Aquatic Ecology

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Aquatic Ecology
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Two Aquatic Life Zones

• Salt Water or Marine
• Freshwater

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Marine

• Estuaries
• marshes
• bogs
• swamps
• Coastline
• coral reefs
• continental shelf
• Open ocean

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Freshwater

• Surface water
• lentic - swamps, bogs, marshes, lakes, ponds -
  standing water
• lotic - streams, rivers and creeks - flowing
  water
• Wetlands
• Groundwater
• aquifers
• underground lakes

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Aquatic Environments

• Light
• Euphotic zone zone of photosynthetic limitation
• Heat surface, middle and bottom layers
• Dissolved gasses
• Oxygen atmospheric and plant inputs unlike
  atmosphere varies widely in aquatic ecosystems
• CO2 atmospheric and animal inputs buffering
  of atmosphere and changes in aquatic ecosystems
• Nutrients
• Availability with depth and water conditions

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Aquatic Organisms

• Plankton free floating animals and plants
• Phytoplankton plant plankton
• Zooplankton animal plankton feeding on
  phytoplankton

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Aquatic Organisms

• Nekton strong swimming consumer organisms
• Fish
• Turtles
• Whales

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Aquatic Organisms

• Benthos bottom dwelling organisms
• oysters
• lobsters
• worms

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Saltwater

• Oceans cover 71 of earths surface
• Regulation of climate
• Stores of Carbon Dioxide and production of Oxygen
• 250,000 species of organisms

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Life zones of the Ocean

• zones defined by amount of solar radiation
  penetrating the water
• zones (in order of declining solar radiation)
• Coastal Zone
• Open Sea
• euphotic zone
• bathyl zone
• abyssal zone

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Coastal Zone

• extends from hightide mark to edge of
  continental shelf
• entirely within the euphotic zone includes
  estuaries, wetlands, barrier islands, coral
  reefs
• nutrientrich the site of most commercial
  fisheries
• high primary productivity sunlight nutrients
  from land ocean currents

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Euphotic Zone

• Euphotic zone the first 150m down

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Bathyl zone

• Extends down from 1000m to 4000m,
• The only light is from bioluminescent organisms
• The only food is what trickles down from above,
  or from eating other animals.

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Abyssal Zone

• Abyssal Zone where the water is freezing and
  there is no light this zone is an amazing 3000 to
  11000m deep. 

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Estuaries and coastal wetlands

• Where freshwater meets saltwater
• Very productive essential nursery grounds
• Filters pollutants and impurities
• Breeding grounds for waterfowl and wildlife

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Estuaries Coastal Wetlands

• nutrient rich
• high primary productivity
• nurseries for fish other aquatic animals
• waterfowl shorebird breeding areas

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Mangrove swamps

• Areas where salt tolerant trees live
• Protective qualities against hurricanes

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Coral Reefs

• high biodiversity like tropical rain forests of
  the ocean
• protect coastlines from storms high waves
• nurseries for many fish species
• disappearing

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Rocky and sandy shores

• Intertidal zone area of life between low and
  high tide
• Niches for life in harsh changing environment
  sand on beaches and rocks on rocky shores
• Sand dunes protection against storms

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Open Ocean

• Euphotic zone most productive
• 90 of water surface but 10 of fish
• Specialized organisms near vents

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Human impacts

• Development along coast
• 3.9 billion people live along or near the coast
• Earth has lost 50 of coastal wetlands , US has
  lost 55
• 37 of coastal fisheries closed due to pollution
• 10 of coral reefs lost, 30 in critical
  condition and about 30 stable
• Over 50 mangrove forests lost

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Barrier Islands

• protect mainland from offshore storms
• shelter inland bays, estuaries, wetlands
• popular recreational residential areas

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Freshwater

• Dissolved salt concentrations less than 1
• Covers 1 of earths surface
• 41 of fish species

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Thermal Stratification of Lakes

• epilimnion warm, upper layer of water
• thermocline zone of lake where temperature
  changes rapidly with depth
• hypolimnion colder, denser lower layer of water
  can be depleted of oxygen in eutrophic lakes

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Overturn in Lakes

• upper layer of water sinks winds mix layers
• redistributes oxygen temperature evenly
• redistributes nutrients from the lower layers
• Dimictic
• Monomictic
• Polymictic

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Oligotrophic Lakes

• Oligotrophic
• low nutrient supply
• low primary productivity
• clear water, few plants fish

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Eutrophic Lake

• Eutrophic
• excess supply of nutrients
• high primary productivity
• murky water, large phytoplankton population

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Stream Order

• Streams with no tributaries are 1st order
• Two first order streams joining form a 2nd order
  stream, etc.
• Entrance of smaller order tributaries does not
  change the order of a stream

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Streams

• Headwaters cold, well oxygenated waters with
  trout, algae and mosses and macroinvertebrates
• Transition warmer water with gentler slopes and
  fewer obstacles increase of phytoplankton with
  mixed warm and cool water fish
• Flood plain deep rivers along flat broad
  valleys. Similar makeup to lakes

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Wetlands

• Where streams meet lakes
• Provides food and habitats for fish, waterfowl
  and wildlife
• Filter toxics from water
• Reduce flooding by releasing water slowly
• Replenish groundwater supplies
• Important for recreation and hunting

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Human Impacts

• Dredging and filling of wetlands mitigation
  banking of wetlands not net loss
• Damming rivers
• Sedimentation
• Fish stocking and introductions zebra mussels