Seawater Physical Properties Layering Water Properties of Water

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Seawater Physical Properties & Layering

Seawater Physical Properties & Layering

Water § Properties of Water: – Water is a polar molecule – Causes ionic

Water § Properties of Water: – Water is a polar molecule – Causes ionic compounds to dissolve

Water Properties of Water: Cohesion - the ability of water molecules to stick to

Water Properties of Water: Cohesion - the ability of water molecules to stick to each other, creating surface tension. Adhesion – the tendency of water molecules to stick to other substances Thus, water can act as a solvent

Water Properties of Water: Heat is energy produced by the random vibrations of atoms

Water Properties of Water: Heat is energy produced by the random vibrations of atoms or molecules. Temperature is an object’s response to input or removal of heat. Freezing point of water 0º C Boiling point of water 100º C

Water has a very high heat capacity Therefore, it resists changing temperature when heat

Water has a very high heat capacity Therefore, it resists changing temperature when heat is added or removed.

The amount of energy required to break the bonds is termed the latent heat

The amount of energy required to break the bonds is termed the latent heat of vaporization. Water has the highest latent heat of vaporization of any known substance.

Water Phase Changes

Water Phase Changes

Temperature § Sea water is warmed by sunlight § Sunlight can penetrate to a

Temperature § Sea water is warmed by sunlight § Sunlight can penetrate to a maximum of 200 meters = Photic Zone § Below 200 meters = Aphotic Zone

Temperature § Temperature layering produced in ocean § Zone of rapid temperature change is

Temperature § Temperature layering produced in ocean § Zone of rapid temperature change is called thermocline – Warm water over cold water is stable – Cold water over warm water is not stable

Temperature § Temperature & Density – Very cold & salty water = dense water

Temperature § Temperature & Density – Very cold & salty water = dense water that sinks and flows – Warm water + less salty water = less dense water – Zone of rapid density change = pycnocline

Density § The ocean is divided into three density zones: – The surface zone

Density § The ocean is divided into three density zones: – The surface zone - the upper layer of the ocean, containing the least dense water. – The pycnocline - a zone in which density increases with depth – The deep zone – contains about 80% of all ocean water.

Sunlight § Sunlight does not travel well in the ocean. § Scattering and absorption

Sunlight § Sunlight does not travel well in the ocean. § Scattering and absorption weaken light. – Scattering occurs when light is bounced between air and water molecules, dust and other objects. – Absorption occurs when light’s electromagnetic energy is converted to heat in the molecules of seawater.

Sunlight § Factors Influencing Light Penetration – Turbidity – Clouds – Angle of the

Sunlight § Factors Influencing Light Penetration – Turbidity – Clouds – Angle of the Sun – Plankton – Pollution

Sunlight § Visible light may penetrate down to a depth of ~200 meters (average

Sunlight § Visible light may penetrate down to a depth of ~200 meters (average depth is ~100 meters) – 60% of light is absorbed in the first meter – 80% of light is absorbed after 10 meters – At a depth of 150 meters, only 1% of visible light is left

Sunlight § Different wavelengths of light are absorbed before others – Long wave lengths

Sunlight § Different wavelengths of light are absorbed before others – Long wave lengths (red) absorbed in the first 10 meters – Shorter wave lengths (blue-green) can penetrate to 160 – 200 meters

Layering in the Oceans § Two Major Types of Water Zonations – Based on

Layering in the Oceans § Two Major Types of Water Zonations – Based on the position of water over the continent – Based on light penetration in the sea

Layering in the Oceans § Zones According to Position Over the Continent – Benthic

Layering in the Oceans § Zones According to Position Over the Continent – Benthic Zones - ocean bottom where water in contact with sediments § Intertidal/Littoral Zone - subjected to (tides) § Sublittoral Zone § Continental shelf (= bathyl region) § Abyssal plain - deep sea floor to ~ 4000 m § Hadal region - deep sea trenches / submarine ridges

Layering in the Oceans § Zones According to Position Over the Continent – Oceanic

Layering in the Oceans § Zones According to Position Over the Continent – Oceanic Zones - area seaward from edge of continental shelf § Neritic Zone – near-shore / sub-littoral – From low tide level to edge of the continental shelf § Pelagic Zone – Water overlying the deep ocean (no contact with sediments)

Layering in the Oceans § Zones According to Light Penetration – Photic Zone –

Layering in the Oceans § Zones According to Light Penetration – Photic Zone – Aphotic Zone

Layering in the Oceans § The Importance of the Photic Zone – Necessary for

Layering in the Oceans § The Importance of the Photic Zone – Necessary for photosynthesis! – Plants need light to survive – Ocean critters need plants to survive – Heats the ocean

Layering in the Oceans § Nutrients and organics – Nutrients required for plant growth

Layering in the Oceans § Nutrients and organics – Nutrients required for plant growth – Need nutrients § N (nitrates) § phosphorous (phosphate) § silicon (silicates) – Nutrients cycles by plant growth/decay – Organics used by organism or buried

Layering in the Oceans § Light Measuring Devises – Beam Transmissometer § Own light

Layering in the Oceans § Light Measuring Devises – Beam Transmissometer § Own light source and receiver; directional light § Measures Clarity – Irradiance Meter or Photometer § Omni-directional light § Ambient light from the surface

Layering in the Oceans § Light Measuring Devises – Secchi Disk § Simple, easy,

Layering in the Oceans § Light Measuring Devises – Secchi Disk § Simple, easy, cheap means of assessing water clarity

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