module 3

• Types of Aquatic Ecosystems

  • Freshwater
  • Marine
  • Transitions between land & sea
• Modes of life - Neuston


  Rest or swim on surface
• Lentic Zonation - Laguna de Bay


  1. Limnetic zone - Depth of effective light penetration - compensation point, no benthos and few if any neuston

  2. Profundal zone - Bottom and deep water region, fewer plankton and no neuston, absent in ponds
• Lake Productivity - Oligotrophic


  Deep, sandy or gravel bottom

  Low nutrients

  Low plant growth, low productivity

  Low decomposition at bottom, oxygen not depleted
• Modes of life - Nekton


  1. Swimming organisms

  2. Go where they want

  3. Fish, squid, frogs, turtles, seals, octopus
• Modes of life - Benthos


  1. Attached or resting on bottom

  Epifauna: live on bottom (crabs, scallops)

  Periphyton: attach to stems & leaves of rooted plants

  Infauna: buried in sediment (clams, worms)
• Stratification

  1. Temperate lakes - mixed twice/year (Brings oxygen to bottom, nutrients to top)

  2. Tropical lakes

  Low elevation: Warm water on top, doesn’t cool regularly, poor to no mixing

  High elevation: Can stratify and mix daily
• Lentic Zonation


  1. Limnetic

  2. Profundal zone

  3. Littoral zone
• Freshwater Ecosystems


  • Lentic - Standing water (Lakes, ponds, bogs)
  • Lotic - Running water (Streams, rivers)
• Thermal Stratification (Changes with season)


  1. Epilimnion: warm surface water

  2. Metalimnion: 0C changes with depth

  3. Hypolimnion: cold deeper waters
• Modes of life - Plankton


  1. Floating, weak swimmers

  Phytoplankton: photosynthesize

  Zooplankton: herbivores & carnivores
• Lake Productivity - Eutrophic


  Shallow, muddy, nutrient rich

  High plant growth, high productivity

  Summer stratifies, no mixing

  Decomposition, depletes O2
• Patterns in Aquatic Ecosystems


  • Shallow vs Deep
  • Fresh vs Salt
  • Swift vs Stagnant
  • Changing vs Constant
  • Ephemeral vs Permanent
  • Limnology vs Oceanography
• 4 modes microaquatic(?) of life

  Benthos, Neuston, Plankton and Nekton
• Limnetic: 


  to depth of light penetration
• Profundal zone: 


  beyond depth of light penetration (Usually absent in ponds)
• Littoral zone: 


  Shallow, light penetrates to bottom, rooted plants, high diversity, subzones of vegetation (Emergent, floating, submergent)
• River


  (From Latin word Ripa “bank”)

  any natural stream of water that flows in a channel with defined banks
• The word stream (derived ultimately from the Indo-European root srou-) emphasizes the fact of flow; as a noun, it is synonymous with river and is often preferred in technical writing.
• Small natural water courses are sometimes called rivulets, but a variety of names—including branch, brook, burn, and creek —are more common, occurring regionally to nationally in place-names
• Arroyo and (dry) wash connote ephemeral streams or their resultant channels
• Tiny streams or channels are referred to as rills or runnels
• Parts of the Rivers

  1. Upper course (Z1: Headwaters)
  2. Middle course (Z2: Transfer zone)
  3. Lower course (Z3: Depositional zone)
• Parts of the Ocean: Upper course


  The part where we find the source of the river (usually in areas with a certain elevation), and usually it has fast-flowing water.

  In this area there is a lot of erosion and transport.
• Parts of the River: Middle Course


  The part where the river widens and the gradient decreases. There is a lot of erosion, transport and sedimentation.
• Parts of the River: Lower Course


  Where the gradient is gentlest and the water flow is slowest. The sediments transported by the river are deposited and in its mouth the river may form an estuary or a delta as large alluvial deposits are created.
• River Nourishment

  1. Precipitation
  2. Direct overland runoff
  3. Through springs and seepages
  4. Meltwater at the edges of snowfields and glaciers
• River Water Losses

  1. Evaporation
  2. Infiltration
  3. Percolation into shallow or deep aquifers (permeable rock layers that readily transmit water)
  4. Seepage
• Major Oceans of the Word

  
• Layers of the Ocean

  Epipelagic Zone

  Mesopelagic Zone

  Bathypelagic Zone

  Abyssopelagic Zone

  Hadalpelagic Zone
• Layers of the Ocean

  Epipelagic Zone


  > The surface layer of the ocean is known as the epipelagic zone and extends from the surface to 200 meters (656 feet).

  > It is also known as the sunlight zone because this is where most of the visible light exists.

  > With the light come heat. This heat is responsible for the wide range of temperatures that occur in this zone.
• Layers of the Ocean

  Mesopelagic Zone

  
  

  > Below the epipelagic zone is the mesopelagic zone, extending from 200 meters (656 feet) to 1,000 meters (3,281 feet)

  > Mesopelagic zone is sometimes referred to as the twilight zone or the midwater zone. The light that penetrates to this depth is extremely faint

  > It is in this zone that we begin to see the twinkling lights of bioluminescent creatures

  > Great diversity of strange and bizarre fishes
• Layers of the Ocean

  Bathypelagic Zone


  > It is sometimes referred to as the midnight zone or the dark zone

  > This zone extends from 1,000 meters (3,281 feet) down to 4,000

  meters (13,124 feet)

  > Here the only visible light is that produced by the creatures themselves

  > The water pressure at this depth is immense, reaching 5,850 pounds per square inch

  > Sperm whales can dive down to this level in search of food

  > Most of the animals that live at these depths are black or red in color due to the lack of light
• Layers of the Ocean

  Abyssopelagic Zone


  > Also known as the abyssal zone or simply as the abyss.

  > Extends 4,000 meters (13,124 ft) to 6,000 meters (19,686 ft)

  > The name comes from a Greek word meaning "no bottom"

  > The water temperature is near freezing, and there is no light at all

  > Very few creatures can be found at these crushing depths Most of these are invertebrates such as basket stars and tiny squids

  > Three-quarters of the ocean floor lies within this zone

  > The deepest fish ever discovered was found in the Puerto Rico Trench at a depth of 27,460 feet (8,372 meters)
• Layers of the Ocean

  Hadalpelagic Zone


  > Extends from 6,000 meters (19,686 feet) to the bottom of the deepest parts of the ocean

  > These areas are mostly found in deep water trenches and canyons

  > The deepest point in the ocean is located in the Mariana Trench off the coast of Japan at 35,797 feet (10,911 meters)

  > The temperature of the water is just above freezing, and the pressure is an incredible eight tons per square inch

  > In spite of the pressure and temperature, life can still be found here.

  > Invertebrates such as starfish and tube worms can thrive at these depths.
• Hydrothermal Vents

  • Hydrothermal vents form at locations where seawater meets magma

  Home to many kinds of animals, including tubeworms, crabs, mussels, zoarcid fish
• Estuary

  • Is where the ocean meets a river in a semi-enclosed area
  • This causes a mixing of fresh and salt water.
  • These areas are home to an immense amount of biological productivity and diversity
  • Tend to be rich in nutrients & productivity due to the trapping of nutrients & sediments.
• Classifications of Estuaries

  
• Classifications of Estuaries based on Geology : Coastal Plain or a drowned river

  • from rising sea levels flooded into its major tributary following the end of the last ice age
  • e.g. Pamlico Sound in North Carolina
• Classifications of Estuaries based on Geology : Tectonic Estuary


  created when a sudden movement of the earth's crust formed a basin that ocean and river water quickly filled in

  • e.g. San Francisco Bay