Rose Atoll :: A World Treasure in Peril :: Part II
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| Debris, wreck of F/V Jin Shiang Fa, Rose Atoll National Wildlife Refuge, American Samoa. Image: 00807 |
Debris, wreck of F/V Jin Shiang Fa, Rose Atoll National Wildlife Refuge, American Samoa. Image: 00827 |
Propellor and debris, wreck of F/V Jin Shiang Fa, Rose Atoll National Wildlife Refuge, American Samoa. Image: 00810 |
Structural reef injury to the southwest arm of the atoll was extensive. The Jin Shiang Fa hit the reef obliquely, plowing a deep trench through several reef spurs before coming to rest hard aground. Debris washed overboard, including fishing line, nets, garbage and plastics, snagging on coral heads at the wreck site and in the lagoon. For months, major hull sections remained perched on the reef ledge against the forereef and gradually broke apart in pounding waves, slamming into the forereef wall and carving deep gouges in the brittle coralline reef structure before being towed off the ledge and dumped into deep water by a salvage tug. Remaining are many fragments of the boat that may never be removed. Mangled refrigeration pipes and balls of line are wedged in the reef ledge and the forereef wall. Thirty-foot long hull plates, boiler tanks and much of the vessel’s superstructure slid in pieces down the outer slope of the atoll, leaving behind a swath of crushed reef. In 1994 many of these massive fragments returned to the shallow reef ledge, lifted by hurricane waves, while some pieces came to rest on the reef flat or all the way into the lagoon. Virtually all of the hull debris is still subject to wave movement and continues to erode and weaken the protective forereef, sending a smothering layer of sand up onto the reef flat.
Changes to the atoll precipitated by the release of toxic chemicals may ultimately prove to be more devastating than the grounding itself. The Jin Shiang Fa’s fuel tanks broke open along with a refrigeration system, spilling approximately 100,000 gallons of diesel, 500 gallons of lube oil and 2,500 pounds of ammonia that eventually spread over portions of the outer reef, reef flat, lagoon and ava. A survey conducted two weeks after the grounding, while the vessel was still leaking oil, found evidence of extensive die-off of reef invertebrates (including Tridacna clams and Echinometra urchins) and major reef-building coralline algae (Lithophyllum and Porolithon). Five months later, most of the southwest reef was covered with invasive filamentous cyanobacteria (blue-green algae) which overgrew the reef-building coralline algae. These patches of cyanobacteria marked areas of stressed or dead coralline algae since, for healthy coralline algae, growth occurs just below a thin surface layer that is constantly sloughed off as a natural defense.
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| Paul W. Gabrielson, Ph.D., collecting algae and coral samples, Rose Atoll National Wildlife Refuge, American Samoa. Image: 00824 |
Debris from wreck of F/V Jin Shiang Fa, Lagoon at Rose Atoll National Wildlife Refuge, American Samoa. Image: 00793 |
Debris, wreck of F/V Jin Shiang Fa, Rose Atoll National Wildlife Refuge, American Samoa. Image: 00814 |
Our survey dives at Rose Atoll were superb. Along the outer reef we could constantly hear the vocalizations of the South Pacific humpbacks that swam near us several times. Well away from the wreck site, vast tracts of pastel pink coralline algae and clear water dominate the underwater landscape, a canvas across which is painted a menagerie of wary gray and black-tip reef sharks, swirling blue-spotted jacks and parrotfish schooling by the hundreds. Near the ava sea turtles cruise the reef, soon to mate in the lagoon and nest on either Rose Island or a small sandbar generously named Sand Island. Sixty-foot coralline towers in the lagoon are home to dense communities of Tridacna clams and strange clusters of procreating nudibranchs.
Yet each dive brought us a measure of dismay to temper our sense of wonder. The physical damage from the Jin Shiang Fa is stunning and contrasts harshly with the sections of pristine reef that we had seen earlier. A deep hull scar leads directly to the grounding site where the engine block and propellers, massive enough to resist hurricane waves, sit in the deep bowls that they have gouged out of the shallow reef ledge. Along the forereef and ledge, thick coralline algae structures lie broken underneath the pipes, hull plating and antenna tower that litter the wreck site. Coral heads are wrapped in balls of fishing line replete with steel hooks poised to snag passersby. Chinese videotapes, hip waders, plastic tarps, storm boots and large metal tanks are spread across the sandy floor and the coral rubble slope inside the lagoon.
Most troubling were our reef flat observations. It seemed that the chemical spill injured the coralline algae, as well as the community of invertebrates that normally graze on cyanobacteria, enough to unnaturally trigger a succession of species that are replacing or smothering the reef-building Porolithon. Cyanobacteria, although ephemeral, was first to recruit and overgrow the reef flat. By our visit it had given way to the finely-branched, non-reef-building coralline alga Jania, which had spread to include about one-third of the entire reef flat, well beyond the wreck site. We found that, although earlier aerial surveys provided useful information on the gross effects of the ship wreck, ground-based and underwater field work is the best way to investigate the temporal dynamics of this tragedy. Unfortunately the remote location of Rose Atoll, which so long kept it pristine, may now hamper scientists who try to monitor its future.
