Abiotic Factors

• Life in water depends on:

  • Temperature

  • Sunlight penetration

    • For photosynthesis

      • Affected by depth and turbidity of water

  • Amount of dissolved oxygen

  • Salinity

  • pH

  • Nutrient availability

    • Shallow waters have lots of nutrients

Organisms and Aquatic Life Zones

• Plankton: free floating, weakly swimmers

  • Phytoplankton

    • Autotroph

  • Zooplankton

    • Heterotroph

  • Ultraplankton

    • Autotrophic bacteria

• Nekton: free-swimming

• Benthos: bottom dwellers

• Decomposers

Oceans

• High biodiversity

• 2 zones

  • Coastal

    • Warm and nutrient rich area

    • 90% of all marine species

  • Open sea

    • Cooler

    • Fewer species

  • Ocean bottom

Types of Estuaries

• Mangrove Forests

  • Swamps and mangrove forests are dominated by trees, while salt marshes are dominated by grasses

• Coastal Zone

  • Enclosed body of water formed where seawater mixes with freshwater from rivers and streams

  • Called “marine nurseries”

    • Habitats for many juvenile fish species

  • Salt tolerant trees that reduce erosion

Estuaries

• Extremely fertile because the river brings lots of sediments

• Stressful conditions and abundant nutrients result in low species diversity, but great abundance of the species present

Intertidal Zone

• The area between high tides and low tides

• Organisms have some adaptation to withstand wave activity

• Rocky shores

  • Areas pounded by waves

  • Varieties of algae, snails, crabs, etc.

• Sandy shores

  • No plants or algae

  • Insects, shorebirds, crabs, and worms

Barrier Islands

• Long, narrow, offshore deposits of sand or sediments that parallel to the coastline

• Aid in protecting mainland, estuaries, and coastal wetlands

• Found along eastern coasts and Gulf of Mexico

• Lots of development

Coral Reefs

• Structure that is formed by coral polyps

• Typically found in warm coastal waters of the tropics and subtropics

• Coral polyps form a hard, stony, exoskeleton made of limestone

Coral Reefs Climate

• Usually found near land in shallow, warm, salty water

Importance of Coral Reefs

• High biodiversity

  • Considered the most diverse and productive

• Grow very slowly

• Complex relationships that exist between many organisms

Damage to Coral Reefs

• Very sensitive to environment changes

• Natural disturbances

  • Hurricanes or typhoons, and predation by a large starfish

• Anthropogenic disturbances

  • Sediment runoff

  • Pollution

  • Reef fishing

  • Coral bleaching

• 300+ reefs are protected as reserves or parks

Freshwater Life Zone

• Cover less than 1% of Earth’s surface

• Low salt concentration

  • Less than 1%

• Types

  • Flowing

    • Streams

    • Rivers

  • Standing

    • Ponds

    • Lakes

    • Inland wetlands

Lake and Pond Zones

• Divided into four zones determined by depth and distance from the shoreline

  • Littoral zone

    • Top layer

    • Shallow

    • Near shore

    • High biodiversity

      • Aquatic plants

      • Grazing snails

      • Clams

      • Insects

      • Crustaceans

      • Fish

      • Amphibians

  • Limnetic zone

    • Sunlit water

    • Surface layer

    • Main photosynthetic layer

      • Plankton

      • Fish

  • Profundal zone

    • Cools and dark layer

    • Low oxygen

  • Benthic zone

    • Bottom layer

    • Decomposers and detritivores

Lake Classification

• Oligotrophic

  • Newly formed

  • Poorly nourished

  • Little sediment

  • Deep water

  • Clear water color

  • Low net primary production

• Eutrophic

  • Excess supply of nutrients

    • Phosphates and nitrates

  • Shallow water

  • Murky water color

  • High net production

Characteristics of Rivers and Streams

• Bodies of flowing water moving in one direction

• Found everywhere

  • Get their start at headwater, which may be springs, snowmelt or even lakes

• Travel all the way to their mouths

  • Usually another water channel or the ocean

Freshwater Inland Wetlands

• Lands that are covered with fresh water year round or seasonally and located away from coastal areas

• High biodiversity

• Vary in size

• Important in filtering pollutants, absorbing excess water from storms, and providing habitats

Impacts of Human Activities on Freshwater Systems

• Dams, cities, farmlands, and filled-in wetlands alter and degrade freshwater habitats

  • Dams, diversions, and canals have fragmented about 40% of the world’s 237 large rivers

  • Flood control levees and dikes alter and destroy aquatic habitats

  • Cities and farmlands add pollutants and excess plant nutrients to streams and rivers

  • Many inland wetlands have been drained or filled for agriculture or urban development