1. Aquatic Ecosystems

2. Aquatic Ecosystems ~71% of Earth’s surface covered by salt water
<1% fresh water
3 Major Types
Marine (salt water)
Freshwater (rivers, lakes, ponds, swamps, most marshes)
Estuaries (coastal wetlands where fresh and salt water mix – brackish water)

3. Who lives there? a. b. c. d. e. Phytoplankton (microscopic plants)
- algae and bacteria
- producers (base of food chain)
- 90% of all O2 in water comes from them
Zooplankton (microscopic animals & larvae)
- protozoa
Nekton (strong swimming consumers)
- fish, turtles, whales, etc.
Benthos (bottom dwellers)
- barnacles, oysters, worms, lobsters, crabs
Decomposers (mostly bacteria)

4. Aquatic Zones Surface Middle Bottom - Euphotic Zone (“good light”)
- Bathyal/aphotic (twilight/no light)
- Abyss/benthic zone (complete darkness)

5. Temperature and salinity (________________) change _____________
Estuary
What are they?
Temperature and salinity (________________) change _____________
**_______________water movement stirs up the nutrient rich ____________________ which makes it readily available for ________________.
Coastal wetlands – mangrove swamps & salt marshes
amount of salt
daily!
Tides
Seasonal variation in fresh water flow
Spring higher – why?
Unpredictable changes due to weather
Heavy rain = more fresh
Hurricane = more salt
Constant
silt/mud
producers

6. Estuary Cont. One of the most productive ecosystems on earth! Why?
~75% of commercially valuable species spend some part of their life cycle in estuaries (great breeding grounds/nurseries).
Because of food richness, great place for wildlife (birds, butterflies, sport fish, shellfish, other invertebrates)
Speedy Decomposition (some communities use salt marshes to break down organic waste instead of landfills)

7. Benefits & Problems of Estuaries Benefits: Problems:
CO2 absorption & nutrient cycling
Reduce storm impact
Economic
Coastal habitat for humans
Source of some pharmaceuticals
Recreation (bird watching)
Being filled in for real estate developments, marinas, golf courses, rice fields, shrimp farms
Water levels rising much faster than species can adapt (global warming)
Major decrease in fish harvest
Increase in storm damage

8. Freshwater Types of freshwater: a) Standing bodies (lentic)
Lakes, ponds, inland wetlands
b) Flowing (lotic)
Rivers, streams, creeks

9. Inland wetlands Characteristics:
Clean water  approx. $1.6 billion worth a year!
Control flooding  approx. $8-31 billion worth a year!
Teeming with life (high biodiversity)
Are beautiful
Provide recreation (boating, hiking, fishing)
Enrich our culture

10. Lakes Different types: 1. Oligotrophic – “few nourish” - CLEAR WATER
- “new” lakes have rocky bottoms
- less nutrients, less O2, few plants/animals
2. Eutrophic – “well nourish”
- MURKY WATER
- older lakes with silt/mud bottom
- more nutrients, more O2, lots of plants/animals

11. Rivers/ Streams Characteristics: Moving water (Lotic = flow)
Get rain water from run-off
(water that is not absorbed by the ground)
Carry and deposit sediment downstream
O2 varies in different zones of a river
Higher temp = less O2
Carry pollutants downstream also
Poison estuaries

12. Flood control levees and dikes also have a negative impact
Human use of Rivers
60% of worlds 237 large rivers are affected by dams, canals, and other diversions (irrigation)
Alters/destroys habitats along rivers
Reduces water flow to deltas/estuaries
Flood control levees and dikes also have a negative impact
Disconnect river from flood plains
Eliminate breeding grounds

13. Marine (oceans & seas) Longer, more complex food chains and webs
Zones affected by four factors
- temperature
- access to sunlight
- nutrient availability
- dissolved oxygen*
*affected by
Temperature
Number of producers (which add O2)
Consumers & aerobic decomposers (which use O2)
Deep ocean circulation
Deeper water = less O2
~250,000 known marine plant and animal species YET less than 5% of oceans have been explored!! What else could be out there??

14. Marine
(oceans & seas)
What do plants & algae (phytoplankton) need to grow?
Water, Light, Minerals
Where is 90% of ocean life found? Why?
In the Neritic Zone – plenty of water, light & minerals (all other zones lack one or more)
Why isn’t it hard to “kill” oceans?
Most people spend their time in the Neritic zone (fishing, drilling for oil, boating, etc)