This in an introduction to oceanography for 1st year students. In geochemistry, geology and misuse of the sea

Resources are:Oceanography: An Illustrated Text C. P. Summerhayes, S. A. Thorpe John Wiley & Sons, May 1996 ISBN: 0470345373 or 0470235748 352 pages

NASA visible Earth: http://visibleearth.nasa.gov/

Essentials of Oceanography (7th Edition) (Paperback)by Harold V. Thurman, Alan P. TrujilloA very good webpage can be found under:http://wps.prenhall.com/esm_thurman_essofocean_7/0,7261,382992-,00.html

Composition of seawaterProcesses controlling seawater compositionMajor drainage systems of riversExplain Rock weathering, vulcanic ashes, aerosols, hydrothermalismFormation of sedimentary rocksHow does the salt get into the seaDominant ocean sediment types and locationsThe biological pump (photosynthesis, settling etc)The physical/solubility pumpVertical profiles of chemical elementsAtlantic versus Pacific comparisonExplain the two box modelOxygen in surface watersThe Marine Carbonate System

CO2 determination from ancient atmospheresCO2 in surface waterscurrent atmospheric CO2 concentration effect on global warmingCO2 saturation in seawater (name the different ions) ∑CO2 concentrations in oceans Lysocline and Carbonate compensation depth Ocean CO2 disposal option

Ocean resourcesEEZoverfishing/clima effectsOil/gas, Sand dredge, Manganese, Medicine, Biotechnology

SedimentologyLandformsBeach characteristicsLongshore current/driftErosional coastsDepositional coastsBarrier islandsCoastal protection

What you should know for the Oceanography exam

The Ocean: A Global Geochemical System

Figure 1

Deployment of a CTD cast. This instrument is routinely used during oceanographic expeditions for in situ measurements of water temperature and salinity. CTD casts can also collect water samples from different depths, stored in the dark grey cylinders visible on the photograph, which can then be used for further chemical analyses on board.

: www.pcweb.liv.ac.uk/ocean/ oceanography/f1f7.htm

Figure 2

Composition of seawaterSeawater is a solution of salts of nearly constant composition, dissolved in variable amounts of water. There are >70 elements dissolved in seawater but only 6 make up >99% of all the dissolved salts; all occur as ions - electrically charged atoms or groups of atoms: their concentrations are mostly conservative and only affected by physical processes

Oceanographers use salinity -- the amount (in grams) of total dissolved salts present in 1 kilogram of water -- to express the salt content of seawater. Normal seawater has a salinity of 35 grams/kilogram (or litre) of water -- also expressed as 35‰. Seawater from Wormly in southern England is used as the international standard for seawater composition.As well as major elements, there are many trace elements in seawater - e.g., manganese (Mn), lead (Pb), gold (Au), iron (Fe), iodine (I). Most occur in parts per million (ppm) or parts per billion (ppb) concentrations. These minor constituets are mostly non-conservative and actively participate in chemical and biological processes that change their concentrations They are important to some biochemical reactions - both from positive and negative (toxicity) viewpoints.

Figure 3

SeawaterRiver water

Figure 18

Figure 6

precipitation

Figure 7

Processes controlling seawater compositionSalts dissolved in seawater come from three main sources:• volcanic eruptions• chemical reactions between seawater and hot, newly formed volcanic rocks of spreading zones (mid-oceanic ridges)• chemical weathering of rocks on the continents

Figure 8

FIGURE 4-3

FIGURE 4-4

Primary source for weathered material is crustal rock

Limestone, sandstone and Shales are themselves sedimentaryproducts

Many salts in seawater originate from weathering of rocks on land. As rocks are weathered to form soils, they release soluble constituents like silica and elements like sodium, calcium, potassium and magnesium. River waters also carry bicarbonate (HCO3) - a by-product of weathering of silicate rocks or dissolution of limestone. Once they enter the oceans the dissolved salts remain, while the water continues to move through the hydrological cycle.

Figure 10

Figure 2

FIGURE 4-5

FIGURE 4-7

Vulcanic ashesVolatiles hydrochlord acid sulphur containimg gases carbon dioxide

Volcanic eruptions produce large volumes of gases that eventually reach the oceans -- most important are sulphate and chloride. Submarine eruptions at spreading ridges inject gases directly into the oceans; gases from subaerial volcanoes are dissolved in rainfall.

Figure 13

FIGURE 4-6

AerosolsAerosols

Aerosols are powders, or droplets, suspended in a gas, with a typical particle diameter of about one micrometer. they can act as a nucleus for the condensation of water to make a relatively large cloud droplet. Once formed, aerosol particles can collide and stick together, or they can grow by further condensation from the vapour phase.

Aerosols

October 13, 2001 Figure 14

Figure 9

FIGURE 4-18