Q

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

  • 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