Transcript Stream Ecology PPT

STREAM ECOLOGY
By
Maggie Bell-McKinnon, biologist
Washington Department of Ecology
Email: [email protected]
Why Should We Care About
Streams?
Wildlife drink water out of streams.
We like to fish and swim in streams.
Fish and other aquatic animals need good
water quality for their homes and for their
food.
Stream Structure
Pool
Riffle
Run or Glide
Woody Debris
Stream Discharge - is the total amount (volume) of water
flowing in the stream.
It is important to know how much water is flowing in a stream because it
affects many things about a stream, for example:
* Salmon need slower flowing areas of a stream to lay their eggs.
* Other aquatic animals (like macroinvertebrates) and algae can’t live in a
stream that has water moving too fast.
Stream
Discharge –
how to
measure
Stream discharge is
measured by multiplying
the area of the stream
by its velocity.
Stream discharge is
measured in cubic feet
per second (cfs).
A Pretend Stream
Stream Discharge =
Area (A) x Velocity (V)
Depth
Area (A) = Depth x
Width
Width
A Real Stream
1
3
10
4
5
6
7
8
9
Stream Area = the area of box 1+box 2+box 3+
box 4+box 5+box 6+box 7+box 8+box 9+box 10
Embeddedness
• Embeddedness refers to how much the rocks (gravel,
cobble, and boulders) are surrounded by, covered, or
sunken into the silt, sand, or mud of the stream
bottom.
Embeddedness
• Generally, as rocks become embedded, fewer living
spaces are available to macroinvertebrates and fish
for shelter, spawning and egg incubation.
Riparian Zone
• The area between the stream and the land
away from the stream.
• Riparian comes from the Latin word, ripa,
which means river bank.
• Because the riparian zone can flood, the
vegetation that grows there must be able to
tolerate having its roots get wet occasionally.
Riparian zones are important to a
stream because:
• They filter pollutants and prevent them from
entering the stream
Riparian zones are important to a stream
because:
• They prevent the streambank from eroding or
wearing away.
Riparian zones are important to a stream
because:
• They supply shade to the stream
Riparian zones are important to a stream
because:
• They provide shelter and food for animals that live in
or near the stream
Examples of Riparian Vegetation
• In a healthy riparian zone, there are
typically three layers of vegetation
that occur:
 Tall trees
 Shorter trees and shrubs
 Flowering plants and ferns
Douglas fir - Pseudotsuga menziesii
Black cottonwood - Populus trichocarpa
Vine maple - Acer circinatum
Devil’s club - Oplopanax horridus
Slough sedge - Carex obnupta
Food Web
Food Web
The Sun
Food Web
Food Web
Food Web
Food Web
Food Web
Black Fly Larvae
Black Fly Larvae on a Rock
Food Web
Caddis Fly Larvae
Food Web
Caddis Fly
Larvae
Food Web
Water Louse
Food Web
Water Strider
Food Web
Food Web
Food Web
Water Quality Parameters
Dissolved Oxygen
• Oxygen in the water comes from the air/ atmosphere and the
aquatic plants (through photosynthesis).
Water Quality Parameters
Dissolved Oxygen
• Aquatic organisms – plants and animals – need to breathe
oxygen, just like people.
Water Quality Parameters
Dissolved Oxygen
• Dissolved oxygen levels change throughout the day based on
water temperature and photosynthetic activity.
200
14
150
12
10
100
8
50
6
4
8/22/03 15:00
0
8/23/03 6:00
8/23/03 21:00
Temp
8/24/03 12:00
pH
DO
8/25/03 3:00
Winklers
8/25/03 18:00
SpC
8/26/03 9:00
SpC (us/cm)
pH (pH units), DO (mg/L), Temp (C)
16
Water Quality Parameters
Temperature
• Stream temperature controls how plants and animals live.
• Warm water contains less dissolved oxygen than cool
water.
Water Quality Parameters
Temperature
• Young salmon need temperatures of around 9°Centigrade;
adult salmon need water that’s 12°Centigrade.
Water Quality Parameters
pH
• A pH measurement tells us
whether a stream is acidic
or alkaline.
• pH values range from 0 to
14; values from 0 to 7 are
considered acidic, 7 is
neutral and above 7 is
considered alkaline or basic.
• The pH of a stream is
determined by what kind of
rocks the stream flows over
and sometimes by humans.
Representative pH values
Substance
Stomach Acid
pH
1.5 – 2.0
Cola
2.5
Vinegar
2.9
Orange Juice
3.5
Coffee
5.0
Healthy Skin
5.0
Urine
6.0
Pure Water
7.0
Health Human Saliva
6.5 - 7.4
Blood
7.3 – 7.5
Seawater
7.7 – 8.3
Baking Soda
Hand Soap
Bleach
8.4
9.0 – 10.0
12.5
Water Quality Parameters
Nutrients
• Nitrate is one of the nutrients
which is used as food by plants .
• Nitrates can come from
decomposing plants and
animals, human sewage,
fertilizers and stormwater runoff.
• Excessive amounts of nitrates
can cause too much algae
growth. This lowers the
dissolved oxygen levels when
the algae die and decompose.
Water Quality Parameters
Turbidity
• Turbidity is a measurement of
how clear or cloudy the water
looks. Water becomes cloudy
when it contains solid
material.
• This solid material can be a
combination of sediment,
algae, aquatic animals anything that can be
suspended in the water.
• Turbidity can affect the ability
of fish to live by clogging their
gills.
Water Quality Parameters
Bacteria
• Not all bacteria are harmful
to humans but some are, like
fecal coliform. These “bad”
bacteria produce toxins
which make people sick.
• It is important to protect
humans from these harmful
bacteria which could occur
both in our drinking water as
well as in the lakes and
rivers where people play and
have fun.
What can you do to help a
stream?