Chlorophyll signatures and nutrient cycles in the Mediterranean Sea: a model sensitivity study to nitrogen and phosphorus atmospheric inputs

International audienceIn this work, the relative importance of nitrogen and phosphorus, considered as external loads, on Mediterranean biogeochemical cycles is evaluated. Biomass concentrations are analysed considering the steady state response of the three-dimensional ECHYM model to three nitrogen and phosphorus atmospheric depositions, considered as continuous in time. After reaching stationary evolutions, chlorophyll surficial maps and vertical transects are compared with existing datasets, showing a good agreement at their large scale sampling. The distributions of nutrients within the biochemical compartments are analysed, highlighting, inside the Mediterranean oligotrophic environment, the role played by ultraplankton, the smaller phytoplankton compartment. For all the three different atmospheric loads, western primary production estimation is about twice than that in the eastern basin, while western secondary production is about three times the eastern one. This numerical exercise suggests that the Eastern Mediterranean, cycling at low nutrient sill, is eventually pushed toward an higher nutrient depletion, when loading new nitrogen and phosphorus

Simulating biomass assimilation in a Mediterranean ecosystem model using SOFA: setup and identical twin experiments

Assessing the potential improvement of basin scale ecosystem forecasting for the Mediterranean Sea requires biochemical data assimilation techniques. To this aim, a feasibility study of surface biomass assimilation is performed following an identical twin experiment approach. NPZD ecosystem data generator, embedded in one eighth degree general circulation model, is integrated with the reduced-order optimal interpolation System for Ocean Forecasting and Analysis. <P> The synthetic &quot;sea-truth&quot; data are winter daily averages obtained from the control run (CR). The twin experiments consist in performing two runs: the free run (FR) with summer-depleted phytoplankton initial conditions and the assimilated run (AR), in which, starting from the same FR phytoplankton concentrations, weekly surface biomasses averaged from the CR data are assimilated. The FR and AR initial conditions modify the winter bloom state of the phytoplankton all over the basin and reduce the total nitrogen, i.e.&nbsp;the energy of the biochemical ecosystem. <P> The results of this feasibility study shows good performance of the system in the case of phytoplankton, zooplankton, detritus and surface inorganic nitrogen. The weak results in the case of basin inorganic nitrogen and total nitrogen, the latter nonperformant at surface, are discussed

Reduced-order optimal interpolation for biomass assimilation

International audienceThe analysis of the evolution of the chemical and biological characteristics of the Mediterranean marine ecosystem requires an integrated approach. Consistently, an ecosystem description, embedded in the MFSTEP one eighth degree three-dimensional general circulation model, is tested and used following a twin experiment approach. The ecosystem model is based on the NPZD trophic chain: inorganic nitrogen, N, phytoplankton, P, zooplankton, Z and detritus, D. Assimilation of synthetic biomass data is performed by means of the reduced-order optimal interpolation system SOFA. The synthetic "sea-truth" data are daily averages obtained from a sixty-nine days reference run (RR). The twin experiments consist in performing two runs: a free run (FR) with wrong summer-depleted phytoplankton initial conditions and an assimilated run (AR), in which, starting from the same FR wrong phytoplankton concentrations, weekly averaged surface biomasses extracted from the RR results are assimilated. The comparison of the FR results with the AR ones shows a good convergence, on a basin Mediterranean scale, confirming improvements of the forecasting in each of the four ecological compartments. Regional trophic regimes are analysed and interpreted in the western and eastern Mediterranean subbasins, for explaining the deteriorating behaviour of the total nitrogen

Water column monitoring at CO2 leaking sites near Panarea Island

The fate and transport of geologically produced CO2 that leaks from the sea floor into the overlying water column has numerous important implications related to large scale carbon cycling and potential impact on marine organisms, and is of interest for the development of improved monitoring techniques and strategies for offshore Carbon Capture and Storage (CCS) sites. The CO2 leakage areas off the east coast of Panarea Island, Italy provides an excellent environment to study these processes given the wide range of different flux rates in relatively shallow water. The water column at this site was monitored using two completely different but complementary approaches, continuous monitoring along short 2D transects using GasPro pCO2 sensors and discrete seasonal sampling along a 700 m transect crossing multiple leakage areas. Results are discussed in terms of the movement of CO2, and associated tracers, in the water column

Anatomía vegetativa e histoquímica en Cynanchum bonariense (Apocynaceae)

Fil: Bravi, V. S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Cosa, M. T. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Pacciaroni, A. del V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Pacciaroni, A. del V. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Wiemer, A. P. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Cynanchum bonariense (Decne.) T. Mey es una enredaderanativa que habita en los bordes de caminos, sobre arbustos, árboles bajos y está ampliamente distribuida en la zona centro y norte de Argentina. Presenta abundante látex de color blanco.El objetivo del presente trabajo fue realizarun análisis anatómico comparativo de los órganos vegetativos con especial atención en los laticíferos.Fil: Bravi, V. S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Cosa, M. T. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Fil: Pacciaroni, A. del V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Pacciaroni, A. del V. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Wiemer, A. P. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Morfología Vegetal; Argentina.Ciencias de las Plantas, Botánic

Exomorfología y anatomía de órganos vegetativos aéreos en especies de Flourensia DC. (Asteraceae) con importancia fitoquímica

El género Flourensia DC. es americano y comprende 32 especies. Son arbustos resinosos utilizados en medicina popular; poseen un potencial valor económico, por lo que, en algunas especies representantes, se han caracterizado sus compuestos químicos y determinado algunos posibles usos. En el presente trabajo, se estudió la exomorfología y anatomía de órganos vegetativos de F. hirta S. F. Blake, F. leptopoda S. F. Blake, F. niederleinii S. F. Blake y F. tortuosa Griseb., especies endémicas del centro de Argentina. Se observó que todas son similares en cuanto a la anatomía de hoja y tallo. En cuanto al estudio de la epidermis foliar, se concluye que es posible diferenciar las especies teniendo en cuenta la frecuencia estomática y la presencia de tricomas. Finalmente, las diferencias más notables se encontraron en la exomorfología foliar ya que se observó una gran variación en cuanto a la forma de las hojas y tamaño de las láminas y pecíolos. Con respecto a las estructuras secretoras, se encontraron tricomas y conductos secretores esquizógenos en las hojas y los tallos de todas las especies, las cuales serían responsables de la producción y secreción de las resinas.The genus Flourensia DC. is American and comprises 32 species. They are resiniferous shrubs used in folk medicine. As they have potential economic value, its chemical compounds have been characterized and some possible uses identified. In this work, the exomorphology and anatomy of vegetative organs of F. hirta S. F. Blake, F. leptopoda S. F. Blake, F. niederleinii S. F. Blake and F. tortuosa Griseb., endemic species from central Argentina, have been studied. All species are similar in leaf and stem anatomy. Regarding the epidermis, it is possible to differentiate the species according to the stomatal frequency and the presence of trichomes. Finally, the most remarkable differences were found in leaf exomorphology, since there was a large variation in shape and size of blades and petioles. Concerning the secretory structures, trichomes and secretory ducts were found in the leaves and stems of all species, which would be responsible for the production and secretion of the resins

Copernicus Ocean State Report, issue 6

The 6th issue of the Copernicus OSR incorporates a large range of topics for the blue, white and green ocean for all European regional seas, and the global ocean over 1993–2020 with a special focus on 2020