Fine scale physical-biological interactions during a shift from relaxation to upwelling with a focus on Dinophysis acuminata and its potential ciliate prey

Wind reversals and quick transitions from relaxation to upwelling in coastal areas cause major changes in water column structure, phytoplankton distribution and dominance, and rates of physiological processes. The cruise "ASIMUTH-Rías" (17–21 June 2013) was carried out in the Galician Rías and adjacent shelf, at the time of a DSP outbreak, to study small-scale physical processes associated with late spring blooms of "D. acuminata" and accompanying microzooplanktonic ciliates with the overall objective of improving predictive models of their occurrence. The cruise coincided with the initiation of an upwelling pulse following relaxation and deepening of a previously formed thin layer of diatoms. A 36-h cell cycle study carried on 18–20 June showed the vertical excursions of the thin layer, mainly delimited by the 13.5–14 °C isotherms and turbulence levels (ε) of 10−8–10−6 m2 s −3, as well as marked changes in phytoplankton composition (increased density and dominance of diatoms). There was no evidence of daily vertical migration of D. acuminata, which remained in the top layer during the cycle study, but the opposite was observed in the ciliate populations. Dinophysis and its potential prey (Mesodinium species) cell maxima overlapped after midday, when the ciliate moved to the surface, suggesting an “ambush” strategy of Dinophysis to catch prey. A remarkable decline (from 0.65 to 0.33 d−1) in division rates (µ) of D. acuminata was associated with increased turbulence (ε 2°C in about 8 h). In contrast, high division rates (µmin ∼ 0.69 d−1) persisted at a mid-shelf station where environmental conditions below the mixed layer were more stable. The onset of upwelling pulses appears to have a double negative effect on the net growth of Dinophysis populations: a direct physical effect due to advective dispersion and an indirect effect, decreased division rates. The latter would be caused by the rapid cooling of the mixed layer, and the increased turbulence at the surface resulting in shear stress to the cells. The short-term impact of upwelling pulses (and the winds promoting it) on the physiology of "Dinophysis" and its ciliate prey, and the role of mid-shelf populations of "Dinophysis" as a relatively undisturbed reservoir for the inoculation of subsequent blooms are discussed.European Commission | Ref. EC FP7-SPACE-2010-1, n. 261860Ministerio de Economía | Ref. CTM2016-75451-C2-2-RInterreg Atlantic Area | Ref. EAPA_182/2016Comisión Nacional de Ciencia y Tecnología Research (CONICYT), Chile | Ref. PAI79160065Comisión Nacional de Ciencia y Tecnología Research (CONICYT), Chile | Ref. REDES17010

FILO Ciliophora

Capítulo de libroEl conocimiento de la diversidad de los ciliados planctónicos en aguas de Galicia hasta la fecha es muy limitado. La mayor parte de los estudios publicados solo incluyen grandes grupos o algunas especies dominantes, que clásicamente se identificaban por microscopía óptica adaptada y hoy en día se se usan técnicas moleculares basadas en la amplificación, clonación y secuenciación de regiones del gen codificador del ARNr 18S, que permite la identificación filogenética de las "especies" o OTUs que componen las comunidades de ciliados planctónicos, por ejemplo. La lista añadida incluye 25 familias y 88 géneros y especies, recogidos en el marco de proyectos de observación sistemática del IEO... La clasificación usada se basa en Lynn&Small (2002) y la nomenclatura empleada en WORMS (Warren, 2011). Diferenciación por ambientes pelágicos.En prens

ANGPTL-4 is Associated with Obesity and Lipid Profile in Children and Adolescents

Angiopoietin-like protein 4 (ANGPTL-4) regulates lipidic metabolism and affects energy homeostasis. However, its function in children with obesity remains unknown. We investigated plasma ANGPTL-4 levels in children and its relationship with body mass index (BMI) and different lipidic parameters such as free fatty acids (FFA). Plasma ANGPTL-4 levels were analyzed in two different cohorts. In the first cohort (n = 150, age 3–17 years), which included children with normal weight or obesity, we performed a cross-sectional study. In the second cohort, which included only children with obesity (n = 20, age 5–18 years) followed up for two years after an intervention for weight loss, in which we performed a longitudinal study measuring ANGPTL-4 before and after BMI-loss. In the cross-sectional study, circulating ANGPTL-4 levels were lower in children with obesity than in those with normal weight. Moreover, ANGPTL-4 presented a negative correlation with BMI, waist circumference, weight, insulin, homeostasis model assessment of insulin resistance index (HOMA index), triglycerides, and leptin, and a positive correlation with FFA and vitamin-D. In the longitudinal study, the percent change in plasma ANGPTL-4 was correlated with the percent change in FFA, total-cholesterol and high-density lipoprotein cholesterol. This study reveals a significant association of ANGPTL-4 with pediatric obesity and plasma lipid profileThis research was funded by INSTITUTO DE SALUD CARLOS III cofounded by FEDER, grants number PI18/00998, PI15/01272, PI11/02042, PI16/01301, and PI16/00871, and FUNDACIÓN MUTUA MADRILEÑAS

The Beaker phenomenon and the genomic transformation of northwest Europe

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries

Fine scale physical-biological interactions during a shift from relaxation to upwelling with a focus on Dinophysis acuminata and its potential ciliate prey

19 pages, 11 figures, 2 tables.-- This is an open access article under the CC BY-NC-ND licenseWind reversals and quick transitions from relaxation to upwelling in coastal areas cause major changes in water column structure, phytoplankton distribution and dominance, and rates of physiological processes. The cruise “ASIMUTH-Rías” (17–21 June 2013) was carried out in the Galician Rías and adjacent shelf, at the time of a DSP outbreak, to study small-scale physical processes associated with late spring blooms of D. acuminata and accompanying microzooplanktonic ciliates with the overall objective of improving predictive models of their occurrence. The cruise coincided with the initiation of an upwelling pulse following relaxation and deepening of a previously formed thin layer of diatoms. A 36-h cell cycle study carried on 18–20 June showed the vertical excursions of the thin layer, mainly delimited by the 13.5–14 °C isotherms and turbulence levels (ε) of 10−8–10−6m2 s−3, as well as marked changes in phytoplankton composition (increased density and dominance of diatoms). There was no evidence of daily vertical migration of D. acuminata, which remained in the top layer during the cycle study, but the opposite was observed in the ciliate populations. Dinophysis and its potential prey (Mesodinium species) cell maxima overlapped after midday, when the ciliate moved to the surface, suggesting an “ambush” strategy of Dinophysis to catch prey. A remarkable decline (from 0.65 to 0.33 d−1) in division rates (μ) of D. acuminata was associated with increased turbulence (ε < 10−4m2 s−3) near the surface and a sharp drop of temperature (> 2°C in about 8 h). In contrast, high division rates (μmin∼0.69 d−1) persisted at a mid-shelf station where environmental conditions below the mixed layer were more stable. The onset of upwelling pulses appears to have a double negative effect on the net growth of Dinophysis populations: a direct physical effect due to advective dispersion and an indirect effect, decreased division rates. The latter would be caused by the rapid cooling of the mixed layer, and the increased turbulence at the surface resulting in shear stress to the cells. The short-term impact of upwelling pulses (and the winds promoting it) on the physiology of Dinophysis and its ciliate prey, and the role of mid-shelf populations of Dinophysis as a relatively undisturbed reservoir for the inoculation of subsequent blooms are discussed.This work and the sampling cruise were funded by project ASIMUTH (EC FP7-SPACE-2010-1 grant agreement number 261860). Additional support came from Spanish project REMEDIOS (MINECO, Programa RETOS, CTM2016-75451-C2-2-R), and the EU Interreg Atlantic Area PRIMROSE (EAPA_182/2016), an IOC-SCOR GlobalHAB endorsed project. Patricio A. Díaz had a PhD student fellowship from BECAS–CHILE, National Commission for Scientific and Technological Research (CONICYT) and is now funded by projects PAI79160065 (The Attraction and Insertion of Advanced Human Capital Program) and REDES170101 (International Cooperation Programme), CONICYT, ChilePeer reviewe

Dinophysis Ehrenberg (Dinophyceae) in Southern Chile harbours red cryptophyte plastids from Rhodomonas/Storeatula clade

Photosynthetic species of the dinoflagellate genus Dinophysis are known to retain temporary cryptophyte plastids of the Teleaulax/Plagioselmis/Geminigera clade after feeding the ciliate Mesodinium rubrum. In the present study, partial plastid 23S rDNA sequences were retrieved in Southern Chilean waters from oceanic (Los Lagos region), and fjord systems (Aysén region), in single cells of Dinophysis and accompanying organisms (the heliozoan Actinophrys cf. sol and tintinnid ciliates), identified by means of morphological discrimination under the light microscope. All plastid 23S rDNA sequences (n = 23) from Dinophysis spp. (Dinophysis acuta, D. caudata, D. tripos and D. subcircularis) belonged to cryptophytes from clade V (Rhinomonas, Rhodomonas and Storeatula), although they could not be identified at genus level. Moreover, five plastid sequences obtained from heliozoans (Actinophryida, tentatively identified as Actinophrys cf. sol), and tintinnid ciliates, grouped together with those cryptophyte sequences. In contrast, two additional sequences from tintinnids belonged to other taxa (chlorophytes and cyanobacteria). Overall, the present study represents the first time that red cryptophyte plastids outside of the Teleaulax/Plagioselmis/Geminigera clade dominate in wild photosynthetic Dinophysis spp. These findings suggest that either Dinophysis spp. are able to feed on other ciliate prey than Mesodinium and/or that cryptophyte plastids from clade V prevail in members of the M. rubrum species complex in the studied area

Fine scale physical-biological interactions during a shift from relaxation to upwelling with a focus on Dinophysis acuminata and its potential ciliate prey.

Wind reversals and quick transitions from relaxation to upwelling in coastal areas cause major changes in water column structure, phytoplankton distribution and dominance, and rates of physiological processes. The cruise “ASIMUTH-Rías” (17–21 June 2013) was carried out in the Galician Rías and adjacent shelf, at the time of a DSP outbreak, to study small-scale physical processes associated with late spring blooms of D. acuminata and accompanying microzooplanktonic ciliates with the overall objective of improving predictive models of their occurrence. The cruise coincided with the initiation of an upwelling pulse following relaxation and deepening of a previously formed thin layer of diatoms. A 36-h cell cycle study carried on 18–20 June showed the vertical excursions of the thin layer, mainly delimited by the 13.5–14 °C isotherms and turbulence levels (ε) of 10−8–10−6 m2 s−3, as well as marked changes in phytoplankton composition (increased density and dominance of diatoms). There was no evidence of daily vertical migration of D. acuminata, which remained in the top layer during the cycle study, but the opposite was observed in the ciliate populations. Dinophysis and its potential prey (Mesodinium species) cell maxima overlapped after midday, when the ciliate moved to the surface, suggesting an “ambush” strategy of Dinophysis to catch prey. A remarkable decline (from 0.65 to 0.33 d−1) in division rates (µ) of D. acuminata was associated with increased turbulence (ε 2°C in about 8 h). In contrast, high division rates (µmin ∼ 0.69 d−1) persisted at a mid-shelf station where environmental conditions below the mixed layer were more stable. The onset of upwelling pulses appears to have a double negative effect on the net growth of Dinophysis populations: a direct physical effect due to advective dispersion and an indirect effect, decreased division rates. The latter would be caused by the rapid cooling of the mixed layer, and the increased turbulence at the surface resulting in shear stress to the cells. The short-term impact of upwelling pulses (and the winds promoting it) on the physiology of Dinophysis and its ciliate prey, and the role of mid-shelf populations of Dinophysis as a relatively undisturbed reservoir for the inoculation of subsequent blooms are discussed

Changes in distributions of phytoplankton functional groups distribution, pigment composition and the realized niche of Dinophysisacuminata at the onset of an upwelling event

19th International Conference on Harmful Algae (ICHA 2021), october 10-15Dinophysis acuminata is the major cause of lengthy harvesting bans in shellfish growing areas in European Atlantic waters. In North Western Iberian shelf waters, the growing season of D. acuminata lasts throughout the upwelling season (ca. from March to September). Once environmental conditions trigger initial population growth, abundance fluctuations are coupled to the event-scale dynamics of coastal upwelling-relaxation/downwelling cycles. The "ASIMUTH-Rias" cruise (17 - 21 June 2013) in the Galician Rias (Pontevedra and Vigo) and adjacent shelf, during a DSP outbreak, aimed to explore small-scale physical processes associated with late spring blooms (> 103 cells L-1) of D. acuminata. The cruise coincided with the initiation of an upwelling pulse following relaxation and deepening of a previously formed thin layer of centric colony-forming diatoms. In this work, a niche (sensu Hutchinson) approach based on an Outlying Mean Index (OMI) analysis was used to describe the realized niche of D. acuminata during transient conditions. The OMI analysis was applied to fine-scale measurements of physical properties, HPLC-derived pigment composition, and phytoplankton functional groups in cross-shelf transects and in a 36 h study at a fixed station. Although having a wide niche breath, the realized niche of D. acuminata (cell maximum 5 × 103 cells L-1 between 3 and 5 m) was characterized by outflowing warmer (15 - 16 °C) waters with high turbulence (ε < 10- 6 m2 s-3), high light intensity, and low nitrate concentrations. These results show that during a transient upwelling-initiation scenario, mid-shelf waters provided a more suitable habitat for D. acuminata and the accompanying dinoflagellate populations than waters inside the ríasN

Niche differentiation of Dinophysis acuta and D. acuminata in a stratified fjord

Dinophysis acuta and D. acuminata are associated with lipophilic toxins in Southern Chile. Blooms of the two species coincided during summer 2019 in a highly stratified fjord system (Puyuhuapi, Chilean Patagonia). High vertical resolution measurements of physical parameters were carried out during 48 h sampling to i) explore physiological status (e.g., division rates, toxin content) and ii) illustrate the fine scale distribution of D. acuta and D. acuminata populations with a focus on water column structure and co-occurring plastid-bearing ciliates. The species-specific resources and regulators defining the realized niches (sensu Hutchinson) of the two species were identified. Differences in vertical distribution, daily vertical migration and in situ division rates (with record values, 0.76 d−1, in D. acuta), in response to the environmental conditions and potential prey availability, revealed their niche differences. The Outlying Mean Index (OMI) analysis showed that the realized niche of D. acuta (cell maximum 7 × 103 cells L−1 within the pycnocline) was characterized by sub-surface estuarine waters (salinity 23 – 25), lower values of turbulence and PAR, and a narrow niche breath. In contrast, the realized niche of D. acuminata (cell maximum 6.8 × 103 cells L−1 just above the pycnocline) was characterized by fresher (salinity 17 – 20) outflowing surface waters, with higher turbulence and light intensity and a wider niche breadth. Results from OMI and PERMANOVA analyses of co-occurring microplanktonic ciliates were compatible with the hypothesis of species such as those from genera Pseudotontonia and Strombidium constituting an alternative ciliate prey to Mesodinium. The D. acuta cell maximum was associated with DSP (OA and DTX-1) toxins and pectenotoxins; that of D. acuminata only with pectenotoxins. Results presented here contribute to a better understanding of the environmental drivers of species-specific blooms of Dinophysis and management of their distinct effects in Southern Chile. Previous articl

Changes in distribution of phytoplankton functional groups distribution, pigment composition and the realized niche of Dinophysis acuminata at the onset of an upwelling event

Dinophysis acuminata is the major cause of lengthy harvesting bans in shellfish growing areas in European Atlantic waters. In North Western Iberian shelf waters, the growing season of D. acuminata lasts throughout the upwelling season (ca. from March to September). Once environmental conditions trigger initial population growth, abundance fluctuations are coupled to the event-scale dynamics of coastal upwelling-relaxation/downwelling cycles. The “ASIMUTH-Rias” cruise (17–21 June 2013) in the Galician Rias (Pontevedra and Vigo) and adjacent shelf, during a DSP outbreak, aimed to explore small-scale physical processes associated with late spring blooms (> 103 cells L-1) of D. acuminata. The cruise coincided with the initiation of an upwelling pulse following relaxation and deepening of a previously formed thin layer of centric colony-forming diatoms. In this work, a niche (sensu Hutchinson) approach based on an Outlying Mean Index (OMI) analysis was used to describe the realized niche of D. acuminata during transient conditions. The OMI analysis was applied to fine-scale measurements of physical properties, HPLC-derived pigment composition, and phytoplankton functional groups in cross-shelf transects and in a 36-h study at a fixed station. Although having a wide niche breath, the realized niche of D. acuminata (cell maximum 5 ×103 cells L-1 between 3 and 5 m) was characterized by outflowing warmer (15-16 °C) waters with high turbulence (? < 10-6 m2 s-3), high light intensity, and low nitrate concentrations. These results show that during a transient upwelling-initiation scenario, mid-shelf waters provided a more suitable habitat for D. acuminata and the accompanying dinoflagellate populations than waters inside the ría