Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Ocean Scientists Assess Impact of Seismic Pulses in Effort to Protect Whales


Scientists investigating the possible effect of underwater seismic pulses on marine mammals have conducted a series of tests, designed to better understand the force of sound waves generated by shipboard airguns. These instruments are used by some 100 vessels worldwide to penetrate into the seabed for oil exploration and geophysical research, with an estimated 15 to 20 active on any given day.

Researchers from the Lamont-Doherty Earth Observatory of Columbia University conducted tests in the northern Gulf of Mexico in 2003, using the 20-gun array aboard their research vessel, Maurice Ewing. Their results will be published July 27 in Geophysical Research Letters (GRL), a journal of the American Geophysical Union. While most other scientific research ships can only deploy much smaller systems, Maurice Ewing’s 20-gun capacity is comparable to those aboard many industry ships. It provides the flexibility to design source arrays of many different sizes and power, allowing scientists to look deep below the ocean’s surface to study problems as diverse as earthquake prediction and the ocean’s role in the carbon cycle.

Maya Tolstoy, lead author of the study, writes that the researchers covered sound frequencies of concern to many species of marine mammals. The GRL paper focuses in part on beaked whales, a relatively little known family of 18 species found, often at great depths, in all of the world’s oceans.

Only one event of stranding of beaked whales that might be related to airgun activity has been recorded, Tolstoy writes, but there is solid evidence that some other species of whales avoid the acoustic output of seismic systems at distances up to 20 kilometers [10 miles]. In 2002, two beaked whales were stranded in the Gulf of California at around the time R/V Maurice Ewing was conducting acoustic research in the area, but a causal relationship has not been established. Some beaked whale strandings have occurred in connection with Navy sonar operations at frequencies of around three kilohertz, Tolstoy says.

Recognizing that different species of marine mammals may be sensitive to different sound frequencies and decibel levels, the researchers are seeking to better understand how strongly and how far sound pulses travel, both in shallow and deep water. The Maurice Ewing cruise was a step in that direction. Using hydrophones (underwater sound detectors), the scientists found that previous models had overestimated the deep water impact of low frequency sound waves, while underestimating their impact in shallow water. This, they say, is because reverberations play a significant role in received sound levels in shallow water, which had not previously been incorporated into the models.

During the experiments, the ship’s airguns were fired in various combinations, in order to determine the radius of the emitted sound in the water at various frequencies and decibel levels. Tolstoy notes that since passage of the Marine Mammal Protection Act in 1972, ships operating in U.S. waters must adhere to increasingly strict guidelines, in order to minimize impacts on whales and other animals. This includes the gradual ramping up of a seismic array over 30 to 60 minutes, to warn whales and give them time to leave the area.

The National Marine Fisheries Service, part of the National Oceanic and Atmospheric Administration, issues permits to vessels whose operations may "harass" marine mammals, an industry term describing any activity that alters a mammal’s normal behavior. The Service issues guidelines as to the radius in which sound pulses might be received at various high decibel levels. In the past, these radii were calculated with computer models. The experiments conducted aboard the Maurice Ewing were the first in which they were actually measured, using well calibrated broadband instruments. Beaked whales are most sensitive to sound in the one- to-20 kilohertz frequency range. Most airgun energy is much lower frequency than that, around five to 100 hertz, and the energy, or decibel, level of sound pulses drops sharply above that frequency.

Tolstoy says that ocean scientists take the threat to whales seriously. "Lamont-Doherty and the National Science Foundation, which funded our study, have already responded to the new data by adjusting the safety radius when they do research involving seismic sound generation," she says. "If a whale enters this radius, they shut down operations until it leaves."

Harvey Leifert | AGU
Further information:

More articles from Earth Sciences:

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

nachricht UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>