Monitoring strategies of stream phosphorus under contrasting climate-driven flow regimes

Climate and hydrology are relevant control factors determining the timing and amount of nutrient losses from land to downstream aquatic systems, in particular of phosphorus (P) from agricultural lands. The main objective of the study was to evaluate the differences in P export patterns and the performance of alternative monitoring strategies in streams under contrasting climate-driven flow regimes. We compared a set of paired streams draining lowland micro-catchments under temperate climate and stable discharge conditions (Denmark) and under sub-tropical climate and flashy conditions (Uruguay). We applied two alternative nutrient sampling programs (high-frequency composite sampling and low-frequency instantaneous-grab sampling) and estimated the contribution derived from point and diffuse sources fitting a source apportionment model. We expected to detect a pattern of higher total and particulate phosphorus export from diffuse sources in streams in Uruguay streams, mostly as a consequence of higher variability in flow regime (higher flashiness). Contrarily, we found a higher contribution of dissolved P in flashy streams. We did not find a notably poorer performance of the low-frequency sampling program to estimate P exports in flashy streams compared to the less variable streams. We also found signs of interaction between climate/hydrology and land use intensity, in particular in the presence of point sources of P, leading to a bias towards underestimation of P in hydrologically stable streams and overestimation of P in flashy streams. Based on our findings, we suggest that the evaluation and use of more accurate monitoring methods, such as automatized flow-proportional water samplers and automatized bankside analyzers, should be prioritized whenever logistically possible. However, it seems particularly relevant in currently flashy systems and also in systems where climate change predictions suggest an increase in stream flashiness

Brazil's new fish farming Decree threatens freshwater conservation in South America

Aquaculture has tremendous importance in providing food for a growing world population. Nevertheless, unsustainable aquaculture causes nutrient buildup and favors biological invasions in natural habitats, demanding strategies to regulate such activity and therefore minimize environmental risks. Contrary to these concerns, the Brazilian Government has recently issued a new Federal Decree (10576/2020) encouraging the farming of invasive non-native species and excluding the Ministry of Environment from the legal process of issuing fish farming permits in reservoirs. The Decree increases the risk of non-native species establishment in inland waters at a national level and their propagation into neighboring countries, such as Argentina, Bolivia, Paraguay, and Uruguay. These consequences will endanger preserved freshwater ecosystems in the continent, including their native biodiversity, which represents both a problem of national sovereignty and a threat to the fundamental human right for a healthy environment. For this reason, the Decree contradicts the Brazilian Federal Constitution and conflicts with international treaties regulating invasive species and promoting sustainable development. It calls for immediate legal action and is yet another unfortunate sign of the increasing gap between science and decision making that has plagued the country in recent years.Fil: Latini, Anderson Oliveira. Universidade Federal de Sao Joao Del-rei; BrasilFil: Mormul, R. P.. Universidade Estadual de Maringá. Departamento de Engenharia Química.; BrasilFil: Giacomini, H. C.. Universidade Estadual de Maringá. Departamento de Engenharia Química.; Brasil. Universidade Santa Cecília; BrasilFil: Di Dario, F.. Universidade Federal do Rio de Janeiro; BrasilFil: Vitule, J. R. S.. Universidade Federal do Paraná; BrasilFil: Reis, R. E.. Pontificia Universidade Católica do Rio Grande do Sul; BrasilFil: Tonella, L.. Universidade Estadual de Maringá. Departamento de Engenharia Química.; BrasilFil: Polaz, C. N. M.. Centro Nacional de Pesquisa E Conservação de Peixes Continentais; BrasilFil: Lucifora, Luis Omar. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lima, L. B.. Universidade Federal do Mato Grosso do Sul; BrasilFil: Teixeira-de-Mello, F.. Universidad de la República; UruguayFil: Lima Júnior, D. P.. Universidade Federal do Mato Grosso do Sul; BrasilFil: Magalhães, A.L.B.. No especifíca;Fil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Jimenez Segura, L. F.. Universidad de Antioquia; ColombiaFil: Azevedo Santos, V. M.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Carvalho, F. R.. Universidade Federal do Mato Grosso do Sul; BrasilFil: D'Anatro, A.. Universidad de la Republica; UruguayFil: Malabarba, L. R.. Universidade Federal do Rio Grande do Sul; BrasilFil: Mandelburger, D.. Ministerio del Ambiente y Desarrollo Sostenible; ParaguayFil: Orsi, M.L.. Universidade Estadual de Londrina; BrasilFil: González Bergonzoni, I.. Cenur Litoral Norte – Sede Paysandú; Uruguay. Universidad de la República; UruguayFil: Cunico, A.M.. Universidade Federal do Paraná; BrasilFil: Petrere Júnior, M.. Universidade Federal do Pará; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Scarabotti, Pablo Augusto. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Vidal, N.. Universidad de la República; Urugua