Aquatic Biomes

1. Aquatic Biomes

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

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. 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 Chemosynthetic Communities Organisms use organic material seeping from the ocean floor as an energy source http://www.gomr.mms.gov/homepg/regulate/environ/chemo/chemo.html

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 • 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. 1 1 1 1 2 2 1 2 3 Stream Order – Strahler Method Stream Order Used to classify a stream in relation to tributaries, drainage area, total length, and age of water. 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

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

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

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