FRESH WATER

The Great LakesThanks 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

Great Lakes song by Pat Dailey…

Cuyahoga River FireNovember 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

Tri-C Eastern Campus BIO 2806 - Environmental Science for Educators: Promoting Watershed Stewardship July 2007

BROWN BULLHEAD (Ameiurus nebulosus)

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

FRESH WATER

Part Two

STREAM ECOSYSTEMS

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

waterLabel these as biotic or abiotic

features…

Stream Morphology

• Size and shape of the stream

• Described by the:– Longitudinal

slope– Dimensions of

cross section– Meander pattern

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:DetritusMuck

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

Tri-C Eastern Campus BIO 2806 - Environmental Science for Educators: Promoting Watershed Stewardship July 2007

Sensitive BenthosStonefliesWater Penny BeetlesMayfliesDobsonfliesAlderfliesSnipefliesMusselsRiffle Beetles

Moderately Tolerant BenthosDamselfliesDragonfliesCrayfishAmphipodsBlackfliesCaddisfliesIsopodsCraneflies

Pollution Tolerant BenthosMidgefliesWormsLeechesPouch Snails

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?