Introduction to Water
Resources
Why is Water Important?
Sustains life on earth
Natural Systems
Agriculture
You are 70% water! It’s the universal
solvent
Modifies the
Why Worry?
Unequal distribution
Canada has 0.5% of world’s population, 20% of
freshwater supply
China has 21% of world’s population, 7% of
freshwater supply
Overuse for irrigation
Increasing populations with no freshwater
Industry
Why Worry?
The Hydrologic Cycle
One water molecule may be used 1000s of
times…it moves around from place to place!
The cycle is powered by solar energy and
gravity
Evaporates from soil and surface
Flows through rivers and streams to rest in lakes
Where is the Water?
Abiotic Components of Aquatic
Habitats
Dissolved Oxygen Biological Oxygen
Demand
Nutrient Loads Substrate
Temperature
Abiotic: Dissolved Oxygen
Aquatic organisms need oxygen in the water
to survive
How does oxygen enter the water?
Some organisms are very sensitive to DO
levels
Temperature affects how water holds
Abiotic: Biological Oxygen
Demand
Also known as BOD
Decomposers need
oxygen
Organic pollution
Abiotic: Substrate
The composition of
matter at the bottom of a water body
Affects fish spawning,
turbidity
How can human use
Abiotic: Temperature
Pumpkinseeds can be found in
shallow, cool to moderately warm water. They are most prevalent in small lakes and ponds or
weedy bays of larger lakes. Preferring cover of some type, such as aquatic vegetation or submerged brush, they are seldom found in open water.
Pumpkinseeds are more tolerant of low oxygen levels than
bluegills are, but less tolerant of warm water.
Nutrients – Time Out
How do nutrients
enter a water body?
Natural
Man-made
Lake Succession
Water bodies will
undergo succession
A young, nutrient poor
water body is called “Oligotrophic”
Over time it undergoes
a process called “Eutrophication”
What adds nutrients?
How do the
Cultural Eutrophication
Eutrophication is a natural process
Humans speed it up by adding nutrients
Fertilizer
Grass clippings
Clearing buffer zone
Animal agriculture
Organic pollution
Types of Water Bodies
Lakes Rivers
Different speeds, widths,
depths
Wetlands
Groundwater
Wetlands
What is a wetland?
Wet or standing water for at least 2 weeks of
the year
Wetland soils
Wetland plants present
It’s not enough just to flood an area…that’s
Marsh
Dominated by grasses
and reeds
High in nutrients
High diversity of wildlife
Great blue heron,
Swamp
Dominated by trees May or may not have
standing water
Very important for
winter wildlife habitat in Northern Michigan
Cedar, hemlock,
Bog
Unique system
“Old” lake
Mined for peat
Bog mat of sphagnum moss
High nutrients, slow
decomposition
Tamarack, cranberries,
pitcher plants, sundew
Next time…
The rest of the water bodies…
