The threat of global climate change to the world’s water resources has jeopardized access to clean drinking water across the world and continues to devastate biodiversity and natural life globally. South Africa operates as a useful case study to understand and analyze the effectiveness of public policy responses to the perils of climate change on issues of water access and ecosystem preservation. After the new South African Constitution was enacted in 1997, protecting water resources and ensuring their equitable distribution across the nation’s population was a paramount goal of the young democratic government. The National Water Act was passed in 1998, nationalizing the country’s water infrastructure and putting in place programs seeking to ensure equitable distributive and environmental outcomes. Thus far, it has failed. Access to South Africa’s water resources is as stratified as access to its economy; its aquatic ecosystems remain in grave danger; and many of the same problems of South Africa’s Apartheid era still plague its efforts to create an equitable water system. Decision-making power continues to be concentrated in the hands of the wealthy, at the expense of historically marginalized groups, whose voices are still not adequately heard. Corporate actors still exert undue influence over legislative policy that favors economic growth over environmental sustainability. The looming threat of climate change is exponentially increasing the chances of disasters like Cape Town’s 2018 feared ‘Day Zero’. The National Water Act’s noble intentions were never actualized, and therefore the people of South Africa remain in serious danger of acute and chronic threats to their water supply.
Nutrient recycling by fish can be an important part of nutrient cycles in both freshwater and marine ecosystems. As a result, understanding the mechanisms that influence excretion elemental ratios of fish is of great importance to a complete understanding of aquatic nutrient cycles. As fish consume a wide range of diets that differ in elemental composition, stoichiometric theory can inform predictions about dietary effects on excretion ratios.
We conducted a meta-analysis to test the effects of diet elemental composition on consumption and nutrient excretion by fish. We examined the relationship between consumption rate and diet N : P across all laboratory studies and calculated effect sizes for each excretion metric to test for significant effects.
Consumption rate of N, but not P, was significantly negatively affected by diet N : P. Effect sizes of diet elemental composition on consumption-specific excretion N, P and N : P in laboratory studies were all significantly different from 0, but effect size for raw excretion N : P was not significantly different from zero in laboratory or field surveys.
Our results highlight the importance of having a mechanistic understanding of the drivers of consumer excretion rates and ratios. We suggest that more research is needed on how consumption and assimilation efficiency vary with N : P and in natural ecosystems in order to further understand mechanistic processes in consumer-driven nutrient recycling.
Grasshoppers Regulate N: P Stoichiometric Homeostasis by Changing Phosphorus Contents in Their Frass
The City of Phoenix Street Transportation Department partnered with the Rob and Melani Walton Sustainability Solutions Service at Arizona State University (ASU) and researchers from various ASU schools to evaluate the effectiveness, performance, and community perception of the new pavement coating. The data collection and analysis occurred across multiple neighborhoods and at varying times across days and/or months over the course of one year (July 15, 2020–July 14, 2021), allowing the team to study the impacts of the surface treatment under various weather conditions.