Lesson 1.3 Wetlands and Watersheds

Lesson 1.3 Wetlands and Watersheds

Pg. 14- 18

Stream Biology

• Streams and Rivers are aquatic ecosystems that are teeming with life– There are three main groups of organisms in most

stream communities • 1. Algae and other protists • 2. Invertebrates• 3. Vertebrates

Algae

• Plantlike protists that make their own food– Producers a.k.a autotrophs – Form the base of most aquatic food chains – Use the energy from the sun & dissolved

nutrients to make their own food

Animal-like Protists

• Includes ciliates and paramecia• Aquatic organisms that eat bacteria,

sediments that contain bacteria, and alage – Saprotrophs feed on decayed organic matter– Raptors eat other protists

Invertebrates

• The most common invertebrates are insects, mollusks, and worms

• shredders are invertebrates that eat the tissues of other organisms, organic matter, and wood

Invertebrates - Insects

• Ingest their prey whole or pierce its tissues and suck out the fluids– Ex. Beetles

• In larval stage live in water, in adult stage live on land

Invertebrates- Mollusks

• Spend most of their lives in water• Feed on plants and algae– Primary consumers – Some are omnivores (eat plants and animals)– Some are carnivores ( eat other animals only)

Vertebrates

• Common stream and water vertebrates = amphibians (frogs and salamanders) and Fish

• Depend on water at various stages of their life cycles

Amphibians

• Most adults live on land• They have a variety of feeding habits– Frogs Are predators– Use their sticky tongues to capture flies and other

insects– Salamanders and newts are also carnivores

Fish

• Grazers, strainers, and suckers are fish that consume algae

• Some fish are predators – Examples: pike, pickerel, gars, and bullheads

• Detritivores feed by shredding sediments that enter the stream or river – or filtering their food directly from sediments in

the water

•Answer Review Questions #’s 1-5

Factors that Affect Freshwater Ecosystems

• Biotic factors are living components of an ecosystem

• Abiotic factors are the nonliving parts of an ecosystem – Examples: stream order, pH, velocity,

Temperature…etc.

• These factors determine the number and kinds of organism that live in the environment

Stream Order

• The smallest streams in a river system = first order streams – First order streams join

to form second order streams

– Second order streams meet to form third order streams…etc.

– 80% of streams in PA are 1st/ 2nd order

Stream Order

• Orders of a stream relates directly to the organisms that live there– 1st order streams = largest insects– 3rd and 4th order streams = plants & game fish– Larger Streams = algae, fish, and other aquatic

organisms

Temperature

• Velocity and depth affect the water’s temperature

• Areas of little or no circulation experience vertical variations in temp.

• Streams and rivers with currents = no temperature differences

• Shallow water = warm Deep Water = Cold• Vegetation also affects water temperature

Temperature• Seasonal Changes effect water temp. – Melting snow can lower temp.

• Temperature affects the kinds and numbers of animals of animals in a river or stream – Some species can live in a variety of temps. • Carps & catfish

– Others can only survive in certain temps• Algae, protists, trout

Currents• Currents in rivers and

streams flow in one direction– They carry load and other

substances

• Currents exert a force on organisms– Mollusks can withstand this

force with their muscular foot

– Fish move against or with the current

Velocity

• An abiotic factor• The change in distance over time • Changes with its course and depth– Decrease in slope= decrease in velocity– Widening of rivers and smoothing of its bed =

increase in velocity – Most rapid velocity of a stream occurs in the

middle of the water column

Substrate

• Substrate is the material that organisms live in, on, or around. – it is made up of organic or inorganic materials • Organic = algae and other small particles of matter• Inorganic = pebbles, rocks, silt…etc.

• Invertebrates live on or under rocky substrates• Freshwater organisms live in the substrate• Other organisms use plants as substrates

Sunlight

• The amount of light an ecosystem receives affects the ecosystem’s biodiversity– Ex. Plants depend on light for photosynthesis to

occur– Areas that have little sunlight = fewer organisms– Areas that have more sunlight = more organisms

Turbidity

• Turbidity reflects the amount of suspended matter in the water

• Several factors affect turbidity– Increase in erosion & high water volume increase

turbidity– Heavy rain or snow = increase in turbidity– Temperature affects turbidity • Ex. Water is very turbid during spring seasons

Dissolved Solids• Common elements found in

dissolved load include: magnesium, calcium, iron, sodium, …etc. – Organisms living in the stream

depend on these elements to survive • Ex. Calcium is needed to

harden fishes bones• Ex. Excess phosphorus and

nitrogen promote excessive algal growth called algal blooms

Dissolved Gases

• Streams and rivers contain dissolved gases such as carbon dioxide and oxygen

• They are both important in determining the biodiversity of the stream

Oxygen

• Oxygen enters the water from the air• The amount of oxygen that enters the water

depends on the temperature – Increase in Temp. = decrease in oxygen

• Amounts of oxygen also depends on photosynthesis & respiration – Photosynthesis adds oxygen– Respiration takes away oxygen

Oxygen Cont.

• Oxygen is also affected by currents– Slower the current = less oxygen

• Decomposition of organic material decreases oxygen levels

Carbon Dioxide

• Comes from groundwater or the Earth’s atmosphere– Decomposition and respiration increases carbon

dioxide levels

Organic Matter

• Organic Matter is used as food – Ex. Plankton, bits of leaves and wood

• Too many nutrients = decrease in oxygen levels

• Too few nutrients = organisms traveling to other parts of the stream to find food or dying because of lack of food

pH

• pH of a solution is a measure of its concentration of specific hydrogen levels

• Ranges from 0-14 – 7 = neutral (pure water)– Under 7 = acidic (rainwater / stream water =

slightly acidic ) – Higher than 7 = basic

• Acidification of stream can kill fish and other organisms

Pennsylvania Streams and Acidification

• Many rivers and stream in PA are susceptible to acidification – There are three reason for this1.PA receives some of the most acidic rainfall in the

US2.Rocks in much of the state contain minerals that

contribute to acidification 3.PA has many coal mines

•Answer #’s 6-11 of the lesson review on

pg. 19