What happens when oil enters a mangrove environment?

The oil spilled by sunken MT Princess Empress has reached the mangroves in Pola, Oriental Mindoro, raising fears from environment advocates and experts that this could affect the survival of the vital coastal habitat.

Oil-covered mangroves were seen in Barangay Calima in Pola, the town hardest hit by the oil spill.

The University of the Philippines-Marine Science Institute earlier estimated that 20,000 hectares of coral reef, 9,900 hectares of mangroves and 6,000 hectares of seagrass in Oriental Mindoro, Occidental Mindoro, Palawan and Antique could be harmed by the oil spill.

The Department of Environment and Natural Resources also said the oil spill could affect 21 marine protected areas.

WHEN OIL ENTERS A MANGROVE ENVIRONMENT

In August 2006, MT Solar 1, hired by Petron Corporation, sank off the coast of Guimaras and leaked over 2.1 million liters of bunker fuel into the sea. It is considered the worst oil spill in the country’s history.

A study of scientists Abner Barnuevo and Resurreccion Sadaba found that acute effects of the oil spill include defoliation of leaves and mortality, while long-term effects involve appearance of albino propagules manifested in Rhizophora stylosa and reduction in canopy cover and leaf sizes.

Mangrove botanist Genea Nichole Cortez explained that mangroves survive in salty, low-oxygen tidal environments because of their pneumatophores or “breathing roots.” If their specialized roots are blocked by waxy substances such as oil, the adaptation of mangroves will be limited and they could die.

She added that mangroves such as Sonneratia alba or pagatpat have glands in their leaves that remove excessive salt.

“We must remember that leaves are sites where plants create their own food. Hence, if covered with oil, it will also compromise their survival,” Cortez told Philstar.com.

IMPORTANT HABITAT

Mangroves provide a range of ecosystem services, including coastline protection, carbon storage and sequestration, and provision of habitats for various species. Mangroves also support the livelihood of coastal communities.

“Death of mangroves, specifically in the seaward zone, would make coastal communities even more prone to storm surges and typhoons because of the ecosystem service of mangroves as buffer zones is lost.

Moreover, this would make the communities less climate-resilient,” Mangrove Matters PH founder Matthew Vincent Tabilog told Philstar.com.

Reduced canopy cover of mangroves could also affect shorebirds and other marine birds, especially those from the northern hemisphere that go to tropical countries during winter season.

Tabilog also stressed the oil spill will adversely disrupt the livelihoods of coastal communities and affect food security.

“Mangroves will not be a viable coastal habitat if exposed [to] oil spill because all life forms that depend on mangroves would be at risk,” he said.

Mangroves take at least 10 years to recover. The study of Barnuevo and Sadaba pointed out that knowing the natural processes and recovery dynamics of the impacted areas is imperative in mangrove restoration.

“Assessment of recruitment, mortality and growth of seedlings in the deforested and or impacted areas can serve as a basic indicator. Otherwise, the good intentions of helping the recovery process could result in further destruction of the already disrupted community,” the study read.

Authorities are scrambling to recover the sunken vessel and contain the oil spill to avoid further damage to the environment and the lives of affected communities. Slick from the oil spill has already reached Antique and Palawan.

The vessel is believed to be lying at about 1,200 feet or 400 meters below sea level. A remotely-operated vehicle will be deployed to pinpoint its exact location.—