The Living World

  • Topics:
    • Ecosystems
    • Terrestrial Biomes
    • Reminder to retrieve the chart from the last class.

The Living World - Aquatic Biomes

Review of Biomes

  • Definition of a Biome:
    • A biome is a region of the globe that shares similar characteristics.
    • On Land:
    • Temperature
    • Precipitation
    • Plant and animal communities
    • In Water:
    • Light availability
    • Salinity (Saltiness)
    • Depth
    • Temperature
    • Currents and tides

Major Aquatic Biomes

Freshwater Biomes: Streams and Rivers

  • Source Zone:
    • Characteristics:
    • Shallow, cold, clear, fast-flowing stream
    • High DO (Dissolved Oxygen)
    • Low nutrient levels = low NPP (Net Primary Productivity)
  • Transition Zone:
    • Characteristics:
    • Wider stream bed
    • Warmer water, slower stream velocity
    • Lower DO
    • More NPP
  • Floodplain Zone:
    • Characteristics:
    • Wide stream bed
    • Warmest temperature
    • High turbidity
    • Least DO
    • Highest NPP
  • Lotic System:
    • Divided into three zones:
    • Falls within a watershed:
    • Area of land where all water drains into a specific river, stream, or lake
  • Importance of Freshwater Biomes:
    • Vital resources for drinking water!

Freshwater Biomes: Ponds and Lakes

  • Littoral Zone:
    • Characteristics:
    • Lots of light (light reaches the bottom)
    • High NPP (Net Primary Productivity)
    • Lots of biodiversity
    • Presence of rooted plants
  • Limnetic Zone:
    • Characteristics:
    • Lots of light
    • Low nutrient levels = low NPP
    • Presence of free-floating plants (algae)
  • Profundal Zone (not in ponds):
    • Characteristics:
    • Low light
    • Low NPP
  • Benthic Zone:
    • Characteristics:
    • No light
    • Lots of nutrients but low DO
    • Low NPP
    • Home to decomposers
    • Refers to the bottom sediment layer of a body of water
  • Lentic Systems:
    • Oligotrophic:
    • Characteristics:
      • Deep, steep-sided banks
      • Fed by ice and snowmelt
      • Low nutrients = low NPP
    • Eutrophic:
    • Characteristics:
      • Shallow, high turbidity
      • High nutrients = higher NPP

Freshwater Biomes: Inland Wetlands

  • Includes:
    • Marshes
    • Swamps
    • Prairie potholes
    • Floodplains
  • Characteristics:
    • Areas of land covered in water year-round or seasonally
    • Highly productive due to high nutrient levels and sunlight
    • Critically important habitats

Services Provided by Inland Wetlands

  • Functions/Services:
    • Filtering toxic water
    • Reducing flooding and absorbing storm runoff
    • Sustaining stream flow in dry seasons
    • Recharge groundwater supplies
    • Maintain biodiversity by providing habitat
    • Recreation
    • Supplying natural products

Marine Biomes: Estuaries and Salt Marshes

  • Characteristics:
    • Among the most biodiverse biomes on Earth
    • High nutrient levels + sunlight = very high NPP
    • Areas where saltwater and freshwater meet = “brackish”

Marine Biomes: Mangrove Swamps

  • Mangrove Forests:
    • Biome occurring along tropical and subtropical coasts
    • Contains salt-tolerant trees with roots submerged in water
  • Dominant Species:
    • Mangrove tree
  • Adaptations:
    • Adapted to living in saltwater
    • Create important breakwaters for storms
    • Critical habitat for marine species

Marine Biomes: Intertidal Zone

  • Characteristics:
    • Narrow band along coastlines between high and low tide marks
    • Habitat variations: sandy to steep and rocky
  • Challenges for Species:
    • Exposure to elements at low tide
    • Rolling surf
    • Highly specialized species reside here.

Marine Biomes: Coral Reef

  • Habitat Characteristics:
    • Warm, shallow seas
    • Water low in nutrient content
    • Coral is a symbiotic organism:
    • Each coral is made of thousands of polyps
  • Polyp Structure:
    • Made of a mouth filled with symbiotic algae called zooxanthellae
    • Zooxanthellae provide nutrients during the day
    • Mouth consumes drifting food at night
  • Productivity:
    • Very high NPP and biodiversity

Marine Biomes: Open Ocean

  • Zones in the Ocean:
    • Euphotic Zone:
    • Same conditions as limnetic zone
    • Lots of sun
    • Low nutrient levels = low biodiversity
    • Abyssal Zone:
    • Comparable to benthic zone
    • No light
    • Little productivity
    • Bathyal Zone:
    • Similar to profundal zone
    • Low light = low NPP
    • Low in nutrients
    • High biodiversity
    • Similar to littoral
    • Photic Zone (upper 200 m)
    • Aphotic Zone:
    • Most of the planet is covered in saltwater
    • Several major biomes exist in the ocean
    • The ocean can be divided into five main zones

Recap

  • Major Factors Influencing Aquatic Biomes Include:
    • Light availability
    • Water depth
    • Water temperature
    • Dissolved oxygen content
    • Nutrient availability
  • Lakes and Ponds:
    • Two types and divided into four zones
  • Streams and Rivers:
    • Divided into three zones
  • Ocean Environment:
    • Divided into five zones and shares similarities with lakes and ponds
  • Estuaries:
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