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Unit 2: Analysis of Habitats
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Ecological concepts
• Habitat• Environment• Population• Ecosystem• Community
Niche: Hutchinson’s n-dimensional hypervolume
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b
Niche: Hutchinson’s n-dimensional hypervolume
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c
Niche: Hutchinson’s n-dimensional hypervolume
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d
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Habitat
• Macrohabitat
• Microhabitat
• Habitat dimensions– atmosphere– lithosphere– hydrosphere– biosphere
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Macrohabitat analysis
• Temporal information– date– time– observers’ names
• Spatial information– specific location, GPS coordinates– topography– drainage characteristics, watershed area
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• Lithosphere– general land forms
• natural• anthropogenic
– soil types• grain size analysis (%sand, %silt, %clay + organic)• Soil Conservation Service area maps• Munsell Soil Color Charts
Macrohabitat analysis
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• Some principal land forms– Table 2A.1– coastal
• delta• coastal plain• outwash• dune• spit
Macrohabitat analysis
• reef• beach• bar• tidal flat• barrier island• swale
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• Atmosphere– measured variables
• wind: speed and direction• percent cloud cover• general weather• air temperature• relative humidity• barometric pressure
– climate
Macrohabitat analysis
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Macrohabitat analysis
• Community type
• Zonation: horizontal patterns
• Stratification: vertical patterns
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Stratification
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Stratification
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Macrohabitat analysis
• Habitat diversity– habitat richness: number of different
habitats present
– habitat heterogeneity versus dominance
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Analysis of aquatic habitats
• Habitat type– marine– estuarine– freshwater
• Communities based on salinity gradients– euryhaline– stenohaline
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Limnology: freshwater
• Lentic systems– calm, slow or non-moving
– lakes and ponds• oligotrophic• eutrophic• mesotrophic• hypereutrophic
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Limnology: freshwater
• Lentic systems– wetlands
• marsh• swamp or slough• bog• pothole or playa lake• bottomland hardwood
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Limnology: freshwater
• Lentic systems– zonation
• littoral zone (shallow, shoreline)
• open water– euphotic zone– compensation depth– aphotic zone
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Limnology: freshwater
• Lotic systems– moving
– rivers, streams, creeks, bayous
– riparian habitats
Water use categories
• Aquatic life– parameters designed to protect aquatic
species– e.g., dissolved oxygen, nutrients, toxics
• Contact recreation– relative risk to humans from swimming and
other water sports
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Water use categories
• Public water supply– indicators used to evaluate water source for
public water systems– e.g., nutrients, toxics
• Fish consumption– indicators for fish health or disease– toxic chemicals contained in fish tissue
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Water quality standards
• Used by EPA / TCEQ to evaluate condition of water and establish limits on permitted dischargers
• Numeric standards– values specific to segments
• Narrative standards– protect aesthetics and designated uses– overall screening limits– not segment specific
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Physical variables in aquatic habitats
• Water temperature– temperature profile
– temperature stratification• epilimnion / hypolimnion• thermocline
– biological effects• reaction rates• migration / reproductive cues• physiological tolerances
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Physical variables in aquatic habitats
• Turbidity– light scatter or penetration in water
– dependent on• dissolved chemicals• suspended particulates• microbes and algae
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Physical variables in aquatic habitats
• Turbidity– sources
• colloidal rock particles• eroded soil• domestic and industrial wastewater• street washings
– environmental significance• aesthetics• photosynthesis
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Physical variables in aquatic habitats
• Turbidity– measurement
• Jackson Turbidity Unit (JTU)• nephelometer turbidity units• Formazin Attenuation Units (FAU)• Secchi disk depth
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• Color– sources
• decomposition of lignin tannins, humic acid, humates
• pollutants
– apparent color (Pt-Co units)
– true color
Physical variables in aquatic habitats
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• Conductivity (specific conductance)– measure of how well water can conduct an
electrical current
– dependent on ion concentration in water
– indirect measure of salinity and other salts
– measured in mmhos, µmhos, mS, µS
Physical variables in aquatic habitats
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Chemical analyses
• Dissolved oxygen (DO)– essential for life processes of most aquatic
organisms
– low DO often results from high organic matter loads or low flow
– excessive DO often results from excess plant production
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Chemical analyses
• Dissolved oxygen (DO)– DO in warm water versus cold water
– effect of salinity
– percent saturation
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Chemical analyses
• Dissolved oxygen (DO)– State of Texas Surface Water Quality
Standards for DO
24-hr mean concentration Absolute minimum
Exceptional 6 mg/L 5 mg/L
High 5 mg/L 4 mg/L
Intermediate 4 mg/L 3 mg/L
Limited 3 mg/L 2 mg/L
No significant DO 2 mg/L 1.5 mg/L
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Chemical analyses
• pH– general indicator of water quality in neutral
range (pH 6-8.5)
– major factor affecting most chemical and biological reactions
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Chemical analyses
• Alkalinity and CO2
– measure of buffering capacity of water
– sources of alkalinity• hydroxides• carbonates• bicarbonates
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Chemical analyses
• Hardness – geographic variation in natural water
hardness
– hardness classificationsmg/L degree of hardness0-75 soft75-150 moderately hard150-300 hard>300 very hard
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Chemical analyses
• Hardness– caused by divalent metal cations
Principal cations causing hardness
Associated anions
Ca2+ HCO3-
Mg2+ SO42-
Sr2+ Cl-
Fe2+ NO3-
Mn2+ SiO32-
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Chemical analyses
• Hardness– total hardness– calcium hardness– magnesium hardness
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• Nitrogen– role as nutrient versus pollutant
– forms• organic
• nitrate TX screening level = 2.76 mg/L• nitrite
• ammonia: TX screening = 0.17 mg/L
Chemical analyses
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• Phosphate– role as nutrient versus pollutant
– TX screening level (orthophosphate P) = 0.5 mg/L
Chemical analyses
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• Other water chemistry parameters– trace metals / sulfate / tannins and lignins
– gases: carbon dioxide, hydrogen sulfide
– BOD• measure of oxygen demanding bacterial composition
of water• measures oxygen consumption by aerobic
microorganisms as they decompose organic material present in water
Chemical analyses
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Biological components
• Phytoplankton• Periphyton• Zooplankton• Nekton