Macroinvertebrates associated with artificial floating islands installed in River Kshipra for water quality improvement

Abstract

Abstract Artificial floating islands (AFIs) are artificial buoyant superstructures vegetated with riparian plant species, especially reed grass (Phragmites karka) floating on waterscape. These structures are mostly installed in lakes and stagnant systems as a green technology for water quality improvement. In the present study, an AFI was installed in the River Kshipra, Ujjain city at a point where wastewater nullah meets the river. The focus was to study the composition of macroinvertebrates associated with AFIs and to monitor AFIs' role in river water quality improvement. The inspection indicated that the coir-based AFIs' substratum supports a variety of macroinvertebrates that are supplementing the role of AFIs for water quality improvement, besides the role of riparian plants. The open river water, far from AFIs, does not support macroinvertebrates in the upper layer of the water column. The installation of AFIs improved the underneath water quality: reducing the pollution load by 46% of total suspended solids (TSS), 51% of turbidity, 37% of total Kjeldahl nitrogen (TKN) and 39% of biochemical oxygen demand (BOD). The AFIs resulted into a development of a floating habitat for diversity of a macroinvertebrates community of predators, filtering collectors, gathering collectors, scrapers and shredders. The AFIs serves a dual purpose: water cleansing green landscape and additional floating niches for aquatic macroinvertebrates.