Effects of dredging on benthic diatom assemblages in a lowland stream

Licursi, Magdalena; Gómez, Nora

doi:10.1016/j.jenvman.2008.03.004

Cited by 37 publications

(24 citation statements)

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“…And variations in the tolerance of the diatom assemblage due to that treatment manifested as a decrease in the sensitive species (oligotrophic and oligosaprobic) and as an increment in the IDP values. This coincides with responses observed in other nutrient-rich Pampean streams, where the proportions of sensitive species, even when low, diminish with the increments of nutrients and organic matter (Gómez et al, 2008;Licursi & Gómez, 2009) The results also show a decrease in stalked diatoms in the treated channels, with slight increments in motile biraphids. The latter include species from the genera Navicula, Nitzschia, and Sellaphora, which are classified as part of the "motile guild"…”

Section: Discussionsupporting

confidence: 86%

“…Another three channels (HIGH treatment) were exposed to a 4°C increase in temperature, 300% increase in nutrients (SRP and DIN), 50% increase in suspended solids and 20% increase in water velocity. The temperature increase was selected to represent the maximum increment predicted by the climatic models of the region (Hulme & Sheard, 1999), while the nutrients, turbidity and water velocity increments are among the largest values measured in different sites throughout the Pampean streams (Gómez & Licursi, 2001;Gómez et al, 2008;Bauer et al, 2002;Giorgi et al, 2005;Licursi, 2005;Licursi & Gómez, 2009). The final three channels (LOW treatment) were exposed to intermediate levels of the manipulated variables: a 1°C increase in temperature, 50% increase in nutrients (SRP and DIN), 15% increase in suspended solids and 5% increase water velocity.…”

Section: Methodsmentioning

confidence: 99%

“…To this end we conducted a laboratory experiment simulating two environmental conditions (LOW treatment and HIGH treatment) employing epipelic biofilm from a mesotrophic Pampean stream (the "Martin" stream). The manipulated temperatures were selected to represent the both the maximum increment predicted by the climatic models of the region (Hulme & Sheard, 1999) in the HIGH treatment and an intermediate situation in the LOW treatment; the nutrients (phosphorous and nitrogen), turbidity and water velocity increments in the HIGH treatment are among the largest values measured in different sites throughout the Pampean streams (Gómez & Licursi, 2001;Gómez et al, 2008;Bauer et al, 2002;Giorgi et al, 2005;Licursi, 2005;Licursi & Gómez, 2009), and in the LOW treatment these variables were increased in an intermediate level between the controls and the HIGH treatment.…”

Section: Introductionmentioning

confidence: 99%

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Changes in the epipelic diatom assemblage in nutrient rich streams due to the variations of simultaneous stressors

2015

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Please cite this article as: Cochero, J., Licursi, M., Gómez, N.,Changes in the epipelic diatom assemblage in nutrient rich streams to the variations of simultaneous stressors, Limnologica (2014), http://dx.doi.org/10.1016/j.limno. 2014.10.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d M a n u s c r i p t results suggest that, in the very short term of the bioassay conducted, the diatom assemblage can modify its structure to respond in a sensitive manner to the abrupt changes in multiple physical-chemical variables.

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Section: Discussionsupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Changes in the epipelic diatom assemblage in nutrient rich streams due to the variations of simultaneous stressors

2015

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“…Kiesel (jkiesel@hydrology.uni-kiel.de) Fine sediment input into waterways has a decisive influence on water quality (Davies-Colley et al, 1992;Ryan, 1991), aquatic life-forms (Berry et al, 2003) and their habitat (Wood and Armitage, 1999), as well as anthropogenic usage like ship traffic and artificial water structures as harbors (Stevens and Ekermo, 2003). Especially in lowland regions, the siltation process of sediment can lead to necessary but harmful measures for the environment like dredging and mud extraction activities (Licursi and Gómez, 2009). Collins and Walling (2004) point out that, though it is difficult to acquire information about sediment entry pathways, it is important to understand sediment sources for deriving management plans and to prevent environmental problems.…”

Section: Introductionmentioning

confidence: 99%

SEPAL – a simple GIS-based tool to estimate sediment pathways in lowland catchments

2009

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Abstract. Even though soil loss in the lowlands imposes not as much a restriction on land use and agricultural productivity as in erosion affected mountainous areas, the input of fine sediment into the rivers and streams is a concern due to water quality issues and substrate siltation. Drains, river banks and agricultural fields are the three main sources of fine sediment in lowland regions. For a successful implementation of measures to decrease sediment input a well-founded knowledge of the individual entry pathways is essential. To assess the importance of possible entry pathways, a GIS based methodology (SEPAL) has been established combining the ABAG, a river bank erosion formula and a regression approach to include the contributions of drains. SEPAL has been applied on a study catchment in Northern Germany. The results show that 15% of the sediment input into the river comes from agricultural drains, 71% from river banks and 14% from adjacent fields. A comparison of the results with field-mapping and -sampling shows that the approach is plausible. The calculated total annual sediment input is 616 t yr −1 , while the measured suspended sediment load is 636 t yr −1 . It can be concluded that the methodology is suitable for estimating sediment entry pathways and annual sediment loads in lowland catchments as a base for modelling projects and further investigations. However, further work is necessary for gaining sound knowledge about uncertainties and especially about the processes forcing sediment input from drains.

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“…The dredging of urban systems in the pampean plain is frequently carried out with the intention of increasing their discharge into the Río de la Plata estuary. The inappropriate use of the land, the inadequacy of urban planning, and the input of contamination frequently accelerate the siltation, thus leading to the need of dredging and mud extraction (Licursi and Gómez, 2008). These physical disturbances were reflected here in the middle and lower reaches of the Don Carlos Stream.…”

Section: Discussionmentioning

confidence: 93%

Different levels of taxonomic resolution in bioassessment: a case study of oligochaeta in lowland streams

et al. 2012

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Aim:This study evaluated the use of oligochaetes at different levels of taxonomic resolution as environmental indicators in Argentine lowland streams affected by different land uses. Methods: Sampling sites were grouped based on the physicochemical and habitat characteristics (low-, moderate-, and high-impact disturbance). Collection of the oligochaetes samples was carried out seasonally in sediment and vegetation habitats. Results: The increases in nutrients and organic matter produced elevated densities of the Oligochaeta, but when the disturbance also involved changes in the physical habitat or enhancements in toxic substances, the abundance decreased significantly to values even lower than those of non-impacted environments. The responses of Naidinae and Tubificinae were similar. The density of the Pristininae decreased with increasing impact, but those of the Enchytraeidae and Rhyacodrilinae increased at the most highly impacted sites. The Opistocystidae were not recorded in high-impact sites. Species richness and diversity (H') were lower in high-impact sites and even lower in sediments. Some species presented no restrictions in the habitat type or with the contamination level: Limnodrilus hoffmeisteri, Dero furcatus, D. digitata, D. pectinata, Pristina longiseta, and P. aequiseta. Moreover, Trieminentia corderoi, Slavina appendiculata, and Aulodrilus pigueti exhibited the highest abundances at low-impact sites and were not registered in high-impact sites. Conclusions: The Oligochaeta show a relatively wide ecological valence through their extensive number of species. Although lower taxonomic levels can give information about environmental status, test-species' sensitivities to different types and degrees of contamination will be of utmost relevance to the evaluation of ecological quality.Keywords: annelids, land use, habitat preferences, sediment, macrophyte.Resumo: Objetivo: Este estudo analisou as uso de oligoquetos em diferentes níveis de resolução taxonômica como indicadores ambientais em rios de planície Argentina afetadas por diferentes usos da terra. Métodos: Os sítios de amostragem foram agrupados com base nas características físico-químicas e habitat (perturbação baixa, moderada ou alta). Amostras de oligoquetos foram coletadas sazonalmente em habitats de sedimentos e vegetação. Resultados: Os aumentos de nutrientes e matéria orgânica resultaram em densidades elevadas de Oligochaeta, mas quando a perturbação também envolveu mudanças no habitat físico ou incrementos em substâncias tóxicas, a abundância diminuiu de forma significativa para valores ainda mais baixos que os de ambientes naõ perturbados. As respostas dos Naidinae e Tubificinae foram semelhantes. A densidade de Pristininae diminuiu com o aumento da perturbação, mas as densidades de Enchytraeidae e Rhyacodrilinae aumentaram nos locais mais altamente perturbados. Os Opistocystidae não ocorreram em locais de alta perturbação. A riqueza de espécies e a diversidade (H') foram menores em locais de perturbação elevada e ainda mais b...

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Effects of dredging on benthic diatom assemblages in a lowland stream

Cited by 37 publications

References 41 publications

Changes in the epipelic diatom assemblage in nutrient rich streams due to the variations of simultaneous stressors

Changes in the epipelic diatom assemblage in nutrient rich streams due to the variations of simultaneous stressors

SEPAL – a simple GIS-based tool to estimate sediment pathways in lowland catchments

Different levels of taxonomic resolution in bioassessment: a case study of oligochaeta in lowland streams

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