Chapter 7: Aquatic Ecology

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Chapter 7 Aquatic Ecology
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Two Major Types of Aquatic Life Zones
1. saltwater or marine (estuaries, coastlines,
coral reefs, coastal marshes, mangrove swamps,
ocean over the continental shelf, deep ocean) 2.
freshwater (lakes, ponds, streams, rivers,
inland wetlands)
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Organisms in Aquatic Life Zones

• Plankton

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Organisms in Aquatic Life Zones

• Nekton

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Organisms in Aquatic Life Zones

• Benthos

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Organisms in Aquatic Life Zones

• Decomposers

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Water Properties Supporting Life

• Buoyancy- physical support allows for larger
  sized creatures with less rigid support
• High Heat Capacity- fluctuations in heat are not
  as great as on land, reduce risk of temperature
  related problems
• Nutrient availability- nutrients are dissolved
  and on tap in surrounding waters
• Waste elimination- wastes are quickly dissolved,
  dispensed, and diluted

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Limiting Factors

• Temperature
• Access to sunlight for photosynthesis
• Photic (euphotic)
• Aphotic
• Compensation point
• Dissolved oxygen content
• Availability of nutrients

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Phosphorus Cycle
Nitrogen Cycle
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Saltwater Life Zones

• 71 of earth's surface
• currents distribute solar heatand regulate the
  earth's climate
• participate in nutrient cycles
• reservoir for carbon dioxide - thus help regulate
  temperature of the troposphere

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Stratification of Marine Life Zones
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Estuary Place where freshwater stream or river
merges with the ocean. Highly productive biome
important for fisheries and feeding places for
water fowl.
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Coastal Wetlands
areas of coastal land covered all or part of the
year by salt water breeding grounds and habitats
for waterfowl and other wildlife
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Mangrove Swamp - tropical coasts dominated by
salt-tolerant trees
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Coral Reefs occur in neritic zones of warm,
tropical water, dominated by cnidarians (corals)
very productive, protect land from storms most
are now dying from rise in global temperatures
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Intertidal Zone
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Human Impacts on Coastal Zones

• 2/3rds of population live within 100 miles of the
  ocean
• Wetlands destruction
• Toxic pollution
• Beach erosion
• Reduced resources

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Some State Percentages of Population
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Freshwater Life Zones

• 1 of Earths surface water
• 41 of fish species
• Lentic
• Lotic

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Freshwater Lentic Systems
Standing bodies of water, i.e., lakes, ponds,
inland wetlands
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Freshwater Lotic Systems
Flowing bodies of water, i.e., rivers and streams
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Zone Explanation of Freshwater Lakes

• Littoral Zone shallow, near shore, rooted
  plants, most productive, high diversity
• Limnetic Zone open water away from shore,
  phyto- and zooplankton, fish
• Profundal Zone deep, too dark for
  photosynthesis, some fish adapted for depth,
  temperature
• Benthic Zone decomposers, detritus feeding
  clams, insect larvae (vermiformes), catfish, carp

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Oligotrophic Lakes
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Eutrophic Lakes
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Mesotrophic Lake
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Thermal Stratification of Lakes

• Epilimnion- warmer water with higher dissolved
  oxygen levels
• Thermocline- separating boundary between
  epilimnion and hypolimnion
• Hypolimnion- lower layer of water, more dense,
  with lower temperatures and dissolved oxygen
• Most lakes undergo fall and spring overturns

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Water Sheds
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Texas Watersheds
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Freshwater Wetlands
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Wetlands includes marshes, bogs, swamps,
seasonal ponds. Among richest biomes with
respect to biodiversity and productivity.
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Human Effects on Inland Wetlands