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General Chemistry. Element composed of atoms Nucleus protons and neutrons electrons. General Chemistry. Molecule a group of atoms held together by chemical bonds. General Chemistry. Bonds covalent bonds form when electrons are shared. General Chemistry. Bonds

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General chemistry
General Chemistry

  • Element

    • composed of atoms

      • Nucleus

        • protons and neutrons

      • electrons


General chemistry1
General Chemistry

  • Molecule

    • a group of atoms held together by chemical bonds


General chemistry2
General Chemistry

  • Bonds

    • covalent bonds form when electrons are shared


General chemistry3
General Chemistry

  • Bonds

    • ionic bonds form by attraction between particles with opposite charges


Water
Water

  • H2O

  • covalent bonds hold the 2 hydrogen & 1 oxygen together


Water1
Water

  • Water molecules have an uneven distribution of charge = polar

    • H positive

    • O negative


Water2
Water

  • Polar nature of water leads to:

    • attraction of other water molecules

    • attraction of other charged or polar molecules


Water3
Water

  • Hydrogen Bonds

    • form between hydrogen of one water molecule and the oxygen of another

    • cohesion


Cohesion
cohesion

Water spider

fnft


3 states of water
3 “states” of Water

  • Solid

  • Liquid

  • Gas

  • (and it can go back and forth between these “states” many times!)



Water4
Water floats!

  • Universal solvent

  • Solution

    • solvent

    • solute


Seawater
Seawater floats!

  • 96.5% water & 3.5% solutes

  • solutes change properties of water


Seawater1
Seawater floats!

  • 96.5% water and 3.5% solutes

  • The SOLUTES are: 85% Salt (Sodium Chloride) and 15% “other.”


Seawater2
Seawater floats!

  • Salinity

    • total concentration of all dissolved inorganic solids

    • average = 3.5% or 35 ppt (35o/oo)


Seawater3
Seawater floats!

  • Source of ocean’s salts

    • weathering of surface rocks

      • sodium, magnesium, calcium

    • outgassing

      • chlorine, carbon dioxide, sulfur, hydrogen


Water is recycled continually between the ocean and the land
Water is recycled continually between the ocean and the land floats!

  • The reservoirs of water include:

    • Oceans:

      • cover 60% of the northern hemisphere

      • cover 80% of the southern hemisphere

      • contain 97% of Earth’s water

    • Rivers, lakes and glaciers

    • Groundwater

      • contains a larger volume of water than all of the combined water in lakes and rivers


  • The hydrologic cycle floats!describes the exchange of water between ocean, land and atmosphere.

    • On land precipitation exceeds evaporation.

    • In the ocean evaporation exceeds precipitation.



Heat vs temperature
Heat vs Temperature floats!

  • Heat

    • energy produced by the random vibration of atoms or molecules

  • Temperature

    • an objects response to the input or removal of heat energy


Heat capacity
Heat Capacity floats!

  • the heat required to raise the temperature of 1 gram of a substance by 1oC

  • Heat capacity of water = 1 calorie

    • the highest of all known substances

  • water resists changing temperature when heat is added or removed


Density and temperature
Density and Temperature floats!

  • density of water increases as water is cooled until a maximum of 1 g/cm3 is reached at 4oC

  • the density decreases as freezing takes place

  • ice is less dense than water



Seawater vs pure water
Seawater vs. Pure Water floats!

  • Seawater has a

    • lower heat capacity

    • lower freezing point

  • density increases until freezing point is reached

    • ice is pure water & cold, salty water left behind sinks


Density of water
Density of Water floats!

  • Depends on temperature and salinity

  • density increases as temperature decreases

  • density increases as salinity increases


Temp., Salinity and Density have a complex relationship – you can

have the SAME density at different concentrations of Temp. and salinity.


Density zones in the ocean
Density Zones in the Ocean you can

  • 1. surface zone or mixed layer

    • temperature and salinity are constant with depth

  • 2. a middle layer where density changes rapidly with depth (because of extreme env. changes) = pycnocline

    • Thermocline: temp. changes rapidly w/ depth

    • Halocline: salinity changes rapidly w/ depth

    • NOTE: These 3 zones can ALL coincide together!

      3. The DEEP ZONE (80% of all ocean water) is the layer below the pycnocline (but little change occurs here).



The surface layer
The you can Surface Layer

  • About 100m thick

  • Comprises about 2% of the ocean volume

  • Is the most variable part of the ocean because it is in contact with the atmosphere.

  • Is less dense than the layers below because of its lower salinity or higher temperature.


Sea surface temperatures
Sea Surface Temperatures you can

  • Insolation and ocean-surface water temperature vary with the season.

  • Ocean temperature is highest in the tropics (25oC) and decreases poleward.


The pycnocline
The Pycnocline you can

  • Is transitional between the surface and deep layers.

  • Comprises 18% of the ocean basin.

  • In the low latitudes, the pycnocline coincides with the thermocline.

  • In the mid-latitudes it coincides with the halocline.


  • Tropical and subtropical oceans are permanently layered with warm, less dense surface water separated from cold, dense deep water by a thermocline.

    • The thermocline is a layer in which water temperature and density change rapidly.

  • Temperate regions have a seasonal thermocline and polar regions have none.


The deep layer
The Deep Layer warm, less dense surface water separated from cold, dense deep water by a

  • Represents 80% of the ocean volume.

  • Water in the deep layer originates at the surface in high latitudes, where it:

    • cools

    • becomes dense

    • sinks to the sea floor

    • flows equatorward across the ocean basin


Density zones in the ocean1
Density Zones in the Ocean warm, less dense surface water separated from cold, dense deep water by a

  • 3. the deep zone

    • a cold (1 to 3oC), dense layer on the bottom

    • most of the ocean (80%)



fnft warm, less dense surface water separated from cold, dense deep water by a


fnft warm, less dense surface water separated from cold, dense deep water by a


fnft warm, less dense surface water separated from cold, dense deep water by a


Contrasting features of shallow and deep ocean water warm, less dense surface water separated from cold, dense deep water by a


Thermocline halocline and pycnocline
Thermocline, Halocline, and Pycnocline warm, less dense surface water separated from cold, dense deep water by a


fnft warm, less dense surface water separated from cold, dense deep water by a


Refraction light and sound
Refraction, Light and Sound warm, less dense surface water separated from cold, dense deep water by a

  • Refraction: The “bending” of waves. Light and Sound are a direct result/reaction of these waves.

  • Light and Sound waves travel at DIFFERENT speeds depending upon the medium that they are in.


Light in the ocean
Light in the Ocean warm, less dense surface water separated from cold, dense deep water by a

  • Sunlight does NOT penetrate (always) to the “bottom.” This is because of many factors such as turbidity (sediments in the water), depth and the scattering/absorption of light through a water medium.

  • Scattering determines how light is absorbed.

  • Water thus absorbs (and scatters) the light

  • PHOTIC vs. APHOTIC zones


Different wavelengths of light produce different colors. As they are

“absorbed/scattered” in the water the colors reach different depths.

Why buy a RED wetsuit?




Sound
SOUND they are

  • Similar to light – sound “waves” travel differently through water.

  • Speed of sound in average seawater (w/ average salinity) is 1500 m/sec.




A side-scan sonar they are

image of the SS

Nailsea Meadow

resting on the

seabed at a depth

of 113 meters

(367 feet).


What does this mean to marine life
What does this mean to MARINE LIFE? they are

  • Light effects WHERE plants and animals can live.

  • Temperature effects WHERE plants and animals can live.

  • Salinity effects WHERE plants and animals can live.

  • Dissolved gases are an important factor too.



Fnft: Yangtze River




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