The call of the wild Antarctic
April 4, 2008
German scientists have put together a live streaming feed of what it sounds like to be swimming beneath the ice of the Antarctic ocean. Using a specially outfitted microphone known (logically enough) as a hydrophone, they intend to use the recordings as an acoustic baseline for what almost-pristine ocean sounds like. As described in Geoff Manaugh's BLDGBLOG:
“This "live stream" is recorded via hydrophones attached to ‘an autonomous, wind and solar powered observatory located on the Ekström ice shelf.’ The observatory is called PALAOA—the PerenniAL Acoustic Observatory in the Antarctic Ocean—and its purpose is "to record the underwater soundscape in the vicinity of the shelf ice edge over the duration of several years."
The data for the feed is transmitted via a WLAN and then via satellite to Germany, where it's dissected. The human-free soundscape allows the scientists to "register species specific vocalizations" and "examine possible effects of the sporadic shipping traffic on the acoustic and locomotive behaviour of marine mammals."
Scientists note this transmission is not meant for entertainment primarily, but for scientific research. It is highly compressed (24k bit Ogg-Vorbis), so the sound quality is not perfect. Additionally, sounds may be very faint. The amplifier settings are a compromise between picking up distant animal voices and not overcharging the system by nearby calving icebergs. Listeners should beware of sudden extremely loud events.
Providing an acoustic live stream of the Antarctic underwater soundscape is a formidable challenge, according to the researchers. After all, more than 15,000 km lie between Antarctica and the Alfred Wegener Institute in Germany. Underwater sound is recorded by means of two hydrophones by PALAOA, the autonomous, wind and solar powered observatory located on the Ekström ice shelf.
Located 1.5 to 3 km distance to the ice shelf edge, the station was established with boreholes of about 100 m length through solid ice, using hot water drill technology. Four boreholes provide access to the water for four hydrophones, lowered to about 70 m below the ice shelf bottom and 90 m above the sea-floor. PALAOA operates autonomously, powered by 8 solar panels, a Savonius wind generator, and a methanol fuel cell. The acoustic recording system covers the subsonic to ultrasound frequency range. Data are buffered locally and continuously transferred to Neumayer Base, from where a compressed, mono audio stream is transmitted in near real-time to the Alfred Wegener Institute, Germany. Beyond the goal of obtaining seasonal abundance data for marine mammals, PALAOA aims at determining the long-term noise budget for a pristine location as well as identifying and quantifying the various acoustic sources in coastal waters of the Weddell Sea.
Data streams collected at PALAOA are transmitted via wireless LAN to the German Neumayer Base. From there, a permanent satellite link transmits the data to the AWI in Germany. A constant hiss pervading the signal is the natural, isotropic background noise made audible here through the use of ultra sensitive hydrophones. Additional broad band noise caused by wind, waves and currents adds to it on occasion. Due to the limited bandwith of the satellite link, jamming of the WLAN link due to storms, or energy shortage, the connection might temporarily be down or scrammed. In this case, please dial in later!
Live streaming feed: http://www.awi.de/en/research/new_technologies/marine_observing_systems/ocean_acoustics/palaoa/palaoa_livestream/
PALAOA: http://www.awi.de/en/research/new_technologies/marine_observing_systems/ocean_acoustics/palaoa/
SOURCES: Wired Magazine; Alfred Wegener Institute for Polar and Marine Research
German scientists have put together a live streaming feed of what it sounds like to be swimming beneath the ice of the Antarctic ocean. Using a specially outfitted microphone known (logically enough) as a hydrophone, they intend to use the recordings as an acoustic baseline for what almost-pristine ocean sounds like. As described in Geoff Manaugh's BLDGBLOG:
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The data for the feed is transmitted via a WLAN and then via satellite to Germany, where it's dissected. The human-free soundscape allows the scientists to "register species specific vocalizations" and "examine possible effects of the sporadic shipping traffic on the acoustic and locomotive behaviour of marine mammals."
Scientists note this transmission is not meant for entertainment primarily, but for scientific research. It is highly compressed (24k bit Ogg-Vorbis), so the sound quality is not perfect. Additionally, sounds may be very faint. The amplifier settings are a compromise between picking up distant animal voices and not overcharging the system by nearby calving icebergs. Listeners should beware of sudden extremely loud events.
Providing an acoustic live stream of the Antarctic underwater soundscape is a formidable challenge, according to the researchers. After all, more than 15,000 km lie between Antarctica and the Alfred Wegener Institute in Germany. Underwater sound is recorded by means of two hydrophones by PALAOA, the autonomous, wind and solar powered observatory located on the Ekström ice shelf.
Located 1.5 to 3 km distance to the ice shelf edge, the station was established with boreholes of about 100 m length through solid ice, using hot water drill technology. Four boreholes provide access to the water for four hydrophones, lowered to about 70 m below the ice shelf bottom and 90 m above the sea-floor. PALAOA operates autonomously, powered by 8 solar panels, a Savonius wind generator, and a methanol fuel cell. The acoustic recording system covers the subsonic to ultrasound frequency range. Data are buffered locally and continuously transferred to Neumayer Base, from where a compressed, mono audio stream is transmitted in near real-time to the Alfred Wegener Institute, Germany. Beyond the goal of obtaining seasonal abundance data for marine mammals, PALAOA aims at determining the long-term noise budget for a pristine location as well as identifying and quantifying the various acoustic sources in coastal waters of the Weddell Sea.
Data streams collected at PALAOA are transmitted via wireless LAN to the German Neumayer Base. From there, a permanent satellite link transmits the data to the AWI in Germany. A constant hiss pervading the signal is the natural, isotropic background noise made audible here through the use of ultra sensitive hydrophones. Additional broad band noise caused by wind, waves and currents adds to it on occasion. Due to the limited bandwith of the satellite link, jamming of the WLAN link due to storms, or energy shortage, the connection might temporarily be down or scrammed. In this case, please dial in later!
Live streaming feed: http://www.awi.de/en/research/new_technologies/marine_observing_systems/ocean_acoustics/palaoa/palaoa_livestream/
PALAOA: http://www.awi.de/en/research/new_technologies/marine_observing_systems/ocean_acoustics/palaoa/
SOURCES: Wired Magazine; Alfred Wegener Institute for Polar and Marine Research
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