Scientists are puzzling over a new mystery of the deep discovered 40 miles offshore from Horry and Georgetown counties last fall while mapping fish habitat with the latest technology.
The mysterious formations look like giant bulldozer tracks under 480 feet of water.
"They are really interesting furrows and scours," said Paul Gayes, a professor of marine science at Coastal Carolina University who has been studying the geology of the state's coast for more than 20 years.
"It doesn't make a great deal of sense why these are out there," he said.
The gouges are similar to some offshore from New Jersey so they are not unique, but they were not known to exist off the Carolinas.
The formations are quite large, about 330 feet wide and 10 feet deep, with raised edges, Gayes said, something like the type of furrow people would make by dragging a shovel across the sand.
And there are not just a few of these trenches.
"There are swarms of them out there," Gayes said.
They had to be created by something more than water movement, he said.
"Currents by themselves typically don't do that," he said.
The researchers used a sonar that records depth to produce information that can be transformed into a display that is almost like a photograph.
Gayes plans to revisit the area in June with the equipment, when he hopes to study the formations more. In the meantime, he is working on finding out what they could be.
Those formations weren't the only new sights turned up by the special equipment.
The scientists uncovered startling views of drowned shorelines, one of which was east of Cape Romain, a 64,000-acre national wildlife refuge in northeast Charleston County, and looked exactly like the existing cape. It was in 180 feet of water and about 40 miles out, said George Sedberry, a senior marine scientist with the state Department of Natural Resources.
"It is really cool-looking," Sedberry said. "It looks like Cape Romain sunk into the water."
And there's another one like it 600 feet deep, he said.
Gayes said the old shorelines are of "tremendous interest" because they can help scientists understand what can happen during a sea level rise like the one that is believed to be occurring now.
"One of the big discussions is accelerated sea level rise," and the effect people may be having on it, Gayes said.
The drowned shorelines probably occurred some 11,000 years ago during an unusually rapid rise in sea level as ice that had covered much of the northern hemisphere melted, he said.
Shorelines naturally move to adjust to the level of the sea, but in the case of the drowned shorelines, the water rose too quickly for them to adjust and they are preserved as they were. The current sea level rise is nowhere near that rapid, Gayes said.
The findings were not related to the purpose of the exploratory search, but the results "are turning out to be rather interesting in terms of general science," Gayes said.
The exploration was a cooperative effort between CCU, the DNR, Scripps Institution of Oceanography in LaJolla, Calif., and the federal Office of Ocean Exploration.
The federal government paid for the work and loaned the equipment, said Sedberry, who was the lead scientist on the project.
It was part of a two-year program to map the undersea floor to find fish habitats so that fisheries can be managed more efficiently, Sedberry said.
Federal and state fisheries agencies believe it is best to protect habitat where the fish spawn, to give them a chance to reproduce.
It is likely that some such areas will be closed to commercial and recreational fishing, but first they have to be identified.
With the new equipment, "we now have ways to really rapidly map where fish habitats are," Sedberry said.
To do the mapping, "we just go back and forth like we're mowing the grass," Sedberry said.
Mapping the sea floor helps identify fish habitat because fish like to gather where there are some features on the bottom, and much of the sea floor off the coast is flat.
"Fish are just attracted to things on the bottom," Sedberry said.
Bottom features, sometimes provided by discarded ships, provide shelter for fish and attract food they eat.
The scientists hope to find the best spawning areas and protect those so that other good fishing spots can be left open.
If the habitat mapping turns up other useful scientific information, that's just a bonus, Sedberry said.
In the first efforts, the cruise mapped two areas off the coast proposed for closing to fishing, but that's only a small part of the offshore area that should be finished in two years, he said.
"Slowly but surely," it will be done along the entire East coast, he said.
The sonar is exciting because it gives a big-picture view of the ocean floor and defines features that were known, but not fully understood as a large system, Gayes said.
"It's like looking at an aerial photograph of Horry County for the first time," he said.
The mysterious formations look like giant bulldozer tracks under 480 feet of water.
"They are really interesting furrows and scours," said Paul Gayes, a professor of marine science at Coastal Carolina University who has been studying the geology of the state's coast for more than 20 years.
"It doesn't make a great deal of sense why these are out there," he said.
The gouges are similar to some offshore from New Jersey so they are not unique, but they were not known to exist off the Carolinas.
The formations are quite large, about 330 feet wide and 10 feet deep, with raised edges, Gayes said, something like the type of furrow people would make by dragging a shovel across the sand.
And there are not just a few of these trenches.
"There are swarms of them out there," Gayes said.
They had to be created by something more than water movement, he said.
"Currents by themselves typically don't do that," he said.
The researchers used a sonar that records depth to produce information that can be transformed into a display that is almost like a photograph.
Gayes plans to revisit the area in June with the equipment, when he hopes to study the formations more. In the meantime, he is working on finding out what they could be.
Those formations weren't the only new sights turned up by the special equipment.
The scientists uncovered startling views of drowned shorelines, one of which was east of Cape Romain, a 64,000-acre national wildlife refuge in northeast Charleston County, and looked exactly like the existing cape. It was in 180 feet of water and about 40 miles out, said George Sedberry, a senior marine scientist with the state Department of Natural Resources.
"It is really cool-looking," Sedberry said. "It looks like Cape Romain sunk into the water."
And there's another one like it 600 feet deep, he said.
Gayes said the old shorelines are of "tremendous interest" because they can help scientists understand what can happen during a sea level rise like the one that is believed to be occurring now.
"One of the big discussions is accelerated sea level rise," and the effect people may be having on it, Gayes said.
The drowned shorelines probably occurred some 11,000 years ago during an unusually rapid rise in sea level as ice that had covered much of the northern hemisphere melted, he said.
Shorelines naturally move to adjust to the level of the sea, but in the case of the drowned shorelines, the water rose too quickly for them to adjust and they are preserved as they were. The current sea level rise is nowhere near that rapid, Gayes said.
The findings were not related to the purpose of the exploratory search, but the results "are turning out to be rather interesting in terms of general science," Gayes said.
The exploration was a cooperative effort between CCU, the DNR, Scripps Institution of Oceanography in LaJolla, Calif., and the federal Office of Ocean Exploration.
The federal government paid for the work and loaned the equipment, said Sedberry, who was the lead scientist on the project.
It was part of a two-year program to map the undersea floor to find fish habitats so that fisheries can be managed more efficiently, Sedberry said.
Federal and state fisheries agencies believe it is best to protect habitat where the fish spawn, to give them a chance to reproduce.
It is likely that some such areas will be closed to commercial and recreational fishing, but first they have to be identified.
With the new equipment, "we now have ways to really rapidly map where fish habitats are," Sedberry said.
To do the mapping, "we just go back and forth like we're mowing the grass," Sedberry said.
Mapping the sea floor helps identify fish habitat because fish like to gather where there are some features on the bottom, and much of the sea floor off the coast is flat.
"Fish are just attracted to things on the bottom," Sedberry said.
Bottom features, sometimes provided by discarded ships, provide shelter for fish and attract food they eat.
The scientists hope to find the best spawning areas and protect those so that other good fishing spots can be left open.
If the habitat mapping turns up other useful scientific information, that's just a bonus, Sedberry said.
In the first efforts, the cruise mapped two areas off the coast proposed for closing to fishing, but that's only a small part of the offshore area that should be finished in two years, he said.
"Slowly but surely," it will be done along the entire East coast, he said.
The sonar is exciting because it gives a big-picture view of the ocean floor and defines features that were known, but not fully understood as a large system, Gayes said.
"It's like looking at an aerial photograph of Horry County for the first time," he said.
By Zane Wilson
The Sun News
The Sun News
