Ocean Noise Can Mutate Baby Shellfish
A pair of Common reef cuttlefish (Sepia latimanus) hovers above a patch of hard coral located on the Far Northern part of the Great Barrier Reef. With the ocean warming, rising, and becoming more acidic, coupled with land runoff, marine pollution and coastal development -- life in Australia's Great Barrier Reef is threatened from all sides and may be placed on the "in danger" designation for UNESCO World Heritage Sites. Can Australia meet the challenge to do a better job of protection by 2014? Here's some photos of what's at risk.
Clownfish protect their eggs hidden in a sea anemone on the Great Barrier Reef.
The most-loved Heart Reef among the Whitsunday Islands in the Great Barrier Reef is part of the protected off-limits areas to SCUBA divers and snorklers.
A flying gurnard (Dactyloptena orientalis), spreads out large pectorals to scare away enemies on the Great Barrier Reef, Australia.
The poisonous blue-ringed octopus (Hapalochlaena lunulata) stalks prey among the coral.
Jeffrey L. Rotman/Corbis
The size isn't intimidating, but the deadly poison is; divers wear gloves to hold the blue-ringed octopus.
A black-blotched moray eel at home in the Great Barrier Reef off the coast of Australia.
The polyps on this stalk of Acropora echinata, a type of Staghorn coral, show vividly colored tips.
Many reefs around the world are threatened by bleaching, as sea temperatures become too warm and stress the corals. The high temperatures kill the colorful polyps, and leave a reef cemetery of coral skeletons.
Staghorn Coral release eggs and sperm in a mass spawning event on the Great Barrier Reef.
The head of a whale shark (Rhincodon typus), near Ningaloo Reef in West Australia - Indian Ocean. Whale sharks feed on the eggs and sperm released from coral during massive spawning events a few days after the full moon between October and December.
What goes in must come out. A sea cucumber (Thelnota ananas) leaves a trail of waste as it processes its food.
The head of an Ocellated Epaulette shark (Hemiscyllium ocellatum), in the Great Barrier Reef, Australia.
Sea level rise poses a real threat to many parts of Australia. Already increased coastal erosion as a result of sea level rise is evident, as here where trees have been undercut and toppled by erosion on Green Island off Cairns in Queensland, Australia.
The world beneath the waves is a surprisingly loud place. Wind and waves, earthquakes, volcanic eruptions, and the rumbling, grinding and crashing of ice all combine to create something of an underwater cacophony. Numerous species use sound to communicate and navigate across distances from centimeters to hundreds of kilometers.
But over the last several decades, those natural sounds have in many places become overwhelmed by noises from human activities, some of them loud enough to be heard halfway across the ocean. By lowering a hydrophone into the water, says Dr. Christopher Clark of Cornell University, “I can hear seismic activity off the north coast of Brazil; I can hear it 2,000 miles away in the middle of the Atlantic Ocean.”
The seismic activity to which he is referring is the search for oil and gas deposits in the seabed: seismic vessels tow an array of air guns, which release a volume of air under high pressure, creating a sound wave from the expansion and contraction of the released air bubble. I’ve been in a ship in the vicinity of a seismic vessel, and it was a discomfiting experience. Each blast from the air guns resonated off our ship’s hull as if Thor were clanging his hammer against the side.
There has long been concern about the impact of such seismic blasts on wildlife such as marine mammals; indeed, the United States Marine Mammal Protection Act requires the presence of observers on board seismic vessels to ensure no seals or whales are in the region before blasting begins. But a new study in the journal Scientific Reports has shown that they can also cause physiological deformations in shellfish – specifically the larvae of New Zealand scallops.
In the study, four flasks of scallop larvae were exposed to playbacks of seismic pulses, while four flasks of scallops were set aside as controls. Within 24 hours, some of the larvae that were being subjected to noise had begun to show physical malformations. After 66 hours, all the larvae in the control group were developing normally, but 46 percent of the noise-exposed larvae showed abnormal growth, with localized bulges in their soft bodies.
The strong impacts observed in the experiment suggest that abnormalities and growth delays could also occur at lower noise levels in the wild, suggesting routine underwater sounds from oil exploration and construction could affect the survival of wild scallops.
In a press release announcing the study, team leader, Dr Aguilar de Soto of the University of St Andrews and the University of La Laguna said that, “Nobody knew that noise exposure could affect the growth of animals so dramatically so it was a real surprise to discover malformations in these microscopic larvae. What is actually going wrong inside the cells is still a mystery that we need to investigate. Shellfish larvae go through radical body changes as they grow and noise seems to disrupt this natural process.
“Fishermen worldwide complain about reductions in captures following seismic surveys used for oil explorations. Our results suggest that noise could be one factor explaining delayed effects on stocks.”
IMAGE: Close up of the brightly colored mantle and rows of minute eyes of the Coral-boring Scallop (Pedum spondyloideum) in Malaysia. (Corbis)