Aquatic Ecosystems Review Flashcards
(23 cards)
What happens when water freezes? Why is this important for aquatic species?
It expands and floats on the top of lake water, letting aquatic species survive it in the winter.
What is a closed watershed?
A watershed with NO outlet to the ocean or adjacent watershed (higher salt content)
Why are aquatic plants so important in aquatic ecosystems?
- Provide FOOD (for some organisms)
- Provide HABITAT (to the animals and insects living there)
- Make a cycle of OXYGEN (through photosynthesis; very beneficial to organisms living in that area)
What’s an example of a keystone species for an aquatic ecosystem? Why?
Beaver - alters where water goes, so more life lives in that area
What would happen if a keystone species was removed?
Removal of such species would have a great impact on the ecosystem structure and other organisms living in the ecosystem
Name two processes that INCREASE dissolved oxygen (DO) in aquatic systems
Physically: by moving water (rapids)
Chemically: by photosynthesis
Name two processes that DECREASE the amount of dissolved oxygen (DO) in a body of water
☆ Water at higher temperatures will hold less oxygen
☆ Less DO in summer due to hypoxic conditions (summer kill)
Why is sedimentation and siltation a problem?
- Light penetration is reduced, photosynthesis restricted (alters entire food web)
- More nutrients with sedimentation (algae growth)
- Impacts fish spawning (clogs fish gills & kills them)
What causes sedimentation and siltation?
Agricultural practices, developments, construction, logging, strip mining, and overgrazing
Describe how wetlands help during flooding AND drought events
They ABSORB a significant amount of WATER and temporarily store it. The vegetation creates SHADE and reduces wind speeds, both reduce evapotranspiration (water cycle). They are valuable SOURCES OF WATER during drought
What are the BENEFITS associated with irrigation?
- Stabilizes agriculture
- Allows crop diversification
- Increases agriculture output (#)
- Increases employment (jobs)
What are the DISADVANTAGES associated with irrigation?
- Saturated soils (fills soils)
- Increased soil salinity (salt)
- Groundwater contamination
- Affects water supplies elsewhere
Eutrophication involves an increase in…
NUTRIENTS
Nutrients such as…
NITRATES
Nutrientz such as…
PHOSPHATES
Nitrates introduced mainly from…
FERTILLIZERS
Phosphates introduced mainly from…
SEWAGE / SOAPS
Nutrients causing…
ALGAE BLOOM
Algae bloom, which depletes…
LIGHT
Light, killing…
- PLANTS
- VERTEBRATES (fish)
Algae bloom, decomposed by…
BACTERIA
Bacteria, which depletes…
OXYGEN
Oxygen, killing…
- VERTEBRATES (fish)
- INVERTEBRATES (not fish)
