(Please start at the bottom of the page to follow our adventures from the beginning.)
The science party for PICTURES includes five biologists (called PSO, for Protected Species Observers) who are charged with scanning the ocean around the ship to detect the presence of protected species. They take photos, identify the different species and keep detailed logs of their observations. The National Oceanographic and Atmospheric Administration (NOAA) has developed a well-defined and strict protocol to protect whales, dolphins, sea lions, seals, sea turtles to protect them from the sound generated to image the subsurface. This protocol includes the requirement that the sound level be ramped up gradually and that it be cut down when protected species are detected within a specified radius that depends on the water depth, source strength and type of animal. This leaves gaps in the data – a small price to pay to share the ocean with its majestic inhabitants.
Because our seismic source is on 24/7, the marine mammal specialists work shifts around the clock (like the rest of the science party). From dawn to sunset, two observers are outside on the observation tower, which provides a spectacular view of the ocean, the ship, and occasionally the Chilean coast, where desert mountains reach the sea. One observer is always stationed in the main lab, with their passive acoustic monitoring system (PAM), which enables 24/7 monitoring. The PAM records signals from a hydrophone (an underwater microphone) that is towed by the ship and records the sounds of the sea e.g. airgun shots, higher frequency chirps for mapping the seafloor (referred to as “the bird” because of the bird-like sound it makes) and, of course, the conversations of whales and dolphins. These sounds are displayed as spectrograms on two computer monitors as well as listened to with earphones.
So far during PICTURES, we have seen many marine mammals and sea turtles. The PSOs are always willing to answer questions from the geophysicists about marine life, or to simply chat and tell jokes. 🙂
– Carsten Lehman, November 2016