Amnesia-Inducing Diatoms Discovered in Luzon's Shellfish Farms
Introduction: The Discovery of Toxic Diatoms
Luzon, the densely populated island housing over half of the Philippine population, includes many residents who regularly consume shellfish. An international research team recently confirmed the presence of two Pseudo-nitzschia diatom species there, known for producing a harmful neurotoxin linked to severe illness and memory loss.
This research has been published in Diatom Research.
What Are Diatoms and Their Risks?
Diatoms: The 'Glass House' Algae
Often described poetically as 'algae that live in glass houses,' diatoms are microscopic aquatic organisms encased in protective, milk-colored silica shells. Although most diatom species pose no harm, nearly half of the 58 identified Pseudo-nitzschia species are known to produce the potent neurotoxin domoic acid (DA).
The Dangers of Domoic Acid (DA)
Individuals who consume shellfish contaminated with domoic acid (DA) may suffer from symptoms like vomiting, nausea, diarrhea, and stomach cramps. In severe cases, DA exposure can result in permanent short-term memory loss, a condition known as amnesic shellfish poisoning (ASP).
Limited Knowledge of Pseudo-nitzschia in the Philippines
Despite these risks, limited information is available on the spread of Pseudo-nitzschia in the Philippines. This knowledge gap led scientists from Ateneo de Manila University's Department of Biology and University Malaysia Sarawak to analyze the physical and genetic traits of the diatoms found in water samples from shellfish farms in Luzon's Bacoor Bay and Pagbilao Bay.
Research Findings: The Identified Toxic Diatoms
New Species Discovery: P. Brasiliana
The researchers identified the DA-producing diatoms Pseudo-nitzschia pungens and Pseudo-nitzschia brasiliana within the samples, with P. brasiliana being recorded for the first time in Luzon.
Harmful Algal Blooms (HABs) and Shellfish Contamination
During periods of excessive growth, known as harmful algal blooms (HABs) or 'red tide,' DA can accumulate in significant quantities in filter-feeding shellfish like mussels and clams.
"Identifying species within a genus where half are known DA producers is essential for HAB monitoring in the Philippines," the researchers emphasize.
Importance of Monitoring and Research
The Need for Monitoring Efforts
Researchers Lorenzo A. Botavara, Janice A. Ragaza, Hong Chang Lim, and Sing Tung Teng emphasize the importance of recognizing the toxic potential of these diatoms and implementing monitoring efforts. "Such efforts must begin by confirming their presence in our waters, yet, to our knowledge, no molecular taxonomy of Pseudo-nitzschia exists in the Philippines."
Future Steps for HAB Monitoring
"Identifying species within a genus where half are known DA producers in essential for HAB monitoring in the Philippines." the researchers emphasize.
Stay Informed and Support Efforts to Protect Public Health
The discovery of Pseudo-nitzschia diatoms in Luzon's shellfish farms highlights the urgent need for effective monitoring and research. We encourage local communities, researchers, and policymakers to collaborate in addressing the potential risks of amnesic shellfish poisoning (ASP) and ensure safe seafood consumption. Stay informed about the latest research developments and support initiatives to protect public health by advocating for regular water checks in shellfish farming areas.
