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FRESH WATER. The Great Lakes. Thanks to Michael W. Rowan, Ph.D. for most of this presentation…. Part One. The Great Lakes. Began to form ~500,000 years ago Took present shape ~10,000 years ago Watershed area = 196,000 sq. miles 34 million people (27.5 million U.S., 6.4 million Canada)
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The Great Lakes Thanks to Michael W. Rowan, Ph.D. for most of this presentation… Part One
The Great Lakes • Began to form ~500,000 years ago • Took present shape ~10,000 years ago • Watershed area = 196,000 sq. miles • 34 million people (27.5 million U.S., 6.4 million Canada) • Water surface area = 94,700 sq. miles • U.S. Great Lakes shoreline > U.S. east coast shoreline
Unique ecosystem, and unique resources • Largest surface freshwater system on earth • Contains 84% of North America’s surface freshwater • Contains 21% of the world’s surface freshwater – know this!
Great Lakes Environmental Issues • Invasive species • Nonpoint source pollution • Urban sprawl • Mercury in fish • Contaminated sediments (dredging?) • Nutrient loading • Water diversion • Climate change • Endocrine disrupters • Atmospheric deposition
Erie – Our Great Lake • Smallest in volume, depth, retention time, watershed area • Largest human population • Warmest, most nutrient-rich, and most productive • Fishery is more productive than the fisheries of other four Great Lakes combined • Largest percentage of land in agriculture
Cuyahoga River Fire November 1952 Dumps into Lake Erie
Brown Bullhead (Ameiurus nebulosus) • Ubiquitous benthic catfish distributed throughout the great lakes • Vulnerable to many hydrophobic contaminants (PAHs – polycyclic aromatic hydrocarbons ) • Sediment PAHs linked to high tumor rates and changes in blood variables
BROWN BULLHEAD (Ameiurus nebulosus) Tri-C Eastern Campus BIO 2806 - Environmental Science for Educators: Promoting Watershed Stewardship July 2007
Tri-C Eastern Campus BIO 2806 - Environmental Science for Educators: Promoting Watershed Stewardship July 2008
Something Fishy • 34 species of Lake Erie Fish are rare, threatened, or endangered • Blue pike – extinct • Lake sturgeon, brook trout, lake trout, . . . • Fish CONSUMPTION ADVISORIES to mercury and PCBs – polychlorinated biphenyls
Coe Lake Lesson “A DROP IN THE BUCKET” Why we must care for our fresh water… Tri-C Eastern Campus BIO 2806 - Environmental Science for Educators: Promoting Watershed Stewardship July 2007
What is a stream? • A flowing body of water confined within a bed and banks • Does a stream really end at the edge of the water? • What do you recall about riparian zones?
Dynamic Nature of Streams • Streams are constantly changing: • Upstream water flows downstream • Amount of water fluctuates • Stream bed changes over time • Anything that affects a watershed will eventually impact the stream
Important Aspects of aStream Ecosystem • Stream morphology • Parts of the stream • Substrate • Riparian buffer zone • Biological communities • Physical & chemical properties of water Label these as biotic or abiotic features…
Size and shape of the stream Described by the: Longitudinal slope Dimensions of cross section Meander pattern Stream Morphology
Parts of the Stream • Riffle – section where water is more shallow and the flow is turbulent What do riffles provide for aquatic organisms?
Parts of the Stream • Run/Glide – section with smooth flow
Parts of the Stream • Pool – section where water is deeper with a slower flow
Substrate • Composition of the stream bottom is very important • Provides important habitat for aquatic life • Organisms show preferences for various substrates • The higher the substrate diversity, the more habitats available
Types of Substrate • Inorganic substrate: Bedrock > Boulder > Cobble > Gravel > Pebble > Sand > Silt > Hardpan • Organic substrate: Detritus Muck
Large Woody Debris • Refers to all wood located within the stream bed • Key aspect of a healthy stream: • Provides important habitat (esp. for fish) • Impacts flow, creating pools • Stabilize banks & minimize erosion • In general, it should not be removed from a stream
Leaf Packs • Accumulation of leaves in a stream • Provide input of energy • Organic molecules leach out, creating a nutrient rich “tea” • Biological communities colonize leaves • Smaller pieces of processed leaves provide nutrients downstream
What is a riparian buffer zone? Area of vegetation along the banks of a river or stream “Green Zone” Can be forest, wetlands, etc.
Importance of Riparian Buffer Zones Slow down the movement of water, minimizing flooding & erosion Stabilize banks, reducing streambank erosion Act as filters, reducing non-point source pollution
Importance of Riparian Buffer Zones Provide important habitat to terrestrial & aquatic species Canopy provides shade to help regulate water temperature Leaves of trees are an important food source for many macroinvertebrates
Impacts on Riparian Buffer Zones Over half in US have been destroyed Most have been degraded or removed due to agriculture or development
Biological Communitiesof Streams Many streams rely on input of riparian vegetation as base of food web In-stream producers may include: Algae Aquatic plants Consumers include a variety of fish and macroinvertebrates
Time for a Life Science Lesson to mix things up a bit – “Riparian Retreat”
What are aquatic macroinvertebrates? Invertebrates that live in an aquatic ecosystem and are visible with the naked eye Also referred to as benthos EPA – Benthic Macroinvertebrates in our Waters
Sensitive Benthos Stoneflies Water Penny Beetles Mayflies Dobsonflies Alderflies Snipeflies Mussels Riffle Beetles Moderately Tolerant Benthos Damselflies Dragonflies Crayfish Amphipods Blackflies Caddisflies Isopods Craneflies Pollution Tolerant Benthos Midgeflies Worms Leeches Pouch Snails Tri-C Eastern Campus BIO 2806 - Environmental Science for Educators: Promoting Watershed Stewardship July 2007
Aquatic Invertebrate Life Cycle Complete Metamorphosis Incomplete Metamorphosis
Identifying Aquatic Macroinvertebrates MACROINVERTEBRATE ACTIVITY Key to Macroinvert. Life in the River Key to the Orders of Benthic Insects Aquatic Macroinvertebrate Key EEK! – Water Critter Key
Functional Feeding Groups of Aquatic Macroinvertebrates Macroinverts. can also be classified based on their role in an ecosystem Shredders Grazers/Scrapers Collectors (filterers, miners & browsers) Piercers Predators
Fish Communities in Streams Types of fish vary based on : stream temp., flow, dissolved oxygen types of aquatic invertebrates present or other food sources Primary Headwater Organisms Fish Identification & Histories Fishes of Ohio’s State Scenic Rivers
Biological Communitiesof Streams Decomposers have a very important role! Fungi and bacteria break down leaves Consumer that feed on the leaves get nutrition from the decomposers Decomposers also break down dead organisms, recycling the nutrients
WHAT DO YOU NEED TO KNOW? • Great Lakes facts – slides 3-5 • Environmental issues of Great Lakes • What are PCB’s and PAH’s? • Specific characteristics of Lake Erie • What are important aspects of stream ecosystems? • Why are riparian zones essential? • What do aquatic macroinvertebrates tell us? • What factors determine the types of fish that are found in streams? • Why are decomposers important in streams?