[OANNES Foro] Underwater acoustic soundscape of the Baltic Sea being mapped for the first time

Mario Cabrejos casal en infotex.com.pe
Dom Mar 3 12:25:41 PST 2013


Underwater acoustic soundscape of the Baltic Sea being mapped for the first time
     
      Finnish Environment Institute 
      2/11/2013  

http://www.ymparisto.fi/default.asp?contentid=427025&lan=en
The underwater acoustic soundscape of the Baltic Sea is being mapped for the first time, in a joint international research project of six countries.

'Our objective is to measure noise induced by humans and nature alike in different parts of the Baltic Sea and in all seasons,' says Senior Adviser Jukka Pajala from the Finnish Environment Institute (SYKE), responsible for the project's implementation in Finland.

The study is part of efforts to determine what characteristics indicate good environmental status for underwater acoustic soundscape.

'We will begin with basic mapping and drawing a soundscape map of the Baltic Sea,' Pajala explains.

The international project, funded by the EU Life, is co-ordinated by the project partner in Sweden. SYKE is responsible for the quality control of the measurements. The other participating countries are Estonia, Denmark, Germany, and Poland. In the project, the soundscape will be measured simultaneously at 40 points, spread across various parts of the Baltic Sea. Based on the results, a soundscape map covering the entire Baltic Sea will be generated. The project also aims at producing a comprehensive standardised measurement system for monitoring underwater noise in future.

Of particular interest is the objective of establishing the ratio between levels of nature- and human-induced (natural and anthropogenic)  underwater noise. For example, shipping and underwater work, such as dredging and explosions, generate noise.

A shallow sea covered by ice for part of the year, the Baltic has different underwater acoustics than, say, the Mediterranean. Moving ice masses cause loud noise, but so do icebreakers and other vessels moving through the ice. Because of the shallowness of the water, some frequencies are filtered out. Unbroken ice cover may also silence the underwater acoustic soundscape, but research data on this phenomenon remain scarce. 

Wind and waves too create natural sounds, which is carried underwater. Storms can be so loud that they mask the noise caused by the engine of a vessel travelling on the surface. On the other hand, vessels increase their engine power and thus cause more noise during stormy weather and in ice.

Water is a fast carrier of sound
Water carries sound four times more rapidly than air does - and sound propagates even more quickly in ice. For example, the stretch of sea between Helsinki and Tallinn is practically one continuous acoustic field: sound crosses it in 30 seconds.

How does noise feel and sound in water? It can be felt as pressure and movement of particles, which fish and marine mammals are able to sense.

'This project will not study the effects of sound on the marine life in the Baltic Sea, but these can be assessed on the basis of earlier findings. It should be essential to understand that human-generated underwater noise is a harmful emission and its levels must be managed,' says Pajala.

The BIAS (Baltic Sea Information on the Acoustic Soundscape) Project was launched at the end of 2012 and will continue until 2016, with a budget of approximately 4.6 million euros, of which SYKE will provide about 0.5 million euros over the four-year term of the project.

More information
Jukka Pajala
Senior Adviser
Marine Research Centre, Finnish Environment Institute (SYKE)
Tel.: +358 400 920 922
E-mail address format: firstname.lastname en ymparisto.fi

Aira Saloniemi
Chief Editor for Web Services
SYKE Communications, Baltic Sea
Tel.: +358 400 148 875
E-mail address format: firstname.lastname en ymparisto.fi
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