SC.912.L17.2 You need to know that different types of organisms exist within aquatic ecosystems due to chemistry, geography, light, depth, salinity, and/or temperature.
The main aquatic ecosystems are lakes, rivers, wetlands, estuaries and the ocean.
The main aquatic ecosystems are lakes, rivers, wetlands, estuaries and the ocean.
What are the major abiotic factors that affect life in aquatic ecosystems?
1. Water depth, and the light (photic zone or aphotic zone) and pressure resulting from it
Notice in the picture below how light can penetrate to about 200 meters only. This is the photic zone, where you can find most photosynthetic autotrophs:
- The photic zone is the sunlit upper layer of water where photosynthesis can occur.
- The aphotic zone is the dark lower layer where photosynthesis cannot occur.
- The benthic zone is found on the bottoms of lakes, streams, and oceans. The organisms that live on the floor of a body of water are called benthos.
Notice in the picture below how light can penetrate to about 200 meters only. This is the photic zone, where you can find most photosynthetic autotrophs:
- Phytoplankton are microscopic organisms able to carry out photosynthesis, supporting most life in the ocean through the food chain.
2. Temperature, and flow rate also determine which organisms can live in an aquatic ecosystem.
4. Concentration of dissolved nutrients (phosphorus, nitrogen, etc.)
- Cold water can hold more dissolved oxygen than warmer water, so dissolved oxygen levels are related to water temperature.
4. Concentration of dissolved nutrients (phosphorus, nitrogen, etc.)
Freshwater & Marine Ecosystems
Aquatic ecosystems are classified based on water salinity (salt concentration):
Freshwater Ecosystems
Low salinity (< 0.05 % salt) Freshwater ecosystems include lakes, ponds, rivers, streams, springs, bogs, and wetlands.
These can be divided based in three groups based on the flow rate of their water:
|
Marine Ecosystems
Higher Salinity Marine Ecosystems are divided into two categories: Ocean and Estuary
|
The water found in wetlands can be saltwater, freshwater, or brackish.
The main wetland types include swamps, marshes, and bogs.
The main wetland types include swamps, marshes, and bogs.
Ecological Succession
Ecological succession is the progressive series of changes in the composition of an ecosystem after a disturbance. These changes can happens in both terrestrial and aquatic ecosystems where one community of organisms will replace another over time.