Oceans Oceanography Marine geology the study of ocean water and its movements the study of the ocean floor and shorelines the study of rocks and minerals from oceanic crust Marine biology Sea versus ocean the study of life forms in the sea oceans are very large Pacific ocean is the largest Less confined than sea areas Have more open waters seas are very confined by land masses Red Sea for example and have more closed waters Bathymetric areas variation of depths in the ocean measures downward from sea level towards the bottom of the sea Continental margin a continent s coastline active continental margin margin that coincides with a plate boundary and thus has a lot of volcanic activity No bathymetric areas here lack slope lack shelf lack fan passive continental margin margin with no earthly action going on in terms of tectonics No volcanic formation no plate movements Continental shelf a broad shallowly submerged fringe of a continent The widest continental shelves occur over passive margins Very flat and expansive area however it is very narrow Continental slope the slope at the edge of a continental shelf leading down to the deep sea floor Marks area between shelf and abyssal plain Abyssal plain broad and relatively flat region of the ocean Wide flat and deep Canyon a narrow steep canyon that dissects divides a continental shelf and slope Associated with all the major rivers in the world Can be pretty deep in some areas and a lot of fishing party boats go to these areas to fish Fan a lump of debris silt sand organic material that is situated at the base of the continental slope and at the beginning of the abyssal plain Fans are the beginning of the continental rise Contour of the landscape goes up around the fan as you walk from the abyssal plaint to the slope big areas of pollution Has all of the crap that goes down our sink and toilet drains it Affects marine biology in these areas Passive active continental margins look above Salinity temperature and density as controls on Marine circulation water temperature and dissolved ions influence the development of currents the worlds marine waters are salty because thee is a large concentration of dissolved ions A dissolved ion is an atom with a positive or negative charge that has been introduced into water When Na is introduced to Cl they combine in water to produce Halite and increase the density of our ocean waters Ocean water contains an average of 3 5 dissolved salt salinity concentration of salt in salt water varies with location salinity of oceans changes with depth warmer water can hold more salt in solution than cold water high salinity occurs from evaporation and sea ice formation lower salinity occurs from rainfall glacial melt and river input temperature ocean surface temperature varies inversely with latitude because of the intensity of solar radiation varies with latitude water temperature in the ocean varies with depth Waters warmed by the sun are less dense and tend to remain at the surface density drives marine currents Controlled by salinity and temperature less dense water is warm and fresh More dense water is cold and salty more salinity the colder the water the more dense it is Thermo Haline current thermo haline circulation the rising and sinking of water driven by contrasting water density which is due in turn to differences in temperature and salinity the circulation involves both deep water and surface currents in the ocean during circulation dense water cold and or saltier sinks whereas water that is less dense warm and or less salty rises As a result the cold water in polar regions sinks and flows back along the bottom of the ocean toward the equator This process divides the ocean vertically into a number of distinct water masses which mix only very slowly with one another The combination of surface currents and thermo haline circulation like a conveyor belt results in the ocean mixing entirely in a 1 500 year period look at video online Gulf Stream warm and fresh less salinity Atlantic Ocean current that flows from the Caribbean area and hugs the eastern part of North America Fresh water is less dense and as a consequence the warm water is a shallow water current Cold salty portions of the gulf stream make up the deep water currents that travel along the ocean bottoms Monsoons What is a monsoon a major reversal in the wind direction that causes a shift from a very dry season to a very rainy season seasonal rains places that have monsoons experience a wet season and a dry season the two key ingredients that produce monsoon rain is temperature wind Temperature is dependent on the tilt of the Earth latitude Incoming solar radiation as a function of latitude and tilt Earth is closest to our sun in the winter and farthest from our sun in the summer Earth s tilt is the reason for the seasons Solstice when there is more day or night than the other 18 hours of day and 6 hours of night or vice versa occurs twice a year when the tilt of the earths axis is oriented directly towards or away from the sun causing the sun to reach its highest and lowest points the summer solstice longest day of the year occurs on June 21 and marks the beginning of summer It is also when the location of the sun is at its furthest north the winter solstice shortest day of the year occurs in the northern hemisphere Occurs on December 21 and marks the beginning of winter when the location of the sun is at its furthest south during winter the Northern hemisphere day lasts fewer than 12 hours and the southern hemisphere day lasts more than 12 hours during this solstice the north pole has a 24 hour night and the south pole has a 24 hour day sunlight strikes the earth most directly at the Tropic of Capricorn Equinox when a day lasts 12 hours and a night last 12 hours at all latitudes equinox literally means equal night sunlight strikes earth most directly at equator occurs twice a year Convection cell flow of air mass in response to temperature gradients Convection is driven by differential solar heating transfer from low to high or high to low pressure systems Low pressure air mass warm air expands becomes less dense and rises moist moves vertically High pressure air mass the air is replaced by sinking cooler denser air dry sinks Hadley cell low latitude convection cells in the atmosphere Ferrell cell middle latitude convection cell in the atmosphere Polar cell high latitude convection cell in the atmosphere Coriolis Effect wind direction