EARTH SCIENCE - B

EARTH SCIENCE - BB.MillerRunning water & ground waterChapter 66.1 Running WaterThe Water cycleThe unending circulation of Earths waterWater moves through solid, liquid & gasInfiltration:Movement of water into rock or soilTranspiration:Water released from plants during photosynthesisThe Water Cycle

Earths Water BalanceThis means, that overall precipitation equals the overall evaporation globallyStreamflowStream velocities range from 1-30 km/hr.Gradient: Slope or steepness of a stream gradient = velocity= erosionChannel CharacteristicsThe shape, size and roughness of a stream channel can also affect the rate of flow.Discharge:The volume of water that passes by a certain point in a systemChanges from Upstream to DownstreamStreams are studied by their profilesProfile is a cross-sectional view from its source (beginning) to its mouth (end)Gradient decreases from the headwaters to the mouth of a streamThe amount of discharge increases along a river, because the number of tributaries increase along the way. Tributaries: are smaller streams that drain into a stream along its path

Base LevelDefined: The lowest point to which a stream can erode its channelUltimate Base Level:Ocean surface, it the lowest point that any stream can erode toTemporary Base Level:When a stream erodes to the surface of a lake or resistant rock layers6.2 The Work of StreamsErosionStreams generally erode their channelsThe water moves particles by abrasion, grinding and by dissolving soluble materialsSediment TransportStreams transport sediment in 3 ways:In solution (dissolved load)In suspension (suspended load)Scooting and rolling along the bottom (bed load)Dissolved LoadUsually dissolved rockExpressed in ppm (parts per million)Suspended LoadVisible cloud of sediment suspended in waterVelocity during flooding increases and more suspended load is carriedBed LoadLarge pieces that are rolled along the stream bottomCompetenceMeasure of the largest particles that a stream can carry

CapacityThe amount of load that a stream can carryDepositionOccurs when a stream flow slows and sediment drops outDeltasSediment dropped at the end of a stream into a lake or oceanThe velocity slows when reaching a larger body of water and drops its loadNatural LeveesParallel ridges to a stream, that build up from past floodsThe sediment naturally piles up and creates a barrier to future floods.Yellow River Delta- Satellite

Levee formation

Stream ValleysNarrow Valleys (Ex: Yellowstone River)Characterized by steep sidesNot much meanderingNo oxbow lakesWide Valleys (Ex: Mississippi)Flat floodplain areaLots of weaving and windingOxbow lakes left after floodingFloods & Flood ControlFloods are caused by rapid snow melt, storms and heavy rainfallWays to control flooding include:Artificial leveesFlood control damsLimiting development

Drainage basin: an entire area that drains into a river or river system6.3 Water Beneath the SurfaceThe amount of water that ends up underground depends on:Steepness of slopesNature of surface materialsIntensity of rainfallType of and amount of vegetationDistribution: (location)Most water seeps down into the soil until it reaches the zone of saturationThe Zone of Saturation is an area in the soil where water fills all the pore spaces in between the particlesMovementStorage or movement of water depends on subsurface materialsPorosity - % of soil or rock that consists of pore spacesPermeability ability to release a fluid, and depends on pore sizes of soil and rockSpringsA spring is a flow of groundwater that emerges naturally at ground surfaceHot springsWater warmer by 6-9C, than the mean annual air temp.More than 1000 in the U.S.Most in the Western statesGeysersAn intermittent hot spring or fountain that shoots up with great forceColumns of water 30-60 metersMost famous is Old Faithful in Yellowstone Nat. parkWellsA hole bored into the zone of saturationMostly for irrigation, some industrial and lastly some home use

Artesian WellsPush water out of the hole on their own. Pressure is created along an aquiferEnvironmental Problems associated with GroundwaterOveruse & contaiminationTreating water as NON renewable:Groundwater seems endless, but we know there is a finite amount of freshwater on EarthThere are intense shortages in areas with high irrigation rates (plains)Subsidence (shrinking of the surface) is occurring in areas of CaliforniaContamination:Runoff from farms and industrial areas, can allow chemicals and fertilizers to contaminate the ground water supplies.This is not a case of water shortage, but of clean water shortage.Ocean water & ocean lifeChapter 1515.1 Composition of WaterSalinity:Salt, total amount of dissolved solids in waterSources of Sea SaltsChemical weathering of rocks on the continentsFrom Earths interior, volcanoes released chlorine, bromine, sulfur and boron when the oceans were formed 4 billion yrs. Ago.Processes Affecting SalinitySurface salinity 3.3-3.8%Precipitation, runoff, melting iceburgs decrease itEvaporation & freezing increases salinityOcean Temperature VariationThe oceans surface water temperature varies with the amount of solar radiationTemp variation with depthGenerally warmer near the surfaceThermoclines: (thermo=heat, cline=slope)A layer of ocean water 300-1000 m deep of rapid temp. changeThis is a barrier to many marine organismsOcean Density VariationDensity = mass per unitFactors affecting seawater density:Increase salinity = increase densityIncrease temperature = decrease density

Pycnoclines (pycno=density, cline=slope)A layer of ocean water 300-1000m deep with rapid density changeOcean LayeringSurface ZoneNearly uniform temps.Extends ~300mMakes up 2% of all ocean waterTransition ZoneBelow the surface zone and above the deep ocean zoneIncludes thermoclines and pycnoclines18% of all ocean waterDeep ZoneSunlight never reaches this zoneTemps are just above freezingDensity is very high80% of the ocean water15.2 Diversity of the OceanClassification of Marine OrganismsPlankton (planktos=wandering)All organisms that driftEx: algae, animals, plants and bacteriaNekton (nektos=swimming)All animals capable of moving on their ownEx: Adult fish, squid, marine mammals, marine reptilesBenthos (benthos=bottom)All organisms that live on or near the bottomCan be shallow or deepEx: angler fish, crabs, sea starsMarine Life Zones3 factors that divide ocean into 3 distinct zones:

Availability of sunlightDistance from shoreWater depth8 Ocean zones1. Photic ZoneUpper part of the ocean; sunlight penetratesEuphotic zone, where photosynthesis occurs2. Intertidal ZoneNarrow strip between high and low tides3. Neritic ZoneFrom the low tide mark outward to seaEntirely within the Photic ZoneRich in Biomass and diversitySupports 90% of commercial fisheries

4. Oceanic ZoneBeyond the continental shelfGreat depths of open oceanLower in nutrients; low biodiversity5. Pelagic ZoneOpen ocean of any depthHome to phytoplankton, zooplankton and nekton6. Benthic ZoneSeafloor organisms exist hereEx. Giant kelp, sponges, crabs, sea anemones, etc.Abyssal ZoneDeep-ocean floorExtremely high pressureLow tempsNo sunlightSparse lifeHydrothermal ventsAlong the mid ocean ridgeSuper heated water, some >than 100CSupports organisms that live no where elseOrganisms rely on chemosynthesis for survival15.3 Ocean ProductivityPrimary ProductivityThe production of organic compounds from the inorganic substances through photosynthesis or chemosynthesisPhotosynthesis uses light energy to convert water and carbon dioxide into glucoseChemosynthesis Microorganisms create organic molecules from inorganic nutrients/minerals2 factors that influence photosynthetic productivity:The availability of nutrientsThe amount of solar radiation (sunlight)Polar Oceans productivityPeaks in May, mostly of phytoplankton (diatoms and algae)The availability of solar energy, is what limits photosynthetic productivity in polar areas

Tropical Ocean ProductivityTypically low in open tropical oceanSunlight is available in high supply all year, but there is no mixing of deep nutrient rich water and surface watersThis thermocline keeps production low because of a lack of nutrientsTemperate Ocean ProductivityProductivity is controlled by both limiting factors (sunlight & nutrients)WinterLow production; low sunlightSpringPhytoplankton blooms; low nutrients; low productivitySummerNutrients get used, then run low quicklyFallA final phytoplankton bloomOceanic Feeding RelationshipsMain oceanic producer:Algae, plants, bacteria-like organismsTrophic Levels:Algae Zooplankton carnivoresTransfer EfficiencyThe energy transfer from trophic level is very inefficientThe majority (90%) of the energy is lost as heat to the environmentFood chains and Food WebsFood ChainSequence of organisms through which energy is transferredA B C DFood WebShows all the possible food chains in an environment D C B AThe dynamic oceanCh 16 (sec. 1 only)16.1 Ocean CirculationSurface CirculationOcean Currents: masses of ocean water that flow from one place to anotherSurface Currents: Develop from friction between wind that blows across its surfaceGyres: (gyres=circle) 5 main gyers..North PacificSouth PacificNorth AtlanticSouth AtlanticIndian ocean5 main Gyres

Gyres are huge circular moving current systemsWind influences most of these, but the spinning of the Earth causes deflection of some called Coriolis EffectOcean Currents and ClimateWhen currents from low-latitude regions move into higher latitudes, they transfer heat from warmer to cooler areas

Cold water currents travel toward the equator and help moderate the temperatures of land areasUpwellingVertical water movementsRising of cold water from deep layers to replace warmer surface watersDriven by winds across the surfaceBrings dissolved nutrients up to the organisms in the shallower waters.Deep Ocean CirculationDensity CurrentsVertical currents of ocean water that result from density differencesDense water sinks and spreadsCooler water is more dense and tends to sink

High Latitudes (toward the poles)High latitudes are colder and thus wat is heavier and ultimately sinksThis tends to slow the conveyor belt movements from the North to SouthEvaporationThe evaporation allows water to evaporate away, leaving the salt behind. Salt water is more dense and therefore sinks

The Conveyor BeltA global system of water continuously moving based on changing density and temperature.The Atmosphere: structure & temperatureCh 1717.1 Atmosphere characteristicsClimate Vs. WeatherWeather: Is constantly changing, and it refers to the state of the atmosphere at any given time and place.Climate:Is based on weather observations collected over many years.Most measureable properties of weather and climate include: Temp, humidity, type & amount of precip, air pressure, and direction and speed of windComposition of the AtmosphereIt has changed drastically over 4.6 billion years.Gases originated from volcanic eruptionsOxygen accumulated beginning ~2.5 billion yrs agoMajor components:99%= nitrogen and oxygen1% = carbon dioxide and argonVariable componentsWater vapor - cloud formation & precip.Dust allows vapor to condenseOzone filters UV radiationHuman InfluenceAir pollutants are airborne particles and some gases in large amounts can endanger the health of organismsPrimary pollutants:Emitted directly from identifiable sourcesEx: emissions from transportationSecondary pollutants:Not emitted directly into the air.Become dangerous when they react with another substanceEx: Sulfurs in exhaust mix with water vapor to create acidic precipitationPhotochemical Reactions:The sun causes a chemical reaction to convert Nitrogen oxides into smogHeight & Structure of the AtmosphereThe atmosphere thins as you travel away from EarthPressure changes:Atmospheric pressure is caused from the weight of the air above usAt sea level = 1 kg/cm2, and decreases as you move up through the atmosphereTemperature changes:There are 4 vertical layersThe thickness of these layers varies in different places on Earth

Thermosphere~50-90 milesTemp. decreasesMesosphere~30-50 milesTemp. increasesStratosphere~8-30 milesTemp. decreasesTroposphere~0-8 miles from the surfaceTemp. increasesEarth-Sun RelationshipsNearly all of the energy that drives Earths weather comes from the sun.Solar energy is not distributed evenly over Earths surface. Lower latitudes, closer to the equator get more direct rays than area toward the polesEarths MotionsRotationThe spinning of Earth on its axisOne rotation every 24 hoursRevolutionMovement of Earth in its orbit113,000 km/hrOne revolution per yearEarths OrientationSeasonal changes occur because Earths position relative to the sun continually changes as it travels along its orbitThe Earth is tilted 23.5 from perpendicular. This changes how directly solar rays strike the surface of the planet

SeasonsSummer solstice:June 21/22Sun passes at highest point in the sky because of Earths potionLongest day of the yearWinter solstice:Dec 21/221st day of winterShortest day of the yearSun is at lowest point in the skyAutumnal Equinox: Sept 22/23 way between seasonsDay and night are equal in lengthSun is mid-way between high and low positions in the skySpring EquinoxMarch 21/22Sun is mid-way btwn high & low pointsDay and night are equal in lengthHeating the Atmosphere3 mechanisms of heat energy transfer:1. Conduction:Transfer of heat through matter my molecular activityEx. Hot handle of a pot cooking on the stove2. Convection:Transfer of heat in the atmosphere by movement or circulation (mixing)Ex. Convection currents that move warm water from the bottom of a heating pan toward the top.

3. RadiationRadiation travels out in all directions from an objectEx. Electromagnetic waves; how the suns energy warms surfaces here on Earth

Radiant energy does not need a medium to travel through. It can travel in a vacuum where no atoms or molecules exist.4 laws of RadiationAll objects emit radiationHotter objects emit more than cool onesHotter radiating bodies produce the shortest wavelengths of energyObjects that are good absorbers of radiation, are also good emitters of radiation.What happens to Solar Radiation?When radiation strikes an object, there are 3 possible results:Energy is absorbedEnergy is transmitted thru the objectEnergy will bounce off, without being absorbed.ReflectionRadiation bounces off an objectThe reflected energy is equal in intensity as the original radiationScatteringReflects many weaker rays than the original ray.Absorption~50% of the solar energy that strikes the top of the atmosphere and reaches Earths surface is absorbedMost is radiated skywardCarbon Dioxide and water vapor allow Earth to hold on to some of the suns energy.This is what allow us to live on this planetGREENHOUSE EFFECT PhotosynthesisSome energy from the sun is absorbed by plants (chlorophyll)This energy is converted into carbohydrates and is the base of most food chains.Temperature controlsWhy does temperature vary?LatitudeHeating of landHeating of waterAltitudeGeographic positionCloud coverOcean currentsLand and WaterLand heats more rapidly and heats to higher temperatures than waterLand also cools faster than waterSo therefore, temperature changes occur very quickly over landGeographic position:Coastal vs. inland: Large nearby bodies of water can influence temperature changes

Urban vs. rural:Cities tend to heat to higher temps and remain warm longer than rural placesAltitude:Within the same latitude, the temps are lower as the altitude increasesSo it gets colder as you get higher from sea level.Cloud cover & Albedo:Albedo is the fraction of radiation reflected by any surfaceClouds reflect some of the suns radiationEx: darker objects reflect very little light, and therefore have low albedo, compared to light objects.IsothermsLines that connect points that have the same temperature across a mapAllows us to study temperature ranges across the globe.