. She noted that rising water temperatures are a key factor in such blooms. The study of algae taxonomy, which is declining in Israel, is crucial for understanding and predicting these phenomena, especially concerning potentially toxic algal blooms.

Scientists from Ben-Gurion University and the Technion are working around the clock to help desalination companies find solutions. A leading theory suggests that sewage discharge from the Gaza Strip, combined with warm water and sunlight, may have contributed to the bloom. Dr. Avner Gross of Ben-Gurion University pointed to satellite imagery showing algae-laden water near the Nile Delta due to fertilizer runoff, and stated that "in our current case, I have no other explanation than a pollution source in the southern Gaza Strip." He further described it as an "ideal storm" due to weak, persistent winds spreading pollutants along the Israeli coast.

However, Professor Tamar Guy-Haim of the National Institute of Oceanography expressed skepticism that Gaza's sewage was the primary cause. She noted that desalination plants in Sinai, including El Arish, have also been non-operational since August 30 due to water turbidity, suggesting a broader regional issue. Egyptian authorities are attempting to mitigate the water shortage by deploying water tankers and urging conservation.

In an effort to combat the turbidity, the Water Authority sprayed copper sulfate pentahydrate, a general algaecide, near Ashkelon. Experts warned this could cause widespread damage to the marine ecosystem. Subsequently, the Ministry of Agriculture imposed a fishing ban in the area, raising questions about the timing of the ban relative to the chemical dispersal.