Aquatic Ecology

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Aquatic Ecology

• Chapter 7
• Freshwater
• life zones
• Marine
• Life zones

• Chapter 24
• Importance of Aquatic Biodiversity
• Human impacts
• Laws of Protection
• Sustainability

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Aquatic Life Zones

• Freshwater -defined as having a low salt
  concentrationusually less than 1
• Lakes
• Ponds
• Rivers
• Streams
• wetlands

• Saltwater or Marine
• Estuaries
• coastlines,
• Coral refs
• Marshes
• mangrove swamps
• oceans

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Organisms of Aquatic Life Zones

• Phytoplankton free floating cyanobacteria
• Zooplankton primary consumers eat
  phytoplankton, secondary consumers eat other
  zooplankton
• Nekton strong swimmers
• Benthos bottom dwellers
• Decomposers - bacteria

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Limiting Factors of Aquatic Life Zones

• Temperature
• Access to sunlight
• Highest in the upper layer (euphotic zone)
• Dissolved oxygen
• Produced by photosynthesis
• Atmospheric interaction (waves)
• Nutrient availability

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Ponds and Lakes

• range in size from just a few square meters to
  thousands of square kilometers
• ponds may be seasonal, lasting just a couple of
  months (such as sessile pools)
• lakes may exist for hundreds of years or more
• may have limited species diversity since they
  are often isolated from one another and from
  other water sources like rivers and oceans

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Ponds and Lakes

• divided into three different zones determined
  by depth and distance from the shoreline
• littoral zone
• limnetic zone
• profundal zone

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Littoral Zone

• warmest since it is shallow and can absorb more
  of the Suns heat
• sustains a fairly diverse community, which can
  include several species of algae (like diatoms),
  rooted and floating aquatic plants, grazing
  snails, clams, insects, crustaceans, fishes, and
  amphibians
• the egg and larvae stages of some insects are
  found in this zone
• vegetation and animals living in the littoral
  zone are food for other creatures such as
  turtles, snakes, and ducks

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Limnetic Zone

• near-surface open water surrounded by the
  littoral zone
• well-lighted (like the littoral zone) and is
  dominated by plankton, both phytoplankton and
  zooplankton
• plankton are small organisms that play a crucial
  role in the food chain most life would not be
  possible without them
• variety of freshwater fish also occupy this zone

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Profundal Zone

• Plankton have short life spanswhen they die,
  they fall into the deep-water part of the
  lake/pond
• much colder and denser than the other two
• little light penetrates all the way through the
  limnetic zone into the profundal zone
• animals are decomposers

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Ponds and Lakes

• Temperature
• varies seasonally.
• Summer
• from 4 C near the bottom to 22 C at the top
• Winter
• from 4 C while the top is 0 C (ice)
• between the two layers is a narrow zone called
  the thermocline where the temperature of the
  water changes rapidly with depth

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Ponds and Lakes

• during the spring and fall seasons is a mixing of
  the top and bottom layers resulting in a uniform
  water temperature of around 4 C
• mixing also circulates oxygen throughout the lake
• many lakes and ponds do not freeze during the
  winter resulting in the top layer being a little
  warmer

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Ponds and Lakes

• ice can develop on the top of lakes during winter
• blocks out sunlight and can prevent
  photosynthesis
• oxygen levels drop and some plants and animals
  may die
• called "winterkill."

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Ponds and Lakes
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Streams Rivers

• bodies of flowing water moving in one direction
• found everywherethey get their start at
  headwaters, which may be springs, snowmelt or
  even lakes
• travel all the way to their mouths, usually
  another water channel or the ocean

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Watershed

• describes an area of land that contains a common
  set of streams and rivers
• drains into a single larger body of water, such
  as a larger river, a lake or an ocean

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Streams Rivers

• characteristics change during the journey from
  the source to the mouth
• Source
• temperature is cooler at the than it is at the
  mouth
• water is also clearer, has higher oxygen levels,
  and freshwater fish such as trout and
  heterotrophs can be found there

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Streams Rivers

• Transition Zone
• the middle part of the stream/river
• the width/depth increases
• Temperature increases
• species diversity increases numerous aquatic
  green plants and algae can be found

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Streams Rivers

• Mouth
• Wider/deeper/slower
• water becomes murky from all the sediments that
  it has picked up upstream
• decreasing the amount of light that can penetrate
  through the water
• less light
• less diversity of flora
• lower oxygen levels
• fish that require less oxygen, such as catfish
  and carp, can be found

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Streams Rivers
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Wetlands
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Wetland Defined

• A wetland is any area that is inundated (flooded)
  or saturated for a certain number of days in a
  row that add up to 7.5 of the growing season in
  an area.
• Contains
• Water
• Hydrophyllic (water loving) plants
• Hydric (saturated) soils with low oxygen content

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Importance of Wetlands

• Wildlife Habitat
• Flood control
• Sediment filters and erosion control
• Water quality
• Water supply
• Recreation

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Types of Wetlands

• Bogs
• Pocosin
• Fen
• Swamps
• Forested
• Marshes
• Tidal
• Salt Water Marsh
• Non-tidal
• Vernal Pools
• Fresh Water Marsh

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Pocosin

• Extremely flat with poor natural drainage
• Thick layers of peat decomposed organic
  material
• Shrub vegetation is common, pond pines, loblolly
  and longleaf pines are also present.
• Fire adapted

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Southern Appalachian Bog

• Fed primarily by rainwater
• Acidic
• Vegetation varies from mosses and grasses to
  trees depending on elevation

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Southern Fen

• Fed by surface and/or groundwater
• Water is alkaline (basic)
• Usually inhabited by mosses and grasses
• Can be a stage in succession from lake to woodland

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Vernal Pool

• seasonal (yearly) marshes that occur in
  depressions of land
• covered with ice and water from winter to spring
• dry during the summer and fall. all.
• bottom of the pools are made of bedrock or hard
  clay which keeps the water from leaking out.
• Creatures may include the spring peeper, eastern
  spotted newt, green frog, spotted salamanders

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Fresh water marsh

• A shallow wetland with few trees and standing
  water for most of the year
• Not Tidal
• Flocks of wading birds, fish, exotic plants,
  alligators, and numerous invertabrates

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Forested Swamp

• Dominated by trees with few shrubs
• water inflow through streams, rivers, and
  run-off.
• Trees have shallow root systems to gain exposure
  to oxygen.
• Common trees include red maple, bald cypress,
  sweet gum and American elm.
• Wood ducks, gray treefrog, wood frogs, barred
  owls and pileated woodpeckers live in the
  forested swamp