BIODIVERSITY OF DIATOMS FOUND IN AGUS IV HYDROELECTRIC PLANT RESERVOIR, NANGKA, BALO-I, LANAO DEL NORTE

Background of the StudyDiatoms are unicellular, photosynthetic

and eukaryotic microorganisms which are easily recognizable because of their silicified cell walls.

They are one of the major food source for freshwater organisms.

They are sensitive to very subtle changes in environmental conditions.

The fishes consume the diatoms, which are affected directly by the distribution of contaminants and physico-chemical factors such as pH and water temperature.

Objectives of the StudyMain objective:

To determine the biodiversity of diatoms found in the sampling site.

Specific objectives:1. determine the physicochemical properties

of the sampling site;2. classify the diatoms up to genus level;3. calculate the biodiversity indices of

diatoms; and4. determine the trophic state of the reservoir.

Significance of the StudyProvide information if the reservoir is

capable of maintaining a healthy freshwater ecosystem.

Serve as basis for future studies that would be dealing with diatom-based water quality monitoring.

Methodology

Sampling AreaCollection of

Diatom Samples

Determination of Physico-chemical properties

Removal of Organic Matter

Observation of samples under

microscope

Calculating the relative

abundance

Calculate the biodiversity

indices

Calculate the significant difference

Sampling Area

Site 1 Site

2

Site 1 is located near the penstock near the spillway of the Agus IV HEP.

Site 2 is located along the highway

Collection of diatom samples

Determination of Physicochemical Parameters

Observation of Samples under the microscope

Gomphonema

Eunotia

Fragilaria

Cocconeis

Achnanthidium

Pinnularia

Fragilariforma

Biodiversity indicesSimpson’s Index:

DSimpson = 1- (Σ ni(ni-1)) / (N(N-1))

Margalef Richness IndexIMargalef  = (S - 1) / ln(N)

Trophic Diatom IndexTDI= Σ sensitive/ Σ tolerant

Relative abundance:Relative Abundance= n1/N *100

Average Physicochemical Parameters and Biodiversity Indices of the Reservoir of Agus IV Hydroelectric Plant.

There was no significant difference in any of the factors and indices between the two sites.

Sampling Site

Physicochemical Factors

pH Temp. Salinity TDSSite 1 6.68 26.74 0 60.17

Site 2 6.52 26.67  0 59.47

Results

Most abundant species◦Site 1: Fragilaria (19.3%)◦Site 2: Pinnularia (30.9%)◦Overall: Fragilaria (20.2%)

Sensitive genera found◦Site 1: Achnanthes (5.0%) Cymbella (7.4%)

Aulacoseira (8.9%) Eunotia (0.50%) Pinnularia (5.0%)

◦Site 2: Achnanthes (3.6%) Cymbella (9.1%) Aulacoseira (0.91%) Eunotia (5.5%)Pinnularia (31%)

Tolerant genera found◦Site 1: Amphora (0.99%) Cocconeis (14%)

Nitzschia (0.50%)

◦Site 2: Amphora (1.8%) Cocconeis (0.91%)Nitzschia (3.6%)

Species found in site 1 but not in site 2Asterionella (2.0%) Brachysira (0.50%)Epithemia (0.50%) Fragilariforma (5.4%)Frustulia (0.99%) Melosira (1.5%)Rossithidium (4.0%) Tabellaria (1.5%)

Species found in site 2 but not in site 1Eunophora (0.91%) Meridion (0.91%)

Trophic Diatom Index (Site 1)

∑sensitive=Achanthes+Aulacoseira+Cymbella+Eunotia+Pinnularia∑tolerant Amphora+Cocconeis+Nitzschia

= 10+18+15+1+10 = 1.692+29+1

Trophic Diatom Index (Site 2)

= 4+1+10+6+34 = 7.862+1+4

Trophic Diatom Index (Overall)= 14+19+25+7+44 = 2.79

4+30+5

Poly-hypertrophic

Eu-polytrophic

Mesotrophic

Trophic states indicated by the TDI (Source: Rott et al., 1999)

Trophic Diatom Index

Trophic state

≤1.0 Ultraoligotrophic

1.1-1.3 Oligotrophic

1.4-1.5 oligo-mesotrophic

1.6-1.8 Mesotrophic

1.9-2.2 meso-eutrophic

2.3-2.6 eutrophic

2.7-3.1 eu-polytrophic

3.2-3.4 polytrophic

> 3.4 Poly-hypertrophic

For Simpson 1-D Index:As the value gets closer to 1, the more greater is the diversity.

For Margalef richness index:Since Margalef's index is used as a way to compare species richness in two communities where different numbers of individuals have been collected, there is no standard value for this index.

ConclusionsDiatoms are diverse in the sampling area.

Site 1 is mesotrophic while site 2 is poly-hypertrophic.

RecommendationThe amount of dissolved oxygen (DO) and

biological oxygen demand (BOD) should also be determined so that the actual levels of oxygen in the body of water will be correlated with the number of diatoms present.

We are now ready to hear your comments and suggestions.