AQUATIC ECOSYSTEMS• Determined by the salinity of water–2 types:• Freshwater : lakes, ponds, rivers,

streams, wetlands

•Marine: coastal marshes & swamps, coral reefs, oceans

CHARACTERISTICS• TEMPERATURE• SUNLIGHT*• OXYGEN• NUTRIENTS

Determines which organisms live where

*Photosynthetic organisms live near the surface

Three types of organisms:based on location & adaptations

• Plankton– Phytonplankton– zooplankton

• Nekton

• Benthos

Plankton – microscopic drifters

Phytoplankton: photosynthethicAlgae (base of food chain)

Zooplankton: heterotrophic microscopic organisms – jellyfish

Nekton – free-swimming

Benthos – bottom dwelling

Decomposers

7-1 Freshwater Ecosystems

• These include rivers, streams, lakes, and ponds.

• Rivers and streams have moving water. The water may be moving fast or slow.

• Lake are usually larger and deeper than ponds.• Just like in the oceans, plants and animals live

in the shallow (less deep) parts. The sun shines more in the shallow parts.

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Lakes & Ponds

• Littoral zone: near shore– Nutrient rich– Diverse life– Plants rooted in mud, stems above water

Littoral zone

Lakes & Ponds

• Open water:– Further from shore– No rooted plants– Phytoplankton starts

food chain

Lakes & Ponds

• Deep Water:– No light– Bacteria &

decomposers live on dead things that drift down

– Fish adapted to cool water

Lakes & Ponds

• Benthic Zone:– Bottom– Decomposers, insect larva, clams

How nutrients affect lakes• Eutrophication= an

increase in the amount of nutrients in an aquatic ecosystem.

• Plants & algae grow• Bacteria feeding on

decaying plants grow• Bacteria use oxygen in

water• Reduced oxygen levels

kills fish • Run-off increase nutrients

Freshwater WetlandsSwamps – woody plantsPoorly drained land,

Marshes – non-woody plants (cattails, grasses)

http://www.bing.com/url?source=images&rch=j5b3zjJoZyetFQAmDgHYOMMJM4o3MfK&url=http://www.learnnc.org/lp/media/collections/cede/cedewet08.jpg&urltarget=_blank&q=swamps&view=detail&id=159CA69E2F19D141AC643D238BB18C203373B1AC&first=301&FORM=IDFRIR&ssIG=efedee01671a4a328018f7a4bf4f978d

http://www.bing.com/url?source=images&rch=DRNE5Y37uxtDrnQVAzgzZQaGAA09axN&url=http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecSaltMarsh/salt_marsh.jpg&urltarget=_blank&q=marsh&view=detail&&id=494C0B299C2306F20A6EB192188EF945DED53E4E&first=0&FORM=IDFRIR&ssIG=2a8778b5e1794fcc9244620d61caf3ef

Function of Wetlands

• Trap & filter sediments, nutrients, pollutants• Reduce flooding• Buffer shoreline against erosion• Spawning grounds & habitat for fish &

shellfish• Provide habitat for rare, threatened,

endangered species• Recreation

Human Impact

• Considered wasteland & breeders of disease carrying insects. Drained, cleared & developed.

• Now we recognize importance as water purifiers & flood prevention.

http://www.bing.com/url?source=images&rch=_mXLC1SBqk73OqcFeGIpdg4cko8mMc3&url=http://academic.emporia.edu/aberjame/wetland/everglade/s_florida1.jpg&urltarget=_blank&q=human+impact+on+wetlands&view=detail&&id=BC4E0B371A41A73F4C6C6B705D38075449DFEF4D&first=0&FORM=IDFRIR&ssIG=f2968234d4b14ed6bc8c2412bbd73f7c

% of Wetlands lost . 22 states have lost 50% of wetlands7 have lost 80% (Indiana, Ill, Miss, Ky, Iowa, Calif, Ohio

Rivers

• Headwaters – origin may be snowmelt or rain• Full of oxygen, runs swiftly through shallow

riverbed• Becomes wider, warmer, slower, contains

more vegetation & less oxygen• Communities & industries affect health of

rivers.

Flint River

Lake Lanier

Atlanta’s drinking water

Characteristics of Aquatic Ecosystems