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TEDx Talks
Published: 2016-12-02
Source: https://www.youtube.com/watch?v=3UFGqjWcVU8
in nineteen fifty six a documentary by Jacques Cousteau one both Pondo an Oscar award this film was called the moon to new seals or the silent world and the premise of the title was that the underwater world quiet world we now know sixty years later that the underwater world is anything but silent although the sounds are inaudible above water depending upon where you are and the
time of year the underwater sound scape can be is noisy as any jungle or rain forest invertebrates like snapping should fish and marine mammals all you sound they use sound to study their habitat to keep in communication with each other to navigate to detect predators and prey and they also you sound by listening to know something about their environment take for example the arctic it's considered
a vast inhospitable place sometimes described as a desert because it is so cold and so remote and ice covered for much of the year and despite this there is no place on earth that I would rather be in the arctic especially as days lengthen and spring comes and to me the arctic really embodies this disconnect between what we see on the surface and what's going on
under water you can look out across the ice all white and blue and cold and see nothing but if you could hear under water the sound you would hear put it first amaze and then delight you I will your eyes are seeing nothing for kilometers but ice your ears are telling you that out there our bonehead and beluga whales walrus and bearded seals the ice to
make sounds it's screeches and cracks and pops in groans as it collides and rubs wind temperature or currents or winds change and under a hundred percent sea ice in the dead of winter beau had wells singing and you would never expect that because we humans we tend to be very visual animals for most of us but not all our sense of sight is how we navigate
our world for marine mammals that live under water where chemical cues and light transmit poorly sound is the sense by which they see and sound transmits very well under water much better than it does in air and so signals can be heard over great distances and in the arctic this is especially important because not only do arctic marine mammals have to hear each other but they
also have to listen for cues in the environment that might indicate heavy ice ahead or open water remember although they spend most of their lives under water they are mammals so they have to surface to brief so they might listen for Finn ice or no ice or listen for echoes off nearby ice arctic marine mammals live in a rich and varied underwater sound scape in the
spring it can be a cacophony of sound but when the ice is frozen solid and there's no big temperature shifts or current changes the underwater arctic has some of the lowest ambient noise levels of the world's oceans but this is changing climate change and decreases MCI's are also altering the underwater sound scape of the arctic which is a direct result of human greenhouse gas emissions we
are in effect with climate change conducting a completely uncontrolled experiment with our planet over the past thirty years areas of the arctic have seen decreases in seasonal sea ice from anywhere from six weeks for months and this decrease in sea ice is sometimes referred to as an increase in the open water season that is the time of year when the arctic is navigable to vessels and
not only is the extent of ice changing but the age and the with the vice news to now you may well have heard the decrease in seasonal see ice is causing loss of habitat for animals that rely on sea ice such as I seals or walrus or polar bears decreasing sea ice is also causing increased erosion along coastal villages and changing prey availability for marine birds
and mammals climate change and decreases MCI's are also altering the underwater sound scape of the arctic now what do I mean by soundscape those of us to eavesdrop on the oceans for a living use instruments called hydrophones which underwater microphones and we record ambient noise the noise all around us and the soundscape describes the different contributors to this noise field and what we are hearing on
our hydrophones are the very real sounds of climate change and we're hearing these changes from three fronts from the air from the water and from land first air wind on water creates waves these waves make bubbles the bubbles break and when they do they make noise and this noises like a hiss or a static in the background no in the arctic when it's ice covered most
of the noise from wind doesn't make it into the water column because the ice acts as a buffer between the atmosphere and the water and this is one of the reasons that the arctic can have very low ambient noise levels but with decreases in seasonal sea ice not only is the arctic now open to this wave noise but the number of storms and the intensity of
storms in the arctic has been increasing all of this is raising noise levels in a previously quiet ocean second water with less seasonal CI's sub arctic species are moving north and taking advantage of new habitat that is created by more open water now arctic wells like this bonehead but they have no dorsal fin because they have evolved to live and swim in ice covered waters and
having something sticking off of your back is not very conducive to migrating through ice and may in fact be excluding animals from the ice but now everywhere we've listened we're hearing the sounds of fin whales and humpback whales and killer whales further and further north and later and later in the season we are hearing in essence an invasion of the arctic by sub arctic species and
we don't know what this means will there be competition for food between arctic and subarctic animals might the subarctic species introduced diseases or parasites into the arctic and what of the new sounds that they are producing doing to the soundscape underwater and third land and by land I mean people more open water means increased human use of the arctic just this past summer a massive cruise
ship made its way through the Northwest Passage the what's mythical route between Europe and the Pacific decreases in sea ice have allowed humans to occupy the arctic more often it is allowed increases in oil and gas exploration and extraction the potential for commercial shipping as well as increased tourism and we now know that shit noise increases levels of stress hormones in Wales and can disrupt feeding
behavior airguns which produce loud low frequency rooms every ten to twenty seconds change the swimming and vocal behavior of wells and all of these sound sources are decreasing the acoustic space over which arctic marine mammals can communicate no arctic remembers are used to very high levels of noise at certain times of the year but this is primarily from other animals or from sea ice and these
are the sounds with which they've evolved and these are sounds that are vital to the very survival these new sounds are loud and there alien and there might impact the environment in ways that we think we understand but also in ways that we don't remember sound is the most important sense for these animals and not only is the physical habitat of the arctic changing rapidly but
the acoustic habitat is to it's as if we pluck these animals up from the quiet countryside and drop them into a big city in the middle of rush hour but they can't escape it so what can we do now we can't decrease wind speeds or keep subarctic animals from migrating north but we can work on local solutions to reducing human caused underwater noise one of the
solutions is to slow down ships that traverse the arctic because a slower ship quieter ship we can restrict access in seasons and regions that are important for mating or feeding or migrating we can get smarter about quieting ships and find better ways to explore the ocean bottom and the good news is there are people working on this right now but ultimately we humans have to do
the hard work of reversing or at the very least decelerating human cost atmospheric changes so let's return to this idea of a silent world underwater it's entirely possible that many of the whales swimming in the arctic today especially long lived species like the bow had well but the Inuit say can live to human lives it's possible that these wells were alive in nineteen fifty six when
