APES 1.3 Aquatic Biomes

Freshwater Aquatic Biomes

• Note: The broadest section of ecology is the biome
  • These listed biomes encompass ecosystems, communities, populations, and organisms within them.

Abiotic Conditions in Aquatic Biomes

• These factors affect both freshwater and saltwater biomes
• Depth
  • Pressure changes according to depth
  • Also affects light
• Light
  • Different organisms live in various degrees of light
• Temperature
  • Affected by depth
• Velocity
• Salinity
  • There is still some dissolved salt (and other solids) in freshwater
• Oxygen
  • Beneficial for plants and animals
• Nutrients
  • Nitrates and phosphates
• Suspended matter
• Botton substrate
  • Sandy, rocky, muddy, etc.

Freshwater Stratification

• The littoral zone is the edge of a pond or lake
  • There is more plant life and nutrients here
• The benthic zone is the bottom of a pond/lake
  • Not always deep
  • Many nutrients
• The limnetic zone is the layer below the littoral zone
• The photic zone is below the limnetic zone
  • Less light reaches this layer, therefore less plant life exists in this zone
• The profundal zone is just above the pond/lake floor

Streams & Rivers

• Not much distinction between these
• Streams are typically smaller, run a little faster, and have a change in elevation
  • Streams empty into rivers or other bodies of water
• Rivers have more volume and empty into a larger body of water

Ponds & Lakes

• Once again, there is no specific point at which a pond becomes a lake or a lake becomes a pond

Wetlands

• These biomes typically have shallow waters with a profusion of plant life
• Due to the low depth and high concentration of nutrients, this is a very productive biome class
• Have trees and larger flora

Marshes

• Alongside swamps, this biome is the most productive
• Have more grasses, very few trees

Bogs

• Another kind of wetland, although not as productive as marshes or swamps

Swamps

• Alongside marshes, this biome is the most productive

Marine Aquatic Biomes

Intertidal

• Between tides
• As the tides come and go, this area transitions from being submerged to above the surface
• Extreme conditions for the organisms living here

Coral Reefs

• Warm, shallow water
• Has extremely high biodiversity and productivity
• Alongside estuaries, coral reefs are the most productive

Open Ocean

• Low productivity due to the low density of organisms in this region

Saltwater Marsh

• Like their freshwater counterparts, marshes are comprised mainly of grasses
• Along coasts, fed by the ocean

Saltwater Swamp

• Swamps have both grasses and trees
• Also fed by the ocean along coasts
• Mangrove swamps are stabilizing and provide valuable habitats

Estuaries

• Alongside coral reefs, estuaries are the most productive

Marine Stratification

• By the coast in the intertidal zone
  • There are many nutrients here that come from the coast
  • Sunlight also means this area can be productive
  • Plants are able to root here
  • These combined factors make it a production region
• The ocean floor, whether right by the coast or at the deepest point, is the benthic zone
  • As things die and sink, their nutrients are deposited on the ocean floor
• Around coral reefs and into the open ocean is the pelagic zone
  • The vast majority of the ocean
  • Phytoplankton and floating plants inhabit this space
• Going deeper is the photic zone
  • Less light reaches here
• At the deepest points of the ocean is the aphotic zone
  • Light no longer reaches and no photosynthesis is taking place
  • Instead, chemosynthesis is what plants use
  • Hydrothermal vents also provide this region with live-giving chemicals and heat

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• Depth, temperature, and salinity can cause marine ecosystems to vary
• Nitrogen and phosphorus, important nutrients, are dense along the coast
  • This can be a result of runoff into rivers and eventually estuaries
• Upwellings bring nutrients from the depth of the ocean to the surface, boosting productivity
• Secondary productivity can be high in cold water where there is lots of dissolved oxygen

Human Impact

• The human impact on water systems will be discussed more throughout the course as it pertains to those topics
• We deplete natural sources of freshwater primarily through agriculture and drinking water
• Runoff containing harmful chemicals or objects has to flow somewhere, that being a body of water
  • The organisms in this body of water are then affected by what is being dumped into their home
• Although we will never run out of water, we are turning freshwater into unusable states quicker than it returns
  • This means that we have more contaminated or salty water that we cannot use, not less water entirely
  • Saltwater can be converted into freshwater through desalinization, but this is an expensive and long process
• The natural flow of water is also disrupted by human development
• The impact of water in the form of floods and storms can be more severe because of human activities
  • Global warming means more water evaporates, creating bigger and more intense storms
  • The removal of trees creates smooth ground that water can run over quickly
  • This means that settlements in basins or valleys may be in danger of particularly intense floods and mudslides

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