Study On Basal Food Trophic In Two Different Freshwater Ecosystem
| dc.contributor.author | Zainodin, Amila Faqhira | |
| dc.date.accessioned | 2017-01-23T02:17:16Z | |
| dc.date.available | 2017-01-23T02:17:16Z | |
| dc.date.issued | 2016-09 | |
| dc.description.abstract | Present study investigated the composition of aquatic insects, their drift activities and their food webs in selected sites in Perak, northern state of Malaysia. Four rivers in Bukit Merah were chosen to study the relationship of aquatic insect composition with the characteristics of the river. One thousand and eighty-seven (1087) individuals from seven orders and 27 families were collected from all study rivers. The most abundant aquatic insect collection was obtained at Ara River with 580 individuals. Besides using composition of aquatic insects, the physicochemical characteristics of the water also has been used to monitor health of rivers world widely. All study rivers in Bukit Merah were classified as clean (Class II) based on the Water Quality Index (WQI). The physicochemistry of the rivers i.e., depth, ammoniacalnitrogen, TSS, COD and velocity affected the distribution and diversity of the aquatic fauna. To further understand aquatic insects’ diversity and their method of dispersal, drift pattern and diel periodicity of aquatic insects was investigated. Drifting aquatic insects were collected at every six hourly intervals within 24-hour period using a drift sampler. Three thousand one hundred and forty-seven (3147) individuals represented by nine orders, 49 families and 81 genera of drifting aquatic insects were collected. There was a significant difference in aquatic insects’ drift between four time intervals (Kruskal-Wallis test, χ2 = 25.68, P = 0.00, df = 3). Greatest drift abundance occurred during night time, where approximately 40 % higher than in the daylight samples, signifying diel periodicity. In addition, moonless nights exhibited more drift rate as compared to bright, full-moonlit nights and differed significantly (Mann-Whitney U test, (Z = - 2.093, P < 0.05). Drifting aquatic insects displayed alternans pattern with the greatest abundance at 0200 – 0800 h interval (1357 individuals with 63 genera). Preys drifted more actively at nighttime (70.42 %) as compared to daytime (29.58 %). The most dominant drifters were Ephemeroptera, Trichoptera and Coleoptera. Overall, the prey-predator ratio in this study was about 8: 1. Stable isotope approach was used to comprehend the aquatic food webs and trophic relationships of two different freshwater ecosystems (rivers and paddy fields). The aquatic insects’ carbon and nitrogen signatures in the rivers ranged from – 15.03 to – 33.08 ‰ for δ13C and 2.59 to 8.11 ‰ for δ15N. In paddy fields, the signatures ranged from – 23.59 to 30.58 ‰ for δ13C and 2.58 to 7.75 ‰ for δ15N. The samples varied significantly between all study sites and trophic levels as determined by one-way ANOVA with Tukey post hoc test (F (6, 62) = 2.69, P = 0.022) for δ15N and (F (6, 62) = 15.35, P = 0.000) for δ13C. Correspondingly, with all the δ13C and δ15N values recorded, it can be deduced that there are four trophic levels existed in the freshwater ecosystems. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/3532 | |
| dc.subject | The composition of aquatic insects, their drift activities and their food webs | en_US |
| dc.subject | in selected sites in Perak, northern state of Malaysia. | en_US |
| dc.title | Study On Basal Food Trophic In Two Different Freshwater Ecosystem | en_US |
| dc.type | Thesis | en_US |
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