Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period

From June 2004 to December 2007, samples were weekly collected at a fixed station located at the mouth of Ria de Aveiro (West Iberian Margin). We examined the seasonal and inter-annual fluctuations in composition and community structure of the phytoplankton in relation to the main environmental drivers and assessed the influence of the oceano-graphic regime, namely changes in frequency and intensity of upwelling events, over the dynamics of the phytoplankton assemblage. The samples were consistently handled and a final subset of 136 OTUs (taxa with relative abundance > 0.01%) was subsequently submitted to various multivariate analyses. The phytoplankton assemblage showed significant changes at all temporal scales but with an overriding importance of seasonality over longer-(inter-annual) or shorter-term fluctuations (upwelling-related). Sea-surface temperature, salinity and maximum upwelling index were retrieved as the main driver of seasonal change. Seasonal signal was most evident in the fluctuations of chlorophyll a concentration and in the high turnover from the winter to spring phytoplankton assemblage. The seasonal cycle of production and succession was disturbed by upwelling events known to disrupt thermal stratification and induce changes in the phytoplankton assemblage. Our results indicate that both the frequency and intensity of physical forcing were important drivers of such variability, but the outcome in terms of species composition was highly dependent on the available local pool of species and the timing of those events in relation to the seasonal cycle. We conclude that duration, frequency and intensity of upwelling events, which vary seasonally and inter-annually, are paramount for maintaining long-term phytoplankton diversity likely by allowing unstable coexistence and incorporating species turnover at different scales. Our results contribute to the understanding of the complex mechanisms of coastal phytoplankton dynamics in relation to changing physical forcing which is fundamental to improve predictability of future prospects under climate change.Portuguese Foundation for Science and Technology (FCT, Portugal) [SFRH/BPD/ 94562/2013]; FEDER funds; national funds; CESAM [UID/AMB/50017]; FCT/MEC through national funds; FEDERinfo:eu-repo/semantics/publishedVersio

The impact of diabetes on multiple avoidable admissions: a cross-sectional study

Background Multiple admissions for ambulatory care sensitive conditions (ACSC) are responsible for an important proportion of health care expenditures. Diabetes is one of the conditions consensually classified as an ACSC being considered a major public health concern. The aim of this study was to analyse the impact of diabetes on the occurrence of multiple admissions for ACSC. Methods We analysed inpatient data of all public Portuguese NHS hospitals from 2013 to 2015 on multiple admissions for ACSC among adults aged 18 or older. Multiple ACSC users were identified if they had two or more admissions for any ACSC during the period of analysis. Two logistic regression models were computed. A baseline model where a logistic regression was performed to assess the association between multiple admissions and the presence of diabetes, adjusting for age and sex. A full model to test if diabetes had no constant association with multiple admissions by any ACSC across age groups. Results Among 301,334 ACSC admissions, 144,209 (47.9%) were classified as multiple admissions and from those, 59,436 had diabetes diagnosis, which corresponded to 23,692 patients. Patients with diabetes were 1.49 times (p < 0,001) more likely to be admitted multiple times for any ACSC than patients without diabetes. Younger adults with diabetes (18–39 years old) were more likely to become multiple users. Conclusion Diabetes increases the risk of multiple admissions for ACSC, especially in younger adults. Diabetes presence is associated with a higher resource utilization, which highlights the need for the implementation of adequate management of chronic diseases policies.NOVASaudeinfo:eu-repo/semantics/publishedVersio

Water column and recent sediment data on diatoms and coccolithophorids, off Portugal, confirm sediment record of upwelling events

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 original spatial variability. The comparison between Living and fossil diatom assemblages indicates that from the two genera which dominate the summer biologic assemblage, Pseudo-nitzschia and Chaetoceros, Pseudo-nitzschia is not represented in the sediments, while Chaetoceros is the dominant form of the sediment. Thalassiosira which occurs in the same abundance in both seasons, responding to both river and upwelling nutrient input, can not be a reliable indicator of any single process. However, this genus distribution in the sediments can be used as an indicator of continuous nutrient availability. Such results are of great importance for paleoceanographic reconstructions since they constitute a good indication that the sediment record, even though somewhat altered with respect to assemblage composition, does reflect the water column characteristics.L'abondance de diatomées et des coccolithophoridés et la composition des populations de diatomées ont été observées le long de la côte du Portugal dans la colonne d'eau et dans les sédiments récents. Pendant l'upwelling (été) la biomasse du phytoplancton dans la colonne d'eau augmente d'un ordre de grandeur avec les diatomées. En l'absence d'upwelling (hiver), les coccolithophoridés prédominent. La répartition de ces groupes dans le sédiment reflète la situation d'upwelling en conservant la variabilité spatiale originelle. La comparaison entre les populations de diatomées vivantes et fossiles indique que l'un des deux genres dominants en étéPseudo-nitzschia, n'est pas représenté dans le sédiment tandis que l'autre, Chaetoceros, y prédomine. Le genre Thalassiosira, présent avec la même abondance pendant les deux saisons en raison de l'apport de nutriments par le fleuve et par l'upwelling, ne peut être l'indicateur fiable d'un processus unique, mais la présence de ce genre dans les sédiments indique la disponibilité permanente de nutriments. Ces résultats sont d'une grande importance en paléo-océanographie car ils montrent que le sédiment reflète les caractéristiques de la colonne d'eau, malgré les modifications observées dans la composition des populations

A bloom of Dinophysis acuta in a thin layer off North-West Portugal

Dinophysis acuta, which is responsible for diarrhetic shellfish poisoning, reached particularly high concentrations on the north-west coast of Portugal in 2003. In the Ría de Aveiro (40°41’N), the species reached a maximumconcentration of 5.0 X 104 cells l–1 on 8 September, the highest value in a 17-year record of monitoring. The bloom followed a brief period of upwelling-favourable winds, at the end of an extremely hot summer marked by weak upwelling, thereby favouring the developmentof highly stratified conditions. In mid-September, during a cruise transecting the shelf 30km south of Aveiro, a subsurface maximum of D. acuta was identified by fluorescence, with cell concentrations exceeding 2.4 X 104 cells l–1. The species was restricted to a relatively thin layer of 5m (with maxima between 18m and 20m depth) within the pycnocline extending 30km offshore. Crossshelf distributions revealed the presence of two smaller forms of D. acuta, the smallest of which was identifiedas D. dens. Their coincident distribution with that of D.acuta reinforced the supposition that these smaller forms correspond to different life-cycle stages of D. acuta, with D. dens representing a gamete of D. acuta.The high cell concentrations in the thin layer are thought to embody a species’ strategy to ensure successful gamete mating during sexual reproduction