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Cabrita M.T.,Portuguese Institute of Sea and Atmosphere IPMA
Environmental Pollution

This work reports changes in suspended particulate matter, turbidity, dissolved Cr, Ni, Cu, Cd, Hg and Pb concentrations, and phytoplankton biomass and composition during a 5-month period dredging operation, in a trace element contaminated area of the Tagus estuary (Portugal). Phytoplankton biomass, diatom:other groups ratio, benthic:pelagic diatom ratio, Margalef's, Simpson's diversity, Shannon-Wiever's, and Warwick and Clarke's taxonomic diversity and distinctness indices, and individual taxa were investigated as indicators of dredging induced changes. Significant rise in sediment resuspension and trace element mobilisation caused by dredging influenced the community structure but not the overall biomass. Benthic diatom displacement into the water column maintained species diversity, and therefore, none of the indices highlighted community changes. Contrastingly, diatom:other groups ratio and benthic:pelagic diatom ratio were reliable indicators for the assessment of dredging induced changes. A shift in composition towards species less susceptible to trace elements was observed, disclosing some individual taxa as potential indicators. © 2014 Elsevier Ltd. All rights reserved. Source

Ospina-Alvarez N.,CSIC - Institute of Marine Research | Caetano M.,Portuguese Institute of Sea and Atmosphere IPMA | Vale C.,Portuguese Institute of Sea and Atmosphere IPMA | Santos-Echeandia J.,CSIC - Institute of Marine Research | And 2 more authors.
Journal of Sea Research

Concentrations of nitrate, nitrite, ammonium, phosphate and silicate were determined in river water, tidal water that floods the intertidal sediment (flooding water) and pore water of those sediments in the Northern Galician Rias of Ortigueira and Viveiro (NW Iberian Peninsula). The field surveys were done in the productive seasons of spring and summer 2008. Short-sediment cores and tidal flooding water were sampled at the intertidal area during the first 20min that the tide inundates the sampling site. Nutrient fluxes of rivers (Lourido and Landro) flowing into the rias were in the order of H4SiO4>NO3 ->NH4 +>HPO4-2 Nutrients input from those rivers were low relative to the nutrient discharge of the entire coastal area. Striking changes of nutrient concentrations in flooding and pore waters of intertidal sediments were observed in the short periods of tidal inundation. Nutrient fluxes driven by molecular diffusion and tide-induced transport across the sediment-water interface were quantified and compared to the nutrient river contribution. Diffusive fluxes ranged from 9.3 to 13.7nmol·cm-2·d-1 for nitrate and nitrite, -1.32 to 30.1nmol·cm-2·d-1 for ammonium, -0.01 to 0.49nmol·cm-2·d-1 for phosphate, and -13.2 to 0.2nmol·cm-2·d-1 for silicate. Tide-induced transport always exceeded diffusive fluxes, with differences reaching up to four orders of magnitude for silicate. The overall results of this study emphasize the relevance of tidal water movement in promoting the sediment-water exchange of nutrients in intertidal sub-ecosystems. © 2013 Elsevier B.V. Source

Anacleto P.,Portuguese Institute of Sea and Atmosphere IPMA | Maulvault A.L.,Portuguese Institute of Sea and Atmosphere IPMA | Barrento S.,University of Swansea | Mendes R.,Portuguese Institute of Sea and Atmosphere IPMA | And 3 more authors.

The trade of live bivalves is a complex chain (harvesting, depuration, transportation), where animals are affected by several stressors that reduce animal condition and promote mortalities, with the consequent economic losses. The aim of this study was to investigate the physiological responses (survival rates, condition index, breakdown products of ATP and glycogen content) of two bivalve species from the Tagus estuary, Venerupis pullastra (native clam) and Ruditapes philippinarum (exotic clam) during two days of depuration and subsequent transport in semi-dry conditions at two temperatures (4 and 22. °C) until reaching 50% lethal time (LT50). Depuration did not negatively affect both species, even enabling additional two day survival extension until attaining LT50. In contrast, transport was an important stressor, with temperature contributing greatly for mortality: R. philippinarum showed higher survival rates than V. pullastra, always reaching LT50 later, especially at 4. °C. The exotic clam survived nine days more at 4. °C, but only one day more at 22. °C than the native species. Nevertheless, native clams showed higher condition index and glycogen content, and also lower nucleotide K-value and adenylate energy charge than exotic clams. The best semi-dry transport conditions to maintain good physiological conditions and high quality of clams should be performed at low temperatures (4. °C). © 2013 Elsevier B.V. Source

Cabrita M.T.,Portuguese Institute of Sea and Atmosphere IPMA | Raimundo J.,Portuguese Institute of Sea and Atmosphere IPMA | Pereira P.,Portuguese Institute of Sea and Atmosphere IPMA | Pereira P.,University of Aveiro | Vale C.,Portuguese Institute of Sea and Atmosphere IPMA
Environmental Science and Pollution Research

This work reports changes of Cr, Cu, Zn, Cd, Hg and Pb concentrations in the dissolved fraction, suspended particulate matter and immobilised Phaeodactylum tricornutum Bohlin (Bacillariophyceae), as well as of microalgae specific growth rates, during a 5-month period dredging operation in a contaminated area of the Tagus estuary, Portugal. Trace element concentrations showed broad variations in the dissolved fraction and suspended particulate matter, presumably reflecting rapid exchanges of redox-sensitive elements between water and particles, in conjunction with the dilution effect caused by the tidal excursion. Immobilised cells exposed to dredging environmental conditions showed significantly higher concentrations of Cr, Cu, Zn, Cd, Hg and Pb than under no dredging conditions. Concomitantly, specific cell growth was significantly lower, suggesting that elements released with dredging affect the microalgae physiology. The results obtained in this in situ work imply that the dissolved fraction and the suspended particulate matter are relatively ineffective indicators of the trace element enhancement during dredging and pointed out immobilised P. tricornutum as a reliable and efficient biomonitoring tool for the assessment of trace element remobilisation. © 2013 Springer-Verlag Berlin Heidelberg. Source

Centenaro G.S.,Federal University of Rio Grande do Sul | Salas-Mellado M.,Federal University of Rio Grande do Sul | Pires C.,Portuguese Institute of Sea and Atmosphere IPMA | Batista I.,Portuguese Institute of Sea and Atmosphere IPMA | And 2 more authors.
Applied Biochemistry and Biotechnology

In this work, chicken and fish peptides were obtained using the proteolytic enzymes α-Chymotrypsin and Flavourzyme. The muscle was hydrolyzed for 4 h, and the resulting peptides were evaluated. Hydrolysates were produced from Argentine croaker (Umbrina canosai) with a degree of hydrolysis (DH) of 25.9 and 27.6 % and from chicken (Gallus domesticus) with DH of 17.8 and 20.6 % for Flavourzyme and α-Chymotrypsin, respectively. Membrane ultrafiltration was used to separate fish and chicken hydrolysates from Flavourzyme and α-Chymotrypsin based on molecular weight cutoff of >1,000, <1,000 and >500, and <500 Da, to produce fractions (F1,000, F1,000-500, and F500) with antioxidant activity. Fish hydrolysates produced with Flavourzyme (FHF) and α-Chymotrypsin showed 60.8 and 50.9 % of peptides with a molecular weight of <3 kDa in its composition, respectively. To chicken hydrolysates produced with Flavourzyme and α-Chymotrypsin (CHC) was observed 83 and 92.4 % of peptides with a molecular weight of <3 kDa. The fraction that showed, in general, higher antioxidant potential was F1,000 from FHF. When added 40 mg/mL of FHF and CHC, 93 and 80 % of lipid oxidation in ground beef homogenates was inhibited, respectively. The composition of amino acids indicated higher amino acids hydrophobic content and amino acids containing sulfuric residues for FHF, which showed antioxidant potential. © 2014 Springer Science+Business Media. Source

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