Volcanic ash supply to the surface ocean – remote sensing of biological responses and their wider biogeochemical significance

Transient micronutrient enrichment of the surface ocean can enhance phytoplankton growth rates and alter microbial community structure with an ensuing spectrum of biogeochemical feedbacks. Strong phytoplankton responses to micronutrients supplied by volcanic ash have been reported recently. Here we: (i) synthesize findings from these recent studies; (ii) report the results of a new remote sensing study of ash fertilization; and (iii) calculate theoretical bounds of ash-fertilized carbon export. Our synthesis highlights that phytoplankton responses to ash do not always simply mimic that of iron amendment; the exact mechanisms for this are likely biogeochemically important but are not yet well understood. Inherent optical properties of ash-loaded seawater suggest rhyolitic ash biases routine satellite chlorophyll-a estimation upwards by more than an order of magnitude for waters with 0.5 mg chlorophyll-a m-3. For this reason post-ash-deposition chlorophyll-a changes in oligotrophic waters detected via standard Case 1 (open ocean) algorithms should be interpreted with caution. Remote sensing analysis of historic events with a bias less than a factor of 2 provided limited stand-alone evidence for ash-fertilization. Confounding factors were poor coverage, incoherent ash dispersal, and ambiguity ascribing biomass changes to ash supply over other potential drivers. Using current estimates of iron release and carbon export efficiencies, uncertainty bounds of ash-fertilized carbon export for 3 events are presented. Patagonian iron supply to the Southern Ocean from volcanic eruptions is less than that of windblown dust on thousand year timescales but can dominate supply at shorter timescales. Reducing uncertainties in remote sensing of phytoplankton response and nutrient release from ash are avenues for enabling assessment of the oceanic response to large-scale transient nutrient enrichment

Coherent manipulation of an Andreev spin qubit

Two promising architectures for solid-state quantum information processing are electron spins in semiconductor quantum dots and the collective electromagnetic modes of superconducting circuits. In some aspects, these two platforms are dual to one another: superconducting qubits are more easily coupled but are relatively large among quantum devices $(\sim\mathrm{mm})$, while electrostatically-confined electron spins are spatially compact ($\sim \mathrm{\mu m}$) but more complex to link. Here we combine beneficial aspects of both platforms in the Andreev spin qubit: the spin degree of freedom of an electronic quasiparticle trapped in the supercurrent-carrying Andreev levels of a Josephson semiconductor nanowire. We demonstrate coherent spin manipulation by combining single-shot circuit-QED readout and spin-flipping Raman transitions, finding a spin-flip time $T_S = 17~\mathrm{\mu s}$ and a spin coherence time $T_{2E}=52~\mathrm{ns}$. These results herald a new spin qubit with supercurrent-based circuit-QED integration and further our understanding and control of Andreev levels -- the parent states of Majorana zero modes -- in semiconductor-superconductor heterostructures

A global perspective on marine photosynthetic picoeukaryote community structure

A central goal in ecology is to understand the factors affecting the temporal dynamics and spatial distribution of microorganisms and the underlying processes causing differences in community structure and composition. However, little is known in this respect for photosynthetic picoeukaryotes (PPEs), algae that are now recognised as major players in marine CO2 fixation. Here, we analysed dot blot hybridisation and cloning–sequencing data, using the plastid-encoded 16S rRNA gene, from seven research cruises that encompassed all four ocean biomes. We provide insights into global abundance, α- and β-diversity distribution and the environmental factors shaping PPE community structure and composition. At the class level, the most commonly encountered PPEs were Prymnesiophyceae and Chrysophyceae. These taxa displayed complementary distribution patterns, with peak abundances of Prymnesiophyceae and Chrysophyceae in waters of high (25:1) or low (12:1) nitrogen:phosphorus (N:P) ratio, respectively. Significant differences in phylogenetic composition of PPEs were demonstrated for higher taxonomic levels between ocean basins, using Unifrac analyses of clone library sequence data. Differences in composition were generally greater between basins (interbasins) than within a basin (intrabasin). These differences were primarily linked to taxonomic variation in the composition of Prymnesiophyceae and Prasinophyceae whereas Chrysophyceae were phylogenetically similar in all libraries. These data provide better knowledge of PPE community structure across the world ocean and are crucial in assessing their evolution and contribution to CO2 fixation, especially in the context of global climate change

Verbal and facial-emotional Stroop tasks reveal specific attentional interferences in sad mood

Mood congruence refers to the tendency of individuals to attend to information more readily when it has the same emotional content as their current mood state. The aim of the present study was to ascertain whether attentional interference occurred for participants in sad mood states for emotionally relevant stimuli (mood-congruence), and to determine whether this interference occurred for both valenced words and valenced faces. A mood induction procedure was administered to 116 undergraduate females divided into two equal groups for the sad and happy mood condition. This study employed three versions of the Stroop task: color, verbal-emotional, and a facial-emotional Stroop. The two mood groups did not differ on the color Stroop. Significant group differences were found on the verbal-emotional Stroop for sad words with longer latencies for sad-induced participants. Main findings for the facial-emotional Stroop were that sad mood is associated with attentional interference for angry-threatening faces as well as longer latencies for neutral faces. Group differences were not found for positive stimuli. These findings confirm that sad mood is associated with attentional interference for mood-congruent stimuli in the verbal domain (sad words), but this mood-congruent effect does not necessarily apply to the visual domain (sad faces). Attentional interference for neutral faces suggests sad mood participants did not necessarily see valence-free faces. Attentional interference for threatening stimuli is often associated with anxiety; however, the current results show that threat is not an attentional interference observed exclusively in states of anxiety but also in sad mood

Delegation of GP-home visits to qualified practice assistants: assessment of economic effects in an ambulatory healthcare centre

<p>Abstract</p> <p>Background</p> <p>Against the background of a decreasing number of general practitioners (GPs) in rural regions in Germany, the AGnES-concept (AGnES = GP-supporting, community-based, e-health-assisted, systemic intervention) supports the delegation of regular GP-home visits to qualified practice assistants. The concept was implemented and evaluated in different model projects in Germany.</p> <p>To explore the economic effects of this concept, the development of the number of home visits in an ambulatory healthcare centre was analysed and compared with the number of home visits in the surrounding county.</p> <p>Methods</p> <p>Information about GP-home visits was derived from reimbursement data of the ambulatory healthcare centre and a statutory health insurance. Information about home visits conducted by AGnES-practice assistants was collected from the project documentation over a time period of 12 consecutive quarter years, four quarter years before the beginning of the project and 8 quarter years while the project was implemented, considering background temporal trends on the population level in the study region.</p> <p>Results</p> <p>Within the ambulatory healthcare centre, the home visits by the GPs significantly decreased, especially the number of medically urgent home visits. However, the overall rate of home visits (conducted by the GPs and the AGnES-practice assistants together) did not change significantly after implementation of the AGnES-concept. In the surrounding county, the home visit rates of the GPs were continuous; the temporal patterns were approximately equal for both usual and urgent home visits.</p> <p>Conclusion</p> <p>The results of the analyses show that the support by AGnES-practice assistants led to a decrease of GP-home visits rather than an induction of additional home visits by the AGnES-practice assistants. The most extended effect is related to the medically urgent home visits rather than to the usual home visits.</p

Primary Production, an Index of Climate Change in the Ocean: Satellite-Based Estimates over Two Decades

Primary production by marine phytoplankton is one of the largest fluxes of carbon on our planet. In the past few decades, considerable progress has been made in estimating global primary production at high spatial and temporal scales by combining in situ measurements of primary production with remote-sensing observations of phytoplankton biomass. One of the major challengesinthisapproachliesintheassignmentoftheappropriatemodelparametersthatdefinethe photosynthetic response of phytoplankton to the light field. In the present study, a global database of in situ measurements of photosynthesis versus irradiance (P-I) parameters and a 20-year record of climatequalitysatelliteobservationswereusedtoassessglobalprimaryproductionanditsvariability with seasons and locations as well as between years. In addition, the sensitivity of the computed primaryproductiontopotentialchangesinthephotosyntheticresponseofphytoplanktoncellsunder changing environmental conditions was investigated. Global annual primary production varied from 38.8 to 42.1 Gt C yr−1 over the period of 1998–2018. Inter-annual changes in global primary production did not follow a linear trend, and regional differences in the magnitude and direction of change in primary production were observed. Trends in primary production followed directly from changes in chlorophyll-a and were related to changes in the physico-chemical conditions of the water column due to inter-annual and multidecadal climate oscillations. Moreover, the sensitivity analysis in which P-I parameters were adjusted by±1 standard deviation showed the importance of accurately assigning photosynthetic parameters in global and regional calculations of primary production. TheassimilationnumberoftheP-Icurveshowedstrongrelationshipswithenvironmental variables such as temperature and had a practically one-to-one relationship with the magnitude of change in primary production. In the future, such empirical relationships could potentially be used for a more dynamic assignment of photosynthetic rates in the estimation of global primary production. RelationshipsbetweentheinitialslopeoftheP-Icurveandenvironmentalvariableswere more elusive

Photosynthesis–irradiance parameters of marine phytoplankton: synthesis of a global data set

The photosynthetic performance of marine phytoplankton varies in response to a variety of factors, environmental and taxonomic. One of the aims of the MArine primary Production: model Parameters from Space (MAPPS) project of the European Space Agency is to assemble a global database of photosynthesis– irradiance (P-E) parameters from a range of oceanographic regimes as an aid to examining the basin-scale variability in the photophysiological response of marine phytoplankton and to use this information to improve the assignment of P-E parameters in the estimation of global marine primary production using satellite data. The MAPPS P-E database, which consists of over 5000 P-E experiments, provides information on the spatiotemporal variability in the two P-E parameters (the assimilation number, PB m , and the initial slope, �B, where the superscripts B indicate normalisation to concentration of chlorophyll) that are fundamental inputs for models (satellite-based and otherwise) of marine primary production that use chlorophyll as the state variable. Qualitycontrol measures consisted of removing samples with abnormally high parameter values and flags were added to denote whether the spectral quality of the incubator lamp was used to calculate a broad-band value of �B. The MAPPS database provides a photophysiological data set that is unprecedented in number of observations and in spatial coverage. The database will be useful to a variety of research communities, including marine ecologists,biogeochemical modellers, remote-sensing scientists and algal physiologists