Relationship between Dissolved Oxygen and the Vertical and Longitudinal Distribution of Zooplankton off the Namibian coast
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Date
2013
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Unioversity of Namibia
Abstract
Zooplankton play an important role in the marine food web and are abundant on the
Namibian coast, which is part of the highly productive Benguela upwelling system. In
the Benguela system zooplankton populations are dominated by copepods and euphausiids.
The abundance and distribution of zooplankton are affected by various environmental
factors such as temperature, light intensity and dissolved oxygen (DO). This study investigated
the relationship between DO and the diversity of zooplankton at different depths
in the water column on the continental shelf off the Namibian coast. There was a positive
correlation between DO and diversity of zooplankton offshore (Pearson’s r =0.83),
while there exists a very weak positive correlation between DO and zooplankton diversity
onshore (r= 0.196). Diversity of zooplankton does not differ significantly with depth at
both onshore and offshore stations (Shannon’s Index H0 < 1). However, Divesity of zooplankton
between offshore (H0=2.8 to 3.6) and onshore (H0=0.8 to 0.9) stations differs
significanty (p = 0:0271;d f = 4) in the top 90m, but is not significantly different below
90m (p = 0:406;d f = 4). Nevertheless, the onshore stations had higher species richness
compared to the offshore stations. Dissolved oxygen does not have a direct effect on the
diversity of zooplankton, but an indirect effect and it is the interplay and interaction between
several biological and environmental factors that affects zooplankton assemblage
composition.
Description
Keywords
Zooplankton, Dissolved oxygen, Namibian coast
Citation
Julies, E.M. 2013. Relationship between Dissolved Oxygen and the Vertical and Longitudinal Distribution of Zooplankton off the Namibian coast. International Science and Technology Journal of Namibia 1(1-2):78-89.