Download Document

Aquatic Biomes
Aquatic Biomes
• Marine
– Ocean
– Estuary
• Fresh Water
– Rivers and Streams (Lotic)
– Lakes and Ponds (Lentic)
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.
Oceans
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.
Oceans
Photic Zone – area of
water that sunlight
penetrates
Aphotic zone – area of
water that sunlight does
not penetrate
Oceans
Thermocline – vertical area where temperature abruptly
changes; restricts the mixing of upper and lower water
masses.
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.
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)
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
Sargasso Sea
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.
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
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
http://www.gomr.mms.gov/homepg/regulate/environ/chemo/chemo.html
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!
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.
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, threecorner 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
Freshwater Marsh
Brackish Marsh
Intermediate Marsh
Salt Marsh
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
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
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
1
1 1
1
2
2
1
33=4
Mississippi River is
classified as a 10th
or 12th order stream.
Headwater stream
classification
Stream Order – Strahler Method
matters
3
2
Major Rivers of The World
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
Name
You will be required to draw a map of the major rivers
of the Mississippi River Basin as part of exam 1.
Distributary – A smaller channel
that takes water away from the
main stem river.
Flow
Mississippi River
(Main Stem)
Atchafalaya River
(Distributary)
River Channel
Deep Holes
Sand Bars
Oxbow Formation
Lakes and Ponds
Ponds – light can reach the entire bottom
Lakes – light can not reach some parts of the bottom
Lake Overturn
Epilimnion
Hypolimnion
Thermocline
22˚
20˚
18˚
8˚
6˚
5˚
4˚C
4˚
4˚
4˚
4˚
4˚C
Summer
Fall overturn
2˚
4˚
4˚
4˚
0˚
4˚
4˚
4˚
4˚
4˚C
4˚C
Winter
Dissolved O2 concentration
4˚
Spring overturn
High
Medium
Low
4˚