Variabilidade e tendencias interanuais no fitoplancto mariño das costas de Galicia

13 páginas, 2 tablas, 7 figuras[EN] The available information on phytoplankton biomass and species composition in Galician waters was studied to find out their spatial variability as well as the annual trends. The areas covered included the oceanic zone, the shelf and the inner part of the Rías. In general a significant drop in diatoms was observed. The series also indicated an increase in dinoflagellates, although it was not statistically significant. The diatom species related to blooms in the area declined, whereas those indicative of weak upwelling or stratificacion showed an increase. Even though not all trends were significant, the available data are consistent with the decrease in upwelling intensity over the last 40 years. The results also suggest that effects of climate changes on phytoplankton may be delayed for several years. In any case, the large oceanographic variability of the region, along with the lack of continuity of some o[GA] Co obxecto de coñecer a variabilidade espacial e as tendencias interanuais do fitoplancto galego, estudáronse as series de datos históricos dispoñibles para Galicia, abarcando desde a zona oceánica ata as zonas máis costeiras das rías e a plataforma continental. En xeral, observouse unha diminución significativa das diatomeas, especialmente na zona oceánica. Tamén hai indicios dun incremento, aínda que non significativo, dos dinoflaxelados. O descenso das diatomeas foi debido á caída das abundancias de especies propias de floracións, tanto primaverais como estivais asociadas ao afloramento. Así mesmo, aumentaron as especies de diatomeas propias de afloramentos febles ou estratificación. Malia que non todas as tendencias foron significativas, os resultados son coherentes cunha diminución da intensidade do afloramento nos últimos 40 anos e un cambio nas condicións climáticas desde a década de 1980. Os resultados indican que os efectos dos cambios climáticos sobre o fitoplancto se poden manifestar con varios anos de retardo. Con todo, a alta variabilidade oceanográfica da zona, especialmente de alta frecuencia, e mais a falta de continuidade de moitas series de datos dificultan o establecemento de relacións claras entre cambios ambientais e o fitoplanctoEsta análise das tendencias do fitoplancto en Galicia foi financiada parcialmente pola Consellería de Medio Ambiente e Desenvolvemento Sostible (Programa CLIGAL) e polo proxecto REFORZA (PGIDT06RMA60401PR) da Consellería de Innovación e Industria da Xunta de Galicia. O traballo de María Huete-Ortega estivo financiado polo Programa Predoutoral de Formación de Profesorado Universitario do Ministerio de Educación y Ciencia.Peer reviewe

Effect of ammonium and high light intensity on the accumulation of lipids in Nannochloropsis oceanica (CCAP 849/10) and Phaeodactylum tricornutum (CCAP 1055/1).

BACKGROUND: Microalgae accumulate lipids when exposed to stressful conditions such as nutrient limitation that can be used to generate biofuels. Nitrogen limitation or deprivation is a strategy widely employed to elicit this response. However, this strategy is associated with a reduction in the microalgal growth, leading to overall poor lipid productivities. Here, we investigated the combined effect of a reduced source of nitrogen (ammonium) and super-saturating light intensities on the growth and induction of lipid accumulation in two model but diverse microalgal species, Phaeodactylum tricornutum and Nannochloropsis oceanica. We hypothesized that the lower energy cost of assimilating ammonium would allow the organisms to use more reductant power for lipid biosynthesis without compromising growth and that this would be further stimulated by the effect of high light (1000 µmol m-2 s-1) stress. We studied the changes in growth and physiology of both species when grown in culture media that either contained nitrate or ammonium as the nitrogen source, and an additional medium that contained ammonium with tungsten in place of molybdenum and compared this with growth in media without nitrogen. We focused our investigation on the early stages of exposure to the treatments to correspond to events relevant to induction of lipid accumulation in these two species. RESULTS: At super-saturating light intensities, lipid productivity in P. tricornutum increased twofold when grown in ammonium compared to nitrogen free medium that increased further when tungsten was present in the medium in place of molybdenum. Conversely, N. oceanica growth and physiology was not compromised by the high light intensities used, and the use of ammonium had a negative effect on the lipid productivity, which was even more marked when tungsten was present. CONCLUSIONS: Whilst the use of ammonium and super-saturating light intensities in P. tricornutum was revealed to be a good strategy for increasing lipid biosynthesis, no changes in the lipid productivity of N. oceanica were observed, under these conditions. Both results provide relevant direction for the better design of processes to produce biofuels in microalgae by manipulating growth conditions without the need to subject them to genetic engineering manipulation

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

Programa de formación complementaria para doctorandos: Aplicación de las nuevas tecnologías y redes sociales (FOCODO)

Este proyecto de innovación docente va dirigido específicamente a los alumnos de doctorado de las Facultades de Óptica y optometría y de Veterinaria de la Universidad Complutense. Pero también es Desarrollar un programa de formación complementaria para los doctorandos en ciencias de la salud que les permita adquirir conocimiento y habilidades en áreas paralelas al ámbito en el que están realizando sus tesis doctorales. El programa de formación tendrá 4 areas temáticas diferenciadas: - Habilidades de comunicación (como escribir un artículo científico, como hacer presentaciones orales y en poster, como escribir un Proyecto científico, como trabajar en equipo, …) - Conocimiento complementario a la tesis doctoral (estadística, metodología científica, lectura crítica de bibliografía, Buenas prácticas de laboratorio, buenas prácticas clínicas, …) - Salidas profesionales durante y después de la tesis doctoral (Becas pre y postdoctorales, búsqueda de proyectos de investigación, como colaborar con otros grupos de investigación,…) - Formación especifica en su área temática (técnicas de laboratorio, técnicas clínicas, revisiones bibliográficas,…) Se generará material de tres tipos: - Seminarios.- Son presentaciones de una hora de duración sobre temas específicos a los que se puede asistir en directo o poder ver grabado a través de YouTube. Estos seminarios serán impartidos por profesores e investigadores de los grupos de investigacion que hacen la propuesta además de contar con especialistas nacionales e internacionales - Pildoras.- Videos cortos de no mas de 3 minutos que resuman los aspectos mas importantes de cada seminario que serán colgados en las pagina de los grupos de investigacion que se creen en las redes sociales. Estas píldoras serán grabadas utilizando herramientas de grabación habituales para videos en redes sociales (croma, focos, …) - Summer/Winter School.- Curos de verano y/o invierno donde en dos-tres días intensivos se imparta formacion especifica en investigacion. En estos cursos participaran profesores y expertos internacionales y estará abierto para la matriculación de estudiantes no complutenses, tanto nacionales como internacionales. Para llevar a cabo este programa se utilizarán varias herramientas: - Plataformas digitales (YouTube) donde se colgarán los seminarios que se realicen. - Redes sociales (Instagram, Twitter,…) donde se colgarán las píldoras que se realicen y además se harán reuniones en directo para debatir temas de alguna de las áreas propuestas anteriormente. - App para móvil desde donde los alumnos puedan encontrar todo el material que se genere durante el programa. Este app puede ser gratuita para los alumnos complutenses y de pago para el resto.Depto. de Optometría y VisiónFac. de Óptica y OptometríaFALSEsubmitte

Export and turnover of transparent exopolymer particles into the deep ocean

2nd Meeting of the Iberian Ecological Society (SIBECOL), XXI conference of the Iberian Association of Limnology (AIL) and 21st National Congress of the Portuguese Ecological Society (SPECO), 3-8 July 2022, AveiroAcidic polysaccharides released by phytoplankton and prokaryotic heterotrophs promote the formation of gel-like transparent exopolymer particles (TEPs). TEPs play a key role in the biological carbon pump due to their carbon-rich composition and their ability to coagulate and sink towards the deep ocean. Yet, very little is known about TEP distribution, export, and turnover at a global scale, particularly at deep ocean depths. We provide the first inventory of TEP from the surface up to 4000 m depth in the Atlantic, Indian, and Pacific Oceans and have assessed their contribution to carbon export into the deep ocean. Primary production determines TEP concentration above the deep chlorophyll maximum, and prokaryotic biomass also contributes in deeper waters. In the deep ocean waters, TEP concentrations are lower and mirror the concentrations in the surface, evidencing the importance of TEP sinking both at the export depth (200 m) with a global value of 2.9 Pg C year-1 and at the sequestration depth (1000 m) of 0.9 Pg C year-1 of particulate carbon. However, incubation experiments across ocean basins depicted rapid TEP turnover rates of 71 and 333 days (on average) within the export and sequestration depths, respectively. These findings reveal that the export of carbon by TEP sinking towards deep oceans escapes from long-term paths of the global carbon cycleN

Large carbon export, but short residence times, of transparent exopolymer particles in the global ocean

ASLO Aquatic Sciences Meeting 2023, Resilience and Recovery in Aquatic Systems, 4–9 June 2023, Palma de Mallorca, SpainAcidic polysaccharides released by phytoplankton and prokaryotic heterotrophs promote the formation of gel-like transparent exopolymer particles (TEPs). TEPs can have a relevant contribution to the biological carbon pump due to their carbon-rich composition and their ability to coagulate and sink towards the deep ocean. However, little is known about TEPs distribution, carbon export, and residence times below the export (200 m) and sequestration (1000 m) depths. We provide the first comprehensive inventory of TEP from the ocean surface to a depth of 4000 meters in the tropical and subtropical Atlantic, Indian, and Pacific Oceans, evaluating its contribution to carbon export and sequestration into the deep ocean. Results indicate that TEP concentration is primarily determined by primary production, with higher concentrations located above the deep chlorophyll maxima. In the deep ocean, TEP concentrations are lower yet mirror the concentrations in the surface, demonstrating the significance of TEP sinking below both the export compartment (2.8 Pg C yr-1; 27% of total POC flux at 200 m) and the sequestration compartment (0.8 Pg C yr-1; 36% of total POC flux at 1000 m). In situ incubation experiments conducted across ocean basins indicate short TEP residence times, averaging 27 and 333 days in the export and sequestration compartments, respectively. These findings reveal that the export and subsequent sequestration of carbon by TEP sinking into the deep ocean diverts it from the long times observed for the dissolved carbon fraction (i.e. centuries) in the global carbon cycleN

A global compilation of coccolithophore calcification rates

The biological production of calcium carbonate (CaCO3), a process termed calcification, is a key term in the marine carbon cycle. A major planktonic group responsible for such pelagic CaCO3 production (CP) is the coccolithophores, single-celled haptophytes that inhabit the euphotic zone of the ocean. Satellite-based estimates of areal CP are limited to surface waters and open-ocean areas, with current algorithms utilising the unique optical properties of the cosmopolitan bloom-forming species Emiliania huxleyi, whereas little understanding of deep-water ecology, optical properties or environmental responses by species other than E. huxleyi is currently available to parameterise algorithms or models. To aid future areal estimations and validate future modelling efforts we have constructed a database of 2765 CP measurements, the majority of which were measured using 12 to 24 h incorporation of radioactive carbon (14C) into acid-labile inorganic carbon (CaCO3). We present data collated from over 30 studies covering the period from 1991 to 2015, sampling the Atlantic, Pacific, Indian, Arctic and Southern oceans. Globally, CP in surface waters ( < 20 m) ranged from 0.01 to 8398 µmol C m−3 d−1 (with a geometric mean of 16.1 µmol C m−3 d−1). An integral value for the upper euphotic zone (herein surface to the depth of 1 % surface irradiance) ranged from  < 0.1 to 6 mmol C m−2 d−1 (geometric mean 1.19 mmol C m−2 d−1). The full database is available for download from PANGAEA at https://doi.org/10.1594/PANGAEA.888182

Plan de comunicación interna y externa de la Facultad de Ciencias Sociales. Programa de Actividades Complementarias y de Difusión Cultural de la Facultad II

Memoria ID-0258. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2014-2015

Resource Supply Overrides Temperature as a Controlling Factor of Marine Phytoplankton Growth

The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated