Phys.org, 3 Oct 13;
Man-made noise in the oceans may have significant damaging effects on shellfish populations, according to a new international study published today.
A team of researchers from the Scottish Oceans Institute at the University of St Andrews, Scotland, the University of La Laguna, Canary Islands and the University of Auckland, New Zealand, found that marine invertebrates, such as shellfish, suffered significant body malformations after being exposed to noise.
The team conducted a sound playback experiment on New Zealand scallop larvae, comparing their development to a control group kept in quiet conditions. The results show that the exposed scallops suffered significant development delays, with 46% of them developing body abnormalities, while no malformations were found in the controlled larvae.
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.
Team leader, Dr Aguilar de Soto, from the University of St Andrews and the University of La Laguna said:
"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 follow seismic surveys used for oil explorations. Our results suggest that noise could be one factor explaining delayed effects on stocks"
MASTS (Marine Alliance for Science and Technology for Scotland) senior research fellow Dr Mark Johnson of St Andrews said:
"Between shipping, construction and oil explorations, we are making more and more noise in the oceans. There is already concern about the possible effects of this on whales and dolphins. Our results show that even small animals could be affected by noise.
It is important to find out what noise levels are safe for shellfish to help reduce our impact on these key links in the food chain"
The full report is published today in the Nature Publishing Group journal, Scientific Reports.
More information: www.nature.com/srep/2013/131003/srep02831/full/srep02831.html
Ocean Noise Can Mutate Baby Shellfish
Kieran Mulvaney, Discovery News, 4 Oct 13;
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.”
Anthropogenic noise causes body malformations and delays development in marine larvae
Natacha Aguilar de Soto, Natali Delorme, John Atkins, Sunkita Howard, James Williams, Mark Johnson
Scientific Reports, 3 Oct 13;
Abstract: Understanding the impact of noise on marine fauna at the population level requires knowledge about the vulnerability of different life-stages. Here we provide the first evidence that noise exposure during larval development produces body malformations in marine invertebrates. Scallop larvae exposed to playbacks of seismic pulses showed significant developmental delays and 46% developed body abnormalities. Similar effects were observed in all independent samples exposed to noise while no malformations were found in the control groups (4881 larvae examined). Malformations appeared in the D-veliger larval phase, perhaps due to the cumulative exposure attained by this stage or to a greater vulnerability of D-veliger to sound-mediated physiological or mechanical stress. Such strong impacts suggest that abnormalities and growth delays may also result from lower sound levels or discrete exposures during the D-stage, increasing the potential for routinely-occurring anthropogenic noise sources to affect recruitment of wild scallop larvae in natural stocks.
