UP researchers: Benham Bank's untouched reefscape is thriving

Researchers from the University of the Philippines’ Marine Science Institute discovered the pristine state and rich deep coral ecosystem at the Benham Bank, an underwater seamount located 50 meters below the sea surface near the eastern coast of Luzon.

The team used Baited Remote Underwater Video Systems to capture the seafloor during a research expedition in 2019. 

The study found at least 11 scleractinian or hard coral genera of varying morphotypes, with four sites having excellent coral cover, 10 octocoral (or soft coral) genera, at least four genera of macroalgae (or seaweed), and some arborescent sponges.

“Benham Bank is in a way resilient to physical and thermal stress. There is stratification or layers with different water properties, which perhaps protected the Benham Bank from the effects of stress,” said Joey Cabasan, one of the researchers. 

According to the UP team, the clear water in the Benham Bank also allowed the corals and algae to survive. 

“Since there are no major sources of nutrients like large rivers, nutrients and chlorophyll in the water column are low, and light is able to penetrate to greater depths. This allows the corals and algae to thrive there,” said researcher Cesar Villanoy. 

The study also led to the discovery of eight probable habitats for organisms in the seamount’s coral ecosystem and could help legislators in properly zoning the area and determining which parts may be designated for protection, fishing, and other uses.

Further, the researchers noted that the location of the Benham Bank could help in the recovery of coral reefs in other areas. 

“[The area] is affected by the North Equatorial Current, which potentially receives larvae from other Pacific islands,” said Cabasan. 

While it is beneficial that it is a three-day trip via ship from the mainland, the researchers recommended another study on the emerging threats near the Benham Bank to protect its pristine state. —Vince Angelo Ferreras/RF, GMA Integrated News