Earth Science Exam 3 Outline I Intro to Oceanography A Four Disciplines 1 Chemical Oceanography the study of the chemical composition of seawater and how it is affected by interactions with the atmosphere the biosphere and the sediments and rocks which form the seafloor 2 Geological Oceanography covers topics in plate tectonics petrology of oceanic rocks sedimentation processes in the ocean and paleoceanography and paleoclimatology 3 Physical Oceanography he understanding of the physical processes that govern the circulation of the ocean and the coupled atmosphere ocean system 4 Biological Oceanography the study of the relationship between living organisms in the ocean and their environment II Chemical Oceanography A Water molecule 1 Covalent Bonds between one hydrogen H and two oxygen O atoms a polarity Dipolar bar magnet Polarity 2 Hydrogen Bonds are weaker than covalent bonds but still strong enough to result in a surface tension High water surface tension cohesion b solubility High solubility of chemical compounds in water c thermal properties Unusual thermal properties of water d unusual density Unusualdensityofwater C States of Matter Water 1 solid 2 liquid 3 gas 4 changes of state a heat and temperature b calorie D Waters Thermal Properties 1 freezing point 2 boiling point 3 heat capacity 4 latent heat E Global Thermostatic Effects 1 Moderates Earths Climate 2 Day Night temperature ranges F Salinity the total amount of solid material dissolved in seawater Expressed in parts perthousand 0 00 Averagesalinityofworldsoceansis350 00 1 measuring salinity 2 sources of salinity 3 salinity and temperature relationship with depth a haloclines b thermoclines III Geological Oceanography A Three Areas of Ocean Floor 1 Continental Margins a Passive Margins margins NOT associated with plate boundaries little volcanism and few earthquakes 1 continental shelf gentlyslopingsurfaceextendingfromtheshorelinetoward the ocean A flooded extension of the continents 2 continental slope steep zone that marks the boundary between continental crust and oceanic crust 3 continental rise wherethesteepcontinentalslopemergesintoamoregradual decline Thick accumulation of sediment that moved downslope from the continental shelf to the deep ocean floor b Active Margins occur where oceanic lithosphere is subducted beneath the edge of a continent Results in a narrow margin with an accretionary wedge 1 accretionary wedge 2 Ocean Basin Floor between the continental margin and the mid ocean ridge a abyssal plain cross section incredibly flat 3 Mid Ocean Ridge Rift Valleys deep ocean valleys along mid ocean ridge system Volcanoes and hydrothermal vents a Rift valleys b Seamounts Submarine volcanoes may build up above sea level to form seamounts As the plate upon which these volcanoes rest moves away from a spreading ridge the volcanoes sink beneath sea level c Guyots have flat tops because they have grown tall enough to be shaved by waves at the ocean s surface Seamounts have a similar origin but retain their more pointed volcano shape because they never reached the surface d Hydrothermal Vents are the result of seawater percolating down through fissures in the ocean crust in the vicinity of spreading centers or subduction zones places on Earth where two tectonic plates move away or towards one another IV Physical Oceanography Currents A Ocean Currents masses of ocean water that flow from one place to another Currents can big or small shallow or deep short lived or permanent 1 Surface Currents develop from friction between the ocean and the wind that blows across its surface a Gyres circular moving current systems or whirls of water b Coriolus Force is an apparent deflection of the path of an object that moves within a rotating coordinate system The object does not actually deviate from its path but it appears to do so because of the motion of the coordinate system 2 Deep Water Currents a thermohaline circulation Over time a complex circulation pattern has been established whereby warm surface waters move poleward while cold deep currents are established in the ocean depths 3 Tidal currents a causes of tides the sun and the moon b Types of tides High Tide The highest level of the sea surface Ebb Tide The time between high and low tide The tide is going out Low Tide The lowest level of sea surface height Spring Tide Tides that have the largest daily variance between high tide and low tide due to the alignment of the moon aand sun as seen during full and new moons Higher high tides and lower low tides Neap Tide Tides that have the least daily variance between high and low tides due to the moon and sun being perpindicular to each other as during 1 4 moon and 3 4 moon Lower high tides and higher low tides 1 Spring Tides 2 Neap tides V Physical Oceanography Ocean Waves A Anatomy of a wave When the wind blows across the water it changes the water s surface first into ripples and then into waves 1 Wavelength horizontal distance between successive crests or troughs 2 Wave Height vertical distance between any crest and succeeding trough 3 Wave Crest The highest part of the wave above the still water line 4 Wave Trough The lowest part of the wave below the still water line 5 Wave Base is the maximum depth at which a water wave s passage causes significant water motion For water depths larger than the wave base bottom sediments are no longer stirred by the wave motion above B Wave Motion 1 circular orbital motion As a wave travels the water passes the energy along by moving in a circular orbit Floating objects also follow circular orbitsOrbital size decreases with depth to zero at wave baseDepth of wave base 1 2 wavelength measured from still water level 2 breaking waves C Tsunamis VI Coastal Processes A Wave Refraction and Longshore Current 1 wave refraction 2 longshore current 3 longshore transport of sediments B Coastal Erosion C Ways to Combat erosion 1 Coastal Armoring a jetties b groins c breakwaters d seawalls 2 Beach Restoration a dredge and fill process b impacts from beach restoration 1 benthic infauna 2 reef and hardbottom 3 sea turtles All material we have discussed in class is fair game for the test There may be material not included in the outline that could be on test