Temporal and spatial trends in marine carbon isotopes in the Arctic Ocean and implications for food web studies

The Arctic is undergoing unprecedented environmental change. Rapid warming, decline in sea ice extent, increase in riverine input, ocean acidification and changes in primary productivity are creating a crucible for multiple concurrent environmental stressors, with unknown consequences for the entire arctic ecosystem. Here, we synthesised 30 years of data on the stable carbon isotope (δ13 C) signatures in dissolved inorganic carbon (δ13 C-DIC; 1977 to 2014), marine and riverine particulate organic carbon (δ13 C-POC; 1986 to 2013) and tissues of marine mammals in the Arctic. δ13 C values in consumers can change as a result of environmentally driven variation in the δ13 C values at the base of the food web or alteration in the trophic structure, thus providing a method to assess the sensitivity of food webs to environmental change. Our synthesis reveals a spatially heterogeneous and temporally evolving δ13 C baseline, with spatial gradients in the δ13 C-POC values between arctic shelves and arctic basins likely driven by differences in productivity and riverine and coastal influence. We report a decline in δ13 C-DIC values (-0.011 ‰ y-1 ) in the Arctic, reflecting increasing anthropogenic carbon dioxide (CO2 ) in the Arctic Ocean (i.e. Suess effect), which is larger than predicted. The larger decline in δ13 C-POC values and δ13 C in arctic marine mammals reflects the anthropogenic CO2 signal as well as the influence of a changing arctic environment. Combining the influence of changing sea ice conditions and isotopic fractionation by phytoplankton, we explain the decadal decline in δ13 C-POC values in the Arctic Ocean and partially explain the δ13 C values in marine mammals with consideration of time-varying integration of δ13 C values. The response of the arctic ecosystem to ongoing environmental change is stronger than we would predict theoretically, which has tremendous implications for the study of food webs in the rapidly changing Arctic Ocean

Atmospheric aerosols at the Pierre Auger Observatory and environmental implications

The Pierre Auger Observatory detects the highest energy cosmic rays. Calorimetric measurements of extensive air showers induced by cosmic rays are performed with a fluorescence detector. Thus, one of the main challenges is the atmospheric monitoring, especially for aerosols in suspension in the atmosphere. Several methods are described which have been developed to measure the aerosol optical depth profile and aerosol phase function, using lasers and other light sources as recorded by the fluorescence detector. The origin of atmospheric aerosols traveling through the Auger site is also presented, highlighting the effect of surrounding areas to atmospheric properties. In the aim to extend the Pierre Auger Observatory to an atmospheric research platform, a discussion about a collaborative project is presented.Comment: Regular Article, 16 pages, 12 figure

The continental margin is a key source of iron to the HNLC North Pacific Ocean

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 35 (2008): L07608, doi:10.1029/2008GL033294.Here we show that labile particulate iron and manganese concentrations in the upper 500 m of the Western Subarctic Pacific, an iron-limited High Nutrient Low Chlorophyll (HNLC) region, have prominent subsurface maxima between 100–200 m, reaching 3 nM and 600 pM, respectively. The subsurface concentration maxima in particulate Fe are characterized by a more reduced oxidation state, suggesting a source from primary volcagenic minerals such as from the Kuril/Kamchatka margin. The systematics of these profiles suggest a consistently strong lateral advection of labile Mn and Fe from redox-mobilized labile sources at the continental shelf supplemented by a more variable source of Fe from the upper continental slope. This subsurface supply of iron from the continental margin is shallow enough to be accessible to the surface through winter upwelling and vertical mixing, and is likely a key source of bioavailable Fe to the HNLC North Pacific.Funding from the US Department of Energy, Office of Science, Biological and Environmental Research Program (JB) and WHOI Postdoctoral Scholars program, the Richard B. Sellars Endowed Research Fund, and the Andrew W. Mellon Foundation Endowed Fund for Innovative Research (PL)

Dissolved Organic Matter in the Upwelling System off Peru: Imprints of Bacterial Activity and Water Mass Characteristics

Microbial degradation of dissolved organic matter (DOM) contributes to the formation and preservation of oxygen minimum zones (OMZs) in the ocean, but information on the spatial distribution and molecular composition of DOM in OMZ regions is scarce. We quantified molecular components of DOM that is, dissolved amino acids (DAA) and dissolved combined carbohydrates (DCCHO), in the upwelling region off Peru. We found the highest concentrations of DCCHO in fully oxygenated surface waters steeply declining at shallow depth. The highest DAA concentrations were observed close to the surface also, but attenuation of DAA concentration over depth was less pronounced. Compositional changes of DCCHO were strongest within more oxygenated waters. Compositional changes of DAA were also evident under suboxic conditions (<5 µmol O2 kg−1) and indicated bacterial peptide degradation. Moreover, specific free amino acids (alanine and threonine) were enhanced within suboxic waters, pointing to a potential production of dissolved organic nitrogen under suboxic conditions. Our results therewith suggest that deoxygenation supports a spatial decoupling of DCCHO and DAA production and degradation dynamics and give new insights to carbon and nitrogen cycling in the OMZ off Peru

Modulation of Myelopoiesis Progenitors Is an Integral Component of Trained Immunity

Trained innate immunity fosters a sustained favorable response of myeloid cells to a secondary challenge, despite their short lifespan in circulation. We thus hypothesized that trained immunity acts via modulation of hematopoietic stem and progenitor cells (HSPCs). Administration of β-glucan (prototypical trained-immunity-inducing agonist) to mice induced expansion of progenitors of the myeloid lineage, which was associated with elevated signaling by innate immune mediators, such as IL-1β and granulocyte-macrophage colony-stimulating factor (GM-CSF), and with adaptations in glucose metabolism and cholesterol biosynthesis. The trained-immunity-related increase in myelopoiesis resulted in a beneficial response to secondary LPS challenge and protection from chemotherapy-induced myelosuppression in mice. Therefore, modulation of myeloid progenitors in the bone marrow is an integral component of trained immunity, which to date, was considered to involve functional changes of mature myeloid cells in the periphery

Seasonal and spatial variability in condition of age-0+ Argentine hake Merluccius hubbsi Marini, 1933, in the San Jorge Gulf (Argentina): A bottom-up perspective

In the north Patagonian region of the Argentinean Continental Shelf, the San Jorge Gulf (SJG; 45°‐47°S, 65°30ʹ‐67°30ʹW) is the main nursery ground of age‐0+ Argentine hake Merluccius hubbsi Marini, 1933, one of the most important fishery resources in Argentina. The gulf exhibits strong seasonal and spatial fluctuations in environmental features, which might affect survival of age‐0+ individuals and recruitment to the adult population. Our main goal was to evaluate the seasonal and spatial dynamics of their nutritional status within the SJG in winter 2016, spring 2016 and summer 2017. Condition indices (relative condition factor Kn, hepatosomatic index HSI and liver lipid content %L) and diet information (feeding incidence and relative importance of prey) were combined with physical (temperature and salinity) and biological (satellite chlorophyll‐a concentration; chl‐a) data. Age‐0+ condition indices and prey intake showed significant seasonal variations, with minimum values in winter, intermediate in summer and maximum in spring, strongly coupled to the mean chl‐a concentration in each season. Herbivorous euphausiids Euphausia spp. were the preferred prey along the study period. A bottom‐up effect on condition of age‐0+ hake is suggested, manifested as lower condition values in winter, the less productive season. Spatially, better conditioned individuals matched sectors of the gulf where chl‐a concentrations were higher, coupled to the presence of frontal systems. Monitoring age‐0+ hake nutritional status is relevant in the current global change scenario, which might modify phytoplankton biomass and composition and, consequently, the herbivorous zooplankton abundances.Fil: Temperoni, Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Massa, Agueda Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Martos, Patricia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; ArgentinaFil: Marrari, Marina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

IRF4 transcription factor-dependent CD11b+ dendritic cells in human and mouse control mucosal IL-17 cytokine responses.

Mouse and human dendritic cells (DCs) are composed of functionally specialized subsets, but precise interspecies correlation is currently incomplete. Here, we showed that murine lung and gut lamina propria CD11b+ DC populations were comprised of two subsets: FLT3- and IRF4-dependent CD24(+)CD64(-) DCs and contaminating CSF-1R-dependent CD24(-)CD64(+) macrophages. Functionally, loss of CD24(+)CD11b(+) DCs abrogated CD4+ T cell-mediated interleukin-17 (IL-17) production in steady state and after Aspergillus fumigatus challenge. Human CD1c+ DCs, the equivalent of murine CD24(+)CD11b(+) DCs, also expressed IRF4, secreted IL-23, and promoted T helper 17 cell responses. Our data revealed heterogeneity in the mouse CD11b+ DC compartment and identifed mucosal tissues IRF4-expressing DCs specialized in instructing IL-17 responses in both mouse and human. The demonstration of mouse and human DC subsets specialized in driving IL-17 responses highlights the conservation of key immune functions across species and will facilitate the translation of mouse in vivo findings to advance DC-based clinical therapies

A call for using natural compounds in the development of new antimalarial treatments – an introduction

Natural compounds, mostly from plants, have been the mainstay of traditional medicine for thousands of years. They have also been the source of lead compounds for modern medicine, but the extent of mining of natural compounds for such leads decreased during the second half of the 20th century. The advantage of natural compounds for the development of drugs derives from their innate affinity for biological receptors. Natural compounds have provided the best anti-malarials known to date. Recent surveys have identified many extracts of various organisms (mostly plants) as having antiplasmodial activity. Huge libraries of fractionated natural compounds have been screened with impressive hit rates. Importantly, many cases are known where the crude biological extract is more efficient pharmacologically than the most active purified compound from this extract. This could be due to synergism with other compounds present in the extract, that as such have no pharmacological activity. Indeed, such compounds are best screened by cell-based assay where all potential targets in the cell are probed and possible synergies identified. Traditional medicine uses crude extracts. These have often been shown to provide many concoctions that deal better with the overall disease condition than with the causative agent itself. Traditional medicines are used by ~80 % of Africans as a first response to ailment. Many of the traditional medicines have demonstrable anti-plasmodial activities. It is suggested that rigorous evaluation of traditional medicines involving controlled clinical trials in parallel with agronomical development for more reproducible levels of active compounds could improve the availability of drugs at an acceptable cost and a source of income in malaria endemic countries

Integrated Management and Visualization of Electronic Tag Data with Tagbase

Electronic tags have been used widely for more than a decade in studies of diverse marine species. However, despite significant investment in tagging programs and hardware, data management aspects have received insufficient attention, leaving researchers without a comprehensive toolset to manage their data easily. The growing volume of these data holdings, the large diversity of tag types and data formats, and the general lack of data management resources are not only complicating integration and synthesis of electronic tagging data in support of resource management applications but potentially threatening the integrity and longer-term access to these valuable datasets. To address this critical gap, Tagbase has been developed as a well-rounded, yet accessible data management solution for electronic tagging applications. It is based on a unified relational model that accommodates a suite of manufacturer tag data formats in addition to deployment metadata and reprocessed geopositions. Tagbase includes an integrated set of tools for importing tag datasets into the system effortlessly, and provides reporting utilities to interactively view standard outputs in graphical and tabular form. Data from the system can also be easily exported or dynamically coupled to GIS and other analysis packages. Tagbase is scalable and has been ported to a range of database management systems to support the needs of the tagging community, from individual investigators to large scale tagging programs. Tagbase represents a mature initiative with users at several institutions involved in marine electronic tagging research