• Aquatic Biomes
Broad aquatic ecological associations can be
characterized by their physical environment, chemical
environment, geological features, photosynthetic
organisms, and heterotrophs
97% oceans
2% glaciers
1% lakes, rivers, streams
Transport
over land
Solar energy
Net movement of
water vapor by wind
Precipitation Evaporation
over ocean
from ocean
Precipitation
over land
Evapotranspiration
from land
Percolation
through
soil
Runoff and
groundwater
30ºN
Lakes
Coral reefs
Rivers
Oceanic
pelagic and
benthic zones
Estuaries
Intertidal zones
Tropic of
Cancer
Equator
Tropic of
Capricorn
30ºS
fresh water or salt water (marine)
Oceans cover about 75% of Earth’s surface and have an enormous impact on the
biosphere
Inland aquatics
“Areas of marsh, fen, peatland, or water, whether
natural or artificial, permanent or temporary, static
or flowing, fresh, brackish, or salt, including areas of
marine water, the depth of which at low tide does
not exceed 6 meters”
International Union for the Conservation of Nature
ENSC 2400 will cover the intertidal in Marine
Biomes lecture
Running water flows down
• Standing water – LENTIC systems
• Flowing water – LOTIC systems
Oligotrophic lakes
Lakes
Eutrophic Lakes
Fig. 52-18d
Streams and Rivers
Current
Life
Effect of
damming
A headwater stream in the Great
Smoky Mountains
The Mississippi River far from
its headwaters
Fig. 52-18c
Wetlands
Okefenokee National Wetland Reserve in Georgia
Fig. 52-18f
Estuaries
An estuary in a low coastal plain of Georgia
Fig. 52-16a
Littoral
zone
Limnetic
zone
Photic
zone
Benthic
zone
Pelagic
zone
Aphotic
zone
Rooted and floating aquatic plants live in the shallow and well-lighted littoral zone
Limnetic zone is too deep
Stratification - Dimictic example, effects oxygen
and nutrient levels in water
2º
4º
4º
4º
4ºC
Summer
Spring
Winter
0º
4º
4º
4º
4º
4ºC
Autumn
22º
20º
18º
8º
6º
5º
4ºC
4º
Thermocline
4º
4º
4º
4º
4ºC
4º
Hydrology and wetland diversity
• Climate (rainfall, temperature, seasonality)
• Geomorphology (soils, geology, relief)
Impact defined by the water budget where the
volume of water depends on
Precipitation
Interception
Surface flow
Groundwater in and outflow
Tidal flow
• General
Water budgets
• Marsh – Borders open water (rivers, estuaries),
high energy, may be tidal, no OM buildup, plenty
of dissolved O2
• Swamp – Occur in depressions, low energy, OM
buildup – peat formation, low O2
• Bog- On level ground
high rain, low evaporation,
low energy, organic sediment,
high water table
Precipitation
Interception
Surface flow
Groundwater in and outflow
Tidal flow
Permanence and periodicity
Hydroperiod:
Frequency of inundation
tidal marsh
groundwater fed (constant)
vernal pool
seasonal rapid flooding from rain or meltwater
Hydrology factors and results
High energy
• Streams, rivers, tidal
marshes
• High dissolved O2
• High flushing
• Open cycling
• Erosion dominant
• Not much organic matter
• High primary productivity
• Benthic invertebrates
Low Energy
• Swamps and bogs and lakes
•
•
•
•
•
•
•
Low dissolved O2
Low flushing
Closed nutrient cycling
Sedimentation dominant
Organic matter accumulates
Variable Primary Productivity
Benthic/planktonic inverts.
Human impacts
• Water removal for human use
– Wetlands drained, rivers
dammed, groundwater
depleted
– Sustainable water usage
requires considering the needs
of the environment
– Global warming effects on
montaine snow
Environmental factors
• Light, Temperature, Dissolved O2, pH, Salinity,
Nutrients, Stratification
Light
• Light penetration depth determines how deep
photosynthesis can occur
• Penetration of light into the water depends on
color of the water and turbidity
– Color – caused by dissolved substances from
decaying organic matter
– Turbidity – from suspended materials (clay, algae)
• Depends on flow, erosion, rainfall rate
Human Impacts - Light
• Clearing vegetation – increased sediment, less
shading, quicker photodegradation of organic
matter
• Runoff from impermeable surfaces (roads)
• Nutrients in sediments cause algal blooms,
clog gills, increase turbidity for other aquatic
vegetation
Temperature and Dissolved O2
Temperature
• Temperature more variable
due to shallower depth
• Changes seasonally or daily
• Affects stratification,
metabolism
• Affects dissolved O2
• Human impacts include:
– Tree clearing reduces shading
– Warm/cold water pollution
release from power plants or
dams
Dissolved O2 (DO)
• Depends on energy of
system, temp,
photosynthesis, and
stratification
• Used during respiration and
decomposition
• Fish kills occur when DO is
low
– Secondary human impacts
due to effects on other things
like temperature
pH (acidity), Salinity
pH
• Decreases due to
decomposition
• Reduces wetland metabolism
at extremes (peat or limestone
bogs)
• Human impacts include acid
rain (Nox, SO2) from power
generation , acid sulfate soils
in depleted waters.
• Lowered pH increases
availability of heavy metals
which then kills fish
• Heavy metal waters can
pollute groundwater
Salinity
• Salts
– Fresh water, brackish, sea
water, salt marsh, hypersaline
• Changes in salt
concentration affect
osmoregulation of animals
pH (acidity), Salinity
pH
Salinity
• Decreases due to
decomposition
• Reduces wetland metabolism
at extremes (peat or limestone
bogs)
• Human impacts include acid
rain (Nox, SO2) from power
generation , acid sulfate soils
in depleted waters.
• Lowered pH increases
availability of heavy metals
which then kills fish
• Heavy metal waters can
pollute groundwater
• Salts
– Fresh water, brackish, sea
water, salt marsh, hypersaline
• Changes in salt concentration
affect osmoregulation of
animals
• Human impacts: secondary
salinity (removal of deeper
rooted perennials with shallow
rooted annuals, or through
irrigation ) causes salts from
the soil to rise and stay in
surface soil. Then runoff adds
salinity to waterways.
Fig. 55-14c
N2 in atmosphere
Assimilation
NO3–
Nitrogen-fixing
bacteria
Decomposers
Ammonification
NH3
Nitrogen-fixing
soil bacteria
Nitrification
NH4+
NO2–
Nitrifying
bacteria
Denitrifying
bacteria
Nitrifying
bacteria
Fig. 55-14d
Precipitation
Geologic
uplift
Weathering
of rocks
Runoff
Consumption
Decomposition
Plant
uptake
of PO43–
Plankton Dissolved PO43–
Uptake
Sedimentation
Soil
Leaching
Oligotrophic lakes
Lakes
Eutrophic Lakes
Eutrophication
• When excess nitrogen and
phosphorus is discharged from
the watershed, massive algal
blooms develop which result in
the depletion of dissolved oxygen.
Pollution
A Dead Zone 6,000-7,000 sq miles develops