Abstract
The macronutrients nitrate and phosphate are aquatic pollutants that arise naturally, however, in excess concentrations they can be harmful to human health and ecosystems. These pollutants are driven by river currents and show dynamics that are affected by weather patterns and extreme rainfall events. As a result, the nutrient budget in the receiving estuaries and coasts can change suddenly and seasonally, causing ecological damage to resident wildlife and fish populations. In this paper, we propose a statistical change-point model with interactions between time and river flow, to capture the macronutrient dynamics and their responses to river flow threshold behaviour. It also accounts for the nonlinear effect of water quality properties via nonparametric penalised splines. This model enables us to estimate the daily levels of riverine macronutrient fluxes and their seasonal and annual totals. In particular, we present a study of macronutrient dynamics on the Hampshire Avon River, which flows to the southern coast of the UK through the Christchurch Harbour estuary. We model daily data for more than a year during 2013–14 in which period there were multiple severe meteorological conditions leading to localised flooding. Adopting a Bayesian inference framework, we have quantified riverine macronutrient fluxes based on input river flow values. Out of sample empirical validation methods justify our approach, which captures also the dependencies of macronutrient concentrations with water body characteristics.
Highlights
River ecosystems are experiencing rapid transformations in response to anthropogenic and climatological stressors, which impact on macronutrient pollution, water quality characteristics, biodiversity and on the ecological health of the rivers (Whitehead et al, 2009)
We present a study on macronutrient dynamics on the Hampshire Avon River, which flows to the southern coast of the UK through the Christchurch
The principal aim of this paper consists in understanding how different macronutrient species respond to changes in river flow, which can be largely driven by weather pattern and severe weather conditions such as storm events
Summary
River ecosystems are experiencing rapid transformations in response to anthropogenic and climatological stressors, which impact on macronutrient pollution, water quality characteristics, biodiversity and on the ecological health of the rivers (Whitehead et al, 2009). Conley et al, 2009; Paerl, 2009; Withers et al, 2014) In addition to these disturbances, natural features of the environment and climate changes can compromise macronutrient cycles in fresh waters (Woodward et al, 2010; Whitehead and Crossman, 2012). Climate changes are likely to impact on weather pattern and bring an increasing number of extreme events, including increased frequency and intensity of storms, leading to high winds and heavy rainfall. These events might cause changes in the process that governs macronutrient behaviour
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
