Diatoms as a paleoproductivity proxy in the NW Iberian coastal upwelling system (NE Atlantic)

The objective of the current work is to improve our understanding of how water column diatom's abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwelling system. Diatom fluxes (2.2 (+/- 5.6) 10(6) valves m(-2) d(-1)) represented the majority of the siliceous microorganisms sinking out from the photic zone during all studied years and showed seasonal variability. Contrasting results between water column and sediment trap diatom abundances were found during downwelling periods, as shown by the unexpectedly high diatom export signals when diatom- derived primary production achieved their minimum levels. They were principally related to surface sediment remobilization and intense Minho and Douro river discharge that constitute an additional source of particulate matter to the inner continental shelf. In fact, contributions of allochthonous particles to the sinking material were confirmed by the significant increase of both benthic and freshwater diatoms in the sediment trap assemblage. In contrast, we found that most of the living diatom species blooming during highly productive upwelling periods were dissolved during sinking, and only those resistant to dissolution and the Chaetoceros and Leptocylindrus spp. resting spores were susceptible to being exported and buried. Fur-thermore, Chaetoceros spp. dominate during spring-early summer, when persistent northerly winds lead to the upwelling of nutrient-rich waters on the shelf, while Leptocylindrus spp. appear associated with late-summer upwelling relaxation, characterized by water column stratification and nutrient depletion. These findings evidence that the contributions of these diatom genera to the sediment's total marine diatom assemblage should allow for the reconstruction of different past upwelling regimes.CAIBEX [CTM2007-66408-C02-01/MAR]; REIMAGE [CTM2011-30155-C03-03]; Spanish Government, EXCAPA project [10MDS402013PR]; Xunta de Galicia; EU FEDER [INTERREG 2009/2011-0313/RAIA/E]; RAIA. co [INTERREG2011/2013-052/RAIA.co/1E]; CALIBERIA project [PTDC/MAR/102045/2008]; Fundacao para a Ciencia e a Tecnologia (FCT-Portugal) [COMPETE/FEDER-FCOMP01-0124-FEDER-010599]; Xunta de Galicia (Spain) [SFRH/BPD/111433/2015]; FCT (Portugal) [SFRH/BPD/111433/2015]; [SFRH/BD/88439/2012

Respiratory and mental health effects of wildfires: an ecological study in Galician municipalities (north-west Spain)

<p>Abstract</p> <p>Background</p> <p>During the summer of 2006, a wave of wildfires struck Galicia (north-west Spain), giving rise to a disaster situation in which a great deal of the territory was destroyed. Unlike other occasions, the wildfires in this case also threatened farms, houses and even human lives, with the result that the perception of disaster and helplessness was the most acute experienced in recent years. This study sought to analyse the respiratory and mental health effects of the August-2006 fires, using consumption of anxiolytics-hypnotics and drugs for obstructive airway diseases as indicators.</p> <p>Methods</p> <p>We conducted an analytical, ecological geographical- and temporal-cluster study, using municipality-month as the study unit. The independent variable was exposure to wildfires in August 2006, with municipalities thus being classified into the following three categories: no exposure; medium exposure; and high exposure. Dependent variables were: (1) anxiolytics-hypnotics; and (2) drugs for obstructive airway diseases consumption. These variables were calculated for the two 12-month periods before and after August 2006. Additive models for time series were used for statistical analysis purposes.</p> <p>Results</p> <p>The results revealed a higher consumption of drugs for obstructive airway diseases among pensioners during the months following the wildfires, in municipalities affected versus those unaffected by fire. In terms of consumption of anxiolytics-hypnotics, the results showed a significant increase among men among men overall -pensioners and non-pensioners- in fire-affected municipalities.</p> <p>Conclusions</p> <p>Our study indicates that wildfires have a significant effect on population health. The coherence of these results suggests that drug utilisation research is a useful tool for studying morbidity associated with environmental incidents.</p

Cardiovascular Safety of Anagrelide in Healthy Subjects: Effects of Caffeine and Food Intake on Pharmacokinetics and Adverse Reactions

BACKGROUND: Essential thrombocythaemia (ET) is a rare clonal myeloproliferative disorder characterized by a sustained elevation in platelet count and megakaryocyte hyperplasia. Anagrelide is used in the treatment of ET, where it has been shown to reduce platelet count. Anagrelide is metabolized by cytochrome P450 (CYP) 1A2, and previous studies of the effect of food on the bioavailability and pharmacokinetics of anagrelide were conducted prior to the identification of the active metabolite, 3-hydroxyanagrelide. OBJECTIVES: The objectives of this study were to determine the effect of food and caffeine on the pharmacokinetics of anagrelide and its active metabolite, 3-hydroxyanagrelide, to monitor electrocardiogram (ECG) parameters following drug administration, and to document the relationship between palpitations, ECG changes and caffeine intake METHODS: Thirty-five healthy subjects who received 1 mg of anagrelide following either a 10-h fast or within 30 min of a standardized breakfast, including two cups of coffee, were studied. RESULTS: Time to maximum (peak) plasma concentration (C(max)) of anagrelide was 4.0 h in the fed and 1.5 h in the fasted group (p < 0.05); similar results were observed for 3-hydroxyanagrelide. The mean C(max) of anagrelide was 4.45 ± 2.32 ng/mL and 5.08 ± 2.99 ng/mL in the fed/caffeine and fasted groups, respectively; peak concentrations were higher for 3-hydroxyanagrelide in both the fed/caffeine and fasted groups. The most frequent adverse events (AEs) were headache (60 %) and palpitations (40 %). There were no serious AEs and all ECGs were normal, although significant reductions in PR interval, QRS length and QT interval were observed in both groups. Heart rate increased after anagrelide administration in both fed/caffeine and fasted states (p < 0.01); however, increased heart rate was significantly more frequent in the fed/caffeine state than in the fasted state (p < 0.001 for heart rate increase in the first hour after drug administration). There was a trend towards a greater heart rate increase in subjects reporting palpitations than in those without (mean heart rate ± SD at 1 h: 10.1 ± 6.4 vs. 8.0 ± 8.4 beats/min [p = 0.35]; at 4 h: 12.7 ± 7.5 vs. 9.1 ± 8.8 beats/min [p = 0.10], respectively). CONCLUSION: We conclude that food/caffeine delayed absorption of anagrelide. Anagrelide was generally well tolerated and had small effects on ECG parameters and heart rate. Caffeine may be implicated in a higher increase in heart rate and increased frequency of palpitations observed following administration of anagrelide with food/caffeine versus fasting

Size-fractionated phytoplankton pigment groups in the NW Iberian upwelling system: impact of the Iberian Poleward Current

15 páginas, 6 figuras, 3 tablasSize-fractionated phytoplankton was studied using pigments and carbon (C) biomass derived from light microscopy at a fixed location on the NW Iberian shelf between May 2001 and June 2002. The annual contributions of pico-, nano- and microphytoplankton to the total autotrophic C biomass were 9.7, 63 and 27.3%, respectively, with unidentified nanoflagellates (63%) and diatoms (22%) being the most important components. The CHEMTAX program was used to determine the chlorophyll a (chl a) contribution of 9 pigment groups in nano-microplankton and 8 in picoplankton. ‘Diatoms II’ (species containing chl c3), ‘haptophytes II’ (species of the genus Chrysochromulina containing chl c2-MGDG [monogalactosyl diacylglyceride] [14:0/14:0] ) and ‘chlorophytes’, represented 34, 17 and 16%, respectively, of the total chl a in the nano-microplankton fraction. The major pigment groups in the picoplankton were ‘chlorophytes’, ‘Synechococcus’ and ‘prasinophytes II’ (Order Mamiellales), which accounted for 34, 22 and 10% of the total chl a in this size class. ‘Prochlorococcus’ was traced using divinyl (DV) chl a and was present seasonally, especially during downwelling and stratified poleward conditions (October to November). The lowest chl a and autotrophic C values throughout the study (152 ± 45 ng chl a l–1 and 31 ± 13 μg C l–1) corresponded to the homogenous poleward flow or Iberian Poleward Current (IPC) from December to February. During this period the phytoplankton composition changed abruptly to a diverse pico-nanoplanktonic community that represented ~95% of the total autotrophic C biomass. ‘Chlorophytes’, ‘cryptophytes’ and ‘haptophytes II’ in the nanoplankton, and ‘chlorophytes’ and ‘Synechococcus’ in the picoplankton were the main contributers to chl a in IPC waters, as calculated by CHEMTAX.Financial support for this work came from the Spanish DYBAGA project (MAR99-1039-C02- 01) and from the EU HABILE project (EVK3-CT-2001-00063). B.G.C. was funded by a pre-doctoral I3P fellowship of CSICESF.Peer reviewe

Underwater light field and phytoplankton distribution during a daily cycle in the Ría of Vigo (NW Spain)

12 pages, 12 figures.[EN] Changes in the air and underwater light fields were analyzed through a daily cycle in an estuarine system (Ria de Vigo, NW Spain). Underwater light quality changed with depth throughout the day, and the variation was related to phytoplankton distribution in the water column and to the angular distribution of the incident light. The contribution of light attenuation at different wavelengths (blue, green, yellow-orange, red and far-red) to changes in the attenuation coefficient of the total radiation (between 350 and 800 nm) was determined. The attenuation of blue (B) and red (R) light was greater than green and yellow-orange, as corresponds to waters with a high content of particles (tripton and phytoplankton). The highest values of vertical attenuation coefficient at B and R bands corresponded to maxima of phytoplankton biomass. The vertical profiles of fluorescence correlated with that of the spectral vertical attenuation coefficient.[ES] Se estudian los cambios en el campo lumínico en aire y bajo el agua durante un ciclo diario en un sistema estuárico (Ría de Vigo, NO España). Los cambios en calidad de luz Ccomposición espectral) con la profundiada a lo largo del día en una estación fija se relacionan con la distribución temporal del fitoplancton en la columna de agua y con la distribución angular de la luz incidente. Se determina la contribución de diferentes longitudes de onda (azul, verde, amarillo-naranja, rojo y rojo-lejano) a los cambios en el coeficiente de atenuanción vertical (K) de la radiación total (entre 350 y 800 nm) a lo largo del día.This investigation was supported by the CICYT Projects MAR-90-0365 and MAR-90-0339, and by EC MAST contract no. 0017 on the Control of Phytoplankton Dominance.Peer reviewe

Cardiovascular Safety of Anagrelide in Healthy Subjects: Effects of Caffeine and Food Intake on Pharmacokinetics and Adverse Reactions

Essential thrombocythaemia (ET) is a rare clonal myeloproliferative disorder characterized by a sustained elevation in platelet count and megakaryocyte hyperplasia. Anagrelide is used in the treatment of ET, where it has been shown to reduce platelet count. Anagrelide is metabolized by cytochrome P450 (CYP) 1A2, and previous studies of the effect of food on the bioavailability and pharmacokinetics of anagrelide were conducted prior to the identification of the active metabolite, 3-hydroxyanagrelide.1.704 JCR (2013) Q3, 167/254 Pharmacology & pharmac

Evaluation of host-guest complex formation between a benzimidazolic derivative and cyclodextrins by UV-VIS spectrophotometry and differential scanning calorimetry

Abstract Interactions between a benzimidazolic derivative, omeprazole (OME), beta-cyclodextrin (ßCD) and a chemically modified ßCD, methyl-beta-cyclodextrin (MßCD) were investigated in aqueous solution by UV-VIS spectroscopy and in solid state by differential scanning calorimetry (DSC). Phase solubility studies were used to evaluate the complexation in aqueous solution. The two solubility diagrams obtained were AL type, indicating the formation of a drug-cyclodextrin complex with 1:1 stoichiometry. The complex of OME with MßCD showed a higher stability constant (K S) than those with ßCD. Some evidences of inclusion complexation in solid state were obtained from DSC. Only in thermal curves of OME-ßCD lyophilized product and in OME-MßCD spray-dried and lyophilized systems the melting point of the drug disappeared completely suggesting the possible formation of an inclusion complex

The role of mixing in controlling resource availability and phytoplankton community composition

We investigate the role of mixing, through its effect on nutrient and light availability, as a driver of phytoplankton community composition in the context of Margalef's mandala. Data on microstructure turbulence, irradiance, new nitrogen supply and phytoplankton composition were collected at 102 stations in three contrasting marine environments: the Galician coastal upwelling system of the northwest Iberian Peninsula, the northwestern Mediterranean, and the tropical and subtropical Atlantic, Pacific and Indian oceans. Photosynthetic pigments concentration and microscopic analysis allowed us to investigate the contribution of diatoms, dinoflagellates, pico- and nanoeukaryotes, and cyanobacteria to the phytoplankton community. Simple linear regression was used to assess the role of environmental factors on community composition, and environmental overlap among different phytoplankton groups was computed using nonparametric kernel density functions. Mixing and new nitrogen supply played an important role in controlling the phytoplankton community structure. At lower values of mixing and new nitrogen supply cyanobacteria dominated, pico- and nanoeukaryotes were dominant across a wide range of environmental conditions, and finally enhanced new nitrogen supply was favourable for diatoms and dinoflagellates. Dinoflagellates were prevalent at intermediate mixing levels, whereas diatoms spread across a wider range of mixing conditions. Occasional instances of enhanced diatom biomass were found under low mixing, associated with the high abundance of Hemiaulus hauckii co-occurring with high N2 fixation in subtropical regions, and with the formation of thin layers in the Galician coastal upwelling. Our results verify the Margalef's mandala for the whole phytoplankton community, emphasizing the need to consider nutrient supply, rather than nutrient concentration, as an indicator of nutrient availability

Marine primary productivity is driven by a selection effect

The number of species of autotrophic communities can increase ecosystem productivity through species complementarity or through a selection effect which occurs when the biomass of the community approaches the monoculture biomass of the most productive species. Here we explore the effect of resource supply on marine primary productivity under the premise that the high local species richness of phytoplankton communities increases resource use through transient selection of productive species. Using concurrent measurements of phytoplankton community structure, nitrate fluxes into the euphotic zone, and productivity from a temperate coastal ecosystem, we find that observed productivities are best described by a population growth model in which the dominant species of the community approach their maximum growth rates. We interpret these results as evidence of species selection in communities containing a vast taxonomic repertory. The prevalence of selection effect was supported by open ocean data that show an increase in species dominance across a gradient of nutrient availability. These results highlight the way marine phytoplankton optimize resources and sustain world food stocks. We suggest that the maintenance of phytoplankton species richness is essential to sustain marine primary productivity since it guarantees the occurrence of highly productive species