Freshwater BiomeCh.10

http://people.eku.edu/ritchisong/birdbiogeography1.htm

Aquatic BiomesWater covers ~ 70% of EarthAquatic habitat: organisms live in or on water

Grouped by depth and salinity of water Rainfall and temp. categorize land biomes, but

temp. of waters is fairly consistent and rainfall does not affect the organisms

Campcrescent.com

SalinitySalinity: amount of dissolved salts in the

waterSaltwater: 30 parts/thousand

Oceans and some lakes (Great Salt Lake in Utah) Many saltwater lakes are 40 parts/thousand…..why?

Freshwater: 0.5 parts/thousand Most lakes, ponds, and rivers

SalinityHydrometer

measures density of water by testing buoyancyBuoyancy

amount of mass that can float on the waterIncrease in salt inc. in density inc. in

buoyancy

http://spot.pcc.edu/~lkidoguc/Aquatics/AqEx/Water_Buoyancy.htm

DepthEcosystem depends on amount of sunlight

that reaches the bottom

More sunlight results in a greater number of plants

Plants-basis of food webMore plants leads to more animals

Depth Zones

Depth zonesPlants only grow in photic and shallow parts

of benthic zoneBenthic animals: insect larvae, snails, catfish,

turtles

Alvin, the research submarine, studied cracks in the ocean floorBase of the food web down there was bacteriaBacteria use energy from chemicals that ooze

through those cracks

Questions1. H0w is salinity determined and measured?

2. Suppose a friend wants to set up an aquarium and discovers that saltwater fish are more attractive, but a freshwater tank is easier to maintain. Your friend decides to set up a freshwater aquarium but buys some saltwater fish to place in it. Predict what the result of this decision would be, and why?

2 types of freshwater biomesStanding water

Ponds, lakes, marsh, swamps

Flowing water

http://rrms-biomes.tripod.com/id10.html

Standing Water:

Abiotic Factors Biotic Factors

Lake Deepest standing water, may have aphotic zone

Main producers: floating algae in the photic zone and benthic plants along shoreline

Pond Light reaches benthic zone; fed by rainfall

Producers: plants and algae that grows on bottom

Marsh Very shallow; soil is saturated; often lacks oxygen….Florida Everglades is the largest marsh in US

Plants roots under water, leaves above; mostly grasses; ducks, waterfowl, and benthic animals are common.

Swamp Poor drainage; soil saturated; along flat land; usually along coastline

Dominated by large trees and shrubs; plants adapted to growth in mud & oxygen-poor soil

Bog Inland wetland with little in or outflow; soil acidic; decay is slow; carbon stored in dead plants

Sphagnum moss is dominant organism

Standing water organismsTop level

Plankton Organisms that drift in water About size of a dust particle

Phytoplankton: carries out photosynthesis Main producers in aquatic biomes

Zooplankton: don’t carry out photosynthesis Consumers: feed on phytoplankton

Benthic ZoneHome to scavengers

Feed on remains of other organisms

WetlandsRoots of plants are submerged under water

at least part of the year

Examples: marshes, swamps, bogsSoil is soaked with water and contains little

dissolved oxygen

Important in biosphereFilter chemicals in waterMigratory fowl breed, feed, and rest thereWater sweeps into and refills aquifersProtection against floods

WetlandsCommon grass is papyrusEgyptians first used to make paper around

3000 bcMost common writing surface in eastern

Mediterranean for over 4000 years

Wetlands-human impactMore than half the wetlands in the U.S. have

been destroyedNot attractiveGive off unpleasant odor (methane from

bacteria)Breeding ground for mosquitoes

Usually on coast so can be ideal for development companies

Large so are used at times as landfillsClean water act: prohibits the filling of

wetlandsIn US only 8% wetlands are federally protected

Florida EvergladesHome to a large number of organisms

Adapted to cycles of growth, drought, and fireWater was drained from the everglades to

create farmland1947: Everglades National Park

Created to save everglades, but needed water1967 a canal was dug to get water to parkWater came too fast in too narrow of a stream

Caused flooding of the area and organisms homes 93% decrease of bird population and decline of

alligators

1983: Save our Everglades campaignDesigned to clean up contamination from farms

and restore a natural water flow100,000 acres of wetland has been restored

Questions1. What is the difference between the role of

phytoplankton and that of zooplankton?

2. The number of migratory birds in the tundra during the summer has been declining. How might changes that have taken place in the wetlands have contributed to this decline?

Flowing WaterRivers, streams, creeks, brooksScientists refer to all above ground bodies of

water as Streams.

Flowing Water OrganismsOrganisms that live in flowing water habitats

are adapted to the rate of water movement.Adaptations:

Hooks (grab plants)Suckers (attach/anchor to rocks)Salmon and trout are well adapted to flowing

water Grow in freshwater but spend adult life in ocean Breeding season they swim upstream to same spot they

hatched Find the “spot” by smelling the small amt of chemicals

in H2O

FlowMost streams begin at high altitude

From runoff of melting snowGravity brings downhillStarts Inland usually then goes out to ocean

Where streams slow down is where a majority of sediment accumulatesSediment provides a place for plant roots to

growColder water contains more dissolved oxygen

and therefore supports more animal lifeWhy pop loses its fizz when room temperature

FlowErosion along the fast-flowing outer edge and

sedimentation along the slow-flowing inner edge result in the winding, or meandering, of a stream

The older a stream is the more curvy it getsHuman activity

Streams have been dammed to make resevoirsDams, dikes, and irrigation canals used to

change stream coursesDams also used to control flooding

Questions1. Why are there fewer organisms in the

headwater of a stream than further downstream?

2. the headwaters of a stream often contain more dissolved oxygen than the water hundreds of kilometers downstream. Why is this true?