Nitrogen fixation in the upwelling region off NW Iberia

Comunicación oralPicoplankton are the most abundant organisms in the ocean, often dominate planktonic biomass and primary production, and they could represent a substantial contribution to the global export of carbon. Nowadays, we have a limited understanding about the factors that control the picoplankton community structure. A recent analysis indicates that light and temperature are the main factors explaining Prochlorococcus and Synechococcus distributions, whereas nutrient concentrations play a minor role (Flombaum et al., PNAS 2013). Methodological difficulties to quantify mixing in the marine enviroments have motivated the use of indirect approaches to determine the input of nutrients into the euphotic zone, however, nutrient concentrations are not necessarily a proxy of nutrient supply. We present a large data set, including open-ocean and coastal regions, of simultaneous measurements of picoplankton abundance, temperature and irradiance, together with estimates of nutrient supply. The transport of nutrients across the nutricline was computed combining nutrient concentrations and small-scale turbulence observations collected with a microstructure profiler. Our preliminary results indicate that nutrient supply also plays a role in the distribution of functional groups of picoplankton in the ocean

Effects of herbaceous covers and mineral fertilizers on the nutrient stocks and fluxes in a Mediterranean olive grove

Altres ajuts: acord transformatiu CRUE-CSICThe preservation of nutrient capital, soil fertility, and carbon (C) sequestration capacity in Mediterranean olive groves requires evaluation of agricultural practices beyond short-term productivity. We aim to contribute with a mechanistic understanding on the effects that the preservation of herbaceous cover and the use of chemical fertilizers have on the performance of olive trees and on the biogeochemical cycles of the agroecosystem. We compared nutrient fluxes and aboveground leafy stocks in an olive grove that had been organically managed for more than 60 years, in a treatment in which the annual spontaneous herbaceous cover was maintained (H), and after two years of shift to conventional management treatments in which the growth of herbaceous vegetation was avoided by the use of herbicides (NH), and where exclusion of the herbaceous cover is also combined with the supply of mineral fertilizers (NHF). Maintenance of herbaceous vegetation in H contributed to the retention of a high aboveground capital of C and nutrients, particularly nitrogen, (N), phosphorus (P) and potassium (K) that were about 2.9, 3.9 and 7.4 times greater than in NH, respectively. The permanence of herbaceous cover stimulated olive tree leaf litter decomposition rates by about 86 % and increased nutrient release. However, the H treatment led to a 37 % decrease in olive yield and lowered olive foliar N and P content as negative short-term effects. The addition of fertilizers (N, P, K, and Mg) in mineral and solid form in NHF resulted inefficient to improve olive tree nutritional status and olive production, and decelerated olive tree litter decomposition rates by 21 % and nutrient release. The nutrient retention in organic forms in the fast-growing species of herbaceous covers and the progressive nutrient release as litter decomposes may contribute to regulate and better adapt nutrient availability to the nutrient requirements of olive trees

A plant economics spectrum in Mediterranean forests along environmental gradients: Is there coordination among leaf, stem and root traits?

12 páginas..- 4 figuras.-- 70 referencias.--Supporting Information: Additional Supporting Information may be found in the online version of this article: Appendix S1. Species list.--Appendix S2. Functional traits list.--Appendix S3. Phylogenetic tree.-- Appendix S4. Pearson correlation coefficients between traits.-- Appendix S5. Relationships between morphologicaltraits, carbon isotope fraction and leaf chlorophyll.-- Appendix S6. Phylogenetic generalized least square analysis.-- Appendix S7. Non-metric multidimensional scaling analysis.-- Appendix S8. Illustration of the scale effects.Questions: Is there any evidence of coordination among leaf, stem and root traits, and thereby of the existence of a plant economics spectrum at the species and community level in Mediterranean forests? Are these traits related to plant size and seed mass? Location: Mediterranean forests and shrublands, Sierra Morena mountains, Córdoba, southern Spain. Methods: We selected nine woody plant communities along a natural local gradient of soil water and nutrient availability. We measured key leaf, stem, root and whole-plant traits for 38 dominant woody plant species. The variation across species of 15 functional traits (of the leaf, stem and root) was analysed and coordination among them was tested. We explored the relationships between these traits (hereafter 'resource-use traits' due to their close association with the acquisition-conservation trade-off) and plant height and seed mass. Finally, we compared results at species level with those calculated at community level, considering community-weighted means (CWMs). Results: We found a significant coordination between traits belonging to different plant organs, and propose the existence of a plant economics spectrum in Mediterranean forests along the environmental gradient. However, weaker relationships were found within groups of species under similar environmental conditions. We did not find the expected orthogonal relationships between plant height, seed mass and resource-use traits. Relationships among functional traits were stronger at the community level than at the species level. Conclusions: This study reveals a high degree of functional coordination between traits belonging to different plant organs at both species and community level, and suggests the existence of a plant economics spectrum across 38 Mediterranean woody plant species. However, this general trend of functional coordination between organs became weaker or disappeared when considering restricted groups of species belonging to environmentally similar sites (e.g. dry vs wet sites), suggesting that the diversification of strategies within communities is not related to the economics spectrum at a lower spatial scale. Interestingly, the high degree of coordination between resource-use traits and seed mass at the community level seems to support the tolerance-fecundity model, which predicts an inverse relationship between fecundity and stress tolerance. © 2015 International Association for Vegetation Science.We thank Miguel Verdú for help with the phylogenetic tree and analyses and Jose Rafael Vera for plant trait analyses. We also thank Jard ın Botánico de Córdoba (Francisca Herrera) and the Semillas Cantueso Company (José Angel Cantueso) for providing seedmass data. We are very grateful to Francesco de Bello for interesting comments on previous versions of the manuscript. This study was funded by the Spanish MEC coordinated project DIVERBOS (CGL2011-30285-C02-01 and C02-02), the Andalusian ANASINQUE project (PGC2010-RNM-5782), the Life + Biodehesa Project (11/BIO/ES/000726), ECO-MEDIT (CGL2014-53236-R) and European FEDER funds. Dr. DavidWalker revised the Englis

Interacciones entre Geomorfología e intervención humana sobre la composición del matorral en la cuenca del río Guadalupejo (Extremadura)

19 páginas, 4 figuras, 2 tablas, 30 referencias.[EN]: The relationships between geomorphology and scrub composition and the effects of management practices on them bave been studied in Guadalupejo River bassin (W. Spain). The mediterranean climate has an annual precipitation of 803 mm and average temperature of 15ºC. Lithology is dominated by slates with surface deposits of conglomerates and clay. The area was subdivided on homogeneous units with geomorphic and management criteria in order to sample vegetation. Pressence/absence and abundance (as cover) of 30 scrub species was recorded on 56 10 x 10m. plots. Cluster analysis was used to classify vegetation types. Main type divisions are related primarily to human management and secondarily to geomorphic and physicochemical characters of substrate. Total plant cover, specific species contribution and pioneer/mature species ratio a1l are influenced by the predominant factors mentioned above. The relative weight of physical, biotic and human factors in determining vegetation composition is discussed. It is proposed that all processes involved may fall into three main categories: limitation, organisation and disruption.[ES]: Se han estudiado las relaciones entre geomorfología y composición del matorral mediterráneo y el efecto de la intervención humana sobre las mismas. Se escogió la parte baja de la cuenca del río Guadalupejo, afluente del Guadiana por su margen derecha. El clima es de tipo mediterráneo (803 mm; y 15°) y el sustrato está formado por pizarras, conglomerados y arcillas. Se sectorizó el área con criterios geomorfológicos y de tipos de intervención humana como base para el muestreo estratificado de la vegetación; se registró la presencia de las especies y se midió su cobertura en 36 parcelas de 10 x 10 m. La Matriz de datos cualitativos se analizó mediante técnicas de análisis de clasificación aglomerativa, para determinar tipos de matorral. Las principales diferencias entre los tipos de matorral se relacionan en primer lugar con la modalidad de intervención humana y en segundo con la geomorfología y composición fisicoquímica del sustrato. La cobertura total del matorral, importancia relativa de las distintas especies y relación entre coberturas especies pioneras/especies maduras también se relacionan con estos factores predominantes. Se discute la importancia de los procesos físicos, bióticos y humanos en la determinación de la composición de la vegetación, considerándolos agrupados en 3 grupos de procesos, limitativos, organizativos y desorganizativos.Peer reviewe

Distributions of phytoplankton carbohydrate, protein and lipid in the world oceans from satellite ocean colour

Energy value of phytoplankton regulates the growth of higher trophic species, affecting the tropic balance and sustainability of marine food webs. Therefore, developing our capability to estimate and monitor, on a global scale, the concentrations of macromolecules that determine phytoplankton energy value, would be invaluable. Reported here are the first estimates of carbohydrate, protein, lipid, and overall energy value of phytoplankton in the world oceans, using ocean-colour data from satellites. The estimates are based on a novel bio-optical method that utilises satellite-derived bio-optical fingerprints of living phytoplankton combined with allometric relationships between phytoplankton cells and cellular macromolecular contents. The annually-averaged phytoplankton energy value, per cubic meter of sub-surface ocean, varied from less than 0.1 kJ in subtropical gyres, to 0.5–1.0 kJ in parts of the equatorial, northern and southern latitudes, and rising to more than 10 kJ in certain coastal and optically complex waters. The annually-averaged global stocks of carbohydrate, protein and lipid were 0.044, 0.17 and 0.108 gigatonnes, respectively, with monthly stocks highest in September and lowest in June, over 1997-2013. The fractional contributions of phytoplankton size classes e.g., picoplankton, nanoplankton and microplankton to surface concentrations and global stocks of macromolecules varied considerably across marine biomes classified as Longhurst provinces. Among these provinces, the highest annually-averaged surface concentrations of carbohydrate, protein, and lipid were in North-East Atlantic Coastal Shelves, whereas, the lowest concentration of carbohydrate or lipid were in North Atlantic Tropical Gyral, and that of protein was in North Pacific Subtropical Gyre West. The regional accuracy of the estimates and their sensitivity to satellite inputs are quantified from the bio-optical model, which show promise for possible operational monitoring of phytoplankton energy value from satellite ocean colour. Adequate in situ measurements of macromolecules and improved retrievals of inherent optical properties from high-resolution satellite images, would be required to validate these estimates at local sites, and to further improve their accuracy in the world oceans

Importance of N2 fixation vs. nitrate diffusion along a latitudinal transect in the Atlantic Ocean

We present ocean, basin-scale simultaneous measurements of N2-fixation, nitrate diffusion, and primary production along a south–north transect in the Atlantic Ocean crossing three biogeographic provinces: the south subtropical Atlantic (SSA; , 31uS–12uS), the equatorial Atlantic (EA; , 12uS–16uN), and the north subtropical Atlantic (NSA, , 16uN–9uN) in April–May 2008. N2-fixation and primary production were measured as 15N2 and 14C uptake, respectively. Dissipation rates of turbulent kinetic energy (e) were measured with a microstructure profiler. The vertical input of nitrate through eddy diffusion was calculated from the product of diffusivity, derived from e, and the gradient of nanomolar nitrate concentration across the base of the euphotic zone. The mean N2-fixation rate in EA was 56 6 49 mmol N m22 d21, whereas SSA and NSA had much lower values (, 10 mmol N m22 d21). Because of the large spatial variability in nitrate diffusion (34 6 50, 405 6 888, and 844 6 1258 mmol N m22 d21 in SSA, EA, and NSA, respectively), the contribution of N2-fixation to new production in the SSA, EA, and NSA was 44% 6 30%, 22% 6 19%, and 2% 6 2%, respectively. The differences between SSA and NSA in the contribution of N2 fixation were partly due to the contrasting seasonal forcing in each hemisphere, which likely affected both N2 fixation rates and vertical nitrate diffusion. The variability in the nitrogen budget of the Atlantic subtropical gyres was unexpectedly high and largely uncoupled from relatively constant phytoplankton standing stocks and primary production rates.CTM2004-05174-C02 CTM2007-28295-E/MAR Programa I. Parga-Ponda

Working memory of emotional stimuli: electrophysiological characterization

Memorizing emotional stimuli in a preferential way seems to be one of the adaptive strategies brought on by evolution for supporting survival. However, there is a lack of electrophysiological evidence on this bias in working memory. The present study analyzed the influence of emotion on the updating component of working memory. Behavioral and electrophysiological indices were measured from a 3-back task using negative, neutral, and positive faces. Electrophysiological data evidenced an emotional influence on the working memory sensitive P3 component, which presented larger amplitudes for negative matching faces compared to neutral ones. This effect originated in the superior parietal cortex, previously reported to be involved in N-back tasks. Additionally, P3 results showed a correlation with reaction times, where higher amplitudes were associated with faster responses for negative matching faces. These findings indicate that electrophysiological measures seem to be very suitable indices of the emotional influence on working memory

Coccolithophore calcification is independent of carbonate chemistry in the tropical ocean

Marañón, Emilio ... et al.-- 13 pages, 7 figures, 1 table, supporting information https://dx.doi.org/10.1002/lno.10295Short-term experiments indicate that seawater acidification can cause a decrease in the rate of calcification by coccolithophores, but the relationship between carbonate chemistry and coccolithophore calcification rate in natural assemblages is still unclear. During the Malaspina 2010 circumnavigation, we measured primary production, calcification, coccolithophore abundance, particulate inorganic carbon (PIC) concentration, and the parameters of the carbonate system, along basin-scale transects in the tropical Atlantic, Indian and Pacific oceans. Euphotic layer-integrated calcification and mean cell-specific calcification in the euphotic layer ranged between 2–10 mgC m−2 d−1 and 5–20 pgC cell−1 d−1, respectively. We found a significant relationship between primary production and calcification, such that the calcification to primary production (CP/PP) ratio was relatively invariant among ocean basins, with an overall mean value of 0.05 ± 0.04. Extrapolating this value to the entire ocean would result in a global pelagic calcification rate of 2.4 PtC yr−1. The mean PIC concentration in surface waters was 1.8 ± 1.6 mgC m−3 and its turnover time averaged 20 d. We combined our data of calcification, primary production, and carbonate chemistry from Malaspina 2010 with those obtained during two previous cruises in the northern Arabian Sea. Both the CP/PP ratio and cell-specific calcification were largely constant across a wide range of calcite saturation state (1.5–6.5), [ inline image]/[H+] (0.08–0.24; mol: μmol), and pH (7.6–8.1), which indicates that calcification by natural coccolithophore assemblages was independent of carbonate chemistry. Our results suggest that coccolithophore calcification, at least in tropical regions, may not be decreasing in the currently acidifying oceanFunding for this study was provided by the Spanish Ministry of Science and Innovation through research projects Malaspina 2010 (grant no. CSD2008-00077), PERSEO (CTM2007-28925-E/MAR), MANIFEST (CTM2012-32017) and TERRIFIC (CTM2014-53582-R). Funding for W.M.B. came from the NSF (OCE-0961660; OCE1220068), NASA (NNX11AO72G; NNX11AL93G; NNX14AQ41G; NNX14AQ43A; NNX14AL92G; NNX14AM77G) and NOAA (NA11OAR4310055).Peer Reviewe

Girişimciliğin ilk aşamasında finansman temin yolları ve finansman temininde karşılaşılan sorunlar: Gaziantep ilinde bir uygulama

Bugün işletmeler gelişen dünya pazarlarında rekabette bulunarak ekonomik ve finansal açıdan avantaj sağlamaktadırlar. İşletmeler, girişimcilerin temel özellikleri ile teknolojiyi kullanan ve geliştiren işletmeler olarak ülkelerin kalkınmasında önemli rol oynamaktadır. Teknolojik yeniliklerin yanında inovasyona da yatırım yaparak gelişimlerini tamamlarlar. Ancak her alanda olduğu gibi, girişimciler finansal açıdan da sorunlarla karşılaşmaktadırlar. Dolayısıyla işletme sayısının artarak ülkeye katkıda bulunabilmesi için finansman teminindeki sorunları farklı olan girişimcilerin desteklenmeleri ve yönlendirilmeleri gerekmektedir. Bu noktada, girişimcileri desteklemek amacıyla kamu kurum ve kuruluşları ve diğer kuruluşlar faaliyetlerini sürdürmektedir. Bu araştırmanın temel amacı, girişimciliğin ilk aşamasında finans temin yollarının belirlenerek finansman temin yönteminde karşılaşılan sorunları ortaya koymaktır. Bununla birlikte, bu çalışmada Türkiye’de girişimciliğin temel özellikleri, girişimcilik finansman türleri ve finansman temininde karşılaşılan sorunlara yönelik önerilerin sunulması amaçlanmaktadır. Araştırma kapsamında nitel ve nicel araştırma yöntemleri uygulanmıştır. Nicel araştırma kapsamında, 408 girişimciye anket uygulanmış, nitel araştırma kapsamında ise 180 girişimciyle yüz yüze görüşmeler yapılmıştır. Araştırma yöntemlerinden elde edilen veriler, çeşitli istatistiksel analizlere tabi tutulmuştur. Girişimciliğin ilk aşamasında, girişimcilerin finansman temininde karşılaştıkları sorunlar belirlenerek, bu sorunlara yönelik çözüm önerilerinde bulunulmuştur. Bu araştırmanın sonucunda, girişimciliğin ilk aşamasında, girişimcilerin finansman temin yöntemi konusunda yeterli derecede bilgi sahibi olmadıkları ve kendi kaynaklarını daha çok kullandıkları tespit edilmiştir