Micro and Macroscale Drivers of Nutrient Concentrations in Urban Streams in South, Central and North America

Abstract

Global metrics of land cover and land use provide a fundamental basis to examine the spatial variability of human-induced impacts on freshwater ecosystems. However, microscale processes and site specific conditions related to bank vegetation, pollution sources, adjacent land use and water uses can have important influences on ecosystem conditions, in particular in smaller tributary rivers. Compared to larger order rivers, these low-order streams and rivers are more numerous, yet often under-monitored. The present study explored the relationship of nutrient concentrations in 150 streams in 57 hydrological basins in South, Central and North America (Buenos Aires, Curitiba, São Paulo, Rio de Janeiro, Mexico City and Vancouver) with macroscale information available from global datasets and microscale data acquired by trained citizen scientists. Average sub-basin phosphate (P-PO4) concentrations were found to be well correlated with sub-basin attributes on both macro and microscales, while the relationships between sub-basin attributes and nitrate (N-NO3) concentrations were limited. A phosphate threshold for eutrophic conditions (>0.1 mg L-1 P-PO4) was exceeded in basins where microscale point source discharge points (eg. residential, industrial, urban/road) were identified in more than 86% of stream reaches monitored by citizen scientists. The presence of bankside vegetation covaried (rho = –0.53) with lower phosphate concentrations in the ecosystems studied. Macroscale information on nutrient loading allowed for a strong separation between basins with and without eutrophic conditions. Most importantly, the combination of macroscale and microscale information acquired increased our ability to explain sub-basin variability of P-PO4 concentrations. The identification of microscale point sources and bank vegetation conditions by citizen scientists provided important information that local authorities could use to improve their management of lower order river ecosystems.

A Water–Energy–Food Nexus Perspective on the Challenge of Eutrophication

“…It is observed that approaches that did not address environmental challenges in a holistic manner produced rebound effects with implications for degradation of water and soil resources [29]. In Brazil, land use has been affecting raw surface-water quality for drinking supply [30], and there is eutrophication of local aquatic systems [31,32].…”

Citizen meets social science: predicting volunteer involvement in a global freshwater monitoring experiment

“…We used data on the participation of 7413 FWW citizen scientists from 13 countries who were trained to participate in the HWP. Participants used a standardized FWW method with the addition of 1 of 25 protocols that varied in the technologies used, site selection procedures, sampling regularity, and degree of coordination (see Loiselle et al 2016 andThornhill et al 2018 for further details). Participants were recruited through an internal promotion campaign within the HSBC bank.…”

Citizen Science for Water Quality Monitoring Applying Foss

“…Citizens' role in some of these project is, for example: -Recognition of images (e.g. taken with robot boat) to verify whether the wild life exists or not in the water (BrooklynAtlantis, 2012); -Water sample collection for localization of clean water habitats in urban landscapes (McGoff, et al, 2017); -Micro and macroscale nutrient concentration monitoring (Loiselle, et al, 2016;Yuchao, et al, 2017); -Quantification of anthropogenic litter on lake beaches (Vincent, et al, 2017); -Water turbidity and water clarity monitoring [ (Leeuw & Boss, 2018); (Seafarers, et al, 2017)].…”