字幕列表 影片播放 列印英文字幕 In the Pacific Ocean, off the coast of British Columbia re two underwater observatories -- NEPTUNE and VENUS They use the latest technology to make amazing discoveries about the largely unexplored world beneath the waves. Discover the ocean. Understand the planet. Welcome to "Ocean Alive!" Hello, I'm Sarika Cullis-Suzuki. As an ocean scientist, I am fascinated about the underwater world. Today, researchers are using new technologies to understand our ever changing and fragile Northeast Pacific Ocean. I'd like to share with you some of their exciting discoveries. This is "Ocean Alive!" As we embark on our exploration of the vast ocean, let's consider how we can gather information about a place that is often deep, dark and dangerous. Let's find out how ocean observatories let us visit this mysterious world. Ocean Networks Canada is a unique facility in the world. And it's unique because it is a place where we can measure the changes in the ocean 24/7 in the Northeast Pacific and, what is called here, the Salish Sea. Ocean Networks Canada operates NEPTUNE and VENUS - 2 cabled observatories off the west coast of British Columbia. The observatories supply power and internet connectivity to a broad suite of sub- sea instruments from the coast to the deep sea. They support research on complex ocean and earth processes in ways not previously possible. So it's very different from other kinds of observatories, it's not one instrument at one time in one place in the ocean it's persistent in a place where the ocean changes over these instruments and we have instruments in the water column, on the seafloor and beneath the seafloor to really understand that incredibly connected system. These underwater labs are bringing us huge volumes of data. What are researchers doing with all this information? Ocean Networks Canada has a pretty broad range of science disciplines that are working on the data and instruments from both NEPTUNE Canada and VENUS and those are related to everything from earthquakes to tsunamis to ecosystems. We are also studying marine mammals, we are studying sounds in the ocean we are studying wave energy and how that impacts things like release of gas hydrates on the seafloor. It is one of the most diverse facilities of its kind studying almost every aspect of the oceans and the seafloor beneath. We were not only here to support excellent science, but we were also here to realize benefits for Canada. It relates to how it helps to stimulate commercial opportunity and how the public can better understand what we're doing and how the science can inform their knowledge of the ocean. The role of the center is to help grow the ocean technology sector in Canada and we do that through mechanisms like the technology demonstration facility where we help develop new sensor technologies and also we help develop new ocean observing systems both within Canada and internationally. One of the major accomplishments obviously has been to build the system. There were many doubters quite frankly who said this can't be done. The fact that we've done it, the fact that we've been operating now successfully with high reliability of most of those systems for the last several years is a testimony obviously to what has been accomplished. We are so excited about the accomplishments of Ocean Networks Canada but we have aspirations to see it grow even further. Already the world is coming to the University of Victoria and Ocean Networks Canada to understand how observatories operate and we know that people are interested in putting these observatories in virtually everywhere in the world. Looks like there's a lot going on at the lab. Coming up next, let's put ONC to work and see what we can discover about the ocean. Here on the West Coast we hear a lot about tsunamis. As we know from recent events in Japan and southeast Asia, tsunamis can be incredibly destructive. So, what exactly are tsunamis and where do they come from? A tsunami is what we refer to as a body wave. It affects the entire water column in an ocean or lake. It is essentially is a wave phenomenon in that energy is propagated away from a source. I kind of, because they've been so destructive, refer to them as stealth killers. The seismic ones generated by earthquakes when you displace the bottom. Off Sumatra in 2004, that huge tsunami that was generated there was displacements of five to ten metres in the bottom where suddenly the bottom goes up on one side and down on the other and all that water, two thousand metres of water, is displaced. Huge waves are generated. So that's earthquake generated tsunamis, seismically generated tsunamis. They happen everywhere in the world. The other kind are landslide generated tsunamis. So a failure of the coast line or some kind of big slump that fails and it pushes the water ahead of it as it fails or a mountain falls into the water. But about eighty percent of the big tsunamis in the world are generated in the Pacific Ocean and the reason that tsunamis occur in these environments is that's where big earthquakes occur, along the Pacific Ring of Fire. It's called that because these earthquakes are also associated with active volcanoes. We get these very explosive, fiery eruptions that occur because these plates are in contact with one another and generating the forces that can create both earthquakes and volcanic eruptions. The speed of a tsunami is basically set by the depth of the ocean so if we use an average depth of the ocean about five kilometres it's basically the speed of a jet. So that's 700-800 kilometres per hour. You're on an aircraft coming from Japan for example towards Canada during the 2011 Japanese tsunami your jet plane would just be able to keep up with that wave as it crossed the ocean. It took it nine hours and fifty-seven minutes to get to Bamfield on the west coast of Vancouver Island. So this massive wave can move at the speed of a jet! What are the odds of a tsunami landing here? And if one does, what should we do? The likelihood of a tsunami coming to Vancouver Island is actually very good. We live in a very seismically active region and so we are at a high risk of tsunamis. So any Pacific based earthquake, and large Pacific based earthquake could cause a tsunami which could impact British Columbia's Pacific coast. We have developed with Rick Thomson very very precise sensors on the bottom of the ocean that actually measure the actual pressure of the water which is really equivalent to the height and we can precisely measure to sub millimeter detail in 3 kilometers of water how high that wave is. And so with those sensors we can then begin to use models to predict the speed and direction and the height of the wave that will impact our coast. If there is a mega thrust earthquake off our coast we will have a major tsunami and we want to be able to provide much more direct warning. Now we wouldn't be doing this directly we have to work with our emergency management teams here in British Columbia, but that's the direction we want to go in. The information and data that's collected from Ocean Networks Canada helps emergency managers to understand what kind of tsunami might be coming in at any given time. We have the ability with the technology we have, to do an early detection of an earthquake when it first hits. We may be able to give places in Vancouver and Victoria a thirty to forty second warning of major ground shaking hitting. That's a lot. People say well that's not very much but it can turn off a valve, it can stop trains, it can set off an alarm in schools. So there's many things we can do with that. So we're working with a team of people in British Columbia over a five year time period to see if we can implement something like that. I think the most important thing about tsunamis is understanding your risks, where you live, where you work and where you play. So if you're travelling to an area that has tsunami risks to understand that there is a tsunami risk and then to understand what you would take, what actions you would take to keep yourself safe in the event of a tsunami. You're walking the beaches in Tofino and there is a big earthquake, don't even wait for any warning just go to higher ground because you're going to have about half an hour at most three quarters of an hour before that tsunami hits and it's going to be big on the outer coast. Today, we've learned how underwater earthquakes generate tsunamis... next let's find out what happens at underwater volcanoes. Few people know that 300 kilometres off the West Coast of Vancouver Island, lies a chain of underwater volcanoes, known as the Juan de Fuca ridge. Part of this region was established as a Marine Protected Area in 2003. This is where we find deep-sea hydrothermal vents. So hydrothermal vents are located at mid ocean ridges. So picture it as seams along a baseball and when you go away from these seams it's almost like the desert. There is not really much life there. It's called the abyssal plain so it just looks like mud flats going on and on and on. When you get closer to these little seams on the baseball at the hydrothermal vents you see an abundance of life. Hydrothermal vents form when two plates are separating away from each other and new crust from the Earth's centre starts migrating upwards. You'll have water that percolates through this really super-hot crust and from pressure and both temperature it'll come back up and start precipitating these minerals out, once it reaches that cold seafloor. So you'll get these precipitations slowly start forming these hydrothermal chimneys and once the temperatures as well as the right conditions are available for new animals they'll start colonizing these hydrothermal vents. So we can go from a volcanic eruption that essentially flattens everything to the beginnings of a vent ecosystem with a number of species within less than a year. They're at depths usually between fifty and one hundred metres to up to four thousand metres below the sea surface. So basically no sun can penetrate these environments. It's in complete darkness. The ambient seawater is usually about two degrees at those depths but at these hydrothermal vents you're getting these just like picture underwater volcanoes, they're spewing out these hot vent fluids that are up to four hundred degrees Celsius in some cases. They're extremely toxic so you have hydrogen sulfide, carbon dioxide, methane, so for you and I there's no way we'd be able to survive at these hydrothermal vents. Wow, pretty extreme conditions at these deep-sea vents. How can anything actually live there? You're on an underwater volcano where there's absolutely nothing alive and then boom you come across this little oasis of life with colour, reds, blues and animals you've never seen before. Everything we brought up had never been seen by a scientist before. Bottom few hundred metres of water contains millions of larva of vent animals that have been released by vent ecosystems in the surrounding area. These larvae are constantly looking for, urgently looking for, a new place to settle down. They detect the vent environment, they come in, settle down on the seafloor and transform into juveniles and then adult animals. So they can colonize in a matter of months. Most of the animals that live there are unusually tolerant of high temperatures, toxic hydrogen sulfide and even heavy metals. There's a really limited number of species that can colonize hydrothermal vents but those that can really cut it do really well. We find incredible biomass in this environment even though there are very small number of species. Some of the more common animals at hydrothermal vents in the North Pacific are the giant tubeworms. These are large worms that can be up to 2 metres in length. They have no mouth, no digestive system. The only way that they can exchange anything with the outside world is through their gills. They survive by the symbiotic relationship with bacteria and essentially what they do is uptake this bacteria into an internal organ called the trophosome and the trophosome houses all these bacteria. And if you have seen a picture of a tubeworm they have these red bushy plumes at the anterior portion of their body and they uptake these dissolved gases which are toxic to you and I so it would by hydrogen sulfide, carbon dioxide as well as oxygen and essentially this feeds the internal bacteria that provide the sole and only nutrition for the tube worms. Hydrothermal vents are a highly ephemeral environment and by ephemeral I mean it's very dynamic in vents are shutting off and then turning back on and starting up in a new location or even vents can shut off and then turn back on again at the same location later on. So life itself at these vents that are turning off usually end up collapsing or dying but then you'll see them pop up at these new hydrothermal vents and recolonize new areas. So it's very dynamic and its constantly circling around as they die out they'll recolonize new vents again. We've learned about hydrothermal vents and the unique species that are found there. From the exotic, now let's take a look at animals you might have seen before... whales. The coastal and offshore waters of British Columbia are home to many species of whales. Let's take a closer look at the world of whales and in particular how we study them. A whale for example with an orca it only spends probably five percent of its time at the sea surface and since that's the only time we can really see them we are pretty limited in terms of what we can, what we can study. They just come up, they take a breath and then go back down so we can't really study much about their behaviour just visually. So what we use is passive acoustics and passive acoustics means you just listen to what they are doing down there. We use hydrophones to study orcas because they can get a different kind of data then photo identification would get or visual surveys would get and also because it isn't possible to do visual surveys for such an extended amount of time or for example at some moments of the year when the weather is not very good to go out at sea on boats. The large baleen whales like the blue whales and the fin whales, those animals produce sounds that are almost below our hearing as human beings and but the low frequency hydrophones can detect them at really low ranges. The high frequency hydrophones are looking for different acoustic signatures. They can detect the signatures of naval sonars for example or dolphins or orcas or sperm whales and shipping noise. Makes complete sense. If the whales are spending 95% of their time underwater then hydrophones are a great way to gather information. So what have we discovered from this research? Since we started using hydrophones we have gained valuable knowledge about orcas. The first one that I can think of is their vocalizations and discovered that they have different dialects. That was kind of a revolution in the acoustic science of killer whales. The hydrophone data is used by the whale researchers to understand when are the whales coming through the area so obviously they need their presence and doing something. Then they try to understand what are the whales doing at that time. Are they socializing? Are they just gathering together? Are they hunting? Are they looking for prey? Are they looking for food? Other than that some studies have been made using hydrophones to study over time how the amplitude changes of their calls over time regarding with environmental noise or background noise or anthropogenic noise. The ocean is getting to be a noisier and noisier place and that's something we are starting to get concerned about. Sounds like we have discovered what most of us could have guessed -- the ocean is getting noisier. So what does this mean to the whales and what can we do about it? The kinds of sounds that disturb orcas in particular are sounds that are continuous in natures and broadband we would say that cover a lot of frequencies. So big problem is ship noise and boat noise. Shipping noise, noise produced by large ships is extremely loud and it goes on for long time as a ship passes. So it can blot out the soundscape easily for you know half an hour when as far as killer whales go are concerned every time a ship goes by. Smaller boats can be much noisier really for their size than large ships, outboard motors in particular are bad. Pile driving or even seismic exploration are all increasing the noise levels in the ocean in which the whales have to live. They have to accommodate whether they have to speak louder or find other dialects to communicate, is all part of the research we are undertaking. The consequences of noise for killer whales is that it effects their communication in particular. It, we call this masking, it can simply block out their communication or make it much harder for them to communicate over longer distances. So that could have a variety of impacts from just affecting the cohesiveness of pods to affecting the way that pods interact with each other. Sound also affects the ability of killer whales to use echolocation. They have to hear these echolocation sounds are quite quiet compared to the sounds they are producing. So killer whales can only compensate by making their sounds louder and they can only do that to a certain extent. We really need to understand the impacts of what we're doing in the ocean to make sure that we modify our behaviour slightly so that we have less of an impact on some of these endangered species or whales in general. Today we had a chance to take a closer look at whale research. As you can see, technology is very important part of ocean science. Coming up next, we'll hear about what the future holds for ONC. Before we wrap the show I had one more question for the team at Ocean Networks Canada. Guys, what's next? What's next for Ocean Networks Canada is Smart Oceans BC. It's an initiative that we've started here at Ocean Networks Canada for taking the technology from NEPTUNE and VENUS and moving it to locations in the northern coast of BC and the northern strait of Georgia and we're taking the data from those systems through our powerful data management system Oceans 2.0 and using high-performance computing provided by IBM Canada and combining those with models to actually provide new information for a wide range of stakeholders communities...industry...and scientists. Smart Oceans BC has 3 important areas that we'll be delivering on. One is marine safety..for example we'll be able to provide information about where marine mammals are located so that ships can avoid hitting them. The second one is environmental monitoring...providing a benchmark so that we can assess how things are changing as the coast develops. And the third is public safety..so we'll be providing notifications developed in partnership with IBM Canada for emergency managers for example. so we can provide them with information about 30 to 90 seconds ahead of a ground-shaking earthquake. Our major funder for this initiative—for Smart Oceans BC...is Western Economic Diversification They've provided a significant amount of the funding to purchase the equipment needed to install Smart Oceans BC in the north and northern Strait of Georgia. We're also partnering with IBM Canada and they're providing high-performance computing so we can actually take the data and develop notifications and information not only for the public -- for government and and industry -- but we'll be able to take information that 's local to coastal communities and allow them access -- free access -- to the ocean right at their doorstep. Well, clearly the future looks exciting at Ocean Networks Canada! But how does technology help keep our ocean alive? While data from the deep allows scientists to gain new insights and make discoveries, it is what we choose to do with this knowledge that will truly make a difference. I'm Sarika Cullis-Suzuki. Thanks for joining us.
B1 中級 活著的海洋!完整節目 (Ocean Alive! Full Program) 115 1 richardwang 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字