Presentation on theme: "Lesson 6.3 Aquatic Ecosystems"— Presentation transcript:
1 Lesson 6.3 Aquatic Ecosystems 75% of Earth’s surface is covered by water.
2 What are the basic needs of aquatic life? CO2O2SunlightNutrients- food & minerals
3 Describing Aquatic Ecosystems Salinity:Amount of dissolved salt present in waterSalt water, fresh water, or brackishPhotosynthesis:Light availabilityDepth & water clarityFlowing or standing waterZones: photic, aphotic, benthic
5 Freshwater Ecosystems Usually 0.005% saltSome exceptions:Great Salt Lakes-5-27% saltDead Sea- 30% saltMoving water- high elevations; cold; high O2; trout; streamlined plantsStanding water- lower elevations; warmer; less O2; bass, amphibians; cattails, rushes
6 Freshwater Ecosystems: Ponds, Lakes, Inland Seas Horizontal zones: littoral and limnetic
7 How is a lake stratified and what lives in each level? Epilimnion- upper layer of warm water; high light & O2; ex: water striders, phyto- & zooplankton, fishThermocline (mesolimnion); middle layer; medium light & O2; ex: phyto- & zooplankton, fishHypolimnion- lower layer of cold water; lower light & O2; ex: fishBenthos- bottom level; no light & little O2; ex: anaerobic bacteria, leeches; insect larvaeLittoral- near the shoreline; cattails, rushes, amphibians, etc.
8 Freshwater Ecosystems: Wetlands Lesson 6.3 Aquatic EcosystemsFreshwater Ecosystems: WetlandsAreas of land flooded with water at least part of the yearMarshes, swamps, bogs, and fensPrevent flooding, recharge aquifers, filter pollutants, and provide habitats.
9 Freshwater Ecosystems: Rivers and Streams Lesson 6.3 Aquatic EcosystemsFreshwater Ecosystems: Rivers and StreamsBodies of surface water that flow downhill, eventually reaching an ocean or inland seaWatershed: area of land drained by a river and its tributariesCharacteristics, such as dissolved oxygen, temperature, water speed, organisms, and others, change from source to mouth.
10 Estuaries Where river flows into the ocean or an inland sea Prevent flooding and soil erosion as well as provide habitats.Coastal estuariesbrackish; organisms must tolerate wide salinity and temperature rangeshome to salt marshes & mangrove forestsEverglades, Florida, wetlandsDid You Know? Salt marshes and mangrove forests are two of the most productive ecosystems on Earth.
11 Lesson 6.3 Aquatic Ecosystems OceansCurrents are driven by water temperature and density differences, wind, and gravity.Surface winds and heating generate vertical currents that transport nutrients and oxygen.Horizontal ocean zones: intertidal, neritic, open oceanVertical ocean zones: photic, aphotic, benthicDid You Know? If the water in the oceans evaporated, a 60 m (200 ft) deep layer of salt would be left behind.
12 Ocean EcosystemsIntertidal: Highly diverse; extreme range of temperature, moisture, and salinityNeritic: Productive kelp forests and coral reefs provide habitats and help protect shorelines from erosion.Open ocean: Low productivity due to low light penetration; phytoplankton base of food chain; deep sea organisms and hydrothermal vent communitiesDid You Know? Over 90% of ocean water on Earth is in the open ocean zone.
13 What factors influence the availability of those basic needs? Substances dissolved in water- Nitrates, phosphates, potassium, O2Suspended matter- (silt, algae) can affect light penetrationDepthTemperatureRate of flowBottom characteristics (muddy, sandy, or rocky)Internal convection currentsConnection to or isolation from other aquatic ecosystems.
14 Transitional Communities ESTUARIESWhere freshwater dumps into oceanBrackish (less salty than seawater)Has rich sediments that often form deltasProductive & biodiverseOrganisms adapted to varying levels of salinity as tide ebbs & flows“Nursery” for larval forms of many aquatic species of commercial fish & shellfish
15 Transitional Communities WETLANDSLand saturated at least part of the yearSwamps- have trees like bald cypress; high productivityMarshes- no trees; tall grasses; high productivityBogs/Fens- may or may not have trees; waterlogged soil with lots of peat; low productivityFens- fed by groundwater & surface runoffBogs- fed by precipitationSwampMarshBogFen
16 Importance of Wetlands Highly productive- get lots of sunlight, ↑ plants =↑ animalsNesting, breeding ground for migratory birdsSlows flooding by absorbing runoffSilt settles, making water clearer & nutrient richTrap & filter waterNatural chemical rxns neutralize and detoxify pollutantsGives H2O time to percolate thru soil & replenish underground aquifers.Threats- artificial eutrophication (see slide 13), draining, sedimentation via construction“Nature’s Septic Tank”
17 Marine Ecosystems SHORELINES Rocky coasts- great density & diversity attached to solid rock surfaceSandy beaches- burrowing animalsThreats- due to hotels, restaurants, homes on beach, more plant life destroyed, destabilizing soil, susceptible to wind & water erosionInsurance high; danger of hurricanes, erosionBuild sea walls to protect people but changes & endangers shoreline habitat
19 MARINE ECOSYSTEMS CORAL REEFS Clear, warm shallow seas Made up of accumulated calcareous (made of calcium) skeletons of coral animalsFormation depends on light penetration.Have a symbiotic relationship with algaeVery diverse, abundant (rainforests of sea)Threats- destructive fishing (cyanide & dynamite to stun fish), pet trade; about 3/4ths have been destroyed
20 What factors can alter aquatic ecosystems? Natural Succession- normal cycle of pond becoming forestArtificial Succession- humans add N & P to water via fertilizer & sewage causing succession to happen faster = EUTROPHICATION
21 What factors can alter aquatic ecosystems? Humans!Find foodRecreationWaste disposalCooling of power plantsTransportationDams, canals