Responses of Aquatic Plants to Eutrophication in Rivers: A Revised Conceptual Model

Abstract

Compared to research on eutrophication in lakes, there has been significantly less work carried out on rivers despite the importance of the topic. However, over the last decade, there has been a surge of interest in the response of aquatic plants to eutrophication in rivers. This is an area of applied research and the work has been driven by the widespread nature of the impacts and the significant opportunities for system remediation. A conceptual model has been put forward to describe how aquatic plants respond to eutrophication. Since the model was created, there have been substantial increases in our understanding of a number of the underlying processes. For example, we now know the threshold nutrient concentrations at which nutrients no longer limit algal growth. We also now know that the physical habitat template of rivers is a primary selector of aquatic plant communities. As such, nutrient enrichment impacts on aquatic plant communities are strongly influenced, both directly and indirectly, by physical habitat. A new conceptual model is proposed that incorporates these findings. The application of the model to management, system remediation, target setting, and our understanding of multi-stressor systems is discussed. We also look to the future and the potential for new numerical models to guide management.

Nutrients, eutrophication and harmful algal blooms along the freshwater to marine continuum

“…Suspended phytoplankton reduce light penetration and the growth of benthic periphyton and aquatic plants in deep rivers. Eutrophication can also increase growth of epiphytes, thus decreasing the abundance of the macrophyte hosts (O'Hare et al, ). Esthetic impairment due to excessive filamentous algae in streams and rivers is increasingly recognized as one of the major results of eutrophication (Figure ; Dodds & Welch, ; Jakus, Nelson, & Ostermiller, ; Suplee, Watson, Teply, & McKee, ).…”

Evaluation of Habitat Preferences of Invasive Macrophyte Egeria densa in Different Channel Slopes Using Hydrogen Peroxide as an Indicator

“…As several changes occur simultaneously in natural rivers, it is not easy to elucidate the primary reason that prevented earlier macrophyte colonization or their increase today. The habitat preferences of macrophytes are normally evaluated by monitoring their growth rate or biomass (Barko et al, 1991;Riis et al, 2012;O'Hare et al, 2018). However, there are various potentially influential factors in the natural environment and each factor changes from time to time during the period of the macrophytes' growth.…”

Assessing the effects of tropical wood leachate to Desmodesmus subspicatus, Lemna minor and Daphnia magna

“…In addition, the wawa and c edrela leachate had the same growth rate to the control, and this could be due to available nutrients such as phosphorus and nitrogen ( Taylor and Carmichael, 2003 ). The high growth rate of algae experienced in the lower concentrations of wawa and c ederela could be due to the transparency of the leachate, organic content and proportion of mixture of the wood leachate to the control medium ( O'Hare et al., 2018 ; Garbowski, 2019 ; Svensson et al., 2013 ). According to ( CEES, 2019 ) water chemistry, nutrient, mixing conditions, turbidity can greatly influence algal growth.…”