2 What are the basic needs of aquatic biota? CO2O2SunlightNutrients- food & minerals
3 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.
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 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.
7 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
8 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
9 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”
10 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
12 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
13 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
14 What factors can alter aquatic ecosystems? Humans!Find foodRecreationWaste disposalCooling of power plantsTransportationDams, canals
15 BiomesWhich biome has the largest total area? The smallest total area?Which biome has the highest % of undisturbed habitat?Which biome has the lowest % of undisturbed habitat?Which biome has the highest % human dominated habitat?Which biome has the lowest % human dominated habitat?
17 LANDSCAPE ECOLOGYLandscape- geographic unit with a history that shapes the features of the land and organisms in it.Landscape ecology- the study of how landscape structure affects the abundance and distribution of organisms.Does not just focus on “untouched nature”
18 LANDSCAPE ECOLOGYUses geographical information systems (GIS) to map patch size, type and configuration to create 3-D mapsThese maps assist land planners in analyzing land use patterns
19 LANDSCAPE ECOLOGYFocus on how neighboring communities of a landscape interact
21 RESTORATION ECOLOGYRepair or reconstruct ecosystems damaged by humans or natural forcesGrowing field of sciencePeople are now being held responsible for their actions- restoring wetlands & habitat for endangered speciesBeforeAfter
22 The 5 “R’s” of Restoration Ecology Restoration- manipulation of nature to re-create species composition & ecosystem processes as close as possible to the state they were in before humans interfered.BeforeAfter
23 The 5 “R’s” of Restoration Ecology Rehabilitation- to bring an area back to a useful state for human purposes rather than a truly natural state.- reverse deterioration if can’t be restored fullyThese people in Africa are trying to use rocks to create a sort of wind break to prevent wind erosion of their soil. The soil will never be like it was but it will hopefully be usable.
24 The 5 “R’s” of Restoration Ecology Remediation- process of cleaning chemical contamination from a polluted area by physical or biological methods to protect human & ecosystem health- Incinerate soil contaminated with oil- use special bacteria to clean up oil spills in water (bioremediation)This is like an artificial wetland- wastewater comes in, settles, roots cleanse the water
25 The 5 “R’s” of Restoration Ecology Reclamation- techniques used to restore the shape, original contour and vegetation of a disturbed site- Surface Mining Control & Reclamation Act (SMCRA) requires mining operations to restore the open pit mines they create to natural state.BeforeAfter
26 The 5 “R’s” of Restoration Ecology Re-creation- attempts to construct a new biological community on a site so severely disturbed that there is virtually nothing left to restore.- often must build a wetland elsewhere to make up for the one destroyed by developer- Read story of Army Corp of Engineers & Florida Everglades restoration
27 Preservationists vs. Restorationists Preservationist- don’t start destructive projects in the first place. Preserve nature- “you can’t always fix what you broke”Restorationists- you are never going to be able to save every bit of land. Who says changes we make in restoring ecosystems is unnatural?Are we members of the community or separate from it?Should we use our creative energies to try to improve nature, or should we leave well enough alone?
28 Tools of RestorationPrairies- collect native prairie grasses from graveyards and plant in abandoned farm fields to reestablish native grasslandsRemove alien species- like nature center; hunting goats on GalapagosWalk away from ecosystem & let recover naturally- N. & S. Korea after the Korean War
29 Restoration EthicsIf habitat was filled with diseased, ugly organisms, should you return it to that state? Should you reintroduce mosquitoes, black flies, leeches, ticks, poisonous snakes?Should you improve on nature?Where do you find plants for restoration? Do you take from small population nearby or find larger population farther away?Is there more than one natural state? What is the history of the area?Since humans are part of nature, whatever changes we make to landscape also are natural. Is that true?Can we use nature to solve human problems? Read story on page 121 about Arcata, California’s artificial wetland project.Canal in China BeforeCanal in China AfterNotice plants used as filtering system
30 Ecosystem ManagementHow can we have progress and still maintain the environment?Aldo Leopold was one of the pioneers on his Sand County farmUS Forest Services, Bureau of Land Management, National Park Service all adopted versions of ecosystem managementPreviously, these agencies used their lands for commercial or recreational uses & did not focus on wildlife habitats, endangered species, etc.