| || || Marine fouling organisms -- Fiji -- Qawa River|
| || || The microbial profiling of the Qawa River using molecular methods |
Author: Bainivalu, Awei
Institution: University of the South Pacific.
Subject: Fouling -- Measurement, Fouling organisms -- Fiji -- Qawa River -- Control, Marine fouling organisms -- Fiji -- Qawa River
Call No.: Pac TD 427 .F68 B35 2016
Copyright:40-60% of this thesis may be copied without the authors written permission
Abstract: The Qawa River situated in the North Eastern part of Vanua Levu near Labasa plays a crucial role in the lives of people within the surrounding area. Many small communities and villages along the Qawa River depend on the river for food, washing, transportation, recreation and agriculture. South of Labasa, a Fiji Sugar Cooperation (FSC) mill is situated along the river and discharge from the mill into the river has been a long standing concern for the residents of Labasa and others living near the river. Over a twelve month period (in April, August, December and March) dissolved oxygen (DO) levels and temperature were measured at sites upstream and downstream from the sugar mill. Water samples were also collected. Estimates of viable counts of bacteria were made and DNA was extracted. The 16S rRNA V3 and V4 region was sequenced on an Illumina MiSeq® platform and analyzed using QIIME software. DO levels were similar between most sites at any one time, but changed dramatically over the sampling period. They were lowest at the FSC mill site during the crushing season, but also low at other sites (excluding Namoli) during this period. Total viable counts for bacteria were greatest at the FSC mill site during the crushing season. QIIME analysis showed that microbial populations were also similar between sites, but these changed over time. It is presumed that high nutrient effluent during the crushing season leads to significant algal and bacterial growth at FSC mill, and that this leads to a high respiration demand which results in the observed dramatic lowering of DO levels up and downstream of the FSC mill. DO levels show significant recovery three months after crushing. However, during the crushing season, organisms of potential health concern can be identified in the river. A suggestion has been made for future monitoring of the river.