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