Exploring the influence of detrital loading of Eichhornia crassipes on water properties under different nutrient gradients in mesocosm experiments

Aim: This mesocosm study assessed the ecological impacts of the detrital loading of Eichhornia crassipes (water hyacinth) on aquatic ecosystems by analyzing changes in the water physico-chemical properties across six nutrient gradients, mesotrophic, eutrophic, and hyper-eutrophic, each at low and high levels. The study focused on detritus-induced hypoxia in nutrient-rich systems and aimed to inform effective management strategies for E. crassipes invasions. Methodology: A total of 252 mesocosms were established in a randomized block design using modified Hoagland solution adjusted to represent six nutrient levels. E. crassipes plants were acclimatized for 15 days before stocking, and control sets were maintained separately. Water quality parameters and detrital loading were monitored fortnightly, with data analyzed using One-way ANOVA, PCA, regression, and cluster analysis. Results: Significant variation was observed in total dissolved solids, pH, total alkalinity, hardness, dissolved oxygen, free CO2, nitrate-N, and phosphate-P across treatments. Higher detrital loading under eutrophic and hyper-eutrophic conditions increased nutrient levels and reduced dissolved oxygen, indicating hypoxia. Correlation analysis revealed positive associations of detritus with pH, nitrate-N, and phosphate-P, and negative with dissolved oxygen. Interpretation: Elevated nutrients accelerate the detrital loading of E. crassipes degrading water quality. The study advocates for nutrient control, sustainable biomass utilization, and integrated water quality management to maintain aquatic ecosystem health. Key words: Detritus dynamics, Eichhornia crassipes, Mesocosm, Trophic gradient, Water quality