APES WATER UNIT (SO FAR…) 1)Water Cycle 2)Water Management 3)Volume Calculations 4)Watersheds 5)Properties of Water 6)Water Quality Tests (will come back to Monday) 7)Aquatic Life 8)Aquatic Life Zones

1) Water Cycle Diagram Definitions of processes

2) Water Management How our water resources are used Conservation vs. Diversion Examples of water management techniques – Pros & Cons of various strategies

3) Volume Calculations Calculating the volume of a body of water VOLUME = AREA x DEPTH or HEIGHT Conversions between km 3, m 3, and L (1000 L = 1 m 3 ) Continue to practice using ALL metric conversions!

4) Watersheds Definition Examples

What is a watershed? Watershed=an area of land where all of the water drains into the same place (a particular stream, lake, river, or wetland). – Watersheds come in all shapes and sizes. “Watersheds can be as small as a footprint or large enough to encompass all the land that drains water into rivers that drain into Chesapeake Bay”

U.S. WATERSHEDS In the continental US, there are 2,110 watersheds.

Major U.S. Drainage Basins 1. Lower Mississippi River 2. Upper Mississippi River 3. Missouri River 4. Ohio River 5. Arkansas River 6. Columbia River 7. Rio Grande River

Major World Drainage Basins

5) Properties of Water Review reading: – Water as a solvent – Liquid water – Temperature/density relationship – High “specific heat”

Properties of Water Video Review Cohesion: attraction between molecules of the same substance -In water, cohesion causes surface tension. Adhesion: attraction between molecules of different substances Surface tension: water molecules at surface form stronger bonds

Examples of Surface Tension Walking on water: Small insects such as the water strider can walk on water because their weight is not enough to penetrate the surface. Floating a needle: A carefully placed small needle can be made to float on the surface of water even though it is several times as dense as water. If the surface is agitated to break up the surface tension, then needle will quickly sink. Surface Tension and Droplets: Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer.

6) Water Quality Tests Review reading and complete assignment with it. These topics will not be on Monday’s quiz, but we will discuss them in more detail on Monday!

7) Aquatic Life Categories of organisms: Plankton – free floating organisms – Phytoplankton – plant plankton – Zooplankton – animal plankton Nekton – strong swimming consumers – Examples: sharks, turtles, fish Benthos – bottom dwellers – Examples: barnacles, oysters, crabs, urchins Decomposers – break down wastes – Examples: hagfish, bacteria

6.5) Benthic Macroinvertebrates Definition Habitat Why they are important – How they indicate water quality – The Big Three

LIVES ON THE BOTTOM SUBSTRATE CAN BEEN SEEN WITH THE NAKED EYE ANIMALS WITHOUT BACKBONES

Animals will pick places that are protected from the current! CURRENT

caddis fly larvae Mayfly larvae Stonefly larvae

Stoneflies have 2 tails Mayflies have 3 tails Caddis flies look like “worms” with legs They build cases!

8) Aquatic Life Zones Equivalent to land biomes. Each aquatic life zone is primarily determined from the water’s salinity. Most are classified as either freshwater or saltwater (marine)

Factors in Aquatic Systems General factors affecting organisms: – Temperature – Access to sunlight – Dissolved oxygen levels – Availability of Nutrients Nitrogen is limiting factors in marine areas Phosphates are limiting factors in freshwater systems

8a) Life Stages of a Lake OLIGOTROPHIC MESOTROPHIC EUTROPHIC

Oligotrophic Lake

Characteristics of Oligotrophic Lakes Younger lake Low productivity – Low amounts of nutrients – Limited plant life – Minimal bacterial growth High dissolved oxygen levels Typically deeper Cold and clear

Mesotrophic Lake

Characteristics of Mesotrophic Lakes Middle-aged lake Intermediate conditions Moderate level of productivity – Medium amount of nutrients Decreased dissolved oxygen levels and increased temperature due to more plant growth

Eutrophic Lake

Characteristics of Eutrophic Lakes Older lake High level of productivity – Nutrient-rich – Increased bacterial growth – Increased plant and algal growth – High diversity of organisms Low dissolved oxygen levels due to high numbers of organisms (what process is using up oxygen??) Typically shallow “Green” with lots of algae and poor visibility May transition to a wetland over time

Natural vs. Anthropogenic Eutrophication

8b) Physical Layers of a Lake Process of thermal stratification and turnover – Results from difference in density (weight) between warm and cold waters What property of water allows the turnover of lakes to occur?

8b) Physical Layers of a Lake Summer Stratification (3 layers): 1.Epilimnion—warmer (lighter) water, well-mixed (lots of O 2 ) 2.Metalimnion—transitional zone with rapidly changing temperature -Thermocline—within metalimnion; point of greatest water temperature change 3.Hypolimnion—colder (heavier) water, usually dark, undisturbed (low O 2 )

Seasonal Turnovers

Summer Stratification

Implications of Stratification See reading Dissolved oxygen – Phosphorus and nitrogen – Metals and other compounds – Fish Temperature

8b) Biological Layers of a Lake 1.Littoral Zone—shallow area of soil and water near shore with sunlight and nutrients – Lots of aquatic plant growth Produce oxygen Provide food and shelter to aquatic animals

8b) Biological Layers of a Lake 2. Limnetic Zone—open sunlit layer away from shore; most productive layer Habitat for: – Zooplankton (microscopic animals) – Phytoplankton (algae), which produce oxygen and serve as basis of lake’s food chain – Fish!

8b) Biological Layers of a Lake 3. Profundal Zone—no sunlight, low oxygen, cold water (only found in deep lakes) Dominated by oxygen consumption, not production Lots of bacterial and fungal growth

8b) Biological Layers of a Lake 4. Benthic Zone—nourished by dead matter from other zones; bottom of the lake Dominated by oxygen consumption, not production Lots of bacterial and fungal growth and decomposition