วันพุธที่ 7 เมษายน พ.ศ. 2553
Residents of Thailand's six coastal provinces bor dering the Andaman Sea were unwittingly caught off guard and totally unprepared on December 26, 2004 when the Indian Ocean Tsunami struck the shore-line. Its destructiveness was extensive, taking lives and leaving behind many injured folk, along with ruined houses, flooded buildings and damage to many other edifices around the coast.But that was only part of the devastation. Massive waves from the Tsunami wreaked havoc on coral reefs severely challenging the ecological system in the Andaman coastal regions. Corals and sea fans were broken, and garbage and debris dragged down to the seabed inflicted further damage to marine life.In response to calls for help, various agencies came together to launch rescue projects aimed at countering the devastation inflicted by the Tsunami.The Sea Fan Rehabilitation Mission at the Similan Islands National Park was launched under the auspices of the United Nations Development Program (UNDP), to rescue and rehabilitate the corals and sea fans damaged by the Tsunami.A survey, conducted with the collaboration of eight universities, the National Park, Wildlife and Plant Conser¬vation Department and the Department of Marine and Coastal Resources to assess the condition of post-Tsunami coral reefs, found that while corals suffered damage, the sea fans around underwater rock formations were in ruins. Expansive colonies of sea fans at the Similan Islands National Park, around the islands' tips, both north and south, which constitute the water channels, were impacted as turbulent tides swept through the area causing sea fans to break and become scattered across the seabed.Sea fans are invertebrate marine creatures forming erect, flattened, branching colonies in tropical and sub¬tropical waters. They typically grow across the current so that their polyps can spread out their tentacles to form a net to catch microscopic plants (plankton) that provide their sustenance, particularly in areas with minimal drifting substances like the Similan Islands National Parkand the Surin Islands National Park. Here they thrive, their fan-like shapes poised against relentless rushes of current. However, deprived of sufficient food, broken sea fans, spread over the seabed as a result of the Tsunami, die eventually. Hence, the Sea Fans Rehabilitation Mission, under the auspices of the UNDP, was adopted.The two cruisers moored off the Similan Islands were home to more than 40 volunteers, locals and foreigners with one single purpose in mind: to come to the aid of damaged corals and sea fans, the most delicate of inver¬tebrate marine animals.Their days were marked by haste; working against the clock, counting each passing minute, to accomplish their mission ahead of the approaching monsoon season in May, by which time any rescue operation would have to be suspended because of severe tidal waves.Involving a whole host of representatives,
from volunteer divers, officers from the Similan Islands National Park, and researchers from Prince of Songkhla University, the Sea Fans Rehabilitation Mission relied on a range.of approaches to return the sea fans to their original positions with their branches secured to the sand by wires. However, this technique could be considered as a temporary measure because the foundation does not make a firm, holding ground, and swirling currents can easily uproot restraining wires.Sea fans can also be attached to rocks or dead coral, and secured by wires to allow them to resume their nor¬mal living patterns. As a last alternative, metal tubes connected by steel rods are held against the seabed and holdfast-free sea fans passed through the metal tubes and secured with plastic restrainers.Before the onset of the monsoon season in the Andaman in May, the rescue team of officers from the Similan Islands National Park and researchers from Prince of Songkhla University adopted two key methods to provide a lasting hold for the sea fans.One method, quick and permanent, was to use a wedge to secure sea fans into cleavages in reefs. Nowadays, there exits a new, effective measureinvolving the use of marine cement. Divers retrieve the broken sea fan branches from the seabed and, on land. bond them to rocks using cement.Using this method, salvage work has to be done with speed, as the cementing process is time - consuming and can have an adverse effect on sea fans - which are, after all, living marine creatures - before they are returned to their original sites, or as close as possible. However, fixing marine cement on land is more practical than underwater as water pressure can affect the bonding process.Constant monitoring will now take place following the rehabilitation efforts to track survival rates and any fur¬ther breakages of sea fans, which could occur in the strong currents or from positioning errors made when bonding sea fans to rocks.This small but impressive operation in the Andaman Sea, carried out so impressively by the volunteers, is a valiant attempt to recreate acceptable, ecological condi¬tions needed to support the underwater world off the Similan Islands to help it to regain its former beauty.