Cinder Dianne Luza – Tabiolo et al IJSRE Volume 06 Issue 04 April 2018 Page 7898 Volume||6||Issue||04||April-2018||Pages-7898-7902||ISSN(e):2321-7545 Website: http://jsae.in Index Copernicus Value- 76.10 DOI: http://dx.doi.org/10.18535/ijsre/v6i4.01
Phytoplankton Primary Productivity And Water Quality Of Lake Danao
Authors
Cinder Dianne Luza – Tabiolo 1 Glenfiddich J. Daymiel 2 Paulina S. Aspilla3
1,2
Jose Rizal Memorial State University Dipolog Campus, Dipolog City
3
Silliman University ABSTRACT
Primary productivity gives information related to the amount of energy available to support bioactivities of the system. The present study aimed to know the status of phytoplankton primary activity of Lake Danao in relation to water quality parameters. Gross primary productivity (GPP) and Net primary productivity (NPP) are determined by the light and dark reactions also known as ‘Light and Dark bottle’ method of Lewis (1970). Results indicate that Primary productivity (GPP and NPP) was significantly higher during the dry period than the wet period. The mean of water temperature, pH and D.O. did not vary across stations. Turbidity , TSS, Hardness and alkalinity is higher on wet period. No change in color in all stations were observed. Phosphates did not differ between periods, while nitrate content increases during wet period. The results are compared to the DENR standards and does not qualify for Class A (Public Water Supply II) and Class B (Recreational Water Class I) intended for primary contact recreation. It indicates that water bodies is polluted and are influenced by pollution-causing activities. In order to maintain the lake, coordination and effort is required from the people and government and non- government organizations. It is necessary to rehabilitate the lake as recreational site for sustainability and protection of the lake.
INTRODUCTION
Photosynthesis is the primary source of energy that supports all aquatic life in the oceans, lakes and reservoirs. It is of fundamental importance since it sets overall constraints on the flow of material and energy in aquatic ecosystems.
Phytoplankton, through the process of photosynthesis, fix atmospheric carbon and become the base of the aquatic food web. Rates of photosynthesis are dependent on the intensity and spectral quality of light, which in the aquatic environment are in turn related to the optical characteristics of the water and the rate at which the phytoplankton circulate through the water column.
Phytoplankton seasonality and distribution in temperate lakes are well studied. The temperate pattern of succession is usually limited by light and temperature and is distinct throughout the four seasons. In contrast, phytoplankton seasonality is not well established in the tropical zones, where there is more or less uniform temperature throughout the year (Campbell, 1999). Instead, precipitation has shown to affect phytoplankton productivity by adding inputs of nutrients from the watershed (Shearer et al., 1999).
Cinder Dianne Luza – Tabiolo et al IJSRE Volume 06 Issue 04 April 2018 Page 7899 The researchers aimed to find out information about the relationship of seasons on phytoplankton primary productivity and water quality of Lake Danao because it supports the biodiversity of its surroundings. Quimpang (2002) reported that the lake is oligotrophic, that is low productivity. To understand the oligotrophy, a deeper research must be undertaken which consider the different conditions brought about by rainfall.
METHODOLOGY
Description of the Study Area.
Lake Danao (latitude 8° 16' N and longitude 123°27' E) is located in Barangay Danao, which is part of the municipality of Sergio Osmena province of Zamboanga del Norte. Lake Danao is not so known, it is a small lake with a surface area of only 0.0804 km . Its maximum depth of 8 m is about at the middle of the almost circular lake. Its shoreline development (SD) is 1.054. Shoreline development is an index of the regularity of the shoreline. Thus, circular lakes would approach the minimum shoreline development value of 1.
The SD of Lake Danao is very close to unity, showing its almost circular shape and implying the limited extent of its littoral zone.. This is true at the northern side of the lake where the forested perimeter occurs. The limited littoral zone substrate bed is soft and muddy and can reach up to a person’s midshin. The significance of shoreline development is that it reflects the potential for greater development of littoral communities in proportion to the volume of the lake (Wetzel, 1983). Because of the small value for development of Lake Danao, the amount of aquatic macrophyte community, as observed, is low. Due to its small size, this small outflow stream is not reflected on the DENR topographic map (Arances and Amoroso, 2004).
Sampling Stations. The study was conducted at Lake Danao, part of the municipality of Sergio Osmena
province of Zamboanga del Norte l from April 2017 to August 2017. A total of ten sampling visits will be done in the study area; eight (8) samplings during the wet period and another eight (8) samplings during the dry period.
Primary Productivity ( Light and Dark reactions)
Gross primary productivity (GPP) and net primary productivity (NPP) were determined by the light and dark reactions (Lewis 1970). Initial dissolved oxygen was determined as in DO determination. Paired BOD bottles, one transparent and the other wrapped in a black plastic bag were suspended at about a foot from the surface of the water, each containing raw water collected from the depths at which bottles were suspended. The samples were allowed to incubate at this depth for 2 days.The observed Gross Primary Productivity (GPP), Net Primary Productivity (NPP) in mg/l/hr were converted into gC/m3 /hr by multiplying these values with a factor of 0.375 using the following formula:
GPP = ( C3-C2 x 1000 x 0.375) = mg C /m3/hr PQ x t
NPP = ( C3-C1 x 1000 x 0.375) / PQ x t = mgC/m3/hr
Physico-chemical parameters. Collection of water samples as well as determination of the following in situ
physico-chemical parameters were done in each site. Sub-surface temperatures using field thermometers; pH using a pH meter; turbidity was determined nephelometrically with a Merck Turbiquant 1500T in three replications, and total dissolved solids using a cyberscan con 200 conductivity meter.
Cinder Dianne Luza – Tabiolo et al IJSRE Volume 06 Issue 04 April 2018 Page 7900 samples for total suspended solids (TSS), total hardness, methyl orange alkalinity, ammonia, nitrate and phosphate.
For the dissolved oxygen and BOD, two sets of BOD bottles were dipped into the water and covered when full while still immersed in the water. At Day 0 ( initial DO determination), oxygen was fixed by treating the samples wih MnSO4 and alkaline KI righ away and covered with dark plastic bags. Winkler titration was
done on-field working station. The second bottle was incubated for 5 days and dissolved oxygen was then determined. BOD was then calculated as DO0 – DO5.
Turbidity of the water samples was determined using a Meck Turbiquant 1500T. Total Hardness was
determined using EDTA compleximetric titration. Fifty (50) mL samples were titrated with standard EDTA. For the MO alkalinity, 50 ,ml samples were titrated with standard HCl solution. For the total suspended
solids (TSS), a 1-L water sample was collected using polyvinyl containers and filtered through GF/C. The
filtrate was collected and transported to Silliman University Laboratory for analysis of nitrate and phosphate.
Nutrient analysis: Phosphates (PO4 –P mg/L) Analysis. Water samples in three replicates were taken from
the three sampling sites and were placed in a glass bottle. Samples were then placed in a styropore box with ice and brought to the laboratory for analysis.
Stock solutions of Sulfuric acid, Ascorbic acid and Mixed reagent were first prepared. Sulfuric acid was prepared through adding 125 ml concentrated H2SO4 to water and was diluted to 500 ml, stored in a plastic
bottle. Ascorbic acid on the other hand, was prepared through dissolving 5 grams ascorbic acid in a glass bottle with 25 ml water, and added with 25 ml sulfuric acid solution, stored in a refrigerator. Mixed reagent was prepared through dissolving 6.25 g (NH4)6Mo7O24•4H2O in 62.5 ml of water. Dissolve 0.25 g
potassium antimony tartrate (with or without ½ H2O ) in 10.0 ml water. Add the molybdate solution to 175
ml of dilute sulfuric acid with the tartrate and was stored in a glass bottle. Then the following were added to a test tube or scintillation vial: 10 ml filtered sample, 0.2 ml ascorbic acid mixed reagent. Absorbance at 880 nm was measured between 5 and 30 minutes.
Determination of Nitrate (NO3-N). Surface water samples were collected in clean bottles and kept in an
icebox and transported immediately to the laboratory. In the lab,six (6) 10-mL from pipet was transferred into separate canisters and to 3 of the canisters it will be added with 0.2 mL of 1.0535 ppm NO3-N (spiked
samples). It is added with 10 mL of ammonium chloride buffer to both unspiked and spiked samples.The mixture is poured into the reductor and collect about 8 to 10 mL to rinse and collect the last 10mL before adding 0.4 mL sulfanilamide and 0.4 mL N-1-naphthylenediamine hydrochloride to the reduced sample. Allow the color of the azo dye to develop for about 15 minutes and measure the absorbance within 1 hour at a wavelength of 540nm.
conc, mg NO3-N/L =
( )
(( ) ( )) Where
Vol of std NO3-N = 0.2 mL Conc of std NO3-N = 1.0535 ppm totalvol = 10.2 mL
vol of sample = 10 mL
RESULTS AND DISCUSSION
Cinder Dianne Luza – Tabiolo et al IJSRE Volume 06 Issue 04 April 2018 Page 7901 needed light to produce organic energy molecules ATP and NADPH while Dark reactions, no light needed instead, use ATP and NADPH to produce energy molecule.
Primary productivity is the rate at which radiant energy is stored by the producers. Gross Primary Productivity (GPP) is the amount of organic matter synthesized by producers per unit area in unit time, while Net Primary Productivity (NPP) is the amount of organic matter stored by producers per unit area in unit time.
The results of the Gross Primary Productivity (GPP) values showed that mean GPP values of 12.10 mgC/m3 /hour were higher in dry period compared to that in wet period with only 2.61 mgC/m3 /hour. While in Net Primary Productivity the dry period with a mean value of 0.68 mgC/m3/hr is higher than -8.04mgC/m3/hr during wet period.
Primary productivity (GPP and (NPP) was significantly higher during the dry period than the wet period. This phenomenon could be due to increased light availability in the water column. The increasing amount of rainfall brought decreasing amount of phytoplankton productivity across stations. This could be due to the conditions of the lake during wet period. Increased TSS (Total Suspended Solids) during the wet period may alter photosynthetic activity of phytoplankton hence lowering productivity. This indicates that productivity is hampered since primary production is dependent upon light availability in assimilating terrestrially-derived inputs.
Table 1. Lake Primary Productivity ( Light & Dark Reactions) between two periods.
STATION
WET DRY
GPP mg/C/m3/hr NPP mgC/m3/hr
GPP mgC/m3/hr
NPP mgC/m3/hr
1 2.60 -8.50 11.91 0.21
2 2.04 -10.89 12.93 1.19
3 3.20 -4.71 11.46 0.63
Mean 2.61 -8.04 12.10 0.68
SD 0.58 3.12 0.76 0.49
The mean water temperature of 26.3 °C during dry period and 25.7 °C in wet period, pH of 7.69 (D) and 6.13 (W), and D.O. of 6.48 (D) and 3.94 (W) did not vary across stations. Turbidity mean of 45.7 was significantly higher during the wet period. TSS mean of 30.1 mg/L was higher during the wet period.
Hardness and Alkalinity with mean of 39.7 and 49.6 increased significantly during wet period. No change in
color in all stations was observed. The results were compared to the DENR standards and does not
qualifyfor Class A (Public Water Supply II) and Class B (Recreational Water Class I) intended for primary contact recreation.
Table 2. Physico-chemical parameters of water.
Parameters
Station 1 Station 2 Station 3 Mean +_ SD
DENR Standards
D W D W D W D W D W
Temp, ₒ C 26.0 25.0 26.0 25.0 27.0 27.0 26.3 25.7 0.58 1.15 26-30
pH 7.63 6.11 7.67 6.13 7.76 6.13 7.69 6.12 0.07 0.01 6.5-8.5
color 50 50 50 50 40 40 47 47 6 6 50
Turbidity 46.3 52.3 40.0 63.2 29.0 21.7 38.4 45.7 8.8 21.5 5
TSS, mg/L 35.2 37.33 27.0 37.07 23.7 16.00 28.6 30.1 5.9 12.2 50-65
DO,mgO2 6.56 4.31 6.35 3.25 6.53 4.27 6.48 3.94 0.11 0.60 5
BOD, mgO 3.58 3.03 3.98 2.94 3.30 2.09 3.62 2.69 0.34 0.52 3-5
Cinder Dianne Luza – Tabiolo et al IJSRE Volume 06 Issue 04 April 2018 Page 7902
Nitrate content mean of 4.46 mg was significantly higher during the wet period. This could be explained by
the rapid uptake by planktons, which are abundant at this time of the year during the wet season as a result of a decrease in the number and activity of phytoplankton.
Phosphates have a mean of 0.255 mg did not significantly differ between periods. This could be due to
less dilution or loss by precipitation in contrast to the observations made by Baluyot (1984) in Laguna lake in which orthophosphate levels increased during dry months. Such differences in both nitrate and phosphate levels might be influenced by other source such as from nearby farm, closed mining activity, households, vegetation, erosion, and lake was serve as quagmire of buffalos.
Figure 1.Nutrient Contents during wet and dry periods.
CONCLUSION AND RECOMMENDATIONS
The present information of Danao Lake showed variation in primary productivity throughout the study period. Primary productivity was integrated not only by seasonal variation but also nutrient content, eutrophication, stratification and agricultural runoff, domestic and industrial effluent similarly anthropogenic activities. Wet periods where evaporation and precipitation of Danao lake did not produced energy which causes eutrophication of lake , while during dry periods there was an increased of GPP and NPP by peak photosynthetic activity. Seasonal variation in primary productivity indicated that Danao lake was found to be slightly eutrophic in nature. It indicates that water body is polluted and were influenced by pollution-causing activities. In order to maintain the lake, coordination and effort is required from the people and government and non- government organizations. It is necessary to rehabilitate the lake as recreational site to sustain and protect the lake.
0
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Nitrates(NO3) Phosphates(PO4)
Wet period
