Ecology Lesson 8: Major Aquatic

Ecosystems

✓ Two divisions: Freshwater (below 1% salt) and Marine (about 3% salt)

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A) Freshwater Ecosystems1) Watersheds

✓ Area of land through which all water drains into a single river or lake

✓ Water always flows downhill

✓ If a pollutant enters a watershed, areas downstream also become polluted

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A) Freshwater Ecosystems2) Moving Bodies Of Water✓ Ex. Rivers and

streams✓ Continually flushed

from upstream

http://www.utdallas.edu/geosciences/remsens/Nile/Nile-in-USA.gif

Bolton strid✓ A portion of the river wharfe in Yorkshire✓ The river Wharfe is quite wide, yet the Strid, being much

narrower, still holds all of the river’s water✓ Nobody knows the depth of the Strid✓ It has a very powerful undercurrent, and a lot of

underwater caves and caverns✓ Nobody who has fallen into the Strid has ever survived

http://www.stuartbriggs.co.uk/wp-content/uploads/2012/04/Bolton-abbey-strid-6.jpg

http://www.stuartbriggs.co.uk/wp-content/uploads/2012/04/Bolton-abbey-strid-6.jpg

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A) Freshwater Ecosystems2) Nearly Stationary Bodies of Water✓ Ex. Lakes, ponds

• Oligotrophic• Low in nutrients• Photosynthetic organisms have trouble getting enough

nutrients to grow, even with a lot of light

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A) Freshwater Ecosystems2) Nearly Stationary Bodies of Water✓ Ex. Lakes, ponds

• Wetlands• Ex. bogs, marshes• Large area of shallow water or saturated soil• Nutrient rich, large population of amphibians, insects,

birds• Filter water

https://www.ecojustice.ca/wp-content/uploads/2014/12/shutterstock_108429443-wetlands.jpg

B) Marine Ecosystems✓ Over 70% of Earth’s surface water is in the ocean✓ Important to biogeochemical cycles

• Most precipitation comes from oceans✓ Marine algae play a critical role in absorbing CO2 and

producing O2

http://web.tuat.ac.jp/~biomol/en/research/marine-biotechnology/images/01/01.jpg

B) Marine Ecosystems✓ Much of ocean supports very little life

• Nutrient poor open ocean• Hard to support

photosynthesizing organisms• Deep ocean with little light,

photosynthesis impossible✓ Shallow water near shore is nutrient

rich with much life

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B) Marine Ecosystems✓ Thalassophobia : the fear of the sea✓ Just how deep does it go?

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Leopard seal under ice

B) Marine Ecosystems✓ Examples of Marine Ecosystems:2) Estuaries

• Partially enclosed body of water• Fresh and salt-water mix• High in nutrients, support shellfish• Gulf of St. Lawrence is the largest

in the world http://emp.baydeltalive.com/assets/5ffd2763a1b5d1a3078c4bd991651244/image/jpeg/1*GDxNfLVemmxKZWffgGnH9A.jpeg

https://eoimages.gsfc.nasa.gov/images/imagerecords/92000/92266/guineabissau_oli_2018137.jpg

B) Marine Ecosystems✓ Examples of Marine Ecosystems:2) Mangroves

• Tropical and semitropical sandy shorelines• Specialized trees live at or below the water's edge• Roots grow into water• Reduce coastline erosion• Create habitat for

marine organisms

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B) Marine Ecosystems✓ Examples of Marine Ecosystems:2) Intertidal zone• Coastal area between high and

low tide lines• Exists as aquatic and terrestrial

ecosystem• May significantly change water

level 4x/day• Seaweeds, barnacles, sea stars,

sea urchins• Highest tides are in Bay of Fundy• Difference of 17m between high

and low tide

https://hollyreichert.files.wordpress.com/2014/02/bay_of_fundy.jpg

Bay of Fundy: Difference between high and low tide