ABSTRACT
The aim of the present research was to summarize the main reasons that explain the distribution of harmful blooms of cyanobacteria in Argentina. It is a large territory with climates ranging from humid tropical to cold temperate. We performed a meta-analysis of the published data and information in technical reports published from 1945 to 2015, and included additional data from personal non-published studies. A total of 122 water bodies affected by planktonic cyanobacterial blooms were recorded and geo-referenced. The analysis showed that blooms, defined as events exceeding 5000 cells/mL, occurred in different types of water bodies, including shallow lakes, rivers, streams, reservoirs, estuaries and storage facilities. Maximum bloom abundance and species and ecological strategies (dispersive, scum-forming, nitrogen fixer) responsible for each event were related to the geographic and climatologic characteristics and type and origin of water bodies. The Puna and the Andean Patagonia eco-regions were mostly free of blooms. The most impaired aquatic systems were shallow lakes and reservoirs (46.7 and 24.6%, respectively). Deep lakes had no reports of blooms and rivers were mainly affected at the regulated reaches, with intensities generally decreasing downstream the dams. Besides, 74.3% of the blooms reported in Argentina exceeded WHO Alert Level 2 for drinking and bathing waters (100,000 cells/mL). Thirty-nine species, identified by Komárek's polyphasic approach to taxonomy, were responsible for the blooms. Microcystis aeruginosa, Dolichospermum spiroides, Dolichospermum circinale, Raphidiopsis mediterranea and Cylindrospermopsis raciborskii were frequently found participating in either mixed or single species blooms. The species distribution was associated with the eco-region and aquatic system typologies and affected by seasonality and climatological and geographic variables. The eco-strategies of cyanobacterial species showed stronger associations with the qualitative and quantitative indicators used in the meta-analysis, and appeared as useful tools for management measures.
Subject(s)
Cyanobacteria , Eutrophication , Argentina , Lakes , PlanktonABSTRACT
El presente artículo plantea un enfoque para la determinación del riesgo que la vivienda urbana precaria conlleva para la salud desde una concepción holística fundamentada en el pensamiento complejo, la salud colectiva y la vulnerabilidad global, centrando el análisis en la vulnerabilidad sociodemográfica desde una perspectiva que integra las nociones de capital social, humano y físico a partir de los activos sociales y la estructura de oportunidades que poseen los hogares. Se propone un modelo conceptual que requiere la aplicación de una lógica de análisis compleja y no lineal para la determinación del índice de riesgo de la vivienda para la salud. El mismo trabaja con información de censos de población para la evaluación sociodemográfica y planillas de recuento de datos de gobiernos locales, para la valoración de la estructura de oportunidades.
In order to determine the risk to health caused by precarious urban dwellings, this paper presents an approach based on complex thought, collective health, and global vulnerability from a holistic conception. The analysis focuses on sociodemographic vulnerability from a perspective that integrates the concepts of both, human and physical social capital, taking into account capital assets and structure of opportunities that a home possesses. A conceptual model is proposed which requires the application of a complex, non-linear logics of analysis for the determination of the risk rate to health caused by dwellings. This model uses the information yielded by population census to carry out the sociodemographic evaluation, as well as forms containing data gathered by local governments to assess the structure of opportunities.
