155 research outputs found
Trends in the species composition at the southernmost estuary of the Atlantic coast of Europe.
Climate change may enhance the establishment of introduced species, as well as the poleward shift in distribution of numerous species over decades. Long-term research and monitoring of an ecosystem at the southernmost point of the Atlantic coast of Europe should be an important priority in order to detect and understand trends in species composition and the related environmental changes. The Guadalquivir estuary (South Spain) is more likely to suffer the exacerbated effects of climate change due to its location in the Mediterranean-climate zone. The long-term data set between 1997 and 2015 in this estuary has allowed us to analyse the variability of the natural and anthropogenic stressors, especially in some dry years and how records of new species have been stabilised as a consequence of expanded connectivity (shipping) and “African Creep”. The mean interannual dissimilarity of the estuarine fauna (Bray–Curtis dissimilarity index) has showed important differences throughout the years, and the species that most contributed to these differences were the exotic species capable of completing their life cycles. Their average annual density has shown a continuous increase during the years of study in a period of expansion. This long-term monitoring of the estuarine community has allowed us to anticipate future events and ecological risk assessment in Europe due to climate change. Management implications are mainly related to the catching of exotic species to control their impact on native communities and reduce the shipping in this sort of ecosystem, which have been especially sensitive in the last 10 years
An integrated model of work motivation applied in a multicultural sample
An integrated model of work motivation was tested in a multicultural sample by analyzing the construct and convergent validity of the measurement tools included in the HSA-Mot model. This model integrates within a relationship network a number of key motivational constructs that operate on different levels: needs, instrumentality, self-efficacy, equity and critical psychological states (knowledge of results, responsibility and meaningfulness). Two cross-sectional studies were conducted. The first concerned four different samples of employees from Chile, Spain, the United Kingdom and Portugal. The construct validity of the measurement tools was studied by means of a CFA. The second study, involving a sample of Mexican workers, analyzed the convergence between the motivational measures proposed by the integrated model and other measures of motivation. The results of both studies were positive and revealed high fit indices between the data and the proposed theoretical model (values above .90 and residuals below .08), as well as high convergence with the other measures used (correlations above .6). The HSA-Mot model shows correct index of validity in its measurement tools and, more importantly, provides key information for tailoring interventions once low levels of motivation have been detected
Effect of high pressure processing on carotenoid and phenolic compounds, antioxidant capacity, and microbial counts of bee-pollen paste and bee-pollen-based beverage
[EN] The optimal high pressure processing treatments (200 400 MPa, 5 15 min) of a pasty matrix of bee-pollen
mixed with peptone water (1.5 g/mL) and bee-pollen added to a pineapple juice-based beverage matrix
(0 10% (w/v)) were studied in order to guarantee food safety and maximum retention of bioactive compounds.
Salmonella and yeasts were used as target microorganisms, while total carotenoid content (TCC), total phenolic
content (TPC), and antioxidant capacity (FRAP) were studied from the food quality point of view. For the pasty
matrix of bee-pollen, the results showed a significant influence of pressure and time, increasing the levels of
TPC, FRAP, and TCC, in comparison with a control sample. A treatment of 395 MPa for 15 min was found as the
optimal. For the pineapple juice-based beverage matrix, the factors pressure and bee-pollen concentration
increased the levels of TPC, FRAP and TCC. Optimal conditions were found at 315 MPa for 14.5 min with
8% (w/v) of bee-pollen.
Industrial relevance: This investigation demonstrated the efficacy of the application of HPP on bee-pollen to inactivate
microorganisms, both pathogenic and spoilage, up to 5-log 10 cycles. Additionally, a structural modification
of the grain was achieved, with a consequent extractability of bioactive compounds and an increasing in
the antioxidant activity, higher than 60% in comparison to fresh bee-pollen. The inclusion of bee-pollen in a
fruit juice-based beverage matrix had a positive effect on the contribution of bioactive compounds that the
fruit juice itself does not contain, such as carotenoids, for which bee-pollen can be considered as a natural additive
that enhances the product functional characteristics.The authors thank the Colombian Administrative Department of Science, Technology and Innovation (COLCIENCIAS) and the Research Direction of Universidad Nacional de Colombia for their support, project AGL 2013-48993-C2-2-R and FEDER funds for resourcesZuluaga, C.; Martínez, A.; Fernández, J.; López-Baldó, J.; Quiles Chuliá, MD.; Rodrigo, D. (2016). Effect of high pressure processing on carotenoid and phenolic compounds, antioxidant capacity, and microbial counts of bee-pollen paste and bee-pollen-based beverage. Innovative Food Science & Emerging Technologies. 37:10-17. https://doi.org/10.1016/j.ifset.2016.07.023S10173
Trophic control in the Guadalquivir estuary and neighbouring waters of the Gulf of Cadiz
The Guadalquivir estuary (SW Spain) is a non-stratified estuary with a gradual change in salinity. It supports an important biodiversity and functions as a nursery area for many commercial species (e.g. anchovy) in the Gulf of Cadiz (GoC). The understanding of the interplay between the environmental forcing (bottom-up) and the trophic regulation is essential to understand its functioning in relation to the GoC fisheries. Here, we seek to study the effects of environmental variables and predator-prey interaction (mysid-anchovy) in the estuary and surrounding marine areas with a particular focus on the zooplankton as key intermediaries between primary production and marine fish juveniles. A long-term (18 yr) monitoring program has been carried out in two sites: Tarfia and Bonanza (32 km and 8 km distance from the river mouth respectively). The latter station samples well the marine water masses advected into the estuary during the ebb flow. Our dataset includes mysids, anchovy larvae and juveniles, temperature, salinity, turbidity, freshwater discharges, precipitation and winds. We used time series-analysis (GAMs) to test the trophic, environmental and anthropogenic effects. Temperature was found to have a positive effect on mysids at both stations while salinity showed a positive effect only at Tarfia. Turbidity showed a strong negative effect on the whole estuary and so did the freshwater discharges at Bonanza, which are regulated by a dam. The results indicate that the trophic control in the estuary of the Guadalquivir is resource-driven. Our models also highlight that marine mysids have a positive effect on anchovy
Modelling the effect of environmental and anthropogenic factors on the abundance of early life-history stages of the European sardine in the Guadalquivir estuary
Estuarine coastal areas play an important role in the recruitment of some small pelagic sh populations mainly when stable salinity-gradients are present. Damming of these ecosystems results in major alterations in this natural hydrological regime. Therefore, changes in the marine/freshwater balance can result in services loss, like the nursery habitat estuaries provide to small pelagic sh, such as sardines. Our previous work showed that the main important recruitment of sardine occurs in spring when this water balance is more variable. However, the drivers of sardine recruitment and particularly the interactive effects of environmental (temperature, salinity, turbidity and winds) and anthropogenic (freshwater discharges) factors are largely unknown. We modelled these effects on the abundance of sardine larvae and juveniles in the Guadalquivir estuary, the most southwestern one in the Atlantic Europe. Sardine early stages tend to occur at the most seaward and more saline sampling site in our study area. The best selected models included the freshwater ow and the wind regimen (northern-southern component) as main drivers explaining their abundance. Freshwater input –tightly controlled by a dam– had a negative short-term effect on the abundance of juvenile sardines above a critical threshold. On top of this, the wind-speed variability in the northern-southern direction showed a clear linear effect: with strong northerly winds enhancing the sardine abundance in the Guadalquivir estuary. These results contribute to the knowledge of the recruitment process of the European sardine and eventually to implementing an ecosystem approach to its fishery in the Gulf of Cadiz
The nursery role of the Guadalquivir estuary for marine fish. A long-term ecological research
Trabajo presentado en el 23rd Biennial CERF Conference (Grand challenges in coastal and Estuarine Science: securin our future), celebrado en Portland (Oregón, US) del 8 al 12 de noviembre de 2015.N
Threatened, endemic and harvested – two overlooked European skates
Sandy ray Leucoraja circularis and shagreen ray L. fullonica are large-bodied skate species occurring in the Northeast Atlantic and Mediterranean on the edge of the continental shelf and upper slope. These areas are not sampled effectively by fishery-independent trawl surveys, and fisheries-dependent data are also limited, as these species are landed as a bycatch. Consequently, there are no formal assessments or reference points, even though they are harvested as part of the Total Allowable Catch (TAC) for generic skates and rays. The implementation of data-limited assessment methods is often reliant on robust life-history data, which was lacking. Therefore, biological data were collected from 116 specimens of L. circularis (21–116 cm LT) and 54 specimens of L. fullonica (19–100 cm LT). Length at 50% maturity for L. circularis was estimated at 81 cm LT and 100 cm LT for males and females, respectively. This large size at maturity makes them more biologically vulnerable than other skate species managed under the generic TAC. This inherent vulnerability, low representation of mature individuals in trawl surveys and bycatch risk due to spatial overlap with important commercial fisheries suggests that both species, assessed as Threatened, would benefit from precautionary species-specific management measures. L. circularis and L. fullonica are respectively, the only IUCN listed Endangered and Vulnerable elasmobranchs that are endemic to Europe and also occur in UK waters. Therefore, with the eastern Atlantic being the main part of their distribution, urgent research and management action is of even greater importance to conserve them
Seasonal variation of zooplankton and environmental conditions along a transect in the Gulf of Cádiz
This study presents seasonal variation in the zooplankton composition of the Gulf of Cádiz was studied between 2001 and 2012. Samples were collected three times per year, in the spring, summer and autumn at three stations situated along a transect perpendicular to the coast. The total zooplankton abundance during the summer was higher than in the spring and autumn. Zooplankton community is characterized by a seasonal cycle mirroring similar cycles in the physical environment. Differences in community composition were also found along the transect, particularly between the coastal station, under the influence of the Guadalquivir River, and the outer station, characterized by oceanic conditions. This study is the first description of the seasonal and spatial variation of this marine component of the Gulf of Cádi
Exploring Deep-Sea Biodiversity in the Porcupine Bank (NE Atlantic) through Fish Integrative Taxonomy
This study combined morphological and molecular approaches to the species assignment of several rare or poorly known deep-water fishes caught between 549 and 1371 m depth during a Spanish bottom trawl survey in the Porcupine Bank, west of Ireland. The following fish species were identified: Nessorhamphus ingolfianus (Schmidt, 1912), Borostomias antarcticus (Lönnberg 1905), Scopelosaurus lepidus (Krefft and Maul 1955), Bathypterois dubius Vaillant, 1888, Evermannella balbo (Risso, 1820), Antimora rostrata (Günther, 1878), Melanonus zugmayeri Norman, 1930, Lyconus brachycolus Holt and Byrne, 1906; Paraliparis hystrix Merrett, 1983, Neocyttus helgae (Holt and Byrne, 1908); Platyberyx opalescens Zugmayer, 1911; Howella atlantica Post and Quéro, 1991, Lycodes terraenovae Collett, 1896 and Pseudoscopelus altipinnis Parr, 1933. The presence of L. brachycolus, P. opalescens and P. altipinnis is reported for the first time in the Bank. The DNA barcoding results were largely consistent with morphological identification in 10 species but four did not fit the current taxonomy, indicating cases of potential cryptic speciation, misidentification, synonymy or recent diversification. Among them, the results strongly suggest that P. garmani and P. hystrix are conspecific, making P. hystrix a junior synonym of P. garmani.Versión del edito
Salinity tolerance as a factor controlling spatial patterns in composition and structure of zooplankton in the Guadalquivir estuary
Trabajo presentado en ECSA 56 (Coastal systems in transition: From a 'natural' to an 'anthropogenically-modified' state), celebrado en Bremen del 4 al 7 de septiembre de 2016.N
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