Phytoplankton diversity effect on ecosystem functioning in a coastal upwelling system.

This work is part of the time series project RADIALES conducted and funded by the Instituto Español de Oceanografía (http://www.seriestemporales-ieo.net) with additional support from project MarRisk (Interreg POCTEP Spain-Portugal) grant number 0262 MARRISK 1 E, from grants Contrato-Programa GAIN-IEO, and grant number IN607A2018/2 of the Axencia Galega de Innovación (GAIN, Xunta de Galicia, Spain). JO was supported by a Junta para la Ampliación de Estudios Fellowship (JAE-Doc programme 2011) from the CSIC and ESF.Species composition plays a key role in ecosystem functioning. Theoretical, experimental and field studies show positive effects of biological diversity (biodiversity) on ecosystem processes. However, this link can differs between taxonomic and functional diversity components and also across trophic levels. These relationships It haves been hardly studied in planktonic communities occurring inof coastal upwelling systems. Using a 28 yr time series of phytoplankton and zooplankton assemblages we examined the effects of phytoplankton diversity on resource use efficiency at the two trophic levels (RUE, ratio of biomass to limiting resource) in the Galician upwelling system (NW Iberian peninsula). Fitting Generalized Least Squares models we show that phytoplankton diversity was the best predictor for RUE across planktonic trophic levels. This link varied depending on the biodiversity component considered: while the effect of phytoplankton richness on RUE was positive for phytoplankton RUE and negative for zooplankton RUE, phytoplankton evenness effect was negative for phytoplankton RUE and positive for zooplankton RUE. Overall, taxonomic diversity had higher explanatory power than functional diversity, and variability in phytoplankton and zooplankton RUE decreased with increasing phytoplankton taxonomic diversity. Phytoplankton used resources more efficiently in warmer waters and at greater upwelling intensity although these effects were not as strong as those for biodiversity. These results suggest that phytoplankton species numbers in highly dynamic upwelling systems are important for maintaining the planktonic biomass production leading us to hypothesize the relevance of likely through complementarity effects. However, we further postulate that a selection effect may operate also because assemblages with low evenness were dominated by diatoms with specific functional traits increasing their ability to exploit resources more efficiently.This work is part of the time series project RADIALES conducted and funded by the Instituto Español de Oceanografía (http://www.seriestemporales-ieo.net) with additional support from project MarRisk (Interreg POCTEP Spain-Portugal) grant number 0262 MARRISK 1 E, from grants Contrato-Programa GAIN-IEO, and grant number IN607A2018/2 of the Axencia Galega de Innovación (GAIN, Xunta de Galicia, Spain). JO was supported by a Junta para la Ampliación de Estudios Fellowship (JAE-Doc programme 2011) from the CSIC and ESF.Versión del edito

Resource use efficiency is affected by phytoplankton community changes and geochemical shifts over time in a coastal upwelling area (NE Atlantic).

abstractTime series records are crucial to understand the dynamical processes that occur within phytoplankton communities. This is even more important in the context of the current global change that is already forcing alterations of unprecedented nature and might have unknown consequences for multiple ecosystem processes. Here we present time series analyses of the biogeochemical trends that occurred in the shelf of the Galician coast (station 2 off A Coruña, NE Atlantic) since late 1980s. Upwelling strength and sea temperature in the area have not changed substantially during the last decades. However, while nitrate fertilization from upwelled waters has remained relatively stable, phosphate concentration has increased leading to a negative trend in the N:P ratio. Those trends have impacted the phytoplankton resource use efficiency jointly with the evenness of the community. Phytoplankton used resources more efficiently at higher values of upwelling strength and at lower values of nutrient concentration and evenness. Phytoplankton communities that were more even had higher dinoflagellate diversity contrasting to dominance of diatoms that used resources more efficiently. Moreover, variability in resource use efficiency increased with evenness.IEO (RADIALES-11

Age, growth, and mortality of Loligo vulgaris wild paralarvae : implications for understanding of the life cycle and longevity

Peer reviewedPreprin

Contemporary ocean warming and freshwater conditions contribute to delay the completion of maturation in Atlantic salmon

The completion of maturation in Atlantic salmon (Salmo salar) depends on environmental conditions that affect both feeding opportunities and growth, which would provide sufficient lipid stores for reproduction. However, if the level of energy reserves of a given fish is below a certain genetic threshold at a critical decision time further gonadal development is arrested and fully maturation postponed. This individual development pattern suggests that the proportion of fish maturing at a given sea age could vary from year to year according to the feeding opportunities in the oceanic migratory habitat, and the growth rate during freshwater residence that might be associated with growth at sea. In this study we show that sea age at maturity of adults caught in multiple Norwegian rivers has increased with increasing sea surface temperature (SST) experienced by the fish in autumn months during their first year at sea. Furthermore, freshwater conditions measured by river discharge during summer months one year ahead of seaward migration is positively related with increasing sea age at maturity. This result is discussed within the broad changes occurring in the North-east Atlantic pelagic food web mostly related with the current ocean warming, and river conditions influencing growth rates

Rapid determination of colistin resistance in clinical strains of acinetobacter baumannii by use of the micromax assay

Colistin is an old antibiotic which has been used as a therapeutic option for carbapenem- and multidrug-resistant Gram-negative bacteria, like Acinetobacter baumannii. This pathogen produces life-threatening infections, mainly in patients admitted to intensive care units. Rapid detection of resistance to colistin may improve patient outcomes and prevent the spread of resistance. For this purpose, Micromax technology was evaluated in four isogenic A. baumannii strains with known mechanisms of resistance to colistin and in 66 isolates (50 susceptible and 16 resistant). Two parameters were determined, DNA fragmentation and cell wall damage. To assess DNA fragmentation, cells trapped in a microgel were incubated with a lysing solution to remove the cell wall, and the released nucleoids were visualized under fluorescence microscopy. Fragmented DNA was observed as spots that diffuse from the nucleoid. To assess cell wall integrity, cells were incubated with a lysis solution which removes only weakened cell walls, resulting in nucleoid release exclusively in affected cells. A dose-response relationship was demonstrated between colistin concentrations and the percentages of bacteria with DNA fragmentation and cell wall damage, antibiotic effects that were delayed and less frequent in resistant strains. Receiver operating characteristic (ROC) curves demonstrated that both DNA fragmentation and cell wall damage were excellent parameters for identifying resistant strains. Obtaining<11% of bacteria with cell wall damage after incubation with 0.5 g/ml colistin identified resistant strains of A. baumannii with 100% sensitivity and 96% specificity. Results were obtained in 3 h 30 min. This is a simple, rapid, and accurate assay for detecting colistin resistance in A. baumannii, with strong potential value in critical clinical situationsThis work has been supported by MagicBullet, Xunta de Galicia 10CSA916020PR, and by REIPI, the Spanish Network for Research in Infectious Diseases (Instituto de Salud Carlos III, REIPI RD12/0015) and the Fondo de Investigaciones Sanitarias (FIS PI12/00552) to G.B. M.J.M. is supported by the Subprograma Miguel Servet from the Ministerio de Economía y Competitividad of Spain (CP11/00314). MagicBullet is a project funded by the European Union–Directorate General for Research and Innovation through the Seventh Framework Program for Research and Development (grant agreement 278232) and has been running since 1 January 2012 (36 months’ duration

Bottom-up control of common octopus Octopus vulgaris in the Galician upwelling system, northeast Atlantic Ocean

This paper investigates the possible underlying causes of the wide interannual fluctuations in catch of the common octopus Octopus vulgaris Cuvier, 1797 in one of the main small-scale fisheries off the coast of Galicia (northwest Spain). Galicia is at the northern boundary of the Iberian–Canary current upwelling system in the northeast Atlantic Ocean, where local winds induce seasonal upwelling, largely driving the annual cycles of primary and secondary production. We hypothesize that such dynamics are also fundamental for the survival of the planktonic stages of octopus and set the year class strength. We address this hypothesis by investigating the influence of upwelling on time-series of octopus fishery data. Wind stress structure during the spring–summer (prior to the hatching peak) and autumn–winter (during the planktonic stage) was found to affect the early life phase of this species, and explains up to 85% of the total variance of the year-to-year variability of the adult catch. Despite this bottom-up modulation via environmental conditions, our results also provide evidence for a between-cohort density-dependent interaction, probably caused by cannibalism and competition for habitat.Postprin

ANALYSIS OF UNCERTAINTY IN THE STANDARIZATION OF CPUE INDEXES

Catch per unit effort (CPUE) indices are considered as one of the main information sources used in fish stock assessment models (Zou et al., 2019). There are many ways for the standardization of these indices: • Generalized lineal models (GLMs) • Generalized additive models (GAMs) • Geostatistical models. To evaluate the accuracy and uncertainty associated with CPUE indices derived from datasets with different spatial information. • How? With the standardization of CPUE indices using geostatistical models in different sampling scenarios, comparing them with GLMs and GAMs models

Predicting long-term disease control in transplant-ineligible patients with multiple myeloma: impact of an MGUS-like signature

Disease control at 5 years would be a desirable endpoint for elderly multiple myeloma (MM) patients, but biomarkers predicting this are not defined. Therefore, to gain further insights in this endpoint, a population of 498 newly diagnosed transplant-ineligible patients enrolled in two Spanish trials (GEM2005MAS65 and GEM2010MAS65), has been analyzed. Among the 435 patients included in this post-hoc study, 18.6% remained alive and progression free after 5 years of treatment initiation. In these patients, overall survival (OS) rate at 10 years was 60.8% as compared with 11.8% for those progressing within the first 5 years. Hemoglobin (Hb) = 12 g/dl (OR 2.74, p = 0.001) and MGUS-like profile (OR 4.18, p = 0.005) were the two baseline variables associated with long-term disease-free survival. Upon including depth of response (and MRD), Hb = 12 g/dl (OR 2.27) and MGUS-like signature (OR 7.48) retained their predictive value along with MRD negativity (OR 5.18). This study shows that despite the use of novel agents, the probability of disease control at 5 years is still restricted to a small fraction (18.6%) of elderly MM patients. Since this endpoint is associated with higher rates of OS, this study provides important information about diagnostic and post-treatment biomarkers helpful in predicting the likelihood of disease control at 5 years