Quadrat Sampling and Physico-chemical Factors in Lake Ecosystems
Transcript of Quadrat Sampling and Physico-chemical Factors in Lake Ecosystems
Grassland Quadrat Sampling
and Physico-chemical Biological factors of Lake
Grassland• Grassland- terrestrial biome consisting
mainly of grasses and few trees and shrubs.
• Quadrat- a square or rectangular plot that encloses the sample
• Species Area curve- a method used to determine the size of the quadrat
• Species richness- refers to the abundance of the species
• Species evenness- equal distribution of the species in a given area.
Species-Area Curve• graph of relationship between number of
species (richness) and area sampled
• Use to determine the size of the the quadrat
• Important in determining the diversity of the area.
• applications– determine adequate community area– estimate sampling adequacy (no. of
Community)– Compare the biodiversity (different
species in an ecosystem
1 m2
4 m2
32 m2
64 m2
Species Area Curve
2 m2
8 m2
16 m2
Species-Area Curve
0
10
20
30
40
0 10 20 30 40 50 60 70
Quadrat Area (m2)
Nu
mb
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of
Sp
ec
ies
(R
ich
ne
ss
)
Quadrat Parameters• Frequency-the frequency of quadrats
occupied by a given species
number of quadrats in which species occurs
• Frequency (F) = ---------------------------------------------------------- X 100
Total number of quadrats
frequency of a species
Rel. Frequency (RF)= -------------------------------------------- X 100
total frequency of all species
Quadrat Parameters• Abundance- compares the number of plants
of that species with the total number of plants of all species in the study area:
number of plants of a certain species • Abundance (A) = ------------------------------------------------------- X 100
Total number of plants
Quadrat Parameters• Density-closely related to abundance but
more useful in estimating the importance of a species is the density. It is defined as the number of plants of a certain species per unit area:
number of plants of a certain species
• Density (D) = --------------------------------------------------------------- X 100
Total area sampled
density of a species
• Relative density (RD)= -------------------------------------------- x 100
total density for all species
Quadrat Parameters• Cover-the proportion of the total area occupied by
the species.
-also commonly called dominance:
Total area covered by a species
Cover (C) = --------------------------------------------------------- X 100
Total area sampled
• Relative cover, like relative frequency and relative density, gives a better indication of the importance of a species than does the absolute value:
cover for a species
• Relative Cover (RC) = -------------------------------------------- X 100
Total cover for all species
• Since it is considered as a grassland the most abundant is the grass e.g. carabao grass, lemon grass
• Least abundant is the weeds e.g. Mimosa Makahiya
• Importance Value- is used to determine the most abundant species by adding the relative values.
Lake Physico-chemical Factors
Definition of Terms
• Lake- a lentic freshwater ecosystem
• Limnetic- refers to the water present in the lake
• Benthic- refers to the bottom or floor of the aquatic ecosystem
• Riparian- the edge of the lake; the boundary of the aquatic and terrestrial ecoystem
Limnetic Zone• Parts of the limnetic zone
1. Epilimnion- upper layer of water where light can penetrate. Also known as photic zone
2. hypolimnion- lower layer of water where light cannot penetrate. Also known as aphotic zone
3. metalimnion- the boundary between the photic and aphotic zone. Also known as the compensation depth.
Benthic Zone• Parts of the benthic zone
1. Littoral zone- portion covered with water and light reaches the substratum.
2. riparian zone- similar with supralittoral
3. benthos- refers to the organisms present in the benthic zone.
4. profundal zone- lower portion of the aphotic zone rich in organic materials.
Light Penetration
• Secchi Disc- the instrument use in measuring the light penetration.
Average light Penetration = disappearance + reappearance
2
Percent Light Penetration = Average Light Penetration x 100
• Total depth
• Epilimnion- photosynthesis will take place; dissolved oxygen (DO) is abundant.
• Hypolimnion- respiration will take place; rich in CO2
• Metalimnion- equal amount of DO and CO2; also known as thermocline
Thermal Stratification• The varying temperature of the strata of lake water.
• Thermal inversion-the overturn of water due to changing temperature of the water layer.
•
• Warm water will rise while cold water sinks.
• What is the importance of thermal stratification and overturn?– Food distribution due to overturn
Total Suspended Solid• Small particles present in the water like silt,
plankton, etc.
• Procedure: pre-weighed filter paper filtering the suspended solids then air dried and weigh the filter paper again.
• TSS= Weight of Air dried filter paper- pre-weight of filter paper.
• Importance: affects the light penetration, temperature and photosynthesis in the epilimnion
Salinity, TDS and Conductivity
• Instrument used salinometer or SCT meter
• Salinity- amount of salts present in the water.
• TDS- total dissolved solids- the elements present in the water e.g. Ca, Magnesium etc.
• Conductivity- determines the ions present in the water.
• Importance- the elements, compounds and ions are the source of minerals needed by plants and animals in the water.
Dissolved Oxygen
• Instrument : DO meter
• The amount of oxygen traps by the molecules of water
• Produced by the atmospheric diffusion and photosynthesis of plants.
• Higher in epilimnion than hypolimnion.
• Importance: used by organisms in respiration; resulted to fish kill if there is deficiency of DO.
Nitrogen, Phosphorus, and Hardness
• Instrument used: Hach test strips
• Nitrogen- building structures of organisms e.g. component of protein. Derived from decomposing organic materials, fixed by nitrogen fixing bacteria and fertilizers
• Phosphorus- used in synthesis of ATP. Derived from decomposing organic materials, leaching of rocks and fertilizers.
• Hardness-amount of Ca, Mg and other metallic elements in the water. Originated from decomposing organic materials, leaching of rocks
pH• Amount of hydronium ions in the water.
• Low pH means acidic which is caused by nonmetallic oxide dissolved in water e.g. NO2, NO3, SO2, SO3 ,CO2
• Acidic lake reduced the DO and characteristic of eutrophic lake.
Aquatic Organisms• Plankton-floating organisms
1. Phytoplankton- floating microscopic plants
2. Zooplankton-poor swimming animals
Plankton Total count= Actual Count x Enumeration Factor
Enumeration Factor= 1000 mm3____
(50 mm) (1 mm) (1mm) (3)
Nekton- swimming organisms e.g fish
Benthos- organism present in the floor of the lake
Phytoplankton
Zooplankton
Achomosphaera Achomosphaera Adnatosphaeridium Alisocysta neptuni ramulifera multispinosum margarita
Hydrophytes
• - large aquatic plants classified as:
1. submergent- plants attached to the substrate and remained under the water.
2. emergent plants- plants attached to the substrate but emerged above the water.
3. Floating plants- plants living on the surface of the water
4. periphyton- plants attached on the surface of the rocks
5. riparian plants- plants living on the edge of the lake.