1. Aquatic Biomes

2. Aquatic Biomes Marine Fresh Water Ocean Estuary
Rivers and Streams (Lotic)
Lakes and Ponds (Lentic)

3. Oceans
Continental Shelf – the portion of the continental plate that lies submerged under the ocean.
Usually has a gentle slope
Width can vary from a few to ten kilometers
Continental Slope – that area that drops from the continental shelf to the full depth of the ocean floor.

4. Oceans
Oceanic zone – any portion of the ocean beyond the continental shelf.
Neritic zone – section of ocean that lies over the continental shelf.
Littoral zone – shoreline between the high and low tide marks.

5. Oceans Photic Zone – area of water that sunlight penetrates
Aphotic zone – area of water that sunlight does not penetrate

6. Oceans
Thermocline – vertical area where temperature abruptly changes; restricts the mixing of upper and lower water masses.

7. Oceans Salinity averages 35 ppt (full strength sea water).
Due to high concentrations of sodium and chloride
Ocean is more than salt and water, but most ocean waters are very poor in nutrients
Phosphate, nitrate, ammonium, iron
Oceans cover ~71% of Earth, but only account for 50% of the Earth’s primary production.
Biological deserts not limited by water, but by nutrients
Unlike terrestrial biomes, production is not higher at equator and lower at the tropics –respond to nutrient concentrations like upwellings.

8. Oceans
Coastal regions are much more productive than non-coastal areas.
Rich nutrient input from coastal rivers
Most of the worlds great fisheries come from the continental shelf
Too many nutrients can lead to algal blooms, which may deoxygenate the water (eutrophication)

9. Some Fish Life History
Anadromous – fish that spend their adult life in salt water but spawn in freshwater
Salmon, striped bass, American shad
Catadromous – fish that spend their adult life in freshwater but spawn in saltwater
American eel

10. Sargasso Sea

11. Ocean Benthic Zone Benthic zone is the ocean bottom
a thick blanket of mud that consists of fine particles that have settled from the overlying water and accumulated over millions of years.
Scientists originally thought that life could not exist in the benthic zone.
Too much pressure, too dark, too cold, lack of food
We now know that there is a lot of life down there.

12. Chemoautotrophic Organisms
Photosynthetic organisms are labeled as autotrophs, specifically phototrophs.
Organisms that are able to harvest energy from inorganic compounds without photosynthesis are called chemoautotrophs.
Usually sulfur-oxidizing (harvesting energy rich electrons from sulfur compounds) organisms

13. Chemosynthetic Communities
Organisms use organic material seeping from the ocean floor as an energy source
Colorful crab perched on top of a large tubeworm cluster at GC 354, depth 532 m. This community was first discovered on this MMS/LSU subdive, August 24, 2000

14. Symbiotic Relationships
Consumer organisms found in chemosynthetic communities rely on a symbiotic relationship with chemoautotrophic bacteria.
Consumer organisms must take up inorganic carbon (CO2) and sulfides and get rid of the bacterial waste.
The bacteria are able to capture energy (oxidize) from the sulfides to reduce carbon dioxide (primary production).
Consumers then absorb nutrients from the bacteria!
Consumer organisms do not have a mouth or gut!

15. Estuaries Where the river meets the sea Most productive biome on Earth
Sometimes classified freshwater, sometimes classified marine
Most productive biome on Earth
Support a diverse fauna including a variety of worms, oysters, crabs, and waterfowl.
Serve as nursery habitat for many organisms.

16. Marsh Types Fresh water marsh salinity < 1.0 ppt.
Plants are not salt tolerant and include maidencane, bulltongue, alligatorweed, cattails, and spikerush
Intermediate marsh salinity averages 3.3 ppt.
Plants are slightly salt tolerant and include spikerush, three-corner grass, arrowhead, cordgrass, wiregrass, roseau cane, and deer pea
Brackish marsh salinity averages about 8 ppt.
typically dominated by cordgrass or wiregrass
Salt marsh salinity averages about 16 ppt.
oyster grass is common, but few other plant species can survive

17. Freshwater Marsh Brackish Marsh Intermediate Marsh Salt Marsh

18. Rivers and Streams
Generally represent the excess of precipitation on land areas over evaporation from them.
Precipitation that falls is either evaporated, transpirated, enters the ground water supply, or flows down rivers
Flow is down-hill and varies seasonally
Related to rainfall and ice/snow melt
Beginning of a river = the source and the end of a river = the mouth
Discharge - volume of water passing a given point during a period of time
Channel Width X Depth X Velocity

19. Rivers and Streams
Flow velocity is important in determining abiotic and biotic components.
Flow related to slope and precipitation
Sediment type, current strength
Only certain organisms can withstand strong flow
The faster the flow, the more material can be transported in the water
Materials are transported by running water in three principal states
Dissolved matter
Suspended solids
Bed load

20. Stream Order
Used to classify a stream in relation to tributaries, drainage area, total length, and age of water. 1 2 3
Stream Order – Strahler Method
1  1 = 2
1  2 = 2
2  2 = 3
1  3 = 3
2  3 = 3
3  3 = 4
Mississippi River is classified as a 10th or 12th order stream.
Headwater stream classification matters

22. Major Rivers of The World
Name
Discharge 103 m3/sec
Length 103 km
Drainage Area 106 km2
Amazon, South America
212.40
6.44
5.78
Congo, Africa
39.65
4.70
4.01
Ganges-Brahmaputra, India
38.50
2.90
1.62
Yangtze, China
21.81
5.98
1.94
Yenisei, USSR
17.39
5.54
2.59
Mississippi North, America
17.30
6.02
3.22
Mekong, Asia
11.04
4.00
0.80
Nile, Africa
3.10
6.65
3.35

23. You will be required to draw a map of the major rivers of the Mississippi River Basin as part of exam 1.

24. Mississippi River (Main Stem) Atchafalaya River (Distributary)
Distributary – A smaller channel that takes water away from the main stem river.
Mississippi River (Main Stem)
Atchafalaya River (Distributary)
Flow

25. River Channel
Deep Holes
Sand Bars

26. Oxbow Formation

27. Lakes and Ponds Ponds – light can reach the entire bottom
Lakes – light can not reach some parts of the bottom

28. Dissolved O2 concentration
Lake Overturn
Epilimnion
Hypolimnion
Thermocline
Summer
Fall overturn
22˚
20˚
18˚ 8˚ 6˚ 5˚
4˚C 0˚ 2˚ 4˚
Winter
Spring overturn
Dissolved O2 concentration
High
Medium
Low