DOC PREVIEW
UMass Amherst GEO-SCI 103 - Water and the Ocean

This preview shows page 1-2 out of 7 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 7 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 7 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 7 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

GEO-SCI 103 Lecture 6Outline of Last Lecture: EXAM 1Outline of Current Lecture: Water and the Ocean (9/23/14) (pages 68-71, 108-119)I. Types of Marine SedimentsA. Terrigenous SedimentB. Red ClayC. Biogenic SedimentD. Authigenic SedimentII. The Unusual Structure of Water A. Water as a SubstanceB. Water Molecule (H20)C. Hydrogen BondsD. Properties of WaterIII. Unique Properties of Water A. Water has a unique response of density to temperatureB. Water has high boiling and freezing pointsC. Water has high heat capacityD. High latent heat of vaporization and High latent heat of Fusion IV. The Hydrologic Cycle and Heat TransferA. Latent heat versus Sensible HeatB. Hydrologic CycleV. Seawater Salinity: the Salt of the OceanA. InputB. OutputVI. Residence Time of water in the OceanA. FormulaB. SignificanceVII. Element Cycling and History of SeawaterA. Geological FindingsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureI. Types of Marine SedimentsA. Terrigenous Sediment: Accumulates along the continental margins and typically mask other sediment types close to the continents because of high sedimentation ratesa. Derived from the weathering of rocks on landb. Composed of sand, salt or clay sized particles derived from the physical and chemical weathering of rocks and soil on landc. Sand and mud are moved across the continental shelves by large storms and gravityd. Much sediment is funneled into submarine canyons at the edge of the continental shelfe. Gravity transports sediment down the continental slopes via slumps and turbidity currentsf. Builds up as deep-sea fans at the base of the continental slope B. Red Clay: accumulates on the abyssal plains, deeper than 4,500 meters a. Red or brown clay is derived from wind blown dust which slowly settles to theseafloor, or it is derived from current transported claysb. Red clay accumulates at very slow rates and is diluted by other sediment in many areas of the deep-seaC. Biogenic Sedimenta. Calcareous Ooze: accumulates on bathymetric highs beyond continental margins, shallower than 4,500 meters. Examples include spreading centers and flanks of volcanoes that stick up above the abyssal plains1. Composed of carbonate shells of plankton2. Dead plankton settle through the water column, or consumed plankton are incorporated into fecal pellets which settle to the seafloor 3. Calcium carbonate dissolves about 4500 m water depth due to cold temperature, high pressure and greater carbon dioxide content of deep waters= Carbonate Compensation Depth (CCD)b. Siliceous Ooze: Accumulates beneath areas of high biological productivity in the surface ocean, such as the equatorial Pacific and around Antarctica 1. Composed of a siliceous shells of plankton2. Areas of upwelling provide the nutrients and silica necessary to sustain a large biomass of siliceous plankton D. Authigenic Sediment: precipitates directly from seawater under specific (bio)chemical conditions related to source, oxidation-reduction, and/or sedimentation rate. a. Ferromanganese nodules form on the abyssal plains by the slow chemical precipitation of metal oxides directly from seawater (facilitated by biochemicalactivity of bacteria and other microorganisms; and by the burrowing activity oflarger organismsb. Hydrothermal activity at the spreading centers is a major source of dissolved metal oxidesc. Phosphorite nodules form on the outer shelf and upper slope where unoxidized organic matter in the oxygen minimum zone is biochemically transformed into phosphorite d. Some authigenic deposits are economically valuable II. The Unusual Structure of WaterA. Water as a Substancea. Water behaves differently from almost any other chemical compound that exists naturallyb. Differences begin with the basic arrangement of the atoms in a water molecule which gives it a dipolar structure: the molecule has an uneven distribution of electrical charge, owning to the asymmetrical shape of the molecule 1. The hydrogen side of the molecule (H2) has a net positive charge, and the Oxygen side (O) has a net negative charge. 2. This occurs because the negatively charged electrons spend more time in the vicinity of the O atom.B. Water Molecule (H20) a. 2 hydrogen (H) atoms, each typically with one proton in the nucleus and one electron in orbit around the nucleus b. Oxygen (O) aton with 8 protons and typically 8 neutrons in the nucleus, and 8 electrons in orbit around the nucleus (2 electrons in the inner orbit and 6 in heouter orbit)c. Water molecule held together by strong covalent bonds: each H shares its one (-) with the O to completely fill the outer electronic shell of the O with 8 electrons, and the O shares (-) to fill single electron shell of each H with 2 (-)C. Hydrogen Bonds: Because of this asymmetrical distribution of electrical charge in the water molecule, the positively charged ends of the water molecules are attracted to the negatively charged ends of adjacent molecules called hydrogen bonds. D. Properties of Watera. Water has a high surface tension (cohesion: hydrogen bonds allow for water to form droplets (ex: raindrops)b. Water occurs in 3 states (phases over a relatively narrow range of temperature: (solid, liquid and gas). THE DEGREE OF HYDROGEN DETERMINES THE THREE PHASES OF WATER1. Solid (Ice)crystalline structure is less dense than liquid water2. Liquid (water)liquid water is more dense than ice3. Gas (water vapor)high energy molecules with few H bonds c. Water is a good solvent that allows it to dissolve many other substances: dipolar structure lets ionic compounds go into solution easily III. Unique Properties of Water A. Water has a unique response of density to temperaturea. Temperature of maximum DensityLiquid water increases its density as it cools until it reaches a temperature of 3.98 degrees Celsius. This occurs because the vibrational energy of the water molecules is at a minimum allowing them to pack more closely together b. As water cools further, hydrogen bonds begin to form that push the water molecules apart and cause the density to decreasec. When water freezes, the hydrogen bonds in the ice form a hexagonal crystalline structure that pushes the molecules even further apart. This lowers the density of the ice below that of liquid water, and as a consequence ice floats. B. Water has “high” boiling and freezing pointsa. Water is the only


View Full Document

UMass Amherst GEO-SCI 103 - Water and the Ocean

Download Water and the Ocean
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Water and the Ocean and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Water and the Ocean 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?