Counter Gradient Research Articles

Direct Analysis of Marine Dissolved Organic Matter Using LC-FT-ICR MS.

Marine dissolved organic matter (DOM) is an important component of the global carbon cycle, yet its intricate composition and the sea salt matrix pose major challenges for chemical analysis. We introduce a direct injection, reversed-phase liquid chromatography ultrahigh resolution mass spectrometry approach to analyze marine DOM without the need for solid-phase extraction. Effective separation of salt and DOM is achieved with a large chromatographic column and an extended isocratic aqueous step. Postcolumn dilution of the sample flow with buffer-free solvents and implementing a counter gradient reduced salt buildup in the ion source and resulted in excellent repeatability. With this method, over 5,500 unique molecular formulas were detected from just 5.5 nmol carbon in 100 μL of filtered Arctic Ocean seawater. We observed a highly linear detector response for variable sample carbon concentrations and a high robustness against the salt matrix. Compared to solid-phase extracted DOM, our direct injection method demonstrated superior sensitivity for heteroatom-containing DOM. The direct analysis of seawater offers fast and simple sample preparation and avoids fractionation introduced by extraction. The method facilitates studies in environments, where only minimal sample volume is available e.g. in marine sediment pore water, ice cores, or permafrost soil solution. The small volume requirement also supports higher spatial (e.g., in soils) or temporal sample resolution (e.g., in culture experiments). Chromatographic separation adds further chemical information to molecular formulas, enhancing our understanding of marine biogeochemistry, chemodiversity, and ecological processes.

Linking methanotroph phenotypes to genotypes using a simple spatially resolved model ecosystem.

Connecting genes to phenotypic traits in bacteria is often challenging because of a lack of environmental context in laboratory settings. Laboratory-based model ecosystems offer a means to better account for environmental conditions compared with standard planktonic cultures and can help link genotypes and phenotypes. Here, we present a simple, cost-effective, laboratory-based model ecosystem to study aerobic methane-oxidizing bacteria (methanotrophs) within the methane-oxygen counter gradient typically found in the natural environment of these organisms. Culturing the methanotroph Methylomonas sp. strain LW13 in this system resulted in the formation of a distinct horizontal band at the intersection of the counter gradient, which we discovered was not due to increased numbers of bacteria at this location but instead to an increased amount of polysaccharides. We also discovered that different methanotrophic taxa form polysaccharide bands with distinct locations and morphologies when grown in the methane-oxygen counter gradient. By comparing transcriptomic data from LW13 growing within and surrounding this band, we identified genes upregulated within the band and validated their involvement in growth and band formation within the model ecosystem using knockout strains. Notably, deletion of these genes did not negatively affect growth using standard planktonic culturing methods. This work highlights the use of a laboratory-based model ecosystem that more closely mimics the natural environment to uncover bacterial phenotypes missing from standard laboratory conditions, and to link these phenotypes with their genetic determinants.

Moisture swing frequency response method for characterization of ion-transport kinetics of CO2 adsorption

Direct air capture of CO2 (DAC) sufficiently mitigates atmospheric CO2 to prevent the impacts of global warming of 1.5 °C above preindustrial levels. To overcome the challenges of the kinetics of sorbent under the ultra-low partial pressure (40 Pa) of DAC, the underlying mechanisms need to be constructed for better designs, simulations, and developments of the separation processes of carbon dioxide. Herein, a transient model based on the diffusion-reaction of ions at the molecular scale is developed for the moisture swing adsorption (MSA) process, disclosing the mechanism of mass transfer of multi-ions of sorbents. To compare the model with the experiment quantitatively, Fourier-transformed moisture-swing frequency response is applied to accurately measure the H2OCO2 concentration response, ensuring a systematic approach for unknown kinetic parameters for the model. The results reveal that the gradient of water vapor causes a counter gradient of CO2 concentration, generating the spontaneous transportation of CO2 of the MSA membrane from one side to another. Specifically, the diffusion coefficient of HCO3− drives the CO2 adsorption process predominantly, where the diffusion coefficient of HCO3− increases about ten times, leading to a nearly 12 times enhanced CO2 separation rate accordingly. Notably, CO2 adsorption kinetics can be stimulated by controlling specific ion conductivity in the moisture swing sorbent. With the enhancement of adsorption kinetics and low capital cost, the progress of CO2 mitigation using Moisture Swing Adsorption can be achieved for direct air capture of CO2.

Dissimilarity of Turbulent Transport of Momentum and Heat Under Unstable Conditions Linked to Convective Circulations

AbstractThe dissimilarity between the turbulent transport of momentum and heat under unstable conditions and its physical mechanisms are investigated in this study, based on the multiple‐level turbulence observation from the Tianjin 255‐m meteorological tower. The transport dissimilarity is observed from the surface layer to the lower part of mixed layer as atmospheric instability increases. Although the transport dissimilarity is accompanied by the development of plumes and thermals under unstable conditions, plumes and thermals can produce intense transport both of momentum and heat simultaneously. It is convective circulations induced by vigorous thermals that cause transport dissimilarity. The horizontal divergence generated by convective circulations imposes a dominant large‐scale reduction in the along‐wind velocity component near the surface, which is related to increased counter gradient transport of momentum, while the temporal variations in temperature mainly reflect the role of plumes and thermals and thus the transport of heat is predominantly down‐gradient. This difference in respective physical processes subsequently leads to dissimilar transport between momentum and heat under unstable conditions. Therefore, it is of great interest to represent the influence of convective circulations on the momentum‐flux estimation in future investigations, aiming to improve the boundary‐layer parameterization schemes for mesoscale numerical weather models.

Pathways of methane removal in the sediment and water column of a seasonally anoxic eutrophic marine basin

Methane (CH4) is a key greenhouse gas. Coastal areas account for a major proportion of marine CH4 emissions. Eutrophication and associated bottom water hypoxia enhance CH4 production in coastal sediments. Here, we assess the fate of CH4 produced in sediments at a site in a seasonally anoxic eutrophic coastal marine basin (Scharendijke, Lake Grevelingen, the Netherlands) in spring (March) and late summer (September) in 2020. Removal of CH4 in the sediment through anaerobic oxidation with sulfate (SO42-) is known to be incomplete in this system, as confirmed here by only slightly higher values of δ13C-CH4 and δD-CH4 in the porewater in the shallow sulfate-methane-transition zone (~5-15 cm sediment depth) when compared to deeper sediment layers. In March 2020, when the water column was fully oxygenated, CH4 that escaped from the sediment was at least partially removed in the bottom water through aerobic oxidation. In September 2020, when the water column was anoxic below ~35 m water depth, CH4 accumulated to high concentrations (up to 73 µmol L-1) in the waters below the oxycline. The sharp counter gradient in oxygen and CH4 concentrations at ~35 m depth and increase in δ13C-CH4 and δD-CH4 above the oxycline indicate mostly aerobic water column removal of CH4. Water column profiles of particulate and dissolved Fe and Mn suggest redox cycling of both metals at the oxycline, pointing towards a potential role of metal oxides in CH4 removal. Water column profiles of NH4+ and NO3- indicate removal of both solutes near the oxycline. Analyses of 16S rRNA gene sequences retrieved from the water column reveal the presence of aerobic CH4 oxidizing bacteria (Methylomonadaceae) and anaerobic methanotrophic archaea (Methanoperedenaceae), with the latter potentially capable of NO3- and/or metal-oxide dependent CH4 oxidation, near the oxycline. Overall, our results indicate sediment and water column removal of CH4 through a combination of aerobic and anaerobic pathways, which vary seasonally. Some of the CH4 appears to escape from the surface waters to the atmosphere, however. We conclude that eutrophication may make coastal waters a more important source of CH4 to the atmosphere than commonly assumed.

Large eddy simulation of highly compressible film cooling in transonic crossflow

Large eddy simulation is performed to study the thermal energy transport and mixing process of compressible film cooling in the fully-turbulent high-Mach-number crossflow. Three Mach numbers, 0.8, 1.2, and 1.4, based on the bulk crossflow velocity, are adopted. And the influence of both the compressibility and shock waves on the transverse jet from cylindrical orifices is discussed in detail. The results reveal that the effects of compressibility should be distinguished from shocks in supersonic flows. The compressibility effect strengthens the jet penetration and lateral spreading by increasing the energy contained in the large-scale coherent structures. The mixing of the jet is enhanced by the strong compressibility in the near field whether shocks exist or not. When the crossflow transits from the subsonic to the supersonic state, the effect of shock waves becomes more significant than that of the compressibility. Various interactions between shocks, coherent structures, and thermal energy transport are analyzed in this study. The results show that the appearance of the separation shock and bow shock reduces the jet penetration and strengthens its interaction with the bottom wall. The generation of this type of shock system suppresses the flow separation on the leeward side of the jet, which results in a higher cooling effectiveness in the jet near field. The incident oblique shock wave also induces lifting of the jet trajectory in the far-field region as a result of the intensified separation trend. In the highly compressible film cooling process with great temperature difference, the advection transport associated with turbulent motion, rather than the one associated with mean motion, turns out to dominate the thermal energy transfer in general. Moreover, the counter gradient behavior of this thermal energy transport in compressible turbulence is also shown.

Who takes care of safety and health among young workers? Responsibilization of OSH in the platform economy

This study explores how young workers experience employment relations and responsibility for Occupational Safety and Health (OSH) in the platform economy. The study is based on 29 qualitative interviews with young Nordic workers (age 18–30) who find work through digital labour platforms and social media platforms. The European Agency for Safety and Health at Work asserts that the placement of responsibilities for OSH in the platform economy is challenged by the unclear categorisations of employers, employees and self-employed, and that existing labour law and OSH legislation might be inapplicable. Even though most platforms position workers as self-employed, the study shows that the young workers rarely experience themselves as being self-employed and assume that the platforms take care of OSH. When operating in this grey zone, the young workers risk being left without protection and societal resources for improving their OSH. Rasmussen’s model ‘migration towards the boundary of unacceptable safety performance’ is used to discuss how work activities in platform work is driven by strong cost and effort gradients, while, the counter gradient, in terms of OSH systems, at the same time is very weak or completely absent.

Lagrangian analysis for turbulent transport in variable-density turbulence

It is shown that the basis functions of gradient transport theory are different when there is an additional materially conserved variable. The turbulent fluxes now depend on the mean density gradient indicating the possibility of counter gradient transport from first principles as seen in some laboratory experiments. It is shown that arguments by analogy from constant density transport for the Favre fluxes are not consistent with the Lagrangian results.

Online Counter Gradient LC-FT-ICR-MS Enables Detection of Highly Polar Natural Organic Matter Fractions.

Natural organic matter (NOM) is a highly complex mixture of natural organic molecules. The recent developments in NOM molecular characterization methods have shown that ESI-FT-ICR hyphenated with liquid chromatography (LC) is a promising approach to also obtain chemical information (such as polarity and molecular size) about NOM molecules. However, due to changing solvent composition during gradient elution in LC-FT-ICR-MS, ionization conditions also change throughout the chromatographic separation process. In this study, we applied a post-LC column counter gradient (CG) to ensure stable solvent conditions for transient ESI-MS signals. Suwanee River Fulvic Acid (SRFA) standard and a peat pore water were used as representative dissolved NOM samples for method development and validation. Our results show that in polar NOM fractions (which elute with <50% methanol) the TIC intensity and number of assigned molecular formulas were increased by 48% and 20%, as compared to the standard gradient (SG) method. Further application of a Q-isolation and selective ion accumulation for low abundance fractions revealed over 3 times more molecular formulas (especially for CHNO, CHOS, CHNOS formula classes) than in full scan mode. The number of detected highly polar NOM compounds (with elemental ratios H/C < 1, O/C > 0.6) were more than 20 times larger for CG-LC mode as compared to direct infusion (DI) (5715 vs 266 MF). We conclude that the application of a postcolumn counter gradient in LC-FT-ICR-MS analyses of NOM offers novel insight into the most polar fractions of NOM which are inaccessible in conventional DI measurements.

Turbulent scalar flux in inclined jets in crossflow: counter gradient transport and deep learning modelling

Abstract

Niche partitioning of methane-oxidizing bacteria along the oxygen-methane counter gradient of stratified lakes.

Lakes are a significant source of atmospheric methane, although methane-oxidizing bacteria consume most methane diffusing upward from anoxic sediments. Diverse methane-oxidizing bacteria form an effective methane filter in the water column of stratified lakes, yet, niche partitioning of different methane-oxidizing bacteria along the oxygen-methane counter gradient remains poorly understood. In our study, we reveal vertical distribution patterns of active methane-oxidizing bacteria along the oxygen-methane counter gradient of four lakes, based on amplicon sequencing analysis of 16S rRNA and pmoA genes, and 16S rRNA and pmoA transcripts, and potential methane oxidation rates. Differential distribution patterns indicated that ecologically different methane-oxidizing bacteria occupied the methane-deficient and oxygen-deficient part above and below the oxygen-methane interface. The interface sometimes harbored additional taxa. Within the dominant Methylococcales, an uncultivated taxon (CABC2E06) occurred mainly under methane-deficient conditions, whereas Crenothrix-related taxa preferred oxygen-deficient conditions. Candidatus Methylomirabilis limnetica (NC10 phylum) abundantly populated the oxygen-deficient part in two of four lakes. We reason that the methane filter in lakes is structured and that methane-oxidizing bacteria may rely on niche-specific adaptations for methane oxidation along the oxygen-methane counter gradient. Niche partitioning of methane-oxidizing bacteria might support greater overall resource consumption, contributing to the high effectivity of the lacustrine methane filter.

A counter gradient of Activin A and follistatin instructs the timing of hair cell differentiation in the murine cochlea.

The mammalian auditory sensory epithelium has one of the most stereotyped cellular patterns known in vertebrates. Mechano-sensory hair cells are arranged in precise rows, with one row of inner and three rows of outer hair cells spanning the length of the spiral-shaped sensory epithelium. Aiding such precise cellular patterning, differentiation of the auditory sensory epithelium is precisely timed and follows a steep longitudinal gradient. The molecular signals that promote auditory sensory differentiation and instruct its graded pattern are largely unknown. Here, we identify Activin A and its antagonist follistatin as key regulators of hair cell differentiation and show, using mouse genetic approaches, that a local gradient of Activin A signaling within the auditory sensory epithelium times the longitudinal gradient of hair cell differentiation. Furthermore, we provide evidence that Activin-type signaling regulates a radial gradient of terminal mitosis within the auditory sensory epithelium, which constitutes a novel mechanism for limiting the number of inner hair cells being produced.

The Copepod Acartia tonsa Dana in a Microtidal Mediterranean Lagoon: History of a Successful Invasion

The Lagoon of Venice has been recognized as a hot spot for the introduction of nonindigenous species. Several anthropogenic factors as well as environmental stressors concurred to make this ecosystem ideal for invasion. Given the zooplankton ecological relevance related to the role in the marine trophic network, changes in the community have implications for environmental management and ecosystem services. This work aims to depict the relevant steps of the history of invasion of the copepod Acartia tonsa in the Venice lagoon, providing a recent picture of its distribution, mainly compared to congeneric residents. In this work, four datasets of mesozooplankton were examined. The four datasets covered a period from 1975 to 2017 and were used to investigate temporal trends as well as the changes in coexistence patterns among the Acartia species before and after A. tonsa settlement. Spatial distribution of A. tonsa was found to be significantly associated with temperature, phytoplankton, particulate organic carbon (POC), chlorophyll a, and counter gradient of salinity, confirming that A. tonsa is an opportunistic tolerant species. As for previously dominant species, Paracartia latisetosa almost disappeared, and Acartia margalefi was not completely excluded. In 2014–2017, A. tonsa was found to be the dominant Acartia species in the lagoon.

A strategy for large-scale scalar advection in large eddy simulations that use the linear eddy sub-grid mixing model

PurposeThe purpose of this numerical work is to present and test a new approach for large-scale scalar advection (splicing) in large eddy simulations (LES) that use the linear eddy sub-grid mixing model (LEM) called the LES-LEM.Design/methodology/approachThe new splicing strategy is based on an ordered flux of spliced LEM segments. The principle is that low-flux segments have less momentum than high-flux segments and, therefore, are displaced less than high-flux segments. This strategy affects the order of both inflowing and outflowing LEM segments of an LES cell. The new splicing approach is implemented in a pressure-based fluid solver and tested by simulation of passive scalar transport in a co-flowing turbulent rectangular jet, instead of combustion simulation, to perform an isolated investigation of splicing. Comparison of the new splicing with a previous splicing approach is also done.FindingsThe simulation results show that the velocity statistics and passive scalar mixing are correctly predicted using the new splicing approach for the LES-LEM. It is argued that modeling of large-scale advection in the LES-LEM via splicing is reasonable, and the new splicing approach potentially captures the physics better than the old approach. The standard LES sub-grid mixing models do not represent turbulent mixing in a proper way because they do not adequately represent molecular diffusion processes and counter gradient effects. Scalar mixing in turbulent flow consists of two different processes, i.e. turbulent mixing that increases the interface between unmixed species and molecular diffusion. It is crucial to model these two processes individually at their respective time scales. The LEM explicitly includes both of these processes and has been used successfully as a sub-grid scalar mixing model (McMurtry et al., 1992; Sone and Menon, 2003). Here, the turbulent mixing capabilities of the LES-LEM with a modified splicing treatment are examined.Originality/valueThe splicing strategy proposed for the LES-LEM is original and has not been investigated before. Also, it is the first LES-LEM implementation using unstructured grids.

Flame Induced Flow Features in the Presence of Darrieus-Landau Instability

The onset of hydrodynamic or Darrieus-Landau (DL) instability can largely impact on premixed flame morphology, turbulent flame speed and induced flow field. In this work, we focus on the latter induced flow by means of two dimensional direct numerical simulations (DNS) of slot burner flames performed in a parametric fashion. Results from linear stability analysis are used to select the adequate parameter range to be investigated. The presence of DL instability is initially assessed using a recently proposed statistical marker related to flame morphology. The differences between stable and unstable flames are then statistically investigated, utilizing a single, laminar, DL-induced corrugation as a reference state. Such DL-induced effects are investigated at various turbulence intensities, in terms of local propagation, induced strain rate patterns and flow field as well as vorticity production and transformation. Using displacement speed as a measure of local propagation, no noticeable statistical difference is observed between stable and unstable flames while strain rate and vorticity patterns are shown to be largely influenced by the DL induced morphology. From the modeling point view, an enhancement of counter gradient type transport for turbulent scalar fluxes is observed for hydrodynamically unstable flames.

Evaluation of k-ε Reynolds stress modeling in an idealized urban canyon using LES

In this study, a large-eddy simulation (LES) was conducted to investigate the validity of the modeling of Reynolds stress in standard k-ε model (k-ε model) for urban canyon flow. It was confirmed that the LES was more reliable than the k-ε model for urban canyon flow, through a comparison of experimental results. The k-ε model failed to reproduce the spatial distribution of the mean velocity within the urban canyon. It underestimated the absolute value of Reynolds stress <u1'u3’> and eddy viscosity coefficient νt, when compared to the LES. On the leeward side of the urban canyon, νt obtained by the LES was negative and the counter gradient diffusion was seen to occur. The budget of <u1'u3’> transport equation was analyzed using the results of the LES. At the top of the urban canyon and within it, the convection and diffusion terms showed an increase when compared to the production and pressure strain correlation terms. The gradient diffusion approximation of <u1'u3’> was not valid because the local equilibrium of <u1'u3’> transport equation was not correct. It was found necessary to incorporate the effect of the convection and diffusion terms in the modeling of <u1'u3’> for urban canyon flow.

Improving peak shapes with counter gradients in two-dimensional high performance liquid chromatography

To achieve the greatest peak capacity in two-dimensional high performance liquid chromatography (2D-HPLC) a gradient should be operated in both separation dimensions. However, it is known that when an injection solvent that is stronger than the initial mobile phase composition is deleterious to peak performance, thus causing problems when cutting a portion from one gradient into another. This was overcome when coupling hydrophilic interaction with reversed phase chromatography by introducing a counter gradient that changed the solvent strength of the second dimension injection. It was found that an injection solvent composition of 20% acetonitrile in water gave acceptable results in one-dimensional simulations with an initial composition of 5% acetonitrile. When this was transferred to a 2D-HPLC separation of standards it was found that a marked improvement in peak shape was gained for the moderately retained analytes (phenol and dimethyl phthalate), some improvement for the weakly retained caffeine and very little change for the strongly retained n-propylbenzene and anthracene which already displayed good chromatographic profiles. This effect was transferred when applied to a 2D-HPLC separation of a coffee extract where the indecipherable retention profile was transformed to a successful application multidimensional chromatography with peaks occupying 71% of the separation space according to the geometric approach to factor analysis.

Linking terrestrial and benthic estuarine ecosystems: organic matter sources supporting the high secondary production of a non-indigenous bivalve

The Asian clam, Corbicula fluminea, is among the most pervasive invasive species in freshwater ecosystems worldwide. Our objective was to study C. fluminea’s functional response in terms of feeding behavior and food selectivity, using the natural variation in organic matter (OM) sources that occur in estuarine environments. Using C and N stable isotopes, we identified and quantified the contribution of different OM sources supporting the production of C. fluminea along the salinity gradient occupied in the Minho River estuary (NW-Iberian Peninsula, Europe), where this species presently dominates the benthic macrofauna biomass. We observed a pronounced shift in the quality of OM available for C. fluminea along the estuarine mixing zone. Stable isotope analysis, POM C/N, and phytoplankton contribution estimates based on C:Chl a revealed that POM was largely comprised of terrestrial-derived OM in tidal freshwater stations (TFW) and was increasingly comprised of phytoplankton, a more palatable food source, towards the polyhaline estuary. A similar shift in the isotopic composition along the estuarine mixing zone was observed in C. fluminea, suggesting a shift in food resources. Accordingly, based on a Bayesian stable isotope mixing model, there was an upstream–downstream counter gradient in the contribution to C. fluminea biomass from terrestrial-derived OM (41–64 % in TFW) and phytoplankton (29–55 % in the brackish estuary). Although the majority of the food sources identified were filtered from the water column (70–80 %), reliance on sediment OM and microphytobenthos provided evidence for deposit feeding by C. fluminea. We conclude that C. fluminea has the ability to adapt to environments with low food quality because it can consume terrestrial-derived OM. This can be a competitive adaptation in systems with perennial low food quality such as the Minho River estuary. Moreover, its ability to couple benthic and pelagic environments and terrestrial ecosystems demonstrates a strong potential to alter food web flows in aquatic ecosystems.

Scale analysis of turbulent channel flow with varying pressure gradient

In this paper orthogonal wavelet transformations are applied to decompose experimental velocity signals in fully developed channel flows with varying pressure gradient into scales. We analyze the time series from turbulent data, to obtain the statistical characteristics, correlations between the adjacent scales and the principal scale of coherent structures in different scales by wavelet transformations. The results show that, in the counter gradient transport (CGT) region, skewness factors and flatness factors deviate strongly from the corresponding values of Gaussian distribution on certain scales. PDFs on each scale confirm this observation. Scale-scale correlations show further that the fluctuations on some certain special scales are more intermittent than nearby. Principal scale of coherent structure is coincident with the scales on which the statistical properties depart from Gaussian distribution. These features are the same for different families of wavelets, and it also shows some different features in the region between favorable pressure gradient and adverse pressure gradient.

Spawning, pelagic and metamorphosis stage duration in European flounder (Platichthys flesus): a latitudinal approach

Event Abstract Back to Event Spawning, pelagic and metamorphosis stage duration in European flounder (Platichthys flesus): a latitudinal approach Filipe Martinho1*, Henk W. Van Der Veer2, Henrique N. Cabral3 and Miguel A. Pardal1 1 Centre for Functional Ecology - CFE, Portugal 2 Royal Netherlands Institute for Sea Research - NIOZ, Netherlands 3 Centro de Oceanografia, Portugal The spawning, pelagic and metamorphosis stage duration were evaluated in European flounder (Platichthys flesus) along a latitudinal gradient in the European Atlantic coast. The main objective was to determine latitudinal trends in the estuarine nursery habitat colonization processes, considering a wide geographical range: from the southernmost population in the Mondego estuary (Portugal), the French coasts (Vilaine and Slack estuaries), the Wadden Sea (Netherlands) to the northern populations in the Sørfjord (Norway). Flounder 0-group juveniles were captured in June/July 2010. Otolith microstructure was used to account for the duration of each stage by analysing daily growth increments. The spawning period took place between mid-January and early-July over the species’ distribution range, with a gap of nearly two months between the Mondego estuary and the Sørfjord populations, as a consequence of warmer water temperature earlier in the season in the southern areas. Both pelagic and metamorphosis stages were longer at the middle of the distribution range, and lasted in total up to two months after hatching. Results also suggested the existence of a counter-gradient growth compensation mechanism in the northernmost populations. Apart from temperature (proxy for the latitudinal gradient), which regulates species’ basal metabolic rates, differences between sites were also related with local features, such as the extension of the continental platform and adaptations to transport and retention mechanisms. Acknowledgements The authors would like to thank Daniel Crespo, Dániel Nyitrai, João Rito, Cláudia Moreira, Rita Guillot and Hans Witte for the help in the sampling campaigns; to Louis Quiniou and Rachid Amara for providing flounder samples from the French estuaries; to Catarina Vinagre and Audrey Geffen for helping with the otolith reading procedures. Filipe Martinho is funded by the Portuguese Foundation for Science and Technology (FCT) through a research contract (IF/01410/2012). Keywords: Flounder, spawning, larval development time, counter gradient growth compensation, latitudinal cline Conference: IMMR | International Meeting on Marine Research 2014, Peniche, Portugal, 10 Jul - 11 Jul, 2014. Presentation Type: Poster Presentation Topic: BIODIVERSITY, CONSERVATION AND COASTAL MANAGEMENT Citation: Martinho F, Van Der Veer HW, Cabral HN and Pardal MA (2014). Spawning, pelagic and metamorphosis stage duration in European flounder (Platichthys flesus): a latitudinal approach. Front. Mar. Sci. Conference Abstract: IMMR | International Meeting on Marine Research 2014. doi: 10.3389/conf.fmars.2014.02.00013 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 May 2014; Published Online: 18 Jul 2014. * Correspondence: Dr. Filipe Martinho, Centre for Functional Ecology - CFE, Coimbra, 3000-456, Portugal, fmartinho@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Filipe Martinho Henk W Van Der Veer Henrique N Cabral Miguel A Pardal Google Filipe Martinho Henk W Van Der Veer Henrique N Cabral Miguel A Pardal Google Scholar Filipe Martinho Henk W Van Der Veer Henrique N Cabral Miguel A Pardal PubMed Filipe Martinho Henk W Van Der Veer Henrique N Cabral Miguel A Pardal Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.