Tag Archives: Net primary productivity

In-Stream Sand Mining and Primary Productivity of Otamiri River in Owerri, South-East Nigeria (Published)

Sand mining involves the excavation of inland dune or river beds for the purpose of economic, developmental, constructional, etc., activities. Primary productivity therefore, is the frequency at which energy is transformed to organic substances by photosynthesis producers (photoautotrophs), which obtain energy and nutrients by requisite sunlight. Probable influence of sand mining on primary productivity of the mined ponds along the banks of the river was considered. The study undertakes an experimental research approach. Six (6) sampling locations were identified as WC1-WC6 along the course of the river. WCI-WC3 was established in area where active mining had ceased (unperturbed) whereas WC4-WC6 was established in area where active sand mining is ongoing (perturbed). The study utilized the light and dark technique to estimate primary productivity, and the set-up was incubated for four (4) hours in a sunny day. In situ measurement was carried out with HANNA 1H9828 pH/ORP/EC/DO meter and the average of the triplicate results obtained was recorded. Descriptive statistics, analysis of variance (ANOVA), student’s t-test and the structure detection of group mean were utilized for the organization of data. Results inter alia revealed that the actively mined ponds of the river had higher GPP (12.781*10-1 MgCL-1d-1) than the location where mining had ceased (i.e., GPP 5.986*10-1 MgCL-1d-1). The average GPP was 18.767*10-1MgCL-1d-1 while NPP and CR had 10.914*10-1 MgCL-1d-1 and 15.453*10-1MgCL-1d-1 respectively. The annual GPP of the study was 1144.800*10-1MgCL-1yr-1 which define low productivity. Thus, it was recommended that an enforcement of various environmental laws as it affects the preservation, maintenance and the sustenance of the aquatic environment be made in a bid to secure aquatic lives.

Keywords: Aquatic Ecosystem, Biomass, Carbohydrate, Community respiration, Gross primary productivity, Net primary productivity, Photosynthesis, Sunlight