During the summer months, algae blooms frequently wreak havoc on coastal communities all over the world. In Costa Rica, there are several factors that exacerbate the problem.

Santa Teresa, Costa Rica. Feb 12th, 2012 – Over the past few days, the communities on the southern end of the Nicoya Peninsula, and the Gulf of Nicoya have suffered from a massive algae bloom that has wreaked havoc on local fish and wildlife. Some forms of the algae can produce toxins that prove harmful for humans if ingested, and can cause irritation of the eyes, respiratory system and skin. No one has ever died from direct contact with red tide, but you can become ill from ingesting contaminated shellfish. Bivalves and mollusks absorb the toxins, and if humans eat these, they can cause serious poisoning.

The algae blooms are caused by several different things; nutrient loading of the water, increased water temperatures, and even coastal upwelling. In Costa Rica, during the summer months there are frequently strong offshore winds that cause upwelling, this pulls up nutrient rich water from the depths, and combined with increased sunlight the perfect environment for phytoplankton is created. Agricultural runoff is another factor that really increases the occurrence and duration of algae blooms along the Pacific Coast.

The main river systems along the Central Pacific drain into the ocean between Jaco and Puntarenas, carrying all the pollution from the Central Valley with them. The increased use of fertilizers over the years has caused the coastal waters to become laden with nitrates and phosphates in extremely elevated concentrations. The phytoplankton thrive in these conditions, and as such, with decreased rainfall, the summer months have all the ingredients for some devastating red tides.

The Gulf of Nicoya is exceptionally hard hit as it is less affected by the strong currents that are present off the coast of the Nicoya Peninsula, with less water movement; the algae blooms stick around longer, and kill more and more fish. For the past few days, there have been dead fish on the beach as a direct result of the red tide. Dogs and birds end up eating the dead fish and become sick themselves, rarely dying, but they are definitely affected. The sight and smell of the red tide is disagreeable, and even feels weird on your skin.

There have been no reported deaths from direct contact with the phytoplankton themselves, but people have become ill and contracted respiratory illnesses from inhaling the stuff. Waves churn up the water, and the wind carries a mist of microscopic organisms over communities on the beach. The problem with red tide is that there are few solutions once a bloom has happened. The solutions lie with prevention, and that ties in with leading a more environmentally friendly life. With more and more agrochemicals being poured into the ocean every day, red tides are getting potent and longer lasting every year. It is a tremendous eyesore for communities that rely on tourism during summer months, a pain for local fishermen, and a nuisance for those that spend time in the ocean every day.

Environmental factors come into play in the formation of red tides, but the warming of coastal waters and overabundance of phosphates and nitrates in the ocean as well have eclipsed them. As the world’s population grows, and fisheries become more fragile than ever before, red tides could become a worrying factor for certain parts of the globe where aquaculture play a prominent role in food production.