Indices based on macrobenthic responses to disturbance remain to be adequately tested for the det... more Indices based on macrobenthic responses to disturbance remain to be adequately tested for the detection of spatial variability by robust sampling designs. We present herein a congruence test to real-world data of the widely used indices AMBI, M-AMBI and BENTIX in tidal flats of a subtropical estuary. We used a hierarchical sampling design to evaluate the spatial variability of the indices in response to distinct levels of sewage contamination. Indices were then tested for correlations with chemical proxies of contamination and for the similarity of responses. BENTIX and M-AMBI produced over-and underestimations of ecological status. We found a low degree of similarity among indices as an expression of the spatial variation of macrofaunal assemblages on their performances. Only AMBI varied at the contamination scale (10 3 m) and was congruent with physical-chemical proxies. Ambiguous responses indicated effects of natural inputs of organic matter rather than environmental quality associated to sewage.
Over the past 100 years, urban growth has been reaching extremely high rates worldwide. Human int... more Over the past 100 years, urban growth has been reaching extremely high rates worldwide. Human interaction with the ecosystem includes consumptive and nonconsumptive activities. The external supply of organic matter causes one of the most severe impacts on coastal marine environments. Montevideo City is currently suffering from the same environmental problems as other capital cities in the world, and its adjacent coastal zone has been influenced by anthropogenic alterations during the past 150 years. By integrating abiotic and biotic data, and using different statistical and ecological approaches, the coastal area of Uruguay close to Montevideo City has been classified into four zones with different environmental quality and degree of anthropogenic perturbation. In this area, several environmental problems and their impacts on economic productivity, human, and ecosystem health are the outcome of political and socioeconomical factors. Therefore, governmental authorities need to follow the concept of sustainable use and development, to preserve and optimize the ecological quality of natural resources and to ensure the availability of this coastal ecosystem to future generations. Solutions to the conflictive uses of environment should be laid down on a solid scientific base to establish priorities and make the best decisions for its management and conservation.
ABSTRACT The vertical distribution of macrobenthic fauna, heavy metals, and other physico-chemica... more ABSTRACT The vertical distribution of macrobenthic fauna, heavy metals, and other physico-chemical and biological characteristics of the sediments were studied in three sediment layers (0–7, 8–14, 15–21 cm) at seven stations in the Ubatuba region, north coast of São Paulo State, Brazil at several temporal and spatial scales. Six stations were located in the inner bay near the riverine run-off, and one was outside the bay, distant from the riverine influence. The samples were collected four times in 1 year, on a seasonal basis. Sediments were basis comprised predominantly of very fine sand and the vertical distribution of grain size was uniform to a depth of 21 cm in all stations. Higher values of total organic matter, organic carbon, sulphur, heavy metals and phaeopigments were recorded at the inner Ubatuba Bay stations, probably due to the riverine influence. C/N ratios indicated a mixed origin of organic matter with a major contribution of terrestrial material in the inner stations. The vertical distribution of heavy metals showed a slight decline with sediment depth in the inner stations, indicating the present contribution. Most of the macrofauna was found at the surface sediment layer. Biological data showed that in the inner stations of Ubatuba Bay, which are under the influence of urban sewage and are moderately polluted, the fauna was distributed more superficially within the substrate than in St. 7, which is located in the external portion of the bay distant from sewage inputs. The environmental quality of the sites studied varied little throughout the year, at least in relation to the variables considered here. Temporal variation in the vertical distribution of benthic fauna was not evident in the four sampling surveys analysed. Only minor changes in the vertical distribution of the total fauna were detected in the seasonal scale, with the organisms located less deep within the sediment column in summer, indicating some influence of the tourism impact and/or rainy season.
During the "El Niño"-Southern Oscillation (ENSO) event 2009-2010, trophic state uni (TSI´s) and m... more During the "El Niño"-Southern Oscillation (ENSO) event 2009-2010, trophic state uni (TSI´s) and multimetric (TRIX´s) indexes were determined in the north coast of the Rio de la Plata (RdlP). The relationships of such indexes with the hydrological, physical and chemical parameters were explored to identify climatic variability or anthropogenic effects on the eutrophication process. Eleven oceanographic sampling campaigns at 25 stations were conducted along the north coast of RdlP from 2009 to 2011. Temperature, salinity and oxygen saturation, water transparency (Secchi depth), chlorophyll (Chl a) content and total nutrient concentrations (total nitrogen and phosphorous) were determined. Trophic indexes (TSI Chl a, TSI TP, TRIX NP-Voll. and TRIX NP-Mvdeo.) were quantified and the RdlP flow was measured. RdlP flow showed significant differences between ENSO phases, with higher values during "El Niño" (EN), and positive and significant correlations with salinity, Secchi depth and total nutrients. The trophic status indexes showed spatial and temporal variability and associations with flow, physical and chemical parameters. Trophic state indexes showed spatial and temporal heterogeneity and were strongly associated to environmental conditions (hydrological and seasonal oscillations) during the study period but also to the anthropogenic factors affecting the north coast of RdlP. The system has been classified as mesotrophic to hypertrophic, depending on the selected indicator. According to these results, we suggest the use of a multimetric trophic state indicator, i.e., the TRIX index, as explains better the causes and effects of the eutrophication processes. To implement the TRIX index, (TRIX NP-Mvdeo.) we suggest researchers to consider a large number of local records (Chl a, nutrients, oxygen) at seasonal scales. This index is adapted to the environmental conditions of the study zone and complemented with other community structure indexes, and should be used for eutrophication assessment programs in the north coast of RdlP.
The relationships between macrobenthic subtidal community structure and the status of sediment po... more The relationships between macrobenthic subtidal community structure and the status of sediment pollution were analysed at 24 sampling stations in the Montevideo coastal zone. In order to judge the status of community perturbation a phylum-level meta-analysis was applied to the production data from the Montevideo coastal zone samples alone and combined with the original training data set from 50 samples collected on the NE European shelf. The community was dominated by the gastropod Heleobia cf. australis. The MDS (multi-dimensional scaling) ordination with abundance data (species-level) and the MDS ordination with production data (phylum level), using only our samples, showed the formation of three groups of stations. Results of the BIO-ENV procedure showed that lead, salinity and polycyclic aromatic hydrocarbons (PAHs) were the variables that best explained the biological pattern observed. However, a clear salinity gradient was observed from the inner stations of Montevideo Bay to the outer coastal stations; the high levels of Pb, PAH and Cr concentrations recorded at stations B, C and D in Montevideo Bay were important in discriminating these locations from the others. The MDS ordination combining the production data from the 24 samples from the Montevideo coastal zone with the original data set showed correct assessment of the pollution status for the 24 samples from Montevideo on a common scale of perturbation. The separation of the Montevideo coastal zone samples seems to be mainly due to the high proportion of molluscs. Our results suggest general applicability of the phylum-level meta-analysis approach, even in such cases as this, with high dominance of only one phylum; however, more studies are still necessary.
Abstract − The taxonomic sufficiency approach has been proposed as a surrogate for the typical an... more Abstract − The taxonomic sufficiency approach has been proposed as a surrogate for the typical analysis of species-abundance data, especially in conditions involving prominent pollution gradients. Here, we evaluate the use of taxonomic sufficiency with infralittoral ...
Abstract The 2009–2010 “El Nino”-Southern Oscillation (ENSO) event was characterized by a warm-ph... more Abstract The 2009–2010 “El Nino”-Southern Oscillation (ENSO) event was characterized by a warm-phase leading to a five-fold increase in the Rio de la Plata river flow and an associated change in trophic state because of organic enrichment. We analyzed the biotic response of benthic communities to such an increased trophic state during this ENSO event using community and biotic indices (diversity indices and AMBI). Polychaeta exhibited the highest richness and second the most abundant values while the small gastropod Heleobia australis was the most abundant and frequent species. An increase in richness and diversity of Polychaeta was associated to a concomitant increase of RdlP flow and the organic enrichment of the macrobenthic species. Community indices (richness and diversity) showed variability at both temporal and spatial scale but only AMBI exhibited spatial variability without significant differences between contrasting environmental conditions (ENOS phases).
Abstract Despite the increased and widespread usage of benthic indices for environmental health a... more Abstract Despite the increased and widespread usage of benthic indices for environmental health assessment, some methodological ambiguities remain to be solved. We tested the congruence and consistency of the benthic indices ITI, BO2A, BENTIX, AMBI and M-AMBI in a subtropical estuary (Paranagua Bay, Brazil). Indices were applied to non-vegetated tidal flats increasingly contaminated by sewage to test: (i) correlations with molecular biomarkers of sewage (consistency); and (ii) evaluate the overall agreement/similarity of responses (congruence). The responses of the benthic indexes ITI, AMBI and BO2A were congruent among themselves and consistent with molecular biomarkers values. BENTIX and M-AMBI were less consistent and congruent and possibly need a readjustment of boundaries for subtropical habitats. The indices seemed robust to natural background yearly variations not related to contamination. Faecal sterols associated to nutrient contents suitably supported the validation of indices and could integrate reference conditions for sewage impacted coastal habitats. Benthic indices can successfully integrate management guidelines, but their suitable application demands further research on tolerance shifts of key indicator species.
Climatic, hydrological, and oceanographic conditions were determined during the 2009-2010 El Nino... more Climatic, hydrological, and oceanographic conditions were determined during the 2009-2010 El Nino/Southern Oscillation (ENSO) on the north coast of the Río de la Plata (RdlP) estuary. The maximum monthly rainfall was observed in the middle and upper La Plata basin during September 2009 and February 2010 ("El Niño" phase, (EN)). The monthly flow of RdlP showed an increase with rainfall and significant differences between ENSO phases. The wind stress showed fluctuations in both phases, being less intense during EN, during which time maximum flow of RdlP was observed. During the EN phase, increased precipitation contributed to variations in salinity and absence of water column stratification in the north coast of RdlP. This was also associated with variations in Secchi depth, oxygen saturation, and nutrient concentrations. The spatial location of the turbidity front was associated with the flow of the RdlP and wind stress, thus conditioning the physicochemical characteristics of the water column, mainly during EN phase.
Limnoperna fortunei (golden mussel) is an alien mollusk in the Plata basin and is native from the... more Limnoperna fortunei (golden mussel) is an alien mollusk in the Plata basin and is native from the Southeastern Asia. Its benthic patches generate macrofouling in hydraulic installations causing additional costs to the affected companies. The objective of this work is to determine the variation of abundance and the size of the valves larval stages of the golden mussel, establishing associations with the water quality parameters in the cooling systems in the three hydroelectric power stations (HP) of the reservoirs of the Negro River (Uruguay) that has been invaded by the species. In the three cooling systems the golden mussel larval density average showed associations with temperature of the water and the percentage of organic material of the column water. Larger larval abundances were registered during warm and minimum during cold months. For the three systems, is suggested a reproductive pause of the species at water temperatures lower than 18oC and the start of the larval cycle at...
The Santos Estuarine System (SES) is a complex of bays, islands, estuarine channels, and rivers l... more The Santos Estuarine System (SES) is a complex of bays, islands, estuarine channels, and rivers located on the Southeast coast of Brazil, in which multiple contaminant sources are situated in close proximity to mangroves and other protected areas. In this study, the composition and structure of the macrobenthic communities of SES were described and ninetynine species were identified, with the predominance of polychaetes and bivalve mollusks. The benthic assemblages also showed strong signs of stress, as indicated by the low abundance, richness and diversity, and the dominance of opportunistic species. Integrated analysis including sediment characteristics related to natural and anthropogenic factors (e.g., sediment chemistry, and toxicity) indicated that benthic fauna from the inner portions of the SES and vicinities of the SSOS diffusers as Santos Bay were affected. Some locations at the mouths of Santos and Sao Vicente estuaries exhibited moderate disturbance. In other sites from the mouth of São Vicente and Bertioga channels, and Santos Bay, the benthic fauna were considered not degraded. Our results suggest that a combination of both environmental factors and contaminants were responsible for the benthic community structure.
Pérez, laura (2); tudurí, adriana (1); venturini, natalia (1); Brugnoli, erneSto (1); Muniz, PaBl... more Pérez, laura (2); tudurí, adriana (1); venturini, natalia (1); Brugnoli, erneSto (1); Muniz, PaBlo (1). (1) oceanografía y ecología Marina, InStituto de ecología y cienciaS aMBientaleS (ieca), facultad de cienciaS, univerSidad de la rePúBlica, Montevideo, uruguay. (2) centro univerSitario regional eSte (cure), univerSidad de la rePúBlica, rocha, uruguay.
Indices based on macrobenthic responses to disturbance remain to be adequately tested for the det... more Indices based on macrobenthic responses to disturbance remain to be adequately tested for the detection of spatial variability by robust sampling designs. We present herein a congruence test to real-world data of the widely used indices AMBI, M-AMBI and BENTIX in tidal flats of a subtropical estuary. We used a hierarchical sampling design to evaluate the spatial variability of the indices in response to distinct levels of sewage contamination. Indices were then tested for correlations with chemical proxies of contamination and for the similarity of responses. BENTIX and M-AMBI produced over-and underestimations of ecological status. We found a low degree of similarity among indices as an expression of the spatial variation of macrofaunal assemblages on their performances. Only AMBI varied at the contamination scale (10 3 m) and was congruent with physical-chemical proxies. Ambiguous responses indicated effects of natural inputs of organic matter rather than environmental quality associated to sewage.
Over the past 100 years, urban growth has been reaching extremely high rates worldwide. Human int... more Over the past 100 years, urban growth has been reaching extremely high rates worldwide. Human interaction with the ecosystem includes consumptive and nonconsumptive activities. The external supply of organic matter causes one of the most severe impacts on coastal marine environments. Montevideo City is currently suffering from the same environmental problems as other capital cities in the world, and its adjacent coastal zone has been influenced by anthropogenic alterations during the past 150 years. By integrating abiotic and biotic data, and using different statistical and ecological approaches, the coastal area of Uruguay close to Montevideo City has been classified into four zones with different environmental quality and degree of anthropogenic perturbation. In this area, several environmental problems and their impacts on economic productivity, human, and ecosystem health are the outcome of political and socioeconomical factors. Therefore, governmental authorities need to follow the concept of sustainable use and development, to preserve and optimize the ecological quality of natural resources and to ensure the availability of this coastal ecosystem to future generations. Solutions to the conflictive uses of environment should be laid down on a solid scientific base to establish priorities and make the best decisions for its management and conservation.
ABSTRACT The vertical distribution of macrobenthic fauna, heavy metals, and other physico-chemica... more ABSTRACT The vertical distribution of macrobenthic fauna, heavy metals, and other physico-chemical and biological characteristics of the sediments were studied in three sediment layers (0–7, 8–14, 15–21 cm) at seven stations in the Ubatuba region, north coast of São Paulo State, Brazil at several temporal and spatial scales. Six stations were located in the inner bay near the riverine run-off, and one was outside the bay, distant from the riverine influence. The samples were collected four times in 1 year, on a seasonal basis. Sediments were basis comprised predominantly of very fine sand and the vertical distribution of grain size was uniform to a depth of 21 cm in all stations. Higher values of total organic matter, organic carbon, sulphur, heavy metals and phaeopigments were recorded at the inner Ubatuba Bay stations, probably due to the riverine influence. C/N ratios indicated a mixed origin of organic matter with a major contribution of terrestrial material in the inner stations. The vertical distribution of heavy metals showed a slight decline with sediment depth in the inner stations, indicating the present contribution. Most of the macrofauna was found at the surface sediment layer. Biological data showed that in the inner stations of Ubatuba Bay, which are under the influence of urban sewage and are moderately polluted, the fauna was distributed more superficially within the substrate than in St. 7, which is located in the external portion of the bay distant from sewage inputs. The environmental quality of the sites studied varied little throughout the year, at least in relation to the variables considered here. Temporal variation in the vertical distribution of benthic fauna was not evident in the four sampling surveys analysed. Only minor changes in the vertical distribution of the total fauna were detected in the seasonal scale, with the organisms located less deep within the sediment column in summer, indicating some influence of the tourism impact and/or rainy season.
During the "El Niño"-Southern Oscillation (ENSO) event 2009-2010, trophic state uni (TSI´s) and m... more During the "El Niño"-Southern Oscillation (ENSO) event 2009-2010, trophic state uni (TSI´s) and multimetric (TRIX´s) indexes were determined in the north coast of the Rio de la Plata (RdlP). The relationships of such indexes with the hydrological, physical and chemical parameters were explored to identify climatic variability or anthropogenic effects on the eutrophication process. Eleven oceanographic sampling campaigns at 25 stations were conducted along the north coast of RdlP from 2009 to 2011. Temperature, salinity and oxygen saturation, water transparency (Secchi depth), chlorophyll (Chl a) content and total nutrient concentrations (total nitrogen and phosphorous) were determined. Trophic indexes (TSI Chl a, TSI TP, TRIX NP-Voll. and TRIX NP-Mvdeo.) were quantified and the RdlP flow was measured. RdlP flow showed significant differences between ENSO phases, with higher values during "El Niño" (EN), and positive and significant correlations with salinity, Secchi depth and total nutrients. The trophic status indexes showed spatial and temporal variability and associations with flow, physical and chemical parameters. Trophic state indexes showed spatial and temporal heterogeneity and were strongly associated to environmental conditions (hydrological and seasonal oscillations) during the study period but also to the anthropogenic factors affecting the north coast of RdlP. The system has been classified as mesotrophic to hypertrophic, depending on the selected indicator. According to these results, we suggest the use of a multimetric trophic state indicator, i.e., the TRIX index, as explains better the causes and effects of the eutrophication processes. To implement the TRIX index, (TRIX NP-Mvdeo.) we suggest researchers to consider a large number of local records (Chl a, nutrients, oxygen) at seasonal scales. This index is adapted to the environmental conditions of the study zone and complemented with other community structure indexes, and should be used for eutrophication assessment programs in the north coast of RdlP.
The relationships between macrobenthic subtidal community structure and the status of sediment po... more The relationships between macrobenthic subtidal community structure and the status of sediment pollution were analysed at 24 sampling stations in the Montevideo coastal zone. In order to judge the status of community perturbation a phylum-level meta-analysis was applied to the production data from the Montevideo coastal zone samples alone and combined with the original training data set from 50 samples collected on the NE European shelf. The community was dominated by the gastropod Heleobia cf. australis. The MDS (multi-dimensional scaling) ordination with abundance data (species-level) and the MDS ordination with production data (phylum level), using only our samples, showed the formation of three groups of stations. Results of the BIO-ENV procedure showed that lead, salinity and polycyclic aromatic hydrocarbons (PAHs) were the variables that best explained the biological pattern observed. However, a clear salinity gradient was observed from the inner stations of Montevideo Bay to the outer coastal stations; the high levels of Pb, PAH and Cr concentrations recorded at stations B, C and D in Montevideo Bay were important in discriminating these locations from the others. The MDS ordination combining the production data from the 24 samples from the Montevideo coastal zone with the original data set showed correct assessment of the pollution status for the 24 samples from Montevideo on a common scale of perturbation. The separation of the Montevideo coastal zone samples seems to be mainly due to the high proportion of molluscs. Our results suggest general applicability of the phylum-level meta-analysis approach, even in such cases as this, with high dominance of only one phylum; however, more studies are still necessary.
Abstract − The taxonomic sufficiency approach has been proposed as a surrogate for the typical an... more Abstract − The taxonomic sufficiency approach has been proposed as a surrogate for the typical analysis of species-abundance data, especially in conditions involving prominent pollution gradients. Here, we evaluate the use of taxonomic sufficiency with infralittoral ...
Abstract The 2009–2010 “El Nino”-Southern Oscillation (ENSO) event was characterized by a warm-ph... more Abstract The 2009–2010 “El Nino”-Southern Oscillation (ENSO) event was characterized by a warm-phase leading to a five-fold increase in the Rio de la Plata river flow and an associated change in trophic state because of organic enrichment. We analyzed the biotic response of benthic communities to such an increased trophic state during this ENSO event using community and biotic indices (diversity indices and AMBI). Polychaeta exhibited the highest richness and second the most abundant values while the small gastropod Heleobia australis was the most abundant and frequent species. An increase in richness and diversity of Polychaeta was associated to a concomitant increase of RdlP flow and the organic enrichment of the macrobenthic species. Community indices (richness and diversity) showed variability at both temporal and spatial scale but only AMBI exhibited spatial variability without significant differences between contrasting environmental conditions (ENOS phases).
Abstract Despite the increased and widespread usage of benthic indices for environmental health a... more Abstract Despite the increased and widespread usage of benthic indices for environmental health assessment, some methodological ambiguities remain to be solved. We tested the congruence and consistency of the benthic indices ITI, BO2A, BENTIX, AMBI and M-AMBI in a subtropical estuary (Paranagua Bay, Brazil). Indices were applied to non-vegetated tidal flats increasingly contaminated by sewage to test: (i) correlations with molecular biomarkers of sewage (consistency); and (ii) evaluate the overall agreement/similarity of responses (congruence). The responses of the benthic indexes ITI, AMBI and BO2A were congruent among themselves and consistent with molecular biomarkers values. BENTIX and M-AMBI were less consistent and congruent and possibly need a readjustment of boundaries for subtropical habitats. The indices seemed robust to natural background yearly variations not related to contamination. Faecal sterols associated to nutrient contents suitably supported the validation of indices and could integrate reference conditions for sewage impacted coastal habitats. Benthic indices can successfully integrate management guidelines, but their suitable application demands further research on tolerance shifts of key indicator species.
Climatic, hydrological, and oceanographic conditions were determined during the 2009-2010 El Nino... more Climatic, hydrological, and oceanographic conditions were determined during the 2009-2010 El Nino/Southern Oscillation (ENSO) on the north coast of the Río de la Plata (RdlP) estuary. The maximum monthly rainfall was observed in the middle and upper La Plata basin during September 2009 and February 2010 ("El Niño" phase, (EN)). The monthly flow of RdlP showed an increase with rainfall and significant differences between ENSO phases. The wind stress showed fluctuations in both phases, being less intense during EN, during which time maximum flow of RdlP was observed. During the EN phase, increased precipitation contributed to variations in salinity and absence of water column stratification in the north coast of RdlP. This was also associated with variations in Secchi depth, oxygen saturation, and nutrient concentrations. The spatial location of the turbidity front was associated with the flow of the RdlP and wind stress, thus conditioning the physicochemical characteristics of the water column, mainly during EN phase.
Limnoperna fortunei (golden mussel) is an alien mollusk in the Plata basin and is native from the... more Limnoperna fortunei (golden mussel) is an alien mollusk in the Plata basin and is native from the Southeastern Asia. Its benthic patches generate macrofouling in hydraulic installations causing additional costs to the affected companies. The objective of this work is to determine the variation of abundance and the size of the valves larval stages of the golden mussel, establishing associations with the water quality parameters in the cooling systems in the three hydroelectric power stations (HP) of the reservoirs of the Negro River (Uruguay) that has been invaded by the species. In the three cooling systems the golden mussel larval density average showed associations with temperature of the water and the percentage of organic material of the column water. Larger larval abundances were registered during warm and minimum during cold months. For the three systems, is suggested a reproductive pause of the species at water temperatures lower than 18oC and the start of the larval cycle at...
The Santos Estuarine System (SES) is a complex of bays, islands, estuarine channels, and rivers l... more The Santos Estuarine System (SES) is a complex of bays, islands, estuarine channels, and rivers located on the Southeast coast of Brazil, in which multiple contaminant sources are situated in close proximity to mangroves and other protected areas. In this study, the composition and structure of the macrobenthic communities of SES were described and ninetynine species were identified, with the predominance of polychaetes and bivalve mollusks. The benthic assemblages also showed strong signs of stress, as indicated by the low abundance, richness and diversity, and the dominance of opportunistic species. Integrated analysis including sediment characteristics related to natural and anthropogenic factors (e.g., sediment chemistry, and toxicity) indicated that benthic fauna from the inner portions of the SES and vicinities of the SSOS diffusers as Santos Bay were affected. Some locations at the mouths of Santos and Sao Vicente estuaries exhibited moderate disturbance. In other sites from the mouth of São Vicente and Bertioga channels, and Santos Bay, the benthic fauna were considered not degraded. Our results suggest that a combination of both environmental factors and contaminants were responsible for the benthic community structure.
Pérez, laura (2); tudurí, adriana (1); venturini, natalia (1); Brugnoli, erneSto (1); Muniz, PaBl... more Pérez, laura (2); tudurí, adriana (1); venturini, natalia (1); Brugnoli, erneSto (1); Muniz, PaBlo (1). (1) oceanografía y ecología Marina, InStituto de ecología y cienciaS aMBientaleS (ieca), facultad de cienciaS, univerSidad de la rePúBlica, Montevideo, uruguay. (2) centro univerSitario regional eSte (cure), univerSidad de la rePúBlica, rocha, uruguay.
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