TITLE:
Investigating Temperature and Nutrients as Drivers of Primary Productivity in Aquatic Environment
AUTHORS:
Dike Henry Ogbuagu, Ugochukwu Obioma Nwahiri, Emmanuel Chikezie Osuebi, Iheoma Ezichi Mbuka-Nwosu, Chinwe Grace Onwuagba
KEYWORDS:
Eutrophication, Riparian vegetation, Primary productivity, Nutrients, Otamiri River
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.7 No.7,
July
26,
2019
ABSTRACT: An
investigation into the relationship between temperature and the nutrients (,, and ) in pelagial primary productivity of the middle
reaches of Otamiri River in Owerri, Southeastern Nigeria was carried out
between October and November, 2018 at ten
sampling points (OTP 1-OTP 10). The estimation of productivity was made with
the light and dark bottle technique. Maximum yields in Gross Primary
Productivity (GPP) (0.8738 mgCL-1d-1), Net Primary
Productivity (NPP) (0.8513 mgCL-1d-1), as well as
Community Respiration (CR) (0.1613 mgCL-1d-1) were
recorded at OTP 3, OTP 3 and OTP 8 respectively that had more vegetation covers
than in segments without cover. GPP is correlated withions (r = 0.400),ions (r = 0.418), and water temperature (r = 0.379) (p 0.05), while CR is correlated with ions (r = 0.500) (p 0.01). The variability of GPP increased mildly with increasing
temperature and the nutrients; with predicted regression model productivities
of 0.1388, 0.5621, and 0.6066 mgCL-1d-1, corresponding
with mean values of 28.41℃, 0.33 mg/L,
1.04 mg/L and 10.25 mg/L recorded for temperature,,, and ions
concentrations. Mean GPP was estimated to result in a comparatively low annual
productivity of 188.75 mgCL-1yr-1. Conservation and
restoration of riparian vegetation covers in watershed corridors of the river
for optimal driver roles were recommended.