# 24.10.15 Aquatic biomes

<span style="font-weight: bold;">Google </span>[<span style="font-weight: bold;">aquatic biome game</span>](https://www.google.com/search?client=safari&rls=en&q=aquatic+biome+game&ie=UTF-8&oe=UTF-8)

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

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

- <span style="font-weight: bold;">Depth</span>: how deep is the deepest part, how much <span style="font-weight: bold;">photosynthesis</span> is possible
- <span style="font-weight: bold;">Distance from shore:</span> shallow water has more life, more things to attach to, more <span style="font-weight: bold;">biodiversity</span>

We separate aquatic biomes into <span id="bkmrk-freshwater" style="font-weight: bold;">freshwater</span> (lakes, rivers, streams) and <span id="bkmrk-saltwater" style="font-weight: bold;">saltwater</span> (oceans, estuaries)  
<span id="bkmrk-freshwater-biomes%3A" style="font-weight: bold;">Freshwater biomes:</span><div id="bkmrk-riparian%3Driver%C2%A0">Riparian=river </div><div id="bkmrk-limnotic%3Dlakes">Limnotic=lakes</div><div id="bkmrk-lakes%3Ashallow-shore-">  
<div><span style="font-weight: bold;">Lakes</span>:</div><div>

- 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

</div><div><figure>![47fc3.png](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/fz1DrPINmeq9NgLQ-47fc3-xrnnibtn.png)<figcaption>47fc3.png</figcaption></figure>  
<span style="font-weight: bold;">Ponds</span> are much smaller, and may freeze in the winter, so their dynamics are different

<span style="font-weight: bold;">Productivity: see also NPP (net primary productivity)</span>

- 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

<div><div><div><span style="font-weight: bold;">Wetlands</span>:</div></div><div>

- 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

</div></div><span style="font-weight: bold;">Ocean zones:</span>

- 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...

<figure>![b3276.png](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/0Rout2Y9nTJB0rDD-b3276-fdz7gjpg.png)<figcaption>b3276.png</figcaption></figure>Summary: (note open ocean is called Pelagic, and deep ocean zones are called Hadal)

<figure>![Marine Biome Zonation.png](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/Ywx6A7lC0RTNmAqB-marine-biome-zonation-h4gtb0b8.png)<figcaption>Marine Biome Zonation.png</figcaption></figure><figure>![Screenshot 2025-09-22 at 3.49.56 PM.png](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/ZqNtZPA7jY7IU2Vt-screenshot-2025-09-22-at-3-49-56-pm-akyczcym.png)<figcaption>Screenshot 2025-09-22 at 3.49.56 PM.png</figcaption></figure><span style="font-weight: bold;">Salt stuff:</span>

- 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

<span style="font-weight: bold;">==================</span>

<span style="font-weight: bold;">Terms to know: Review</span>

<div>Zones:  
photic zone=light  
aphotic=no light  
benthic=really no light, never, ever ever. don’t even think about it.</div><div>Hadal=too dark to imagine, named after Hades (hell)  
  
</div><div><span style="font-weight: bold;">Marine animals:</span>  

- 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?)

<div><span style="font-weight: bold;">Rivers, ponds and lakes, oh my...</span></div>

- 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

<span style="font-weight: bold;">Wetlands:</span>  

- 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

<div><span style="font-weight: bold;">River stuff:</span></div>

- rivers-"oxbow" lakes and meander (usually in very flat lands like Nebraska)
- continuity concept: source-&gt;tributary-&gt;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

</div><div><span style="font-weight: bold;">Oceans——</span></div><div>

- 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

<span style="font-weight: bold;">Photic (light) zones-again</span>  

- 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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