It’s not like a major revelation for environmentalists, but wastewater and agricultural pesticide residue that runoff into the ocean are indeed damaging near-shore coral reefs and infecting green sea turtles with chronic and sometimes lethal tumors, a new study from the University of Hawaii researchers just published in the journal PeerJ shows.
“For years, local ocean lovers have known that our green turtles have had awful tumors on their heads, eyes and front flippers,” said UH Manoa Marine Biology Professor Celia Smith, who worked with Kyle S. Van Houton of NOAA’s Turtle Research Program on the new study, said in an Oct. 6 news release. “Many hypotheses were offered to explain the tumors, but we kept coming back to the observation that urban reefs—those near dense populations—are the sites with greater numbers of sick turtles. We had no mechanism for this disease.”
Put simply, the runoff perpetuates the growth of non-native “superweeds” on the reefs. “Turtles that graze on blooms of invasive seaweeds end up with a diet that is rich in a particular amino acid, arginine, which promotes the virus that creates the tumors,” states the UH news release.
“More than 60 percent of turtles in Kane‘ohe Bay have been observed to bear tumors,” states the news release. “Kihei, Maui, has been called a ‘ground zero’ for fibropapillomatosis, the disease that is caused by a herpes virus and manifests as tumors in turtles. Humans appear unaffected by the disease.”
The end result, is something of an ecological disaster for species that once thrived in pre-pollution times.
“The native species we have as our limu, fish and corals evolved for millions of years in low nutrient environments,” Smith said in the news release. “Any added nitrogen that enters our tropical coasts begins to alter the fundamental competition among species. With too much nutrient input, as we have seen on Maui, new dynamics of fast growth by non-native superweeds occurs. These weeds take over our reefs, and we tend to lose our native species.”
Click here to read the new study.
Photo of juvenile green turtle severely afflicted with fibropapillomatosis, a tumor-forming disease associated with α-herpes viruses; August 2012; Makena, Maui: Chris Stankis, Flickr/Bluewavechris