Expert Warns Against Water Authority's Copper Sulfate Use in Mediterranean Sea

Professor Moshe Gophen, an expert in water systems and former head of the Kinneret Research Laboratory at the National Institute of Oceanography, has warned that the Water Authority's decision to disperse copper sulfate into the Mediterranean Sea will cause more harm than good. The measure was taken to combat a bloom of cyanobacteria, identified as 'Synechococcus,' which had clogged the filters of Israel's desalination plants, leading to their shutdown.

Professor Gophen stated that the decision was made out of urgency and was not well-considered. He explained that while copper sulfate is used in closed systems, like treating fish parasites or agricultural produce, to clump algae so they don't enter filters, its application in an open natural system like the Mediterranean could lead to severe consequences. He fears it might be worse than taking no action at all.

The Synechococcus bacteria, a tiny cyanobacterium measuring less than a tenth of a millimeter, is capable of photosynthesis. Gophen noted that this specific bacteria doesn't typically cause blooms and most strains don't fix free nitrogen from the air. The current outbreak raises questions, as decades of sewage discharge into the Mediterranean have not previously caused such blooms.

Gophen speculates that the bloom may be due to a low nitrogen-to-phosphorus ratio, which is naturally high in the Mediterranean. This shift could be caused by local phosphorus leaks or a distant external source, possibly brought by the Nile from Ethiopia, though this has not been investigated. High water temperatures and the bacteria's small size, which allows efficient nutrient absorption, created optimal conditions for its proliferation and entry into the systems.

Drawing on his experience advising São Paulo, Brazil, during a similar crisis with a different cyanobacteria, Gophen recalled that tons of copper sulfate were dumped into a reservoir. While it killed larger bacteria, they settled and poisoned the environment and fish. The smaller, remaining Synechococcus then bloomed, passed through filters, and reached residents' taps. Gophen fears a similar scenario in Israel, where the copper sulfate might not solve the problem but could allow for a more severe bloom and pose a toxic risk of copper residues in drinking water if not properly removed.