Red water in pond: a natural phenomenonPOSTED: 09/17/15 12:50 AM
The water color in the Étang de la Barrière will return to normal once weather conditions change. Photo courtesy Binkie van Es
CUL DE SAC – When birdwatcher and nature lover Binkie van Es recently paid a visit to Cul de Sac on the French side he could not believe his eyes when he saw the water in the Étang de la Barrière, located right next to the ferry landing for Pinel island.
“I noticed a disturbing degradation of the mangroves,” Van Es wrote in an email to this newspaper. “This week the deterioration went in overdrive. The pond water is blood red – probably algae bloom – and the mangroves are nearly all dead.”
Last year the connection of the pond to the open ocean was closed to provide access for Fish Day. “This was never reopened and now this whole natural area is on the brink of death,” he observed.
Van Es called on French-side authorities for action and he quickly received a response from La Réserve Naturelle –an environmental watchdog.
Due to El Nino, the island experiences the most severe droughts of the past fifteen years, the organization explained. Because there is hardly any rain the ponds that depend on rainwater dry up. “This is temporary and things will return to normal with the return of rainfall,” La Réserve Naturelle stated to Van Es.
The drought could lead to “substantial changes in the physico-chemical conditions of the water. There is an increase in temperature and salinity and significant decrease in the oxygenation of the water. These new conditions may contribute to the development of a different flora and fauna,” the Réserve Naturelle wrote.”
The change of the water color is due to the development of micro algae, usually the Dunaliella salina, the organization stated. “This coloration is totally natural and will change as soon as the weather conditions change.”
Opening the pond to the ocean is not possible due to the presence of large amounts of Sargassum seaweed. “Opening the pond would lead to a massive entry of Sargassum in the pond where hot and stagnant water would accelerate its degradation and the production of H2S just next to the two schools.”
H2S is hydrogen sulfide, a colorless, flammable and extremely hazardous gas that smells like rotten eggs.