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de Vareilles M.,University of Algarve | de Vareilles M.,University of Bergen | Richard N.,University of Algarve | Gavaia P.J.,University of Algarve | And 11 more authors.
Journal of Applied Ichthyology | Year: 2012

In order to investigate the effects of dietary protein hydrolysates (PH) on larval growth performance, skeleton quality and proteome expression, triplicate groups of white seabream (Diplodus sargus) larvae were co-fed from first-feeding with live feed and three microencapsulated diets differing in the molecular weight of their PH fraction (Control - inclusion of CPSP-90; H - inclusion of a high amount in 0.5-30kDa hydrolysates; L - inclusion of a high amount in <0.5kDa hydrolysates). At 15days after hatching (DAH), proteome expression changes were assessed in entire larvae by two-dimensional gel electrophoresis and the quality of larval skeleton was analysed at 28DAH through double staining of cartilage and bone. Dietary PH fractions tested affected growth, the larvae fed diet L being significantly larger than those fed diet H, but it did not affect the incidence of deformed larvae, nor the number of deformities per fish. Two-dimensional analysis of larvae proteome allowed the detection and the comparative quantification of a total of 709 protein spots having a pI between 4 and 7, around half of which had an expression significantly affected by dietary treatment, the main difference being between proteome of Control larvae with those of both groups L and H. From these spots, 52 proteins involved in diverse processes such as cytoskeletal dynamics, energetic, lipoprotein, amino acid (AA), and nucleotide metabolisms, protein chaperoning and degradation, and signal transduction, were identified. This study revealed that the molecular weight of the dietary protein hydrolysate fraction had a minor impact on skeletal deformities in white seabream larvae, but affected growth performance and had a strong impact on larvae whole body proteome. © 2012 Blackwell Verlag, Berlin.

Goncalves C.,Instituto Nacional dos Recursos Biologicos INRB IPIMAR | Brogueira M.J.,Instituto Nacional dos Recursos Biologicos INRB IPIMAR | Camoes M.F.,University of Lisbon
Ciencias Marinas | Year: 2012

To evaluate the influence of upwelling events on nitrous oxide (N2O) levels and sea-air exchange in Setúbal Bay (SW Portugal), measurements of dissolved N2O were carried out from the surface down to 200 m depth in May 2006 and May 2007. During the weak upwelling event (May 2006), higher N2O concentrations (values up to 14 nmol L-1) were observed in the upper and deeper layers. In the upper layers a positive correlation between ΔN2O (N2O excess) and apparent oxygen utilization was calculated, suggesting that nitrification contributed to N2O production. During the stronger upwelling event (May 2007), N2O values were lower and did not surpass 12 nmol L-1. Production of N2O could not be disentangled and apparently upwelling provided an effective pathway for ventilating N2O from subsurface waters to the atmosphere. Surface waters were, in general, supersaturated with respect to the atmosphere (percent saturation values 95-160%), indicating that the study area was acting as a source of atmospheric N2O. Higher upwelling-favorable winds (values up to 9 m s-1) registered in May 2007 contributed to increase N2O emissions, which attained a maximum value of 15.2 μmol m-2 d-1 in this period. Lower N2O sea-air fluxes were estimated in May 2006 and values did not surpass 8.8 μmol m-2 d-1. Taking into account the N2O flux in our study area, the contribution of Portuguese coastal upwelling to N2O emission was estimated, varying from 0.040 to 0.102 Gg N yr-1. These values are lower than those reported for most upwelling systems and represent a minor source to atmospheric N2O.

Rosa F.,University of Algarve | Rufino M.M.,CIIMAR – Interdisciplinary Center of Marine and Environmental | Ferreira O.,University of Algarve | Matias A.,University of Algarve | And 2 more authors.
Geologica Acta | Year: 2013

This study examines sediment distribution patterns in the Southeastern Algarve inner shelf (southern Portugal), an area characterized by marked variations in its coastal environment and low continental supply of sediments. The specific goals of this study were to identify the principal sediment sources and the factors influencing sediment transport paths and deposition. A total of 199 samples, collected along the shelf from the Guadiana River mouth to Olhos de Água, were analyzed. Grain-size distribution and parameters were measured for all the samples. Terrigenous and biogenic components of sand were identified in 38 samples, and results analyzed using multivariate non-linear multidimension scaling (MDS) and cluster analysis. Patterns of sediment distribution in this area of the inner shelf vary according to water depth and exhibit significant longshore variation, related mainly to coastal processes (littoral drift and storm currents) and to a lower degree to sediment sources. Sand is dominant at all depths, reflecting the influence of littoral drift in the supply and redistribution of shelf sediments. Fine and gravelsized deposits are significant in specific areas and are usually associated with changes in sediment composition. Five sectors have been identified according to sedimentary dynamics. The results, based on geostatistical and multivariate analysis, have allowed detailed sediment distribution maps to be generated, which represent an update of the existing cartography and serve as a tool for the management of coastal and marine resources. They have been furthermore compared with inner shelf sediment dynamics in other regions worldwide, to distinguish between specific regional responses to forcing mechanisms and processes that are more generalized within this type of shelf environments. In this context, the results obtained results in the Algarve study area are of great interest for the understanding of sediment dynamics of sand dominated inner shelves with reduced continental supply.

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