| Author | Guttman, Hans |
| Call Number | AIT Thesis no. AE-91-34 |
| Subject(s) | Fish ponds
|
| Note | A thesis submitted in partial fulfillment of the requirements for the
degree of Master of Science |
| Publisher | Asian Institute of Technology |
| Abstract | A provisional technique for field (outdoor) algal assay
procedure was devised; using either a 125 mL Erlenmeyer flask or
a 70 mL test-tube as an incubation vessel with a 25 to 30 mL
sample covered with a loose fitting aluminum cap, incubating
under a shade cloth for 3-4 days at ambient air temperatures and
shaking the vessel s three times daily.
An algal assay methodology for determining the limiting
nutrient (carbon, nitrogen or phosphorus) for fertilized fishponds
using the above technique and indigenous algal cultures
was devised and tested. Results indicated full agreement between
assay results and nutrient limitation for prepared algal growth
media. Tests of pond waters showed a good agreement between
assay responses and nutrient ratios of the waters tested.
Visual assessment of assay responses were evaluated and
found that over 90% of people involved (n= 15) could separate a
chlorophyll a difference of < 10 mg/m3 for a 100 mL sample
filtered on to a Whatman GF/C filter.
Algal yield dose response patterns to phosphorus spiking of
phosphorus limited cultures followed a asymptotic relation (r2 >
0.86, p < 0.001 for six trials). Analysis of the regression
slopes showed a significant correlation (r2 = 0.85, p < 0.01)
between the s lopes and the initial dissolved inorganic nitrogen
(DIN) of the culture media. This lends support to the underlying
theories for assessment of DIN through a l gal assays. Dose
response experiments showed a significant and relatively close
correlation (r = 0.68, p< 0.001) between initial DIN and visually
assessed spike saturation levels (the amount of spike needed to
make DIN limiting) for phosphorus limited algal cultures.
Investigations by algal assay of pond/tank waters used for
fish culture at the Asian Institute of Technology, Bangkok,
showed a dominance of nitrogen limitation (six out of nine
cases). From these results a pattern of increased algal yield
(measured as % over control) was determined as C:N ratio
increases and N:P ratio decreases. |
| Year | 1991 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Knud-Hansen, Christopher F.; |
| Examination Committee(s) | Edwards, Peter;Lin, Chang Kwei; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1991 |