UNIT 3: Physical Oceanography

three gradients

• latitudinal gradient

• depth gradient

• coastal to open water gradient

latitude

the imaginary lines that measure the distance north or south of the equator

things that vary based on latitude

• intensity of sunlight

• amount of daylight hours

intensity of sunlight

• near the poles it is less intense than near the equator

• based on the latitude we're at and the season we're in

amount of daylight hours

based on latitude and season

what is the first thing that affects the amount of light that can penetrate the ocean depth?

amount of light the ocean received

what is amount of light received dependant on?

• time of day

• amount of cloud cover

• latitude

• season

turbidity

- amount of suspended particles in the water (clay, sand, algae, phytoplankton, etc.)

turbidity and light

the higher the turbidity, the less penetration the light will get

turbidity affects light in three different ways

• reflects - hits a particle and reflects the light

• scatters - hits a particle and goes in a random angle

• absorbs - lights sucked in

what is white light

all the colors together (ROYGBIV)

wavelength of colors

red has the longest wavelength, violet has the shortest wavelength

as depth increases

• the intensity of light decreases

• wavelength changes

things that change with depth

• light

• temperature

• pressure

• amount of dissolved gas

• amount of dissolved nutrients

• surface mixing

light

amount of light the ocean receives changes

temperature

surface waters receive sunlight which warms and becomes less dense and floats on colder bottom water

thermocline

warm water floats on cold water, between the two is:
a zone of rapidly changing water temperature

pressure

for every 10 meters of depth, pressure increases 1 ATM

amount of dissolved gas

oxygen decreases with depth, carbon dioxide increases with depth

amount of dissolved nutrients

compounds need for the growth and development of an organism

growth and development

• to get bigger

• gaining new physical and behavioral traits

nutrients

• nitrates

• phosphates

• calcium

• magnesium

nitrates

helps to make amino acids / proteins

phosphates

help to make up phospholipids / cells / DNA / RNA

calcium

helps make bone, shells, coral skeletons

magnesium

helps make chlorophyll

nutrients and depth

nutrients are low at the surface and build up with depth

producers

• producers absorb nutrients from the environment in a process called uptake

• in the photic zone, they uptake nutrients reducing their overall abundance

• as organisms die, they are decomposed and release nutrients with sinks

surface mixing

wind causes waves and currents which mix the surface waters which extends above the thermocline in the photic zone (about 200 meters)

coastal to open water gradient

divided into 3 zones

• littoral zone

• pelagic zone

• neritic zone

littoral zone

• area between high tide and low tide

• characterized by extreme shallowness of water

• this change in depth of water causes extreme environmental conditions

environment vs ecosystem

ecosystem includes biotic and abiotic factors, environmental is just abiotic

extreme environmental conditions

• wet to dry

• large temperature change

• swings in salinity

neritic zone

• area above the continental shelf

• the area tends to be well lit

• temperature tends to be fairly stable

• the area tends to be well mixed

pelagic zone

• the area over continental slope and the abyssal plain

• characterized by extreme depth of water

upwelling

the movement of nutrient rich bottom water to the surface