Influence of Humic Acid on Water Quality and Growth of Algae in Freshwater Ecosystem
One of the approaches to improve aquaculture production is through improvement of fertilization program for phytoplankton production and water quality variables. There are serious problems with the use of raw organic fertilizer in ponds and environment. Oxygen depletion, degradation of water qual...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2001
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/10547/1/FP_2001_7.pdf http://psasir.upm.edu.my/id/eprint/10547/ |
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| Institution: | Universiti Putra Malaysia |
| Language: | English English |
| Summary: | One of the approaches to improve aquaculture production is through
improvement of fertilization program for phytoplankton production and water quality
variables. There are serious problems with the use of raw organic fertilizer in ponds
and environment. Oxygen depletion, degradation of water quality, reduced light
penetration, and spread of diseases frequently occur after large doses of manure are
added to a pond at irregular intervals. This study was conducted to investigate the
influence of humic acid (HA) on primary productivity (phytoplankton production)
and water quality variables in a freshwater aquatic ecosystem.
Two experiments were carried out to evaluate effects of humic acid alone or
in combination with inorganic (urea and single super phosphate) or organic fertilizer
(cow manure) on the phytoplankton productivity. Prior to the experiments, HA
contents of cow manure (CM), chicken manure, compost and tropical peat were
estimated to determine the suitable source (quantity) for HA extraction. The results
showed that tropical peat contained 46.5% (dry weight basis) HA and 11.6-17.2 folds higher than the other organic fertilizers. Humic acid from the tropical peat was used
in the subsequent experiments.
An experiment was conducted at the Gharehsoo Station of Fisheries Research
Centre of Mazandaran (FRCM) in North of Islamic Republic Iran (July and August
1999) to study the effects of HA and inorganic fertilizer (urea and single super
phosphate) on growth of selected freshwater phytoplankton and water quality
variables. The experiment was carried out in eighteen 1.5 Liter transparent plastic
bottles (control , 25 ppm HA+UP, 50 ppm HA+UP, 100 ppm HA, 100 ppm HA+UP,
150 ppm HA+UP). Three species of green algae (Chlorella vulgaria, Scenedesmus
quadricauda, and Oocystis solitaria) and a species of blue-green alga (Oscillatoria
agardii) were selected for the study.
The results showed that highest population (bloom) was achieved in week 3
by 100 ppm HA. All treatments with a combination of HA and urea-phosphate led to
a blue-green algal (Oscillatoria agardii) dominancy with a low phytoplankton bloom
and low total nitrogen (TN) and total phosphorus (TP) ratio (0.7-1.03). The green
algal dominance was associated with a high TN:TP ratio (16-17) in culture media.
pH of HA treatment was within the suitable range (7.84-8.51) for phytoplankton
production. Light penetration correlated well with blue-green algal population |
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