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Campsurus violaceus is a benthic species that play an important role in sediment bioturbation processes. We explored aspects of its basic biology and life-cycle in a subtropical lake (Laguna del Sauce, Uruguay). We elucidated the habitat preference of C. violaceus and evaluated if might foster a more diverse and abundant macroinvertebrate community. The population of C. violaceus showed univoltine behavior with nymphs all year around. The spatial distribution of Campsurus in the system was related with various sediment attributes, particularly granulometry. A clear positive relationship between abundance of C. violaceus and the associated macroinvertebrate community was found. This association could not be explained by the availability of basal resources, nor sediment preferences, but direct or indirect biotic interactions appeared to be important

Made available in DSpace on 2018-11-26T17:29:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) PPGCC/UNESP Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The atmospheric effects that influence on the signal registered by remote sensors might be minimized in order to provide reliable spectral information. In aquatic systems, the application of atmospheric correction aims to minimize such effects and avoid the under or overestimation of remote sensing reflectance (R-rs). Accurately R-rs provides better information about the state of aquatic system, it means, establishing the concentration of aquatic compounds more precisely. The aim of this study is to evaluate the outputs from several atmospheric correction methods (Dark Object Subtraction DOS; Quick Atmospheric Correction - QUAC; Fast Line-of-sight Atmospheric Analysis of Hypercubes - FLAASH; Atmospheric Correction for OLI 'lite' - ACOLITE, and Provisional Landsat-8 Surface Reflectance Algorithm - L8SR) in order to investigate the suitability of R-rs for estimating total suspended matter concentrations (TSM) in the Barra Bonita Hydroelectrical Reservoir. To establish TSM concentrations via atmospherically corrected Operational Land Imager (OLI) scene, the TSM retrieval model was calibrated and validated with in situ data. Thereby, the achieved results from TSM retrieval model application demonstrated that L8SR is able to provide the most suitable R-rs values for green and red spectral bands, and consequently, the lowest TSM retrieval errors (Mean Absolute Percentage Error about 10% and 12%, respectively). Retrieved R-rs from near infrared band is still a challenge for all the tested algorithms. (C) 2017 COSPAR. Published by Elsevier Ltd. All rights reserved. Sao Paulo State Univ, Dept Cartog, Roberto Simonsen St,305, BR-19060900 Sao Paulo, Brazil Sao Paulo State Univ, Dept Cartog, Roberto Simonsen St,305, BR-19060900 Sao Paulo, Brazil FAPESP: 2012/19821-10 FAPESP: 2015/21586-9 CNPq: 400881/2013-6 CNPq: 472131/2012-5

Retrieval of the inherent optical properties and estimation of the constituents' concentrations from satellite ocean colour data in turbid and eutrophic waters are important as these products provide innovative opportunities for the study of biological and biogeochemical properties in such optically complex waters. This paper intends to develop models to retrieve absorption coefficients of phytoplankton, suspended sediments and coloured dissolved organic matter and describe vertical profiles of chlorophyll and suspended sediments from satellite ocean colour data. These models make use of the relationships between remote sensing reflectance ratios Rrs (555)/Rrs (443) and Rrs (620)/Rrs (490) versus aph (443) and aph (555), and acdom (443), and ad (443) to derive the model parameters. Validation with the in-situ data obtained from coastal waters around India and other regional waters (e.g., NASA bio-Optical Marine Algorithm Data-Set, NOMAD) shows that the new models are more accurate in terms of producing the spectral absorption coefficients (aph, ad, acdom across the entire visible wavelengths 400-700nm) in a wide variety of waters. Further comparison with existing models shows advantage of the new models that have important implications for remote sensing of turbid coastal and eutrophic waters. The retrieved absorption coefficients of phytoplankton and suspended sediments (non-algal matter) are also found to relate better to chlorophyll and total suspended sediments. Taking advantages of this, we derive models to determine and describe the vertical profiles of chlorophyll and suspended sediment concentrations along the depth. The model parameters are derived empirically. These new parameterizations show potential in estimating the vertical profiles of chlorophyll and suspended sediments with good accuracy. These results suggest robustness and suitability of the new models for studying the ecologically important components of optically complex turbid and eutrophic waters using remote sensing data. � 2014 Elsevier Ltd.

Three hundred and thirty-one phytoplankton taxa were identified from Lake Uluabat over a 12-month period in 1998–1999. Phytoplankton richness varied between 35 and 79 taxa, and the Shannon-Wiener diversity index range was 1.574–3.151. Lake Uluabat was characterized by a high variety of Bacillariophyta (152 taxa), Chlorophyta (89 taxa), and Cyanobacteria (42 taxa). Total diversity was strongly correlated with dissolved oxygen and pH, but total species richness and total density were mostly influenced by temperature and Secchi depth. The lake supported a dynamic phytoplankton community through most months of the year.

We proposed to use artificial channels in laboratory assays to expose periphyton to substances released in rural environments in order to test the following hypotheses 1) a high concentration of humic substances decreases the biofilm biomass and alters its metabolism; 2) periphyton biomass and metabolism increase in response to nutrient addition in spite of the previous high nutrient concentration; 3) periphyton response to nutrient addition is smaller in the presence of humic acids. Nutrient loading associated with nonpoint pollution often occurs both during and after signiûcant precipitation events. Humic acids also increase their levels after rain. This may limit the availability of light and thus, the development of the autotrophic. However, the influence of these pollutants on periphyton in eutrophic environments may be either modest or too difficult to detect using traditional endpoints. We found that in short exposures: 1) humic substances do not decrease the biomass of periphyton nor alter its metabolism; 2) periphyton biomass and metabolism increase in response to the addition of fertilizer but not to the addition of a single nutrient; 3) periphyton response to nutrient addition is smaller in the presence of humic acids. These finding have implications for river ecosystems as they suggest that changes produced by nutrient inputs into the eutrophic stream could be fast and clearly affect periphyton algae and other related organisms such as grazers and decomposers. In addition, the presence of humic acids decreases these responses. Fil: Vilches, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; Argentina Fil: Giorgi, Adonis David Nazareno. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; Argentina Fil: Rodríguez Castro, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; Argentina Fil: Casco, Maria Adela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Division Ficología; Argentina

We present a case study of the development of Sacrower See, a stratified, eutrophic lake in northeastern Germany, over the past 13,000 years. Total epilimnetic phosphorus (TP) concentrations were reconstructed quantitatively using a diatom-TP transfer function. Fossil chironomid assemblages were used to support the trophic reconstruction and helped assessing past hypolimnetic oxygen availability. The results indicate eutrophic and anoxic conditions during the Younger Dryas cold period (∼12,700-11,600 cal. BP) preceding the present interglacial. Throughout the early and mid-Holocene (∼11,600-4000 cal. BP) stable oligo- to mesotrophic conditions with diatom-inferred TP values of ∼20 μg L-1 prevailed. First evidence of increasing Holocene TP is recorded at ∼3500 cal. BP associated with Bronze Age human impact and for the past 900 years diatoms indicate increasing TP values of 30-60 μg L-1. During the early Holocene and the past two millennia chironomids indicated anoxic hypolimnetic conditions. The chironomid fauna is considered typical of oligo- to mesotrophic lakes. As a consequence of strongly increased primary production the hypolimnion of Sacrower See became anoxic again during the past 140 years. Our results indicate that highly productive eutrophic conditions can exist prior to cultural eutrophication. At Sacrower See the shift from eutrophic conditions in the Lateglacial to oligo-mesotrophic conditions in the early and mid-Holocene was associated with the climatic warming at the Younger Dryas/Holocene transition. The high productive state during the cold Younger Dryas is associated with changes in seasonality: the prolonged winters caused longer ice cover, stronger stratification, anoxia in the hypolimnion, and consequent internal phosphorus loading. During the warm Holocene, however, hypolimnetic anoxia and internal phosphorus loading decreased significantly, resulting in a substantially lower productivity.

We present a case study of the development of Sacrower See, a stratified, eutrophic lake in northeastern Germany, over the past 13,000 years. Total epilimnetic phosphorus (TP) concentrations were reconstructed quantitatively using a diatom-TP transfer function. Fossil chironomid assemblages were used to support the trophic reconstruction and helped assessing past hypolimnetic oxygen availability. The results indicate eutrophic and anoxic conditions during the Younger Dryas cold period (∼12,700-11,600 cal. BP) preceding the present interglacial. Throughout the early and mid-Holocene (∼11,600-4000 cal. BP) stable oligo- to mesotrophic conditions with diatom-inferred TP values of ∼20 μg L-1 prevailed. First evidence of increasing Holocene TP is recorded at ∼3500 cal. BP associated with Bronze Age human impact and for the past 900 years diatoms indicate increasing TP values of 30-60 μg L-1. During the early Holocene and the past two millennia chironomids indicated anoxic hypolimnetic conditions. The chironomid fauna is considered typical of oligo- to mesotrophic lakes. As a consequence of strongly increased primary production the hypolimnion of Sacrower See became anoxic again during the past 140 years. Our results indicate that highly productive eutrophic conditions can exist prior to cultural eutrophication. At Sacrower See the shift from eutrophic conditions in the Lateglacial to oligo-mesotrophic conditions in the early and mid-Holocene was associated with the climatic warming at the Younger Dryas/Holocene transition. The high productive state during the cold Younger Dryas is associated with changes in seasonality: the prolonged winters caused longer ice cover, stronger stratification, anoxia in the hypolimnion, and consequent internal phosphorus loading. During the warm Holocene, however, hypolimnetic anoxia and internal phosphorus loading decreased significantly, resulting in a substantially lower productivity.

In shallow lakes, macrophytes have important effects on food webs, community structure and nutrient dynamics. For this reason they play a significant role in the restoration of degraded systems. Particularly when present with large coverage, they establish mechanisms favoring low phytoplankton biomass and a decrease of nutrient concentration in the water column. Even if these effects are documented from a number of systems, little evidence comes from shallow mountain lakes. In this study, we report temporal patterns of phytoplanktonic chlorophyll a and nutrient concentration in six eutrophic mountain ponds showing contrasting macrophyte coverage. Six ponds, situated in the Italian Apennines at altitudes ranging from 1164 to 1604 m, were monitored from March to November 1997. Four subsurface water samples were collected at each pond on every visit and analysed for chlorophyll a and nutrients following standard methods. Ponds were divided into two groups: vegetated (VP) and unvegetated (UP) according to their summer macrophyte coverage (respectively > 30% and < 30% of pond area). A nested ANOVA was used to detect macrophyte coverage, season and date (nested within season) effect on phytoplanktonic chlorophyll a concentration, dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP). Chlorophyll a was affected by coverage (P < 0.01) and by season (P < 0.05). In both groups chlorophyll a concentration increased from spring to summer, but differences were higher in UP than in VP. DIN was affected by coverage and season but temporal pattern was not consistent among UP and VP (interaction among coverage and season was significant, P < 0.01). SRP was not affected by coverage (P = 0.158) and season (P = 0.169). Our results on mountain ponds are consistent with those of similar lowland systems. We conclude that managing the presence of macrophytes can be an effective tool for the restoration of eutrophic shallow lakes also in mountain areas.