A Study of Phytoplankton and Zooplankton Diversity in the River Sabarmati, Gujarat, India

Abstract

Abiotic and biotic components are divided into two categories to describe the structural ecosystem. Aquatic plants and animals can find a suitable habitat in the river's water body. Planktons are an important component of the wetland ecology and may serve as a marker of altering water quality. Zooplankton mostly obtains its nutrition from phytoplankton, an ecosystem producer. Most fish larvae and other plankton-eating fishes feed primarily on zooplankton species. All aquatic ecosystems' dynamics revolve around primary productivity, which sustains various food chains and food webs. The overgrowth of macrophytes, pesticides from agricultural runoff, household garbage, sewage sludge, feces near rivers, bathing of domestic animals, washing of clothing and utensils, etc. have all put pressure on river ecosystems over the past many years. Most plants and animals struggle to survive in polluted environments, but those that can handle the stress of pollution on their own may be able to. These creatures can serve as pollution indicators, or more particularly, as bioindicators of the ecosystem's trophic condition. In this article, Sabarmati River's phytoplankton and zooplankton communities were evaluated at six different locations. The current investigations were researched from January 2017 to December 2019 over a period of around 3 years.  Several published plankton manuals were used for plankton collection and identification. Aquatic flora analyzed here in two respects i.e., phytoplankton and aquatic vegetation or aquatic weeds. Phytoplankton were represented by four groups, viz. Bacilariophyceae, Chlorophyceae, Cyanophyceae, and Euglenophyceae. Diversity study reveals common planktonic forms present at different sites of sampling. In general, aquatic weeds like Hydrilla, Valesneria, Chara, Nymphea, Pistia, Typha etc. were commonly found in the study area. Protozoa, Cladocera, Copepoda and Rotifers are the main groups of zooplankton found in freshwater bodies. Six Molluscans and sixteen Arthropods were identified to be the most commonly occurring riparian fauna. The annual values of all zooplankton showed greater densities at site-1 and site-6 followed by other sites, respectively. When the data were analyzed for contribution of each phylum to the overall zooplankton densities, it was dominated by Protozoa and Arthropods throughout the study period. This was followed by Rotifera, Annelid and Nematoda, respectively. The percentile composition of protozoan fauna at six study sites suggested that on more than half of the sampling occasions their major contribution was recorded at sites 1, 2 and 6  followed by sites 5, 4 and 3, respectively.