The relation of the density of green-pigmented algae and blue-green algae to chlorophyll concentration in the floodwater of paddy fields in Los Baños, Laguna ,Philippines

Date

5-2001

Degree

Bachelor of Science in Biology

Major Course

Major in Cell Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Milagrosa, R. Martinez-Goss

Abstract

A total of 29 species of green and blue-green algae (BOA) were collected and identified in four wetland rice plots in Barangay Maahas, Los I3afios, Laguna during the wet season of the rice cropping cycle, between November 18, 2000 to January 7, 2001 Thirteen of these species belonged to Division Cyanophyta while sixteen species were of the green-pigmented type and belonged to two divisions, Chlorophyta and Euglenophyta. The most dominant and frequently occurring species were Euglena oxyuris Schm and Phacus caucknus Hueb , followed in decreasing order by Oscillaioria agardhi Gom., Spiruhna major Kutz., Anahaem sp , and Trachelomonas granulosa Playf The euglenophytes were the most dominant type of algae in all the rice plots throughout the sampling period. The green-pigmented algae developed their maximum density (411,250 cells/ml) at the beginning of the cultivation cycle or at 34 days after transplanting (DAT) (December 8, 2000), and then gradually decreased. Mostly filamentous and non-N2-fixing forms of BGA were observed and their maximum cell density (93,500 cells/nil) was also reached at 34 DAT Trends in algal succession coincided with previous observations that green algae developed their maximum density at the beginning of the cultivation cycle, while the BOA rarely became dominant during early growth of the rice plant No significant relationship was found between chlorophyll (chl) a content and the number of total algae, total greens, and total BGA, except in plot 2 where chl a was found to be highly correlated with total BGA (r = 0.91857), where r is Pearson's correlation coefficient No significant correlation was observed between green-pigmented algae population and chl h concentration The chl a:h ratios, on the other hand, were significantly correlated with population densities of specific genera such as Euglena in plots 1 and 4 (r = 0 68494 and 0.75006, respectively) Phacus and Trachelomonas population densities were also significantly correlated with chl a:b ratio in plot 4 (r = 0.78645 and 0 92054, respectively). Dissolved oxygen (DO) was highly correlated with chl a (r = 0 71776 - 0.93729) and chl h (r = 0.69290 - 0 84980) content in all four plots. Other abiotic factors like water depth and pH were also significantly correlated with the total algal count in 2 plots Values of r for water depth ranged from -0.78848 to -0.81927, indicating an inverse relationship with the total algae, while the r-values for pH ranged from 0 75173 to 0.90239, indicating a positive or direct relationship between the two variables. Based on results of correlations between chlorophyll concentrations and the densities of green-pigmented algae and BGA, it was determined that pigment analysis is not a suitable method for estimating algal abundance in the floodwater of paddy fields.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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