Quarter 4 Earth Science Review

this is all the notes and parts of the study guide the fourth quarter in Mr.Apeli's class

oceanography

is a science that draws on the methods and knowledge of geology, chemistry, physics, and biology to study all aspects of the worlds oceans

what is the largest and smallest ocean basins

the pasfic is the biggest and the artic is the smallest

continental margins

the edge where continental crust transitions into oceanic crust, can be active or passive

passive continental margins

a margin where there isn’t any tectonic activity along the coast, far from tectonic activity, East coast if the US

continental shelf

a gently sloping, submerged surface which extends from the shore, capped in sedimentary rocks

continental slope

a steep gradient that leads into the deep ocean floor

continental rise

when the continent gradually falls into the sea floor

deep sea fan

muddy sediment which falls from canyons

active continental margin

marks the location of a plate boundary at the edge of a continent, japans edge

accertionary wedge

accumulation of sediments and deformed scraps of oceanic crust. the larger the wedge the longer subduction has occured

how does the continental slope form in a passive margin

it forms when a oceanic plate begins to do divergence, it causes the nearby continental plate to thin until it sea floor spreading stops

Submarine canyon

a valley that was cut on the continetal shelf during a time when sea level was lower or by turbidity currents

turbidity current

a underwater landslide which comes from submarine canyons

why do turbidity currents start

they start when a pile of sediment falls from the continental shelf and cuts to make valleys due to sediment being less dense than water

ocean basin

deep ocean floor between 2 continental margin features

volcanic islands

A volcanic island is an island formed by the accumulation of lava and ash from underwater volcanos

undersea plateus

large, flat areas on the ocean floor that rise above the surrounding seafloor.

abyssal plain

relatively flat plain between passive margins

seamount

underwater volcano

guyots

undersea mountains with a flat top

terrigenous sediments

primarily mineral grains that were eroded from continental rocks and transported to the ocean by rivers, wind, or ice

biogenous sediments

consists of shells and skulls of tiny sea animals

hydrogenous sediments

consists of minerals that crystallize directly from ocean water through various chemical reactions (rare) only found near divergent boundries

how do guyots form

form by a moving plate which carries inactive volcanoes away from where they formed, then they gradually sink under and the top is shaved off

how do undersea plateus form

they form by lava from the mantle pours upward, causes balsaltic igenous rock

hydrothermal vents

vents near divergent boundries where they eject hot water full of mineral which then turn into hydrogenous substances

how do hydrogenous substances form

seawater sinks very close to the oceanic crust and heats up due to magma. the water gets taken in byhydrothermal vents which spread the hot water with minerals, the minerals crystallize due to heat diffrences and fall to the ocean floor

who discovered atolls

charles darwin

what is a atoll

rings of coral in the middle of the ocean

how do atolls form

coral begins to form on active seamounts which go over the ocean surface. the volcano begins to sink but the coral begins to grow. Finally, the volcano fully sinks but the coral grows above the ocean surface and all that is left is a atoll ring

what is salinity

the total amount of solid materials dissolved in water

what is the ratio of minerals to water in seawater

3\.5% dissolved minerals and 96.5% water

what is the main mineral in seawater

sodium cholride

what are the sources of sea salt

continental rocks get eroded and wash on shore, outgassing from volcanic eruptions, precipitation, underwater volcano explosions

what processes decrease salinity

precipitation, run off from land, melting of icebergs

how do melting icebergs decrease salinity

the icebergs are made by freshwater so when they melt they add freshwater

processes that increase salinity

evaporation of sea water and formation of sea ice

how does formation of sea ice increase salinity

as the water freezes it takes only water, removing water leaving more minerals

what is the surface salinity for most oceans

33% to 38%

what ocean in the saltiest

the atlantic ocean because of alot of evaporation

thermocline

rapid change in temperature , only found in low latitudes

where does thermocline occur

in low latitudes and in the first 1000 meters of sea water

why does thermocline only occur in low latitudes

only occurs near the equator because sunlight is able to reach the first 1200 meters, so as you down from the surface of the water the temperature slowly drops but near the poles, sunlight doesn’t reach so the isn’t a temperature difference from the top, and bottom of the ocean

pycnocline

rapid change in density near the equator

why is there only pycnocline in low latitudes

it is because the change in temperature near the equator causes density changes but near the poles, there is no temperature change so no density change either

what two factors effect density

salinity and tempreture

how is the ocean layers classified on

by depth and density

surface mixed zone

0-200m depth, sun-warmed, zone mixing, influenced by currents,

transition zone

200-1000 m depth, thermo and pycnocline due to temperature and density differences

deep zone

0ver 1000m, sunlight never reaches, temperature almost freezing, consistent high density water

what relationship does thermo and pycnocline have

inverse relationship

isothermal

no rapid change in temperature (poles)

isopynal

no change in density (poles)

as you go down in the ocean what happens

density and pressure go up, temperature goes down

what is the rate for sea pressure

for every 100m of depth pressure increases by 10 times the air pressure at sea level

how to find sea pressure

1. take the depth and divide by 100 2. multiply that by 10 3. times that by 14.7

pH

how acidic or alkaline something is

buffering

adding ions to make substances more acidic or alkine

how to make things more alkiline

add hydroxide ion

how to make things more acidic

hydrogen ion

photic zone

the upper zone where light is seen, many plankton in the water, sunlight varies on season

euphotic zone

part of the photic zone where there is enough light for photosynthesis, shallow area

aphotic zone

where there is no sunlight, animals use biolumlmescence to see

intertidal zone

where the ocean and land overlap, species that live here have to adapt to changes in the water and tides

neritic zone

covers the continental shelf and shelf break, includes the photic zone, includes most fishes and sealife

oceanic zone

found beyond the continental shelf, small biomass because less nutrients

pleagic zone

open ocean of any depth, animals float freely, has big squids and planktons which adapted to the darkness

benthic zone

only sea bottom surfaces, has benthos animals like starfish

abyssal zone

subdivison of the benthic zone, sparse and cold, has decomposers and hydrothermal vents

upwelling

the rising o cold water from deeper layers to replace warmer surface water

what does upwelling bring

it brings new water and new nutrients

thermohaline circulation

deep ocean circulation based off of salinity and density

currents

water rivers in the ocean, can be surface and underwater, can be warm or cold, powered by wind

gyres

large circles of currents, moves in circles because of the Coriolis effect

what are the three things that effect wind currents

corolis, windbelts, and continents

how do surface currents affect weather

is a costal city is next to a warm current the weather will be warm and vice versa

shore line

the line that marks contact between sea and land, it can vary because the water can erode the land

shore

the area that extends between the lowest tide level and the highest elevation on land that is affected by storm waves

coast

extends inland from the shore as far ocean related features can be found

what are the 2 things thermo haline circulation helps with

heat distribution and giving oxygen to life at the bottom of the ocean

how does the thermohaline system work?

it starts when wind pushes warm currents near the equator and they die down. the cold salty water at the pole sinks due to being dense and oxygen and other gases go down aswell. these turn into deep ocean currents and then this water which is full of nutrients from decomposers go up by upwelling.

passive gas exchange

where gases get taken in and sinks with salty and dense water, takes in oxygen, nitrogen, carbon dioxide, etc

why is carbon dioxide harmful to get exchanged during passive gas exchange

it makes water acidic which bleaches and kills coral

how does oxygen that sinks is helpful

it brings life to the animals at the bottom of the sea, especially decomposers do because they bring nutrients during upwelling

how is upwelling helpful

it brings new currents, new life due to nutrients and best for fishing

ocean waves

energy traveling along the interface between ocean and atmosphere, often transferring energy from storm over seas

how are waves powered

wind

crests

tops of waves

troughs

lower parts of waves

still water level

in between crest and trough

wave height

vertical distance between crest and trough

wave length

horizontal distance between crest and trough

wave period

time for 1 full wave to pass

the height, length, and period of waves depends of what

wind speed, length of wind blowing, fetch- the distance wind has traveled over time

what decreases waves energy

friction and upward slope

how does circular orbital motion work

when energy moves forward through the water while the induvisual water particles that transmit the wave around in a circle. the wave isn’t moving but it is just the water reacting to the energy

what happens to the circular motion as you go deeper into the ocean

it get weaker because it is getting further from the energy which is coming from the water’s surface

wave base

bottom of the wave where there is no energy

how to find the wave base

find the wavelength and divide that by 2

steeper the ocean slop the ______ wave

stronger waves because the wave has less time to slow down