IKENWEIWE Bolatito Nafisat SENIOR LECTURER DEPARTMENT OF AQUACULTURE AND FISHERIES MANAGEMENT UNIVERSITY OF AGRICULTURE, ABEOKUTA - PowerPoint PPT Presentation

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IKENWEIWE Bolatito Nafisat SENIOR LECTURER DEPARTMENT OF AQUACULTURE AND FISHERIES MANAGEMENT UNIVERSITY OF AGRICULTURE, ABEOKUTA

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Title: IKENWEIWE Bolatito Nafisat SENIOR LECTURER DEPARTMENT OF AQUACULTURE AND FISHERIES MANAGEMENT UNIVERSITY OF AGRICULTURE, ABEOKUTA


1
IKENWEIWE Bolatito Nafisat SENIOR
LECTURER DEPARTMENT OF AQUACULTURE AND FISHERIES
MANAGEMENT UNIVERSITY OF AGRICULTURE, ABEOKUTA
  • AQUATIC ECOLOGY AND LIMNOLOGY

titobola2007_at_yahoo.com, 08033770265
2
AQUATIC ECOLOGY AND LIMNOLOGY
  • FIS 703
  • (3 Units)

3
Course outline
  • Classification of aquatic systems. 
  • Physio-Chemical parameters of aquatic environment
    plankton and benthos. 
  • Primary and Secondary Production,
  • energy budget

4
The basic needs of aquatic biota?
  • Carbondioxide
  • Oxygen
  • Sunlight
  • Nutrients- food minerals

5
Types of Aquatic Ecosystems
  • Freshwater Ecosystems
  • Standing Water- lakes ponds
  • Moving Water- rivers streams
  • Transitional Communities
  • Estuaries
  • Wetlands- bogs/fens, swamps, marshes
  • Marine Ecosystems
  • Shorelines
  • Barrier Islands
  • Coral Reefs
  • Open Ocean

6
Freshwater
  • Freshwater contribute about 0.31 and many of
    the large rivers of the world lie in the tropical
    and sub-tropical zones

7
Transitional Communities
  • ESTUARIES
  • Where freshwater dumps into ocean
  • Brackish (less salty than seawater)
  • Has rich sediments that often form deltas
  • Productive biodiverse
  • Organisms adapted to varying levels of salinity
    as tide ebbs flows
  • Nursery for larval forms of many aquatic
    species of commercial fish shellfish

8
Transitional Communities
  • WETLANDS
  • Land saturated at least part of the year
  • Swamps- have trees like bald cypress high
    productivity
  • Marshes- no trees tall grasses high
    productivity
  • Bogs/Fens- may or may not have trees waterlogged
    soil with lots of peat low productivity
  • Fens- fed by groundwater surface runoff
  • Bogs- fed by precipitation

Swamp
Fen
Bog
9
Marine Ecosystems
  • SHORELINES
  • Rocky coasts- great density diversity attached
    to solid rock surface
  • Sandy beaches- burrowing animals
  • Threats- due to hotels, restaurants, homes on
    beach, more plant life destroyed, destabilizing
    soil, susceptible to wind water erosion
  • Insurance high danger of hurricanes, erosion
  • Build sea walls to protect people but changes
    endangers shoreline habitat

10
MARINE
  • Oceans,
  • Seas, and
  • Other saline water
  • They all constitutes 97.69 and few usually
    contains higher nutrient concentrations than the
    sea water

11
Universal solvent
  • Water is a universal solvent.
  • There are also a number of minor constituents in
    solution,
  • variety of colloidal materials, both inorganic
    and organic.
  • Several gases are also found in natural water.
  • Water contains larger or smaller concentration of
    all elements found in the earth crust and in the
    atmosphere.
  • Furthermore, most of the organic compounds
    synthesized by living organisms may be found in
    water.

12
Dissolved gases
  • The gases that can be found in dissolved form in
    water include
  • oxygen,
  • carbon dioxide,
  • nitrogen,
  • ammonia,
  • hydrogen sulphate and
  • methane

13
Mineral constituents
  • Mineral constituents of water include calcium,
    magnesium, sodium, potassium, iron, manganese,
    aluminium, zinc, copper, molybdenum, sulphur,
    chlorine, fluorine, iodine, boron and silicon.
    These elements are usually present as ions or
    complex organic or inorganic molecules.

14
Soluble Organic Matter
  • Water soluble organic matter include
  • sugar, fatty acids,
  • humic acids, tannin,
  • vitamins, amino acids,
  • peptides, protein,
  • plant pigments, urea and
  • many other biochemical compounds

15
Suspended Inorganic Matters
  • The suspended inorganic matters include
  • colloidal clay and
  • coarse suspension of soil particles.

16
  • Colloidal or suspended particles are
  • remains of organism in various stages of decay,
  • living phytoplankton, zooplankton, fungi and
    bacteria

17
TYPES OF WATER
TYPES OF WATER
Lotic i.e flowing water
Lentic i.e. static or stagnant water
18
LIMNOLOGY
19
LIMNOLOGY
  • LIMNO means lake,
  • LOGY means study

20
LIMNOLOGY
  • It is the study of fresh water habitat which
    involves the study of physical chemical and
    biological as well as geographical location
    (longitude and latitude) characteristics of fresh
    water environment.

21
Limnology is divided into two
  • Lentic water which is static, water lakes and
    pond
  • Lotic water which is flowing, streams and rivers

22
PHYSICAL LIMNOLOGY
  • These include
  • Temperature, Light,
  • Turbidity (colour), Viscosity,
  • Water density,
  • Water current (speed and direction),
  • Depth,
  • Amount of suspended/floating/sinking organisms,
    and
  • Physical nature of substance (atoms).

23
TEMPERATURE
  • Temperature is defined as the degree of hotness
    or coldness.

24
Effects of temperature
  • Affect states of water (solid, liquid and gas).
  • Temperature also affect dissolved gas e.g.
    amount of soluble salt in water increases as
    temperature increases
  • Affect biology of aquatic organisms.

25
  • Difficult to transfer fish geographically except
    when water is heated artificially in cold region
  • It also affect solubility e.g. in warm water,
    fertilizer dissolved faster, herbicides act
    quicker, rotenone degrades faster and rate of
    oxygen consumption by decaying manure is greater.

26
Effects of temperature contd
  • Metabolism
  • In high temperature rate of metabolism is
    increase, hence increase growth as the organisms
    require more than enough food to supply energy
    with which to compensate the high metabolic rate

27
Effects of temperature contd
  • Reproduction
  • Tropical fish would breed only at temperature
    greater than 20oC. Embryo develops into
    fingerling slow at low temperature of less than
    20oC.
  • At high temperature (30oC) some aquatic organism
    hibernate in mud, under stones
  • zooplankton lay eggs with cyst preparing for
    drought.

28
Effects of temperature contd
  • Thermal stratification and mixing
  • Water is divided into 1,2, or 3 parts. Upper part
    warmer, lower part colder and temperature
    decreases with depth,
  • Dividing water into Epilimnion, Hypolimnion and
    middle Metalimnion with a a sharp change in
    temperature called Thermocline.

29
  • At high temperature water become lighter, less
    dense and mixing (upwelling is increase).
  • Even at different part of a river e.g. edges are
    warmer, lighter, cooler and denser towards
    middle.
  • Shallow depth at the edge with low volume i.e.
    horizontal zonation.

30
VARIATIONS IN WATER TEMPERATURE
  • The variation in temperature of water bodies
    are
  • Partial variation in temperature
  • Diurnal variation
  • Seasonal variation

31
WATER STRATIFICATION (THERMAL)
  • Due to temperature difference, Lentic water is
    divide into three layers,
  • Epilimnion,
  • Hypolimnion and
  • Metalimnion

32
UPWELLING
  • Upwelling is caused as a result of thermal
    stratification

33
Classification of Upwelling
  • Upwelling classified on the basis of number of
    times to occur includes
  • MONOMICTIC - upwelling occur once in a year e.g.
    in Nigeria, it occur during rain of July - Oct.
  • DIMITIC - upwelling that occurs twice in a year.
    During rain and harmatan e.g. North Nigeria

34
  • POLYMICTIC - upwelling occurring several times in
    a year. Most ideal for aquaculture.
  • MEROMICTIC - uncompleted upwelling only some
    partial, not reach lower part
  • HOLOMICTIC - complete mixing of both lower and
    upper part

35
Measurement of temperature
  • Simple mercury in glass thermometer that ranges
    between 0oC-50oC e.g. reversing thermometer and
    thermogram can be used to measure temperature of
    1000km away on satellite.

36
Temperature can also be measured using
  • Electrical thermometer operated using batteries
    and resistance wire with amount of current to
    temperature

37
DENSITY
  • Density is mass per unit volume (g/cm3).
  • Closely related to viscosity and specific
    gravity. Viscosity is the relative amount of
    water molecules in relation to one another.
  • Water density affect movement of organisms.
    Organisms can move on dense water than on light
    water by floating.

38
Density and Temperature
  • Density is also affected by temperature,
    increase in temperature result in low density
    though to a maximum temperature of 4oC when it is
    constant

39
Water Density and Salinity
  • Water density is also affect by salinity (amount
    of salt in water).
  • Water containing high salt concentration has
    increase water density compared with water with
    low salt concentration.

40
Measurement of Density
  • Density can be determined by using
  • Hydrometer
  • Specific gravity bottle

41
LIGHT/WATER TRANSPARENCY
  • This is the amount of light entering the water

42
Factors Affecting Water Transparency
  • Light intensity
  • Angle of incident ray
  • Geographical area (higher in the tropics)
  • Time of the day
  • Water movement
  • Season
  • Water quality

43
TURBIDITY
  • Amount of suspended solids in water

44
Effect of Turbidity
  • When light penetrated water, suspended solid
    absorb/reflect light rays reducing amount of
    light going beyond them.

45
  • Thus, the more dissolved solid, the more turbid
    water and the less light penetrate it.

46
Effects of Light Intensity
Light intensity affect
  • Embryo activity
  • Breeding period
  • Visibility
  • Avoidance of enemies

47
Effects of light intensity contd
  • At optimum light intensity
  • Higher photosynthesis thus dissolved oxygen
    released into the atmosphere and carbon dioxide
    is removed
  • More nutrients NO3-, PO4-, etc are utilized thus
    pH becomes greater (alkali) as all the acidic CO2
    are used up.

48
Measurement of water transparency
  • PHOTOMETER which convert radiant energy of light
    into electric energy and recorded.
  • SECCHI DISC measure light depth penetration.

49
WATER COLOUR
  • True water colour is caused by the amount of
    substance in solution/ colloidal suspension in
    it.
  • colour result from unabsorbed light ray.

50
The main reason the ocean is blue is that water
itself is a blue-colored chemical. Optical
scattering from water molecules provides a second
source of the blue color, but colored light
caused by scattering only becomes significant
with extremely pure water
51
WATER DEPTH
  • Depth shows relative distance between the beds
    of water to the overlain shallow water.

52
Water Depth is related to
  • Light penetration
  • Thermal stratification
  • Volume
  • Photosynthesis and
  • Distribution of organism in the water body

53
CHEMICAL LIMNOLOGY
54
CHEMICAL LIMINOLOGY
Involves
  • DISSOLVED OXYGEN
  • SALINITY
  • HYDROGEN ION CONCENTRATION
  • CARBON DIOXIDE
  • ALKALINITY
  • NITROGEN
  • SULPHUR
  • SILICON

55
DISOLVED OXYGEN
  • It is important in the tropics due to relatively
    high temperature which allow low dissolved
    oxygen.
  • At high temperature, metabolic activity rate
    increase at each 10oC hence more oxygen is
    required whereas low dissolved oxygen is
    available.

56
SOURCES OF DO
  • from atmosphere, air by simple diffusion into
    surface water.
  • photosynthesis - green plants, all bacteria,
    phytoplankton and higher plants
  • oxidation processes which is a chemical process
    e.g. Fe2 Fe3,
  • NH3 O2, NO2 NO3 C CO2/CO3 P PO4-

57
Factors Affecting DO Concentration In Water
  • There are variety of factors which affect
    dissolved oxygen in water either positively or
    negatively.
  • Some of these factors are listed below.

58
  • These factors include
  • Temperature
  • Diurnal variation
  • Atmospheric pressure. Low pressure gives low DO
  • Altitude. At higher up the mountain, temperature
    is low and DO is high.
  • Water movement

59
Factors Affecting DO Conc. In Water (contd)
  • Photosynthetic activities during the day time
  • respiration
  • Organic concentration
  • Presence of suspended materials which intercept
    with light penetration
  • Water chemistry- chemical reaction due to
    oxidation of Fe2, NH3, C and P
  • High salinity also result in low dissolved oxygen
    e.g. 20mg salt decreases oxygen by
    0.008mg/threshold.

60
Variation in DO
  • Observed variation in DO can be described as
  • Diurnal (day and night)
  • Seasonal (dry and wet seasons)
  • In running water (rivers and stream, due to water
    movement, mixing occur, hence high DO)

61
  • Spatial variation-(upper and lower parts deep
    and shallow water)
  • Thermal stratification In deeper water bodies,
    occasionally mixing increases DO at onset of
    thermal stratification, hypolim has high
    dissolved oxygen and latter falls.

62
DISSOLVED OXYGEN AND FISH CULTURE
  • In good water quality
  • NH3 NO3,
  • C CO2/CO3,
  • P PO4
  • Thus, help to sanitized the water, converting
    some toxic substances into useful ones.

63
  • In high DO, fish feed well and the rate of
    metabolism increases resulting in growth.
  • In low DO, there is low metabolic rate, fish feed
    poorly and result in low growth as it waste
    energy gasping for oxygen

64
In Low DO
  • Pathogenic bacteria, fungi, leeches thrive well
  • Disease outbreak is encouraged leaving damage on
    fish skin

65
  • Super saturation of dissolved oxygen causes fish
    mortality
  • This result because of gas bubble disease in
    young fish. As a result of excess oxygen in their
    blood

66
AERATING THE WATER TO INCREASE DO
  • Using aerators to pump air into water
  • Water agitators act like propellers
  • Some paddle like
  • Allow water to drop from a shower-like tap into
    the water body.

67
DETERMINATION OF O2 LEVEL
  • Using oxygen meter, (in mg/litre or percentage
    oxygen saturation)
  • WINKLER'S THMETRIC method
  • TITRATION

68
  • If one spit on water and the spit remain intact
    without mixing, it implies low oxygen
    concentration.
  • If water body is stirred and it foams, it implies
    pollution and low oxygen concentration

69
SALINITY
70
Salinity
  • It is the amount of dissolved salt in water in
    parts per thousand use

71
  • salinity is the amount of salt dissolved in one
    litre of water.
  • Fresh water has little salt (lt0.05 of salt in
    one litre), marine 20-37, brackish 5-20.

72
  • Based on salt content Water bodies are
    classified as
  • hyposaline,
  • mesosaline, and
  • hypersaline.

73
EFFECTS OF SALINITY
  • Salinity affect productivity
  • Excess salt results in water pollution
  • Osmoregulation In fresh water, organisms spend
    more energy to control osmoregulation.

74
  • Increase in salinity affect organisms
    distribution (fresh and marine water).
  • Salinity also affects biology of organism in
    water.

75
Variation in salinity
  • Seasonal variation
  • Raining season
  • Dry season
  • Spatial variation
  • low in areas with lot of rain
  • high in place with little or no rain

76
  • Water body
  • lakes are greatly saline
  • saline in standing water bodies is greater than
    that of flowing river

77
Factors Affecting Salinity
  • Temperature
  • Rainfall
  • Organisms
  • certain mollusks and fishes absorb salt to make
    their body shell
  • Decaying organisms
  • Man
  • Geochemistry of the bed rock

78
MEASUREMENT OF SALINITY
  • Evaporated at temperature of 60-80oC (not use in
    fresh water)
  • Measuring the amount of chlorine using salt meter
  • using titration method -titrate AgNO3 saline
    water using K2Cr2O7 (chromate) as indicator

79
SALT CONCENTRATION AND CONDUCTIVITY
  • Electrical conductivity is determined based on
    number of charge.
  • The more the salt, the greater the charges
  • Using two electrodes with conductivity meter,
    current is measured in mho/cm or ohm-1/cm.

80
HYDROGEN ION CONCENTRATION (pH)
  • This is the degree of acidity or alkalinity of
    water.
  • It ranges from 1-14 (1-6.9 is acidic, 7.0 is
    neutral, 7.1-14 is alkaline).

81
  • pH also reflects presence of salts in water
  • Rain water contains CO2 which form carbonic acid
    and makes the water more acidic i.e. low pH.

82
  • Urban water contain sulphur compounds which form
    H2SO4 with water
  • Urban water also contain heavy metals, divalent
    elements e.g. Ca, Mg, which is alkali.

83
VARIATIONS IN pH
  • Diurnal variation
  • Bed rock
  • Productivity

84
  • lime is added to water to regulate its pH.

85
MEASUREMENT OF pH
  • using pH meter
  • pH solutions e.g. methyl red
  • pH paper
  • Litmus paper dips in water

86
CARBON DIOXIDE (CO2)
  • This is the dissolved carbon dioxide in water
  • Concentration of carbon dioxide depends on
    photosynthetic and respiratory activities in water

87
PHOSPHORUS
88
  • Phosphorus is one of the key metabolic nutrient
  • Its presence regulate phytoplankton and plant
    product
  • Presence of H3PO4 IONIZABLE ORGANIC phosphates
    from effluents, soluble organic phosphorus.

89
NITROGEN
90
  • Most Nitrogen in organic matter exist as acids in
    CHON which are de-aminated to give NH3.
  • Nitrogen undergoes ammonification to release NH3
    into environment by a heterotrophic process i.e
    aerobic/anaerobic release NH4 used by aquatic
    plants.

91
Sources of Nitrogen
  • Biological,
  • Meteorological and
  • Industrial.

92
  • When Nitrogen is used in fertilizing the pond,
    the concentration declines quickly
  • Must have been absorb by plants which release it
    to bottom mud when dead.
  • denitrified in hypolimnion plus mud.
  • absorb by mud.
  • loss through volatilization of NH3 during high pH
    in the afternoon.

93
PRIMARY PRODUCTIVITY
This is the synthesis of organic materials from
inorganic materials, needed for the sustenance of
an ecosystem.
94
Primary Production Contd
  • Primary production set in energy into the
    ecosystem.
  • The producers are the chlorophyll bearing algae,
    macrophyte, autotrophic bacteria and other
    phytoplankton.
  • Chemoautotrophic bacteria can be responsible for
    up to 25 of the primary production.

95
Further Readings
  • Water Quality Textbook by Boyd and Lichtopler
  • Ikenweiwe, N.B, D. Odulate, B. Adigun (2011)
    Ichthyology and Limnology Tools In Fisheries
    Management Fisheries Management. United Kingdom.
    Lap Lambert Academic Publishing. ISBN
    978-3-8433-9364-5. Available online at
    http//dnb.b-nb.de 127 pages
  • Ikenweiwe B. and S. Otubusin (2010). Limnology
    and Plankton Abundance. Germany. Verlag
    Publisher. ISBN- 10 3639253167, ISBN-13
    9783639253160 (Available online at
    http//www.researchbooks.org/3639253167/LIMNOLOGY-
    PLANKTON-ABUNDANCE-FISH-PRODUCTION/). 249 pages.

96
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