Junk accumulating on ocean floor
Junk accumulating on Monterey Bay ocean floor: Scientists find increasing levels of debris in the deep sea
By JANE PALMER
Posted: 02/09/2010 01:30:45 AM PST
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SANTA CRUZ -- Deep below the pale blue surface of the Monterey Bay lies a ton of trash.
"We have even seen artillery shells -- large artillery shells -- spools of cable and a little unbroken teapot just sitting on the sand," said Diana Watters of National Oceanic and Atmospheric Administration's Southwest Fisheries Center on Santa Cruz's Westside near Long Marine Lab.
Watters and her co-workers have been recording the amounts of debris on the ocean floor in the Monterey Bay and in the Santa Barbara area since 1993. The team released its findings last month in a marine biology journal.
More typically, researchers see discarded or lost recreational and commercial fishing gear or simply bottles and cans. The most common item is monofilament fishing line, the line used in rod-and-reel fishing rods.
"The fishing line most likely gets caught on rocks and gets broken off accidently," Watters said.
Jim Barry of the Monterey Bay Aquarium Research Institute, whose work as a deep-sea ecologist offers him a unique perspective on the ocean floor, said he sees more debris in areas frequented by fishing boats. In his work in the more remote and deep Monterey Canyon, however, he sees little debris.
"I think most of it gets buried in the sand whereas over a fishing spot it is tin cans and beer bottles," Barry said.
Most studies have focused previously on the highly visible trash on beaches and in shallow water, Watters said. The NOAA researchers, however, investigated debris that accumulates in deeper waters, between 65 and 1,150 feet deep.
The scientists recorded their debris finds on 300 separate dives in a tiny two-person submersible. While studying fish and habitats at these depths, they also recorded sightings of trash and videotaped their expeditions. Analysis of the videotapes identified a disturbing trend.
"Overall the amount of debris has increased over time," Watters said.
In the 1990s researchers found two items every 330 feet on average. By 2007, that amount had doubled.
While the accumulating junk is certainly not aesthetic, the researchers found few instances where it was seriously harming the sea life.
"It is not a good thing to do but it has not had large impacts on the animals in the deep sea," Barry said.
The researchers also found few instances of "ghost fishing," where animals get trapped in discarded nets or traps and die.
To help prevent this from happening, the Monterey Bay National Marine Sanctuary recently started a project to remove abandoned and discarded fishing gear. Using lists provided by the NOAA scientists, crews have been able to locate and remove some of the objects, Watters said.
While current impacts may appear low, the scientists are concerned that the accumulation of debris is altering sea-floor habitats important to hundreds of species of fishes and invertebrates, Watters said.
The most troubling finding is that the majority of the debris is made from plastic, she said. "Plastic is very durable so it is likely these will persist for decades or even centuries."
Watters hopes the study will make people more aware of the impacts of their daily activities.
"Prevention is the key in this case," Watters said. "It is not like we can organize a beach cleanup at 1,000 feet."
