What would ocean basins look like, if we drained away all of the water? Like a big bathtub, with a wide, flat bottom in the middle? Or like a round bowl, with the deepest spot at the very middle? Neither, really. Each ocean basin has a unique outline shape, but all have abundant underwater landscape features much like the continents, including mountain ranges, hills, valleys, flat plains and undersea canyons. Show  Global topography map of the land (warm colors and greens, with darker warm colors representing higher elevations and darker greens lower), and the oceans (blues, where darker blues represent lower undersea elevations). This variable undersea (and on land) topography results from the dynamic nature of the planet, particularly plate tectonics. The outer shell of the Earth (the lithosphere, or "crust") is made up of numerous plates "riding" on a hot, deformable layer in the interior (the asthenosphere). As plates pull apart from one another, the upper asthenosphere melts into magma and rises upwards to fill the rift, cooling and creating new ocean crust. This new crust is relatively hot and buoyant, and rides high in the asthenosphere, forming mountains called Mid-Ocean Ridges. Check out the articles in this Nature special for more on rifting, and this Saltwater Science post to read about the unique organisms that live on hydrothermal vents near Mid-Ocean Ridges. So, what makes the deep spots? As ocean crust moves away from the Mid-Ocean Ridges and ages, it cools and becomes denser, riding lower in the asthenosphere. In places where plates move towards one another, the old, dense ocean crust is pushed down into the asthenosphere underneath more buoyant, younger ocean crust or a continent (which are always more buoyant than ocean crust because they are made of a different rock type). This is called subduction. At subduction zones, where the downgoing plate bends and dives beneath the overriding plate, we get oceanic trenches. These are the deepest parts of the ocean. The Mariana Trench, located in the western Pacific, is the deepest trench of all. Scientists still know little about the bottom of the ocean, mostly because it is dark and hard to get to (we can't just get down there using SCUBA gear to look around). Before last year, when James Cameron went to the bottom of this deepest part of the ocean in a custom-built submersible, it had only been visited once before. Just think of all the interesting creatures that live in the black depths, enduring water pressure more than 1,000 times that at the surface! How do you think other topographic features, like canyons and seamounts, form under the ocean? from Multimedia Library Collection: Fothergill, Alastair and Andy Byatt. Deep Blue—A Natural History of the Oceans. Berlin: Greenlight Media GmbH, 2003. 35 mm, 90 min. https://youtu.be/LsKnO7Ipl2M.
© 2003 Greenlight Media GmbH. Trailer used with permission. About the Environmental Film Profiles collection Further readings:
Dive into the science of the sea as we explore the physical factors that determine life underwater and along our coastlines. Available as a primary school science incursion within Australia or as a
video conference to any school around the globe! Online Class VersionWe’ve run live interactive distance programs since 2010 and are highly experienced in making online classes engaging for students on a variety of web conferencing platforms.
If you connect with us via Zoom
Quick LinksAustralian ACARA Content Outcomes: Australian National Curriculum Mapping for all our science workshops & shows NSW Science Syllabus Content: A student: STe-5PW-ST STe-3LW-ST ST1-8PW-S ST2-4LW-S ST2-6MW-S ST2-8PW-ST ST2-9PW-ST ST3-4LW-S ST3-6MW-S ST3-8PW-ST ST3-9PW-ST NSW K – 10 Science Syllabus mapping for all our incursions Print a PDF which details K to 6 mapping of all our science visits Science Show Demonstrations
Light attenuationWhat happens to light as we go deeper? Under pressureHow does pressure change as you descend into the ocean? Colourful currentsHow do heat and salinity affect ocean currents? EcholocationWe look at how whales & dolphins hunt prey It glows!How is luminescence used by some organisms underwater? Science of SCUBADivers avoid decompression sickness... how & why? Ocean acidificationCorals can't handle big changes in pH. How is this a problem now? HydropowerWe can harness the energy of the waves! Weird sealifeWe look at the diversity of life underwater Whale snot samplingSeriously, this is a thing! Using drones in current research Fresh vs salt waterHow much freshwater is there really in the world? Cleaning our oceansHow are scientists & engineers combating pollution in our oceans?
Feedback about this marine science school showRequirements
During Social Distancing – Contact us CostFizzics Education AwardsWhat lives in the deep blue sea?The words are fish, whale, octopus, crab, lobster, starfish, dolphin, shark, and jellyfish.
How deep is the middle of the ocean?The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam. Challenger Deep is approximately 10,935 meters (35,876 feet) deep.
Why is the deep blue sea so blue?The ocean acts like a sunlight filter.
The ocean is blue because water absorbs colors in the red part of the light spectrum. Like a filter, this leaves behind colors in the blue part of the light spectrum for us to see.
Where is the deep blue sea found?The Mariana Trench, located in the western Pacific, is the deepest trench of all. Scientists still know little about the bottom of the ocean, mostly because it is dark and hard to get to (we can't just get down there using SCUBA gear to look around).
|
How deep is the deep blue ocean?
Postagens relacionadas
direito autoral © 2024 cemle Inc.
