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Registros recuperados: 10
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Biomass distribution and physiological capabilities of bacteria in the water column above a sea grass system. ArchiMer
Velimirov, B; Herndl, G; Kavka, G.
The distribution pattern of bacteria in the water column above and within a Posidonia oceanica bed near Ischia (off the Gulf of Naples) was investigated and correlated with DOC and POM data for autumn and winter. Data from samples of 5 stations along a transect from shallow to deep showed rather low bacterial densities (10 super(4).ml super(-1)) for both seasons. The number of attached bacteria was higher in late winter as compared to autumn when the leaves are shed from the stands. Except for occasional peaks DOC ranged between 1.5 and 4.5 mg C/1 while POM concentrations ranged form 4 to 14 mg AFDW.1 super(-1). Hydrolytic capabilities of isolated bacterial colonies showed that more carbohydrate substrates could be fermented in winter as compared to...
Tipo: Text Palavras-chave: Posidonia oceanica; Microorganisms; Physiology; Seasonal distribution; Algae; Bacteria; Particulate organic matter; Metabolism; Water column; Fermentation; Sea grass.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-954.pdf
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BP Gulf Science Data Reveals Ineffectual Subsea Dispersant Injection for the Macondo Blowout ArchiMer
Paris, Claire B.; Berenshtein, Igal; Trillo, Marcia L.; Faillettaz, Robin; Olascoaga, Maria J.; Aman, Zachary M.; Schlueter, Micheal; Joye, Samantha B..
After the Deepwater Horizon oil platform explosion, an estimated 172.2 million gallons of gas-saturated oil was discharged uncontrollably into the Gulf of Mexico, causing the largest deep-sea blowout in history. In an attempt to keep the oil submerged, massive quantities of the chemical dispersant Corexit (R) 9500 were deployed 1522 m deep at the gushing riser pipe of the Macondo prospect's wellhead. Understanding the effectiveness of this unprecedented subsea dispersant injection (SSDI) is critical because deepwater drilling is increasing worldwide. Here we use the comprehensive BP Gulf Science Data (GSD) to quantify petroleum dynamics throughout the 87-day long blowout. The spatio-temporal distribution of petroleum hydrocarbons revealed consistent higher...
Tipo: Text Palavras-chave: Oil spill; Deep-sea blowout; Chemical dispersants; Water column; Macondo; Subsea dispersant injection; Petroleum; Gulf Science Data.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00634/74617/74546.pdf
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Mercury behaviour in the water column of an impacted coastal lagoon: Ria de Aveiro (Portugal) as a case study IPB - Escola Superior Agrária
Ramalhosa, Elsa; Pereira, Eduarda; Duarte, Armando.
As mercury presents high toxicity and is of great concern when dealing with protection of human health, mercury pollution related issues are the main subject of this work. At first, two general themes are discussed, namely: I) Mercury: highlights of physicochemical and biogeochemical properties of interest and of the main natural and anthropogenic metal sources; and II) Biogeochemical cycling of mercury in the water column of natural waters. Secondly, a case study performed in Ria de Aveiro (Portugal) during the last 10 years will be presented, focusing on water column processes. Ria de Aveiro is a coastal lagoon, located along the Atlantic Ocean on the north-western coast of Portugal, which was subjected to a discharge of an effluent rich in mercury from...
Tipo: BookPart Palavras-chave: Mercury; Water column; Coastal lagoon.
Ano: 2008 URL: http://hdl.handle.net/10198/3646
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Mercury cycling between water column and upper sediments in a contaminated area (Largo do Laranjo, Aveiro, Portugal) IPB - Escola Superior Agrária
Ramalhosa, Elsa; Río-Segade, Susana; Pereira, Eduarda; Vale, Carlos; Armando, Duarte.
The fate and reactivity of anthropogenic mercury in aquatic environment is of major concern owing to its toxicity to most organisms and man. In Ria de Aveiro, a chloralkali plant has been discharging mercury during decades into one of the remotest branches. Most of the discharged mercury settles down in Largo do Laranjo, an inner bay of 1.5 km'. Since 80's, several works have identified high mercury concentrations in sediments, suspended particulate matter and water [I, 2, 3]. The highest concentrations of mercury (max. 35 Og g") were found in sediments at 40 cm depth, corresponding to the period of maximum industrial production [2]. However, there is an escape of particulate mercury when surface sediments are resuspended and transported by the tide to the...
Tipo: ConferenceObject Palavras-chave: Mercury; Water column; Sediments; Cycling.
Ano: 2004 URL: http://hdl.handle.net/10198/3655
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Methane concentration in water column and in pore water of a coastal lagoon (Cabiúnas lagoon, Macaé, RJ, Brazil) BABT
Fonseca,André Luiz dos Santos; Minello,Murilo; Marinho,Claudio Cardoso; Esteves,Francisco de Assis.
The aim of this study was to evaluate methane concentration in water column and pore water at limnetic and littoral regions of a coastal lagoon. At the littoral region samples were taken from three monospecific macrophytes stands (Typha domingensis, Eleocharis interstincta and Potamogeton stenostachys). The methane concentration in the pore water at the littoral region was higher than the concentration found at the limnetic region in each fraction of the sediment. The higher methane concentration in the superficial fraction of the sediment (0-2 cm) was shown at the P. stenostachys stand (3.7 mM). It was the only significantly different (p<0.05) from the limnetic region. The pore water methane concentration increased with depth at the aquatic macrophytes...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Methane; Water column; Sediment; Aquatic macrophytes; Coastal lagoons.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132004000200018
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Nitrogen cycling in sub-oxic water colmns Gayana
Dalsgaard,Tage; Thamdrup,Bo; Mark Jensen,Marlene.
The current knowledge about nitrogen removal processes in suboxic water columns will be reviewed. The most recent development in the understanding of these processes is the documentation of anaerobic ammonium oxidation with nitrite (anammox) in these areas, and the balance between the traditional denitrification and anammox will be in focus.
Tipo: Journal article Palavras-chave: Denitrification; Anammox; Water column; Nitrogen removal.
Ano: 2006 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300004
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PCDD/F and PCB multi-media ambient concentrations, congener patterns and occurrence in a Mediterranean coastal lagoon (Etang de Thau, France) ArchiMer
Castro Jimenez, J; Deviller, Genevieve; Ghiani, A; Loos, R; Mariani, G; Skejo, H; Umlauf, G; Wollgast, J; Laugier, Thierry; Heas Moisan, K; Leaute, Frederique; Munschy, Catherine; Tixier, Celine; Tronczynski, Jacek.
Ambient concentrations, congener patterns and multi-media distribution of PCDD/Fs and PCBs were determined in air, water, sediment and mussels in a semi-enclosed marine ecosystem (Thau lagoon, France). Sigma 2,3,7,8-PCDD/F and Sigma 7ICES PCB air concentrations (0.2-1.4 and 31-57 pg m(-3), respectively) were typical of rural areas. Concentrations in the water column were very low for PCDD/Fs (163-476 fg L-1) and low for PCBs (138-708 pg L-1). PCDD/F and PCB concentrations found in surface sediment (0.15-1.6 and 2.5-33 ng g(-1) d.w., respectively) and mussel (13-21 pg g(-1) d.w. and 10-39 ng g(-1) d.w., respectively) were medium levels. PCDD/F congener patterns observed in air, water particulate phase and sediments were similar suggesting direct coupling...
Tipo: Text Palavras-chave: Water column; Mussel; Air Sediment; POPs.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-4807.pdf
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Seasonal to hour variation scales in abundance and production of total and particle-attached bacteria in the open NW Mediterranean Sea (0-1000 m) ArchiMer
Mevel, G.; Vernet, M.; Goutx, M.; Ghiglione, J. F..
We present the vertical and temporal dynamics of total vs. particle-attached bacterial abundance and activity over a 5 week period under summer to autumn transition in NW Mediterranean Sea. At a weekly time scale, total bacterial biomass and production in the euphotic layers was significantly correlated with phytoplanktonic biomass. At an hourly time scale, total bacterial biomass responded very rapidly to chlorophyll a fluctuations, suggesting a tight coupling between phytoplankton and bacteria for resource partitioning during the summer-autumn transition. In contrast, no influence of diel changes on bacterial parameters was detected. Episodic events such as coastal water intrusions had a significant positive effect on total bacterial abundance and...
Tipo: Text Palavras-chave: Nucleic acid content; Free living bacteria; Top down control; Flow cytometry; Atlantic ocean; Water column; Spring bloom; Bottom up; North sea; Biogeochemical signifiance.
Ano: 2008 URL: https://archimer.ifremer.fr/doc/00208/31973/30408.pdf
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Water column and recent sediment data on diatoms and coccolithophorids, off Portugal, confirm sediment record of upwelling events ArchiMer
Abrantes, F; Moita, Mt.
Diatom and coccolithophorid abundance and diatom assemblage composition found in the water column along the Portuguese margin, during upwelling and non-upwelling conditions, are compared to the distribution patterns observed in the recent sediments from the same area. The water column results indicate a one order of magnitude increase in phytoplankton biomass during upwelling conditions (summer). with diatoms being the most important contributors. Coccolithophorids, on the contrary, dominate the phytoplankton in winter (non-upwelling). The comparison of the upwelling and non-upwelling spatial distribution of these phytoplankton groups to their sedimentary record reveals the sediment record as a reflection of the upwelling situation, preserving most of its...
Tipo: Text Palavras-chave: Upwelling; Portugal; Diatomée; Colonne d’eau; Sédiment; Upwelling; Portugal; Diatom; Water column; Sediment.
Ano: 1999 URL: http://archimer.ifremer.fr/doc/00325/43613/43915.pdf
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Water column and recent sediment data on diatoms and coccolithophorids, off Portugal, confirm sediment record of upwelling events ArchiMer
Abrantes, F; Moita, Mt.
Diatom and coccolithophorid abundance and diatom assemblage composition found in the water column along the Portuguese margin, during upwelling and non-upwelling conditions, are compared to the distribution patterns observed in the recent sediments from the same area. The water column results indicate a one order of magnitude increase in phytoplankton biomass during upwelling conditions (summer), with diatoms being the most important contributors. Coccolithophorids, on the contrary, dominate the phytoplankton in winter (non-upwelling), The comparison of the upwelling and non-upwelling spatial distribution of these phytoplankton groups to their sedimentary record reveals the sediment record as a reflection of the upwelling situation, preserving most of its...
Tipo: Text Palavras-chave: Upwelling; Portugal; Diatomée; Colonne d'eau; Sédiment; Upwelling; Portugal; Diatom; Water column; Sediment.
Ano: 1999 URL: http://archimer.ifremer.fr/doc/00325/43630/43253.pdf
Registros recuperados: 10
Primeira ... 1 ... Última
 

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