FW Ecology

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FW Ecology
2012-05-08 12:44:51
Final Exam

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  1. Definition of eutrophic
    • well nourished
    • the enrichment of waters by plant nutrients resulting in increased algal growth and related chemical and biological changes in a water body
  2. oligotrophic
    poorly nourished
  3. Mesotrophic
    intermedite nutrition levels
  4. Dystrophic lakes
    were highly colored due to dissolved organic matter and poor in plankton
  5. Natural Causes of Eutrophication
    • forest fire in a lake catchment,
    • volcanic ash fall,
    • infilling by sedimentation
  6. Cultural Causes of Eutrophication
    • land clearance,
    • intensive agriculture,
    • sewage outfall
  7. Effects Of Eutrophication
    • species diversity decreases
    • plant and animal biomass increase
    • turbidity increase
    • rate of sedimentation increase
    • anoxic conditions develope
  8. Changes in algal groups and abundance cause changes in consumer groups e.g. ________________e.g. higher biomasses of fish but species tolerant of ______ conditions at intermediate stages of eutrophication
    • zooplankton and benthic animals and fishes
    • low oxygen
  9. Limiting Nutrient in lakes
  10. When Food webs change as a lake become eutrophic
    • macrophytes are shaded out by algal blooms.
    • carp out-compete less tolerant species
  11. cultural eutrophication
    caused by humans
  12. Bottle bioassay
    • small test in various bottles contaning sewage or treated liquid
    • Bottle bioassays are useful starting points to understand limiting nutrients but there may be serious limitations for interpretation of the results
    • Bottles are closed systems with no exchange with the sediments or atmosphere or larger biota.
  13. condition that make a nutrient limiting
    • Concentration alone cannot determine the limiting nutrient
    • It is the rate of supply rather than the absolute amount that determines which nutrient will be limiting
  14. non-point source
    • agricultural runoff,
    • rain
  15. point source
    are in principal easy to contain technologically but expensive
  16. Process Model Correlates:
    • Sources
    • Geology
    • Land use
    • Population
    • Processes
    • Residence time
    • Depth
    • Stratification
  17. Fisheries Science includes:
    • Fisheries science
    • Fish species richness
    • Fish classification
    • Fish anatomy
    • Life history
    • Fish growth
    • Fisheries management
    • Fish productivity
    • aquaculture
  18. Ecological Principla of fish
    Species number increases with increasing surface area of ecosystem and decreases latitude
  19. Species richness Increases with
    • System surface area
    • Drainage size
    • Larger catchment, less steep
    • -More wetlands, habitat types, slower rivers
    • Smaller catchment, more steep
    • -Fewer wetlands, habitat types
    • -Faster rivers (harder for passage)
  20. Species Richness Decreases with
    • Latitude
    • Altitude
  21. Factors affecting species richness in fisheries
    • Lake size
    • Latitude (climate, temperature, ice cover)
    • Altitude (climate, accessibility)
    • Dissolved organic carbon
    • Total aluminum concentration
  22. Reason for few species in lakes than in rivers
    Attributed to increased habitat variability in rivers
  23. Within lake species richness increases with:
    • Time available for evolution of species
    • Spatial habitat variability
    • Colonization
    • -Available species pool
    • -Lack of geographical barriers
    • Survival of immigrants
    • -Feeding
    • -Growth
    • -Reproduction
  24. Geologically Young system
    • Laurentian Great Lakes ~ 170 species (six endemics)
    • Glaciated European regions ~ 200 species
  25. Geologically old systems (high endemism; >90% endemic)
    • Lake Malawi ~ 600-1000 species;
    • Lake Tanganyika ~ 400 species; more disparate
  26. Most fish are
    • Ray fined
    • (actinopterygill)
  27. Characteristics of lungfish
    • High temperature, low latitude wetlands
    • Periodically hypoxic or anoxic
    • Survive out of water
    • -damp habitat
    • -burrowing
  28. Characteristics of Ray finned fish
    • Wide range of temperatures and latitudes
    • Migrate to avoid low DO
    • Die if DO declines below minima
    • Low altitude species may gulp air
    • -above surface or at well oxygenated layer
  29. Life history traits of fish
    • Growth
    • Mortality rates
    • Number & size of eggs
    • Breeding
    • Brooding
    • Schooling behavior
  30. Piscivorous
    feed on fish
  31. Zooplanktivorous
    - feed on zooplanktion including predaceous zooplankton and fish
  32. Planktivorous
    – feed on plant material
  33. Benthivorous
    – feed on insects, mollusks, and crustaceans, benthic invertebrate predator
  34. Ominovorous
    feed on anything
  35. Insectivorous
    feed on insects
  36. Micrograzers
    • heterotrophic protozoans,
    • rotifers,
    • veligers
  37. Mesograzers
    • crustaceans,
    • herbivorous zooplankton,
    • benthic invertebrate nonpredator
  38. Physical changes as fish grow
    • Gape & body size
    • -Changes in food choices, types and energetics
    • -Predation risk
    • Vision
    • -Choices in consumption
    • -Risk of predation
    • Swimming
    • -Risk of predation
    • -Migration
    • Reproduction
  39. Detriments of fish growth
    • Environment
    • -Temperature
    • -Water clarity
    • Consumption,Predation
    • -DO
    • Food availabilit
    • -Population size, Competition
    • -Prey availability,Timing, Abundance, Location
  40. Determining fish growth
    • Directly from recapture of marked fish by measuring
    • -Increase in length
    • -Change in weight which is correlated with length
    • -Energy content (used less)
    • Based on aging fish
    • -Structures
    • -Tags
    • -Physical modifications
    • -Length frequency distributions
  41. Physical aging structures of fish
    • Patterns of calcium salt deposits on
    • Scales
    • Otoliths (inner ear bones)
    • Operculum (gill cover) vertebrae
    • Fin spins
  42. Underlying principal is more diversity of habitat and more resources
    • Larger catchment, less steep
    • More wetlands, habitat types, slower rivers
    • Smaller catchment, more steep
    • Fewer wetlands, habitat types
    • Faster rivers (harder for passage)
  43. 3 main genious in Bony fish
    • perch,
    • catfish,
    • carp
  44. Life histories (definition)
    are those traits of organisms that are related to their age at maturity, fecundity and age at death
  45. “r” selected
    • live fast die young
    • Can populate quickly in areas where resources are relatively plentiful
  46. K” selected
    • live slow but specialize in tough environments
    • Populate slowly but can compete when resources are low
  47. Stunting
    growth rate is changed to accommodate resource availability
  48. Logistic growth equation
    • K=Carrying Capacity
    • r=intrinsic rate of growth
  49. Catch at this density _____ permits maximum sustainable yield
  50. Maximum sustainable yield
    • assumes a population will have a maximum in productivity at a density below the natural carrying capacity
    • assumes that natural mortality can be replaced by fishing mortality without degradation of the population
  51. Toxicology
    scientific study of adverse affects chemicals or physical agents that may produce in living organisms under specific conditions adverse affects
  52. Inland aquaculture is about _____ of marine wild capture fishery
  53. Effects of toxicology
    • Water quality- nutrient pollution N and P
    • Habitat destruction bays,
    • wetlands desirable for pens
    • Exotic introduction of genetically altered stock
    • Depletion of low value wild fish stocks for fish meal
  54. Aquatic ecotoxicology-
    the study of toxic substances within aquatic ecosystems.
  55. Aquatic etoxicology includes
    • This includes direct toxic effects on individual aquatic organisms
    • the consequences for population viability of sensitive organisms
    • the indirect effects on other species which may result from exposure to toxic substances
  56. Acute toxicity
    a large dose of poison of short duration is usually lethal
  57. chronic toxicity
    a low dose of poison over a long time may be either lethal or sublethal
  58. Adverse toxic effects
    are identified from toxicity studies often starting in the laboratory to control other factors
  59. Acute
    coming speedily to a crisis
  60. Chronic
    continuing for a long time, lingering
  61. Lethal
    causing death, or sufficient to cause it, by direct action
  62. Sublethal
    below the level which directly causes death
  63. Cumulative
    brought about or increased in strength by successive additions
  64. Lethal concentration
    where death is the criterion of toxicity. The results are expressed with a number (LC50, LC70), which indicates the percentage of animals killed at a particular concentration
  65. Effective concentration (EC)
    term used when an adverse effect other than death is being studied
  66. Incipient lethal level
    the concentration at which acute toxicity ceases, usually taken as the concentration at which 50 per cent of the population of test organisms can live for an indefinite period of time.
  67. Safe concentration
    maximum concentration of a toxic substance that has no observable effect on a species after long-term exposure over one or more generations.
  68. Maximum acceptable toxicant concentration (MATC)
    concentration of a toxic waste which may be present in a receiving water without causing harm to its productivity and its uses.
  69. Bioaccumulation
    Capacity to enter food chain
  70. Persistence
    Resistance to degradation under environmental conditions
  71. Volatility
    Ease of evaporation and atmospheric transport
  72. additive
    toxicity remains proportional to their individual effect
  73. synergistic
    if the effect is more than additive
  74. antagonistic
    means one toxicant reduces the impact of the other
  75. Endocrine disruptors
    exogenous substances that cause adverse health effects in an intact organism, or its progeny, dependent on endocrine function
  76. Know X and Y axis
  77. biomarkers must be
  78. Risk Assesment Paradigm
    • Hazard Identification
    • Dose-Response Assessment
    • Exposure Assessment
    • Integrated Risk Assessment
    • Risk Management -necessary?
  79. Big Three
    • Cadmium
    • Lead
    • Mercury
  80. Persistent organic pollutants (POP)
    flame retardant, foam, plastic…
  81. Pharmaceuticals and personal care products(PPCP)
  82. Veterinary Medicine-
    antibiotics, antifungal
  83. Endocrine disrupters (EDC
    synthetic estrogens and androgens
  84. Nanomaterials
    carbon nanotubes and nanomaterial
  85. Hazard Identification:What is the problem
    • requires definition of the following:
    • 1.Organism, function, ecosystem
    • 2.What is the environment of concern
    • 3.Primary endpoints e.g. mortality, fecundity etc
    • 4.What is the origin of the problem
  86. Bioconcentration
    –the net accumulation of a contaminant by an aquatic organism as a result of preferential and/or selective uptake of specific substances directly from an aqueous solution to a specific location in the its body, tissues or cells
  87. BCF—Bioconcentration Factor
    the ratio of the concentration (w.w.) in an organism to its concentration in water
  88. Biomagnification
    –The increase in tissue concentration of contaminants or substances through a series of predator-prey relationships i.e. by means of ingestive accumulation
  89. Bioaccumulation
    The net accumulation of a contaminant or substance resulting from any or all environmental sources
  90. Metals ____ bioconcentrate but ____ biomagnify because they can be excreted by animal kidneys
    • strongly
    • Weakly
  91. methylation
    form stable organic compounds
  92. metallothionein
    can bind metals and render them non-toxic
  93. TEF
    EC50 (TCDD), EC50 (compound)
  94. TEQ
  95. Bioaccumilation (calculation example)
    concentration in flesh sample (60mg/kg) / amount in water (5 nanograms per liter) = 12,000,000
  96. POP’s bioaccumlation is complex:
    • Related to trophic position
    • Related to growth rates of prey and predators
    • Study demonstrates a correlation between factors that influence growth rate characteristics in lake trout lake food webs
  97. Biological Invaders
    Biotic invaders are species that establish a new range in which they proliferate, spread and persist to the detriment of the environment
  98. Definition of pollution
    The introduction by man into the environment of substances or energy liable to cause hazards to human health, harm to living resources and ecological systems, damage to structure or amenity, or interference with legitimate uses of the environment
  99. Mechanisms of biological pollution
    • The invading species has no natural predators in the new environment
    • The invader is a superior competitor relative to the native fauna
    • The new ecosystem has a vacant niche
    • The new ecosystem is lacking species richness
    • The new ecosystem is suffering from some sort of disturbance that makes it susceptible to the new invader
    • A combination of the above conditions
  100. Consequences of biological pollution
    • Reduction in biodiversity
    • Destruction of habitat
    • Economic losses
  101. Control/remediation of biological invaders
    • Prevention
    • Eradication
    • Biotic Controls
  102. Prevention of Biologic Invaders
    This is the most cost effective measure and involves identification of potential invader species and vectors of those species, identification of vulnerable habitats and above all vigilance in enforcement of quarentines.
  103. Eradication of biologic invaders
    This method often employs chemical agents which unfortunately may have side effects as a result of not being specific to the invader. Mechanical means of eradication are costly and usually not effective once an invader is established.
  104. Biotic control of biological invaders
    This approach can be useful but requires thorough testing before application.
  105. Water hyacinth
    • Forms dense mats, especially in areas that are nutrient rich that interfere with navigation, recreation, irrigation, and power generation.
    • These mats competitively exclude native submersed and floating-leaved plants.
    • Low oxygen conditions develop beneath water hyacinth mats and the dense floating mats impede water flow and create good breeding conditions for mosquitoes
  106. Dreissenid mussels zebra and quaqqas
    • Filtering removes plankton increasing light penetration
    • Excretions (dissolved and particulate enrich the benthic substrate
  107. Cladophora
    filamentous green algae is fluorishing in parts of Lakes after introduction of mussles
  108. Reasons for introduction of Nile perch
    • Diverse, once abundant native fish populations had collapsed:
    • • Human overpopulation had increased demand for animal protein
    • • Unregulated and more efficient gill netting destroyed native fishes (tragedy of the commons)
    • •‘Untapped’ haplochromine biomass envisioned as food source for Nile perch
  109. Puzzle: 25 years passed between Nile perch introduction (1950s) and their domination (1980s). Why?
    People and agriculture had been creating a more eutrophic lake
  110. Why did the Nile Perch finally succeed
    • Increased P
    • Increased chlorophyll Increased invertebrates
    • Nile Perch “r” traits
    • Superior competitor
    • Fecund
    • Fast growing
  111. Hypotheses for haplochromine collapse in lake Victoria
    • Nile perch ate them
    • Decreased light compromised growth and reproduction
  112. Lake Victoria summary
    • Human caused exotic introductions and eutrophication
    • Increased primary productivity
    • Increased productivity at higher trophic levels
    • Decline in biodiversity from hybridization, predation, habitat loss
  113. Factors that determine successful invasion
    • The invading species has no natural predators in the new environment
    • The invader is a superior competitor relative to the native fauna
    • The new ecosystem has a vacant niche
    • The new ecosystem is suffering from some sort of disturbance that makes it susceptible to the new invader
    • The new ecosystem is lacking species richness
    • A combination of the above conditions
  114. Acid Precipitation
    Increased atmospheric CO2 is resulting in the acidification of the ocean (8.178-8.068 ph ) since the industrial revolution
  115. intenal combustion of oil and gas
    NOx + H2O ↔ 2HNO3 ↔ 2H+ + NO3-
  116. The main sources of acid precipitation are:
    sulphur and nitrogen.
  117. Type of waterbody will affect _____ of acidification
    degree and speed
  118. Acidification: streams
    • Ratio of runoff volume to stream volume large
    • Pulses especially snow melt can lower pH rapidly
  119. Acidification: lakes
    Volume of lake relative to runoff volume larger, therefore lake more buffered than stream (if geology similar)
  120. Acidification: Wetlands
    Depending on redox conditions can remove N and S and produce alkalinity
  121. Effects of acidification on fish
    • Breaks down dissolved organic carbon
    • Food supply- crayfish declined
    • Habitat loss – invasion of filamentous green alga Mougeotia changed littoral nursery area
    • Physiology- gill function was affected at high Al+ concentration.
    • Reproduction- egg membranes were affected at low pH
  122. Remove the nonpoint sources of a idification
    reduce burning of fossil fuels
  123. Remove the point sources of acidification
    • Scrubbers and precipitators
    • precipitate S in power plants and smelters
  124. Liming
    The application of limestone (calcium carbonate) provides alkalinity
  125. Chlorine, fluorine and bromine are:
    powerful ozone depleters
    • Warmer surface waters
    • Earlier onset of stratification
    • Possible change to meromictic
  126. Longer summer stratification and deeper thermocline depth ___likelihood that hypolimnetic waters would be depleted of oxygen
  127. Cumulative impact of multiple stressors on freshwater
    • Climate warming
    • Acid precipitation
    • Ozone depletion
    • Eutrophication, organic pollution
    • POPs, metals, oil
    • Exotics
  128. Deeper thermocline:
    • Fish species needing cold waters will be concentrated into smaller hypolimnions and in shallow lakes these fish may be lost altogether.
    • Increased transparency in the epilimnion will allow more harmful UV light penetration and will reduce protected habitat for many shade adapted shallow water species.
  129. Decreased run-off
    slower water renewal rates will result in higher concentrations of chemicals including contaminants