Differential ecophysiological responses to inorganic nitrogen sources (ammonium versus nitrate) and light levels in the seagrass Zostera noltei

eagrasses can use both ammonium (NH4+) and nitrate (NO3−) as inorganic nitrogen (N) sources. However, NO3− uptake and assimilation are energetically more expensive and tightly regulated than NH4+ uptake. The objective of this study was to test the complex interactive effects between different forms of N enrichment (NH4+ and NO3−) and light levels on the morphological and physiological traits in the intertidal seagrass Zostera noltei. Plants were cultured over 40 d under 2 levels of light (low and high) with 2 inorganic N concentrations supplied at the same dose, NO3− (25 μM) and NH4+ (25 μM), and a control, following a 2-factorial design. Results showed a differential response in Z. noltei depending on the inorganic N source and light dose. NH4+ enrichment negatively affected almost all morphometric and dynamic variables analyzed, both in isolation and combined with low light conditions. In contrast, NO3− enrichment had a positive effect on Z. noltei survival compared with the control treatment in terms of net growth rate and rhizomatic growth, mainly under high light conditions. Therefore, our study demonstrated that the effects promoted by nutrient enrichment largely depend on the source of N used. Light levels play a crucial role in this response by potentially shifting the effects from toxic (under low light) to beneficial (under high light) when NO3− is the main N source. Our findings highlight that N form in eutrophication events should be considered when evaluating the potential impacts of nutrient enrichment and light reduction on seagrass communities14 página

Resistance and recovery of benthic marine macrophyte communities to light reduction: Insights from carbon metabolism and dissolved organic carbon (DOC) fluxes, and implications for resilience.

A crucial factor in the long-term survival of benthic macrophyte communities under light-reduction stress is how they balance carbon metabolism during photosynthesis and respiration. In turn, the dissolved organic carbon (DOC) released by these communities, which can be highly light-dependent, stands as a source of carbon, fuelling marine communities and playing an important role in the ocean carbon sequestration. This is the first study to evaluate light-reduction stress and recovery in the seagrass Zostera noltei and the macroalga Caulerpa prolifera. Light reduction led to a significant decrease in the production of both communities from autotrophic to heterotrophic. Results indicated that most of the DOC released by vegetated coastal communities comes from photosynthetic activity, and that the net DOC fluxes can be greatly affected by shading events. Finally, both communities showed resilience underpinned by high recovery but low resistance capacity, with C. prolifera showing the highest resilience to unfavourable light conditions

Guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados

Primera guía visual de las especies de animales (25 especies) y macroalgas (25 especies) más habituales y/o curiosas de los roquedos del intermareal de La Caleta (Cádiz) y roquedos intermareales asociados .Fundación Biodiversidad del Ministerio para la Transición ecológica, CEIMA

Praderas de fanerógamas marinas en la bahía de Cádiz: conservación y gestión

Comunicación técnicaLa bahía de Cádiz es un humedal costero protegido por figuras de protección nacionales (Parque Natural) e internacionales (LIC, Convención Ramsar) dada su importancia ecológica. La biodiversidad biológica incluye numerosas especies de macroalgas, invertebrados, peces y aves. Un hecho de singular importancia, y poco conocido por las administraciones públicas, es que en este humedal conviven 3 de las 4 especies de fanerógamas marinas, o más estrictamente angiospermas marinas, de Europa. Las praderas de Cymodocea nodosa y Zostera noltii junto con escasos rodales de Zostera marina, proporcionan numerosos servicios ecológicos que están siendo estudiados por el grupo de Estructura y Dinámica de Ecosistemas Acuáticos de la Universidad de Cádiz. Desde hace 15 años hemos desarrollado proyectos tanto nacionales como internacionales en la bahía con el fin de poner en práctica bases ecológicas para la gestión de estas praderas como parte integrante del ecosistema. Estas herramientas abarcan desde un nivel ecofisiológico muy reduccionista (tasas fotosintéticas, incorporación de nutrientes), hasta un nivel más holista (mapas de cobertura, efecto a gran escala de variables ambientales, utilización de información para la estimación de la calidad ecológica de la masa de agua). Las actuaciones desarrolladas incluyen la consolidación de una red de voluntariado (FAMAR) para la recogida y análisis de la información. El trabajo que se presenta resume la información disponible, con series de datos recogidos y analizados durante la última década, para la gestión de las praderas y el estado de conservación de las mismas. Se incluyen además algunas perspectivas para la gestión.Proyecto ECOLAGUNES del programa europeo Interreg del espacio SUDOE (SOE1/P2/F153), proyecto IMACHYDRO, del Ministerio de Ciencia e Innovación (CTM2008-00012/MAR), proyectos de excelencia de la Junta de Andalucía FUNDIV (P07-RNM-02516), PAMBIO (P08-RNM-03783) y BAHÍA (P06-RNM0163713 página

Nueva guía visual de la fauna y flora marina del intermareal de La Caleta y roquedos intermareales asociados.

Nueva guía visual de las especies de animales (54 especies) y macroalgas (52 especies) más habituales y/o curiosas de los roquedos del intermareal de La Caleta (Cádiz) y roquedos intermareales asociados. Se incluyen mas del doble de las especies que aparecían en la guía publicada en 2019. Dos de las especies de animales añadidas fueron recientemente descritas como nuevas para la Ciencia a partir de material encontrado en La Caleta (en parte).Universidad de Cádiz Ministerio de Ciencia e Innovación Fundación Española de Ciencia y Tecnología (FECYT) Campus de Excelencia Internacional del MAR (CEIMAR)108 pagina

The morphometric acclimation to depth explains the long-term resilience of the seagrass Cymodocea nodosa in a shallow tidal lagoon

Cadiz Bay is a shallow mesotidal lagoon with extensive populations of the seagrass Cymodocea nodosa at intertidal and shallow subtidal elevations. This work aims to understand the mechanisms behind the resilience of this species to gradual sea level rise by studying its acclimation capacity to depth along the shallow littoral, and therefore, to gradual variations in the light environment. To address this objective, these populations have been monitored seasonally over a 10 year period, representing the longest seasonal database available in the literature for this species. The monitoring included populations at 0.4, -0.08 and -0.5 m LAT. The results show that C. nodosa has a strong seasonality for demographic and shoot dynamic properties - with longer shoots and larger growth in summer (high temperature) than in winter (low temperature), but also some losses. Moreover, shoots have different leaf morphometry depending on depth, with small and dense shoots in the intertidal areas (0.4 m) and sparse large shoots in the subtidal ones (-0.08 and 0.5 m). These differences in morphometry and shoot dynamic properties, combined with the differences in shoot density, explain the lack of differences in meadow production balance (i.e. meadow growth - meadow losses) between the intertidal (0.4 m) and the deepest population (-0.5 m), supporting the long term resilience of Cymodocea nodosa in Cadiz Bay. This study contributes to the understanding of the mechanisms behind seagrass stability and resilience, which is particularly important towards predicting the effects of climate change on these key coastal ecosystems, and also highlights the value of continuous long-term monitoring efforts to evaluate seagrass trajectories

Colombian consensus recommendations for diagnosis, management and treatment of the infection by SARS-COV-2/ COVID-19 in health care facilities - Recommendations from expert´s group based and informed on evidence

La Asociación Colombiana de Infectología (ACIN) y el Instituto de Evaluación de Nuevas Tecnologías de la Salud (IETS) conformó un grupo de trabajo para desarrollar recomendaciones informadas y basadas en evidencia, por consenso de expertos para la atención, diagnóstico y manejo de casos de Covid 19. Estas guías son dirigidas al personal de salud y buscar dar recomendaciones en los ámbitos de la atención en salud de los casos de Covid-19, en el contexto nacional de Colombia

Elevated ammonium concentrations and low light form a dangerous synergy for eelgrass Zostera marina

We studied the effect of ecologically relevant ammonium concentrations and light on several morphological and physiological properties, nitrogen metabolism and carbon reserves of eelgrass Zostera marina L. Eelgrass was grown under mesocosm conditions at 3 levels of ammonium enrichment (target concentrations of 0, 10 and 25 μM) and 2 levels of light (low and high light). High ammonium supply combined with low light had a negative effect on several morphological and physiological response parameters, while no such effects were found when ammonium was supplied under high light. N enrichment caused an increase in the content of total N, intracellular ammonium, free amino acids and residual N in the plants and this response was more pronounced under low-light conditions than under high light. The soluble proteins content de - crea sed, in contrast with external ammonium enrichment. The accumulation of free amino acids and residual N in NH4 +-enriched plants was followed by a substantial drop in carbohydrate reserves (sucrose and starch), which was larger in plants grown under low-light conditions. Our results indicate that N enrichment increases the demand for C skeletons and energy, and that photosynthesis cannot supply enough C and energy to cover that demand under low-light conditions. Eelgrass plants exposed to reduced light conditions, for example close to their depth limit or when covered by drift macroalgae, may thus be especially susceptible to enhanced ammonium concentrations. Our study demonstrates that ammonium toxicity may explain why eelgrass and other seagrasses deteriorate under nutrient-rich, low-light conditions