Thursday, July 29, 2010

Intro to MMO ( Marine Mammal Observers)

I guess you may not know there is someone studying animals on our seismic survey ship. Animals and seismics? What relationship? Actually, they have. And they have much more power than you could expect. The marine animal folks have the right to stop our seismic survey at any time when applicable. Who are they? Let me introduce to Marine Mammal Observers (MMO).
Marine seismic survey requires the transmission of strong acoustic pulses into the water, done by suddenly releasing compressed air from an array of air-guns. Although the acoustic energy attenuates with increasing distance down to the seafloor or horizontally spreading, some of the pulses are still strong enough to be detected by marine mammals and other marine animals at distance of about 50-100 km, and have potential to disturb them like whales in the study area. And disturbance events will result when marine mammals or sea turtles near the seismic activities are close enough that they might experience temporary reduction in their hearing sensitivity or react behaviorally to the sounds generated. That is why MMOs show up during our seismic cruise, under the U.S. Marine Mammal Protection Art (MMPA) to minimize the disturbance of marine mammals. However, no serious injury and/or death is anticipated fortunately. (More information)
Pictures shown here are the observing station on the very top of the boat and one of the MMO group watching carefully with 'Big Eye' equipment to make sure no marine mammals appear within potential disturbing distance. If not! They will call stop the air-gun shooting, and all of us are forced to have a break.

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