TITLE:
Relationships of Dissolved Oxygen with Chlorophyll-a and Phytoplankton Composition in Tilapia Ponds
AUTHORS:
Kornkanok Kunlasak, Chanagun Chitmanat, Niwooti Whangchai, Jongkon Promya, Louis Lebel
KEYWORDS:
Dissolved Oxygen; Chlorophyll-a; Phytoplankton Composition; Tilapia Ponds; Elevation, Season
JOURNAL NAME:
International Journal of Geosciences,
Vol.4 No.5B,
October
11,
2013
ABSTRACT: This study investigated the relationships among the
parameters of dissolved oxygen, chlorophyll-a and phytoplankton composition in
tilapia ponds. Each pond (a total of 18 ponds) was sampled once in the dry,
winter season between January and March and again early in the rainy season
between May and June. The data were analyzed by examining correlations among
parameters as affected by season, altitude and culture system. Observations
were made at sites located in 5 selected provinces of northern Thailand:
Chiangrai, Chiangmai, Phayao, Lampang and Nakornsawan. Mean elevation of these
areas range from 25 to 582 meters above sea level (masl) and were categorized
into low (400 masl) elevation sites. Ponds were 0.8 - 2.0 m
deep, 0.16 - 0.64 ha in area and could be further categorized into high and low
input systems.Mean air temperature in winter ranged between 16.5°C - 35.8°C
while mean water temperature ranged between 25.5°C - 27.1°C.
In rainy season, air temperature ranged between 22.0°C - 37.3°C
and water temperature ranged between 29.4°C - 31.8°C. The amount
of chlorophyll-a in both seasons were comparable (p > 0.05),
but chlorophyll-a in high input system was significantly higher (p 0.05)
than in low input ponds. Only weak correlation was found between chlorophyll-a,
DOmax and DOmin. Multifactor-ANOVA was used to analyze
the difference of total bacteria and filamentous cyanobacteria in ponds based
upon elevation, culture systems and season. Result shows that there is a
significant interaction observed between elevation, culture system and season
(p 0.05). Species diversity and composition of phytoplankton in fish
ponds in 2 seasons revealed the presence of 90 genera of phytoplankton under
all 7 divisions. Divisions Chlorophyta and Cyanophyta had the most number of
genera identified in both seasons with Pediastrum spp., and
Scendesmus spp., and Anabaena spp. as dominant genera/genus,
respectively.