Resumo Objetivo A urbanização leva a mudanças rápidas na estrutura e função do ecossistema. Terras úmidas em câmpus universitários sujeitos ao desenvolvimento da urbanização podem ser usados como estudos de caso de pesquisa aquática multidisciplinar e boas práticas ambientais que promovam a sustentabilidade. Métodos Foi realizado um estudo paleolimnológico em um lago semiartificial em um campus universitário no sul do Brasil para inferir impactos históricos e mudanças ecológicas desde a década de 1970 por meio de abordagens complementares: dados históricos, nutrientes, isótopos estáveis δ13C e δ15N, diatomáceas, microplásticos e análise da comunidade microbiana associada. Resultados O processo de eutrofização começou a se intensificar após o uso noturno por aves aquáticas de árvores como poleiros, e especialmente após o estabelecimento de construções ao longo das margens com fossa séptica de esgoto sanitário, que ocasionalmente transbordava e carreava material para o lago. Ao longo de décadas, identificamos um processo limnológico de hipertrofização que induziu a florações recorrentes de cianobactérias e proliferação maciça de macrófitas, juntamente com mudanças isotópicas e ocupação de algas com várias transições entre estados alternativos de lagos rasos. Tal processo limnológico foi claramente espelhado nas tendências de eutrofização paleolimnológica e mudanças isotópicas da matéria orgânica sedimentar. A deposição de microplásticos foi detectada como proxy para a intensificação da urbanização especialmente durante a construção das instalações da Universidade. Conclusões O uso combinado de dados paleolimnológicos e limnológicos históricos representa uma abordagem poderosa para identificar os impactos naturais e culturais no lago e identificar estratégias de manejo baseadas em tais informações científicas.

Abstract Aim Urbanization leads to rapid changes in ecosystem structure and function. Wetlands on university campuses under urbanization pressure could be used as case studies of multidisciplinary aquatic research and good environmental practices promoting sustainability. Methods A paleolimnological study was undertaken in a semi-artificial lake on a university campus in southern Brazil to trace historical impacts and ecological changes back to the mid-1970s through complementary approaches: historical data, nutrients, δ13C and δ15N stable isotopes, diatoms, microplastics and associated microbial community analysis. Results The eutrophication process started to intensify after the lake was used for nocturnal roosting by waterbirds, and especially after the establishment of constructions along the margins with septic tank sanitary sewage, which eventually spilled and leached into the lake. Over decades, we identified a limnological hypertrophication process leading to recurrent cyanobacterial blooms and massive macrophyte proliferation coupled with changes in isotopic ratios and algal occupation with several transitions between shallow lake alternative states. Such a limnological process has resembled the paleolimnological eutrophication trends and isotopic changes in sedimentary organic matter. The microplastic deposition was detected as a proxy for the intensification of urbanization, especially during the construction of the University facilities. Conclusions The combined use of paleolimnological and historical limnological data represents a powerful approach for inferring both natural and cultural impacts on the lake, and identifying management strategies based on such scientific information.

The diversity of ascidians from the Southwestern Atlantic between 30°S and 40°S (southern Brazil, Uruguay and northern Argentina) remains as one of the poorest known of the West Atlantic. The objective of this work is to compile, analyze and discuss all published records of ascidians from Uruguay. They show the historical relevance of the studies performed by Herdman, Monniot F. and Monniot C. on ascidians collected at deep-sea stations by the HMS Challenger and the RV Atlantis II in the Argentine Basin. Total literature records include 38 ascidian species which are enumerated here for the first time. On the basis of the current knowledge, the ascidian fauna of Uruguayan waters encompasses: a) shallow-water species with temperate distribution (3 spp.); b) shelf and deep-sea species with Antarctic and Sub-Antarctic distribution (13 spp.); c) deep-sea species until now only collected off Río de La Plata (11 spp.); d) deep-sea species displaying a wide distribution (11 spp.). Only nine species have been recorded for the continental shelf; the remaining species were collected either from the slope (21) or the abyssal plain (5) or both deep-sea zones (3). Future research should be directed to record coastline and shelf species, assess the presence of exotic elements, and re-describe enigmatic species first described by Herdman (1882, 1886).

La diversidad de ascidias del Atlántico Sudoccidental entre 30°S y 40°S (sur de Brasil, Uruguay y norte de Argentina) sigue siendo una de las más escasamente conocidas del Atlántico occidental. El objetivo de este trabajo es compilar, analizar y discutir todos los registros publicados de ascidias de Uruguay. Muestran la relevancia histórica de los estudios realizados por Herdman, Monniot F. y Monniot C. sobre las ascidias recogidas por el HMS Challenger y el RV Atlantis II en la Cuenca Argentina. Los registros de la literatura incluyen 38 especies de ascidias que se enumeran aquí por primera vez. Sobre la base de los conocimientos actuales, la fauna de ascidias de aguas uruguayas comprende: a) especies de aguas someras con distribución templada (3 especies); b) especies de plataforma y de aguas profundas con distribución Antártica y Sub-Antártica (13 especies); c) especies de aguas profundas hasta ahora sólo se recolectaron en la desembocadura del Río de La Plata (11 especies); d) especies de aguas profundas que muestran una amplia distribución (11 especies). Sólo se han registrado nueve especies para la plataforma continental; las especies restantes se recolectaron en el talud (21), en la planicie abisal (5) o en ambas zonas de aguas profundas (3). Las investigaciones futuras deben orientarse a registrar las especies costeras y de plataforma, evaluar la presencia de especies exóticas y volver a describir especies enigmáticas descritas por primera vez por Herdman (1882, 1886).

ResumoA cidade de Montevidéu, com mais de 1,5 milhões de habitantes, circunda a Baía de Montevidéu, onde um dos portos mais ativos e poluídos da América do Sul está localizado. No presente trabalho, foram avaliados esteróis fecais, metais traço, compostos organoclorados e derivados de petróleo nos sedimentos superficiais do Porto de Montevidéu, analisando sua distribuição espacial no interior do porto, bem como em dois dos principais tributários que chegam ao interior da baía. Especificamente para os sítios do porto, foi realizada uma comparação temporal dos metais pesados e hidrocarbonetos, considerando dados pretéritos de 12 anos. Foram observadas alterações significativas nos sítios estudados. Metais, tais como o Pb, Cr e Zn, apresentaram redução nas suas concentrações, enquanto os hidrocarbonetos alifáticos aumentaram seus valores em quase todas as estações. Foram observadas também diferenças entre o verão e o inverno, sugerindo mudanças no padrão de sedimentação, nos ingressos de substâncias e/ou mudanças hidrodinâmicas na área. Os resultados podem vir auxiliar na compreensão do estado atual e para o desenvolvimento de medidas de gestão necessárias para melhorar a qualidade ambiental do porto e da baía.

AbstractSituated opposite the Freshwater Front, Montevideo city with its more than 1.5 million inhabitants encircles Montevideo Bay, where one of the most active and polluted harbors in South America is located. Faecal sterols, trace metals, organochlorine compounds and petroleum derivatives in the sediments of Montevideo Harbor were evaluated and their spatial distribution inside the harbor as well as in the input of two main tributary streams analyzed. Specifically for the harbor sites, a temporal comparison of metal and hydrocarbons was made with previous measurements taken 12 years ago. Clear changes were observed at these sites. The concentration of metals such as Pb, Cr and Zn have diminished, while aliphatic hydrocarbons have increased their values at almost all of the stations studied. Differences were observed between summer and winter suggesting sedimentation, input or hydrodynamic changes in the area. These results help one to understand the present situation and develop the management measures needed to improve the environmental quality of the harbor and bay.

The Río de la Plata Estuary (RdlP) is a fluviomarine system that drains into the Southwestern Atlantic Ocean with the Paraná and Uruguay rivers as main tributaries. The estuary is fed by a 3,100,000 km2 catchment area which extends over the territories of Argentina, Paraguay, Brazil, Bolivia and Uruguay (Acha et al., 2008). The RdlP exhibits significant natural decadal- and annual-scale, hydrodynamic and oceanographic variability associated with the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO) and the El Niño/ La Niña Southern Oscillation (ENSO) (Depetris and Pasquini, 2007b; Chiessi et al., 2009; Garreaud et al., 2009). Such variability affects the moisture budget over the surrounding continental areas and leads, thus, to changes in the river discharge. PDO is associated with ENSO as both appear to display similar hydrological responses, though their inherent mechanisms are not yet fully understood (Garreaud et al., 2009). In this sense, warm and cold PDO phases strongly resemble El Niño and La Niña events, respectively (Garreaud et al., 2009). During El Niño episodes, an increase in precipitation over the RdlP drainage basin is commonly observed (Boulanger et al., 2005; Camilloni, 2005; Garreaud et al., 2009; García-Rodríguez et al., 2014), and consequently increased Paraná and Uruguay river discharges are displayed (Depetris and Pasquini, 2007a). Campos et al. (1999) have recorded a freshwater plume of low salinity and temperature (32, 18 ºC respectively) associated with an increase in RdlP discharge during the El Niño event of 1997, expanding northwards up to 23ºS. Furthermore, during negative AMO phases it was recorded an increasing trend on the precipitations over the SE South America (SESA) and, as a consequence, a concomitant increase in the Rivers Paraná and Uruguay discharge was recorded, while the opposite pattern was observed during positive phases (Chiessi et al., 2009). The aim of this paper is to infer the link between changes in the delivery of terrigenous sediment to the adjacent Atlantic Ocean with recorded hydrological variability of the RdlP. To achieve this, we used sedimentological and geochemical proxies from two sediment cores, which were retrieved from the inner continental shelf off Uruguay and encompass the past 100 AD. Sediment Core GeoB 13813-4 was taken from the inner-shelf “RdlP paleo-valley mudbelt” (Fig. 1;34°44’13’’S, 53°33’16’’W) during research cruise M76/3a (Krastel et al., 2012; Lantzsch et al., 2014). Sediment Core BAR1 was retrieved in the innershelf “Barra del Indio” zone (Fig. 1; 35°03’00’’S, 56°09’00’’W), performed by the Faculty of Sciences, Universidad de la República (Uruguay). For Core GeoB 13813-4, we analyzed the relative abundance of major elements (Ca and Ti) obtained by an X-ray fluorescent sediment core scanner AVAATECH and the Ca/Ti ratio was used to infer continental versus marine influence. This chemical elemental ratio was chosen according to previous successful applications within the Atlantic Ocean (Chiessi et al., 2009; Mahiques et al., 2009; Govin et al., 2012; Bender et al., 2013; Burone et al., 2013). Furthermore, the arithmetic mean grain size distribution was studied from both sediment cores, using the GRADISTAT program (Grain Size Distribution and Statistics Package for the Analysis of Unconsolidated Sediments) version 8 (Blott and Pye, 2001) (Fig. 4). For Core GeoB 13813-4 grain size were obtained by Laser Particle Sizer LS200 and for Core BAR1 were obtained by Malvern Mastersizer 2000 Laser analyser. The chronology from both cores was assessed by 210Pbxs dating (Table 1 and Fig. 2; Appleby, 2001; 2008). For core BAR1 we selected the CRS (Constant Rate Supply) model (which is highly used for estuarine systems), while for GeoB 13813-4 the CFCS (Constant Fluxe: Constant Sedimentation Rate) model was applied (Appleby, 2008; Bernal et al., 2010). In the last case, the decision of using the CF-CS model was due to the lack of a complete 210Pb dataset, which would bring very high sedimentation rates uncertainties (Sanchez-Cabeza and Ruiz-Fernández, 2012). To assess the climatic variability over the past century as inferred from the sediment proxies, we evaluated the climatic indices PDO and Southern Oscillation Index (SOI), of the Joint Institute for the Study of the Atmosphere and Ocean, University of Washington (http://jisao.washington.edu), as well as the AMO from the NOAA (http://www.aoml. noaa.gov/phod/amo_faq.php). We further compared these data with temporal series (encompassing the last century) of the Paraná and Uruguay fluvial discharges (http://www.hidricosargentina. gov.ar/acceso_bd.php), river-flow anomalies were calculated following the approach of Piovano et al. (2004). The generated proxy data were analyzed by running cluster analyses using the stratigraphically constrained Moristia similarity index, in PAST program version 3 (http://folk.uio.no/ohammer/ past/). The generated groups are represented with red lines in figure 3. The sedimentation rate of core GeoB 13813-4 was assumed to be constant with a mean value of 1.3 cm yr-1 (Table 1; Perez Becoña, 2014), while for the sedimentation rate of core BAR1 three groups were observed: 1911-1973; 1976-1984 and 1986-2010. The mean sedimentation rate for the above groups showed an increasing trend from 0.24 ± 0.13 cm yr-1 to 0.31 ± 0.14 cm yr-1 and 0.37 ± 0.10 cm yr-1, respectively. The most positive and stable values of SOI (La Niña events) were recorded during 1910-1970. After 1970, a higher variability and a trend towards more negative values was observed (El Niño events). After the year 2005, very negative SOI values occurred (Fig. 4). PDO showed either negative or close to zero values during the early period 1910-1970 (cold phase). During the subsequent interval, i.e., 1970- 2005, positive values (warm phase) were observed. Regarding with AMO, a positive phase was observed from 1925-1960, followed by a negative phase (1960- 2000), but then a shift to a positive phase until the present was observed. The Paraná river discharge anomalies for the years 1910-1970 were mostly associated with negative values (Fig. 4), while between 1970 and 2010 positive anomalies were documented. Between the years 2000 and 2010, we mostly registered values close to zero. Furthermore, the trends in AMO and SOI indices were negatively associated with the anomalies of both Paraná and Uruguay rivers flows, while PDO index were positive associated with such anomalies. A change in mode polarity observed for PDO and AMO took place by the middle 1970s, in addition to more frequent and intense El Niño events that led to the increased rainfall over SESA (Garreaud et al., 2009). Thus, the increase in rainfall over SESA was concomitant with positive anomalies in the Paraná and Uruguay river discharge rates after 1970 (Camilloni, 2005). In this sense, the Paraná river discharge was 20% higher during the past 30 years than the historical average of the 20th century (Mauas et al., 2008). The results of the cluster analyses groups (Fig. 3) showed a differentiation in both sediment cores that correspons to the beginning of the 1970s, which could be associated with the increasing discharge trend recorded for the Parana and Uruguay rivers over the last three decades. The increase in RdlP discharge led to a higher accumulation rate of terrigenous sediments, as inferred from the high sedimentation rate and mean grain size (BAR1), and the lowest Ca/ Ti ratio (GeoB 13813-4), and explains both the spatial and temporal sedimentological and geochemical variability. Ca/Ti ratio in the RdlP was successfully used to infer marine vs. continental influence, as Ti is associated with a continental RdlP discharge, while Ca is associated with autochthonous marine productivity (e.g. foraminifera, Burone et al., 2013). Thus, the highest continental sediment supply to the inner continental shelf is observed in GeoB 13813-4 after 1970, associated with a decrease in the Ca/Ti ratio (Fig. 4). Regarding with Core BAR1 the grainsize distribution and the sedimentation rate were both associated with the estuarine hydrodynamic changes. After 1970, the highest and most variable sedimentation rate and mean grain size was found, probably associated to an increase in both the Paraná and Uruguay river discharges during the past three decades, while the lowest and more stable sedimentation rates and mean sediment grain size recorded before 1970, is indicating a reduced RdlP freshwater supply to the study area. This study shows that both sediment cores contain a distinct continental runoff record as the result of climatic changes (PDO, AMO and ENOS), which have influenced the precipitation patterns over SESA. Both sites reflect similar responses to these environmental changes for the last 100 yr in continental terrigenous sediment supply from the RdlP watershed towards the inner continental shelf. We conclude that it is possible to assess the temporal? RdlP discharge patterns variability within the estuarine and adjacent oceanic area through the study of terrigenous proxies from sediment cores retrieved within the continental shelf.

El Río de la Plata (RdlP) presenta significativas variaciones naturales (hidrodinámicas y oceanográficas) asociadas a diferentes condiciones climáticas. El propósito de este trabajo es inferir los cambios de aportes continentales de sedimentos y su relación con las variaciones hidrológicas del Río de la Plata, a través del análisis de proxies sedimentológicos y geoquímicos en testigos de sedimentos de la plataforma interna uruguaya que registran los últimos 100 años, aproximadamente. A partir de la datación por 210Pb de dos testigos de sedimentos (GeoB 13813-4 y BAR1) se reconstruyó la geocronología del ambiente, y se relacionó con datos de las forzantes climáticas Pacific Decadal Oscillation, El Niño/La Niña Southern Oscillation, Atlantic Multidecadal Oscillation, y las anomalías hidrológicas de los ríos Paraná y Uruguay. Los valores más positivos y estables del Southern Oscillation Index, los cuales corresponden a fases La Niña, se observan en el periodo correspondiente entre 1910-1970, respecto al resto de la serie, donde se aprecia una mayor variabilidad y una tendencia hacia valores más negativos (eventos El Niño). Se hicieron dendrogramas (clustering) jerárquicos para ambos testigos. Para el testigo GeoB 13813-4, se utilizó la relación Ca/Ti y la granulometría, mientras que para BAR1 se recurrió a variables granulométricas y la tasa de sedimentación. El mayor aporte continental hacia la región de la plataforma adyacente al Río de la Plata registrado a partir del año 1970, podría ser el factor principal de los agrupamientos observados en los clusters para ambos testigos. Las agrupaciones mostraron una diferenciación en la década de 1970, lo que estaría asociado al aumento de los caudales de los ríos Paraná y Uruguay, durante las últimas tres décadas del siglo XX. Por otra parte se observa que la granulometría del testigo BAR1 presentó un mayor tamaño de grano y más variabilidad que en el caso del testigo GeoB 13813-4. También se determinó una mayor acumulación de sedimentos a través del tiempo en el cinturón de barro del Río de la Plata (plataforma continental adyacente), comparado con aquel registrado en la Barra del Indio (límite entre zona intermedia y externa del estuario). Estas diferencias podrían estar relacionadas con la influencia del Río de la Plata, el cual genera un ambiente altamente dinámico sobre la Barra del Indio y un ambiente más estable sobre el cinturón de barro en la plataforma continental.

15 communities were selected in the influence area of two evaluated phosphate deposits in order to apply a contingent valuation of these mineral resources and its environment. The Tembabichi deposit is in the east margin of the Peninsula, at the Gulf of California coast and the Santo Domingo deposit is in the Pacific coast of Baja California Sur, Mexico. The mean willingness to pay of the people of the studied area is of $29.77 monthly pesos, this, to collaborate with the improvement cautions of their environment. Hypothetically a contingent valuation in the whole study area is of $227,859.58 monthly pesos, that is, $2,734,314.9 annual pesos. It is a considerable amount of money to contribute to improvements in the environment for rural communities in socioeconomic underdevelopment.

Se seleccionaron 15 localidades ubicadas en el radio de influencia de dos depósitos evaluados de fosfato, esto con la finalidad de aplicar el método de valoración contingente del recurso y su medio ambiente: el depósito de Tembabichi en el margen del Golfo de California y el depósito de Santo Domingo en la costa del Pacífico en Baja California Sur, México. Se encontró una disposición media a pagar por los habitantes del área de estudio de $29.77 pesos mensuales para colaborar con el medio ambiente de su región. Hipotéticamente se daría una valoración contingente en el total del área de estudio de $227 859.58 pesos mensuales, es decir, $2 734 314.9 pesos anuales. Es una cantidad considerable de recursos para contribuir a mejoras en el medio ambiente por comunidades rurales con signos de marginación socioeconómica.

Si bien hasta ahora el sistema de comercio se ha desarrollado en forma independiente del sistema de protección ambiental, se están produciendo importantes esfuerzos para compatibilizar los objetivos de ambos. Están comprometidas en esta tarea organizaciones internacionales globales, como la Organización Mundial del Comercio (OMC), instrumentos como el Tratado de Libre Comercio de América del Norte (TLCAN) y las convenciones internacionales sobre el medio ambiente que se han realizado en los últimos diez años. La relación entre comercio internacional y medio ambiente será uno de los ejes obligados de la política exportadora para los países latinoamericanos durante la presente década. En estos países se ha ido consolidando un modelo de desarrollo basado en el crecimiento de las exportaciones, por lo que sus economías se verán enfrentadas al desafío de cumplir con los estándares ambientales, por lo general más estrictos, en los países compradores. En el contexto de la inserción de los países de América Latina en los mercados internacionales, el tema ambiental no ha sido, hasta ahora, tratado con la profundidad que se requiere. Esto se traduce en la escasez de estudios sobre las relaciones entre inserción global y medio ambiente, en una actitud pasiva frente a las exigencias externas y en la ausencia de un perfil ambiental congruente con el sistema natural, económico y social. El desarrollo de este último es indispensable para poder continuar con el proceso de inserción global, lo que implica reconocer tanto las realidades institucionales y legales del país, como el manejo y potencialidades de sus recursos naturales. Todo indica que la búsqueda de los consensos entre comercio y medio ambiente es la tendencia que predominará en la próxima década.

Even though the international trade system has evolved without consideration of environmental protection frameworks, efforts are being made to join environmental and political aims. International Institutions such as the World Trade Organisation (WTO) are committed to this task, as also are signatories of both North American Free Trade Agreement (NAFTA) and international environmental conventions adopted during the past ten years. The relationship between international trade and environment will become compulsory in Latin America’s export policies during this decade. These developing countries base their development on increase of exports and will have to adopt environmental standards of well developed countries. In the context of their insertion in international markets, environmental topics have been ignored. This explains the lack of studies on the relationship between globalization and environment, the passive attitude towards setting and compiling international standards, and the absence of clear environmental policy profiles. The development of such profiles seems to be indispensable to keep Latin America within the process of global insertion, implying the consideration of legal and institutional realities, and also natural resources and environmental management. The search for consensus between trade and environment will predominate in the coming decade.

Até agora o sistema de comércio desenvolveu-se em forma independente do sistema de proteção ambiental, mas estão sendo feitos muitos esforços para compatibilizar os objetivos de ambos. Estão comprometidas nesta tarefa organizações internacionais globais, como a Organização Mundial do Comércio (OMC), instrumentos como o Tratado de Livre Comércio da América do Norte (TLCAN) e as convenções internacionais sobre o meio ambiente que foram realizadas nos últimos dez anos. A relação entre comércio internacional e meio ambiente será um dos eixos obrigatórios da política exportadora para os países latino-americanos durante a presente década. Nestes países foram se consolidando um modelo de desenvolvimento baseado no crescimento das exportações, pelo que suas economias se verão enfrentadas ao desafio de cumprir com os padrões ambientais, de forma geral mais estritos, nos países compradores. No contexto da inserção dos países da América Latina nos mercados internacionais, o tema ambiental não foi, ate agora, tratado com a profundidade que se requer. Este se traduz na escassez de estudos sobre as relações entre inserção global e meio ambiente, em uma atitude passiva frente às exigências externas e na ausência de um perfil ambiental congruente com o sistema natural, econômico e social. O desenvolvimento deste último é indispensável para poder continuar com o processo de inserção global, o que implica reconhecer tanto as realidades institucionais e legais do país, como o manejo e potencialidades de seus recursos naturais. Tudo indica que a busca dos consensos entre comércio e meio ambiente é a tendência que predominará na próxima década.