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24.10.15 Aquatic biomes

Migration

Google aquatic biome game

Recall terrestrial biomes are defined by temperature and precipitation (rain)

Aquatic biomes are by definition underwater, so they are defined by 

  • Depth: how deep is the deepest part, how much photosynthesis is possible
  • Distance from shore: shallow water has more life, more things to attach to, more biodiversity
We separate aquatic biomes into freshwater (lakes, rivers, streams) and saltwater (oceans, estuaries)
Freshwater biomes:
Riparian=river 
Limnotic=lakes

Lakes:
  • Shallow shore area=littoral (means shallow), see the "littoral Navy", photosynthesis here (shallow, light shines through)
  • Open water area=limnetic zone, no rooted plants (too deep), phytoplankton here, only as deep as sunlight can penetrate
  • Deep water=profundal ("profound") or deep zone: no light penetrates, bacterial decomposition.
  • Bottom=benthic zone: mud, dark, cloudy

47fc3.png
47fc3.png


Ponds are much smaller, and may freeze in progressthe winter, so their dynamics are different

Productivity: see also NPP (net primary productivity)

  • n.b. usually related to photosynthesis (plants)
  • Oligo (few) trophic=low productivity
  • Meso (middle) trophic=medium
  • Eutrophic (eu=good trephien=food)=lots of productivity (sometimes too much, like in "Poisoned Waters")
  • Freshwater wetlands-submerged most of the time (swamps, marshes, bogs) this is the history of all coal and oil we now use
Wetlands:
  • Freshwater wetlands-submerged most of the time (swamps, marshes, bogs) this is the history of all coal and oil we now use
  • Salt marsh: usually connected to the sea, act as a coastal buffer for Hurricanes, very productive, many nutrients, lots of organic material
  • Mangrove swamp: special adapted version of this in Tropical areas (e.g. Florida)
  • Intertidal zone: area between high and low tide or seasonal variations

Ocean zones:

  • Coral reefs-see coral bleaching, pH, temperature and salinity sensitive (see Hamakua coast vs. Puako)
  • Intertidal zone: between high and low tide
  • Photic (light) zone-shallow, photosynthesis, kelp, others
  • Aphotic (dark) zone-too dark for photosynthesis
  • Chemosythesis/thermosynthesis: deepwater steam vents, based on Sulfur instead of Oxygen, bacteria generate energy with methane (CH4) and H2S (instead of H20)
  • Benthic=deep ocean
  • Pelagic=open ocean (think of big sailing ships, whales, stuff like that)
  • Hadal zones: like Hades: deepest, darkest zones. Weird fish, no light...

b3276.png
b3276.png


Summary: (note open ocean is called Pelagic, and deep ocean zones are called Hadal)

Marine Biome Zonation.png
Marine Biome Zonation.png

Screenshot 2025-09-22 at 3.49.56 PM.png
Screenshot 2025-09-22 at 3.49.56 PM.png

Salt stuff:

  • salt water = 30-50 ppt (parts per thousand)
  • know what these mean, we will see them soon: ppt, ppm, ppb
  • fresh water = 0.5 ppt
  • in between 0.5-30 ppt = brackish (anchialine ponds in Kona)
  • salinity, wind and temperature determine flow

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Terms to know: Review

Zones:
photic zone=light
aphotic=no light
benthic=really no light, never, ever ever. don’t even think about it.
Hadal=too dark to imagine, named after Hades (hell)

Marine animals:
  • aquatic mammals must surface for air
  • fishies don’t-they have gills
  • DO dissolved oxygen (very important) depends on plants (so depth) and temp (cooler water can hold more O2)
  • warm water has low O2 generally.
  • best place to fish: cool water after a waterfall (why?)
Rivers, ponds and lakes, oh my...
  • flowing water: rivers
  • standing water: ponds
  • lakes can become inland seas (drought lowers level, unable to drain, forms a lake)
  • littoral=shore, limentic=away from shore benthic=botttom
Wetlands:
  • terms: marshes, swamps, bogs and fens
  • marshes marshes marshes!-tall grasses
  • swamps-some trees
  • bogs-acidic, poor decomposition, floating stuff, decay slowly-ancient cheese story, peat moss
  • fens-freshwater spring underneath, less acidic, better nutrients
River stuff:
  • rivers-"oxbow" lakes and meander (usually in very flat lands like Nebraska)
  • continuity concept: source->tributary->mouth (delta)
  • slope exponential as distance from source (one reason dams do not last long)
  • deposition rates (rapids vs. plains, think of sedimentation)
  • silt carrying capacity, turbidity
  • estuaries-like deltas
  • tidal estuary: e.g. hudson river: deeper than the body it serves
Oceans——
  • 200 ft. of salt if all oceans evaporated
  • oceans were red (iron) then ppt out (iron range in WI, MI) (see PBS Nova episode)
  • salinity, wind and temperature determine flow
  • upwelling (recall Peruvian fisherpersons)
  • also downwelling
Photic (light) zones-again
  • intertidal zone-makes sense, between tides
  • neritic zone-close to shore, less than 200 ft. deep (not in Hawaii, we have no continental shelf-boo hoo)
  • open ocean (pelagic) zone
  • kelp forests-e.g. california coast
  • coral reefs-away from fresh water, coastal, photic
  • open ocean-scary stuff

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