Chapter 7 Flashcards
What is an aquatic life zone?
Aquatic biome
What is salinity?
Amounts of various salts such as sodium chloride (NaCI) dissolved in a given volume of water
What are the 2 types of aquatic life zones?
Saltwater/marine and freshwater
Saltwater and freshwater systems cover what % of Earth’s surface?
71%
Saltwater and freshwater systems contain what 4 major types of organisms?
- Plankton
- Nekton
- Benthos
- Decomposers
Why is it difficult to count and manage populations in aquatic systems?
There is less pronounced and fixed physical boundaries than terrestrial eco systems.
Are food chains/webs more complex in aquatic systems than terrestrial biomes?
Yes
What is the euphotic zone?
Upper layer, where sunlight can penetrate and photosynthesis can happen
- Dissolved O2 levels are higher
- Dissolved CO2 levels are lower
What is the mesopelagic zone?
Very little sunlight, 200m-1,000m below surface. Known as the “twilight zone” because sun can still be detected
Oceans have which 2 zones?
Coastal zone and open sea
What is the coastal zone?
Warm, nutrient-rich shallow water, and contains 90% of all marine species
What is an estuary?
Partially enclosed area of coastal water where sea water mixes with freshwater and nutrients from rivers/streams
What are coastal wetlands?
Land areas covered with water all or part of the year
What is the dominant organism in mangrove forest swamps?
Trees that can grow in salt water - extensive roots above the water where they can get oxygen
What is the intertidal zone?
Area of shoreline between low and high tide (not easy to live because of waves and high tides, changing levels of salinity)
Why are coral reefs vulnerable?
They grow slowly and are disrupted easily
What conditions do coral reefs thrive in?
Clear, warm, shallow water with constant high salinity, temperatures of 18-30 degrees Celsius.
Bleaching triggered by an increase of just 1 degree Celsius.
What are the biggest threats to coral reefs?
Sediment runoff and other human activities
What is the freshwater life zone?
Water with dissolved salt content below 1%
What are lakes?
Large, natural freshwater bodies
What is an epilimnion?
A layer of warm, well-oxygenated water
What is a hypolimnion?
A layer with lower concentration of oxygen because it’s isolated from the surface
What is fall turnover?
Surface water sinks to the bottom and brings nutrients up, and mixes oxygen down from the surface
What is an oligotrophic lake?
New lake with generally small supply of nutrients, and deep with steep banks
