Speaker 1: Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,
Speaker 1: Lauren Vogal Bomb. Here, someone gazing out at the ocean
Speaker 1: from the main coast sees very different hues than someone
Speaker 1: squinting at the sea from a sunny beach on a
Speaker 1: Greek island. But why does the ocean come in so
Speaker 1: many shades of blue? Of course, ocean water isn't inherently blue.
Speaker 1: It's clear the colors that we see on the surface
Speaker 1: are the result of light being absorbed and reflected by
Speaker 1: the water itself, whatever is floating and living in it,
Speaker 1: and the surface of the ocean floor below it. A
Speaker 1: glass of water will of course appear clear as visible
Speaker 1: light passes through it with little to no obstruction. But
Speaker 1: if a body of water is deep enough that light
Speaker 1: isn't reflected off the bottom, it appears blue. Basic physics
Speaker 1: explains why light from the sun is made up of
Speaker 1: a spectrum of different wavelengths. The longer wavelengths appear to
Speaker 1: our eyes as the reds and oranges, while the shorter
Speaker 1: ones appear blue and green. When the Sun's strikes the ocean,
Speaker 1: it interacts with water molecules and can be either absorbed
Speaker 1: or scattered. If nothing is in the water except water.
Speaker 1: The longer red portions of the spectrum tend to be
Speaker 1: absorbed by the water molecules, whereas the light of those
Speaker 1: shorter wavelengths is more likely to go deep, hit water
Speaker 1: molecules there, and scatter back up towards our eyes, making
Speaker 1: the ocean appear blue. Depth and the ocean bottom also
Speaker 1: influence whether the surface appears a dusky dark blue, as
Speaker 1: in parts of the Atlantic, or casts a sapphire like shiver,
Speaker 1: as in many tropical locations. We spoke with NASA oceanographer
Speaker 1: Jeane carl Feldman. He said, in Greece, the water is
Speaker 1: this beautiful turquoise color because the bottom is either white
Speaker 1: sand or white rocks. What happens is the light comes
Speaker 1: down and blue light gets down, hits the bottom, and
Speaker 1: then reflects back up, So you make this beautiful light
Speaker 1: blue color in the water. Darker sand rocks or other
Speaker 1: formations mean darker water. The color is further complicated by
Speaker 1: the fact that the ocean is rarely just water, but
Speaker 1: is instead teeming with tiny plant and animal life, plus
Speaker 1: suspended sediment or other natural or band made contaminants. Oceanographers
Speaker 1: monitor the ocean's color the way that doctors read vital
Speaker 1: signs of their patients. Colors seen on the ocean's surface
Speaker 1: reflect what's going on in its vast depths. Feldman, who
Speaker 1: is based at the NASA Goddard Space Flight Center in Maryland,
Speaker 1: studies images taken by the sea viewing wide field of
Speaker 1: view since her satellite launched in from its perch more
Speaker 1: than four hundred miles above Earth or nearly six hundred
Speaker 1: fifty kilometers, The satellite captures van go like swirls with
Speaker 1: the ocean's colors. The patterns are not only mesmerizing, but
Speaker 1: they also reflect where sediment and runoff may make water
Speaker 1: appear a dull brown, and where microscopic plants called phytoplankton
Speaker 1: collect in nutrient rich waters, often tinting it green. Phytoplankton
Speaker 1: used chlorophyll to capture energy from the sun to convert
Speaker 1: water and carbon dioxide into energy and then waste. Through
Speaker 1: this process called photosynthesis, phytoplankton generate about half of the
Speaker 1: oxygen we breathe. Oceans with high concentrations of phytoplankton can
Speaker 1: appear blue green to green, depending on the density. Some
Speaker 1: lend the water a yellow, reddish or brown tint. Phytoplankton
Speaker 1: serve as the base of the food web and primary
Speaker 1: source of food for zooplankton, which are tiny animals eaten
Speaker 1: by fish. The fish are then eaten by bigger animals
Speaker 1: like whales and sharks. It's when oceans become polluted with
Speaker 1: runoff that the amount of phytoplankton can escalate to unhealthy levels.
Speaker 1: Phytoplankton feed on the pollutants, flourish, and then die, sinking
Speaker 1: to the bottom to decompose in a process that depletes
Speaker 1: oxygen from the water. Over the past fifty years, ocean
Speaker 1: zones with depleted oxygen have more than quadrupled to an
Speaker 1: area roughly the size of the European Union. Part of
Speaker 1: the cause may be an increase in ocean temperature due
Speaker 1: to climate change, since warmer water supports less oxygen. In
Speaker 1: still areas, phytoplankton blooms are suspected to be the cause.
Speaker 1: Phytoplankton may serve as the base of the ocean food chain,
Speaker 1: but as Feldman says, too much of a good thing
Speaker 1: is not a good thing. On a map on Feldman's
Speaker 1: office wall is a marker showing where there's little human
Speaker 1: interference and ocean water is perhaps the clearest on the planet.
Speaker 1: In this region, off the coast of Eastern Island in
Speaker 1: the Southeast Pacific Ocean. The water is deep and remarkably
Speaker 1: clear due to its location in the middle of a
Speaker 1: giant oceanic eye, which is a large circular current. Its
Speaker 1: central location means there's minimal mixing of ocean layers and
Speaker 1: nutrients aren't pushed up from the deep bottom. The purity
Speaker 1: of the water they're coupled with the depth make the
Speaker 1: ocean appear a deeper indigo than perhaps anywhere else. Feldman said,
Speaker 1: the light just keeps going down, down, down. There's nothing
Speaker 1: that bounces it back. Here is the deepest blue you'll
Speaker 1: ever see. Today's episode writtain by Amanda Onion and produced
Speaker 1: by Tyler Clang. Brain Stuff is a production of I
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