Boracay’s algal bloom is a natural phenomenon

ASIA'S 24/7 ISLAND. The water along the long beach remains safe for swimming based on the result of water sampling conducted by the DENR-EMB. As observed, the green algae occurs during the months of February to June and will eventually disappear starting the month of September bringing back to its natural beauty of being the best tropical white beach in the world.
ASIA’S 24/7 ISLAND. The water along the long beach remains safe for swimming based on the result of water sampling conducted by the DENR-EMB. As observed, the green algae occurs during the months of February to June and will eventually disappear starting the month of September bringing back to its natural beauty of being the best tropical white beach in the world.

What is deemed “dirty” is actually a work in progress, a natural phenomenon and is part of the ecosystem cycle. It is called the algal bloom.

The algal bloom is an unusual, even ugly sight for the many tourists visiting the world’s famous beach, Boracay. But there is nothing alarming about it.

“It occurs at the onset of the summer season in February and ends in May. An algal bloom indicates presence of nutrients in water as well as other contributory factors such as sunlight availability, surface temperature and sea dynamics. It’s a natural phenomenon that may have adverse consequence to the aesthetic of the beach but it does not mean that the coastal waters of Boracay is unsafe,” said Arjunn Marven Calvo, Chief, Planning Programming Environmental Education and Special Concerns Section (PPEESCS) of the Environmental Management Bureau (EMB), a line bureau of the Department of Environment and Natural Resources (DENR).

“Since green algae compete with the photosynthetic activity of other marine aquatic life such as sea grasses and corals, it eventually wins. Meanwhile, aquatic marine life that thrives on sea grasses and corals are temporarily deprived of their food and habitat,” Park Superintendent (PaSu) Dennis Piñosa explained.

But the whole picture does not end there.

After the summer season, when the seawaters become cooler, the algal bloom ends.

In time, what is green that covers the front beach turns white. It becomes the famous white sands of Boracay which is cool to the feet, even with the hot midday sun. This transformation is accepted as “normal occurrence” by the natives of the island, calling the green algae “their sand.”

What actually contributes to algal bloom are the presence of Nitrates which is one of the content of many liquid soaps and shampoos. Also contributory are the Phosphates which are common ingredient in agricultural fertilizers, manure and organic wastes in sewage and industrial effluent. The concentration of Nitrates and Phosphates in water results to eutrophication (nutrient enrichment) which is a major factor to algal bloom.

The other factors are:

  • Temperature, when water temperature is higher and there is increased light, growth of green algae is sustained.
  • Light, green algae have optimal growth when exposed to intermittent high light intensities.
  • Stable Conditions, green algae loved stable water conditions with low flows, long retention times, light winds and minimal turbulence
  • Turbidityis caused by the presence of suspended particles and organic matters (flocs) in the water column. Low turbidity occurs when there is only a small amount of suspended matter present in the water column. When this happens, water moves slowly or stagnates and more light penetrates through the water column which then creates optimal condition for algal growth.

Despite the algal bloom, water quality in Boracay Island remains within standards.  As per water quality assessment conducted by the Environmental Management Bureau for CY 2017, the following are reported:

  • All monitoring stations complied to the Total and Fecal coliform standard of 200 MPN/100 ml as a primary parameter under DAO 2016-08.
  • Generally, coliform results for CY 2016 from each monitoring stations is lower compared to CY 2013 and CY 2015. Overall Average Total and Fecal coliform concentration decreased for the past 5 years.
  • Phosphate Concentrations are compliant and within the standard of 0.05 mg P/L for both Class SB and Class SC waters.