Particulate Organic Matter Distributions in the Water Column of the Chukchi Sea During Late Summer

We investigated the distribution and composition of particulate organic matter in waters from the northeast Chukchi Sea during two late summer periods (September 2016 and August 2017). During both cruises we measured a variety of properties (salinity, temperature, density, chlorophyll fluorescence and particle beam attenuation). We also collected individual water samples from specific depths and measured the concentrations of suspended particulate matter, particulate organic carbon and nitrogen, chlorophyll-a and pheophytin (a chlorophyll degradation product). These measurements revealed highly stratified conditions throughout the study area, with surface waters exhibiting relatively low particle and biomass concentrations, middepth waters with well-defined subsurface chlorophyll maxima and moderate biomass, and turbid bottom waters with intermediate concentrations of particulate organic carbon and elevated levels of pheophytin. Large contrasts in the composition of particulate materials in both cruises were related to the distribution of different regional water masses. In addition, we observed increases in biogeochemical tracers of phytoplankton production in response to downwelling- and upwelling-favorable wind events. Overall, our work suggests that under the right conditions, phytoplankton production may occur under highly stratified conditions both in surface and sub-surface waters, extending the productive season along Arctic marginal seas

Effects of Low Tide Rainfall on Intertidal Zone Material Cycling

Sediment transport by rainfall-runoff processes is well documented for terrestrial landscapes but few studies have focused on rainfall-runoff effects in intertidal areas. Here we present geochemical analyses performed on sediment samples collected during low tide irrigation experiments, and tidal channel turbidity measurements taken during natural rainfall over North Inlet Marsh, South Carolina. Order of magnitude approximations indicate that a single 10 minute storm may entrain 8-15% of the local annual average sediment accumulation. This rainfall-entrained material is enriched in organic nitrogen and marine algal matter, and therefore of high nutritional quality

Distribution and sources of organic matter in surface marine sediments across the North American Arctic margin

As part of the International Polar Year research program, we conducted a survey of surface marine sediments from box cores along a section extending from the Bering Sea to Davis Strait via the Canadian Archipelago. We used bulk elemental and isotopic compositions, together with biomarkers and principal components analysis, to elucidate the distribution of marine and terrestrial organic matter in different regions of the North American Arctic margin. Marked regional contrasts were observed in organic carbon loadings, with the highest values (1 mg C m(-2) sediment) found in sites along Barrow Canyon and the Chukchi and Bering shelves, all of which were characterized by sediments with low oxygen exposure, as inferred from thin layers (\u3c2 \u3ecm) of Mn oxihydroxides. We found strong regional differences in inorganic carbon concentrations, with sites from the Canadian Archipelago and Lancaster Sound displaying elevated values (2-7 wt %) and highly depleted C-14 compositions consistent with inputs from bedrock carbonates. Organic carbon:nitrogen ratios, stable carbon isotopes, and terrigenous organic biomarkers (lignin phenols and cutin acids) all indicate marked regional differences in the proportions of marine and terrigenous organic matter present in surface sediments. Regions such as Barrow Canyon and the Mackenzie River shelf were characterized by the highest contributions of land-derived organic matter, with compositional characteristics that suggested distinct sources and provenance. In contrast, sediments from the Canadian Archipelago and Davis Strait had the smallest contributions of terrigenous organic matter and the lowest organic carbon loadings indicative of a high degree of post-depositional oxidation

Biogeochemical characterization of carbon sources in the Strickland and Fly rivers, Papua New Guinea

The highstanding islands of Oceania are recognized as a source of significant particulate organic carbon delivered to nearshore marine environments. The existing data on carbon export in Oceania are largely derived from small mountainous watersheds (<10,000 km2) with little or no sediment storage capacity and located in subtropical to temperate regions. The Fly-Strickland fluvial dispersal system is the largest in tropical Oceania and has high sediment yields, aged organic matter in its suspended-sediment load, and lowland sediment storage capacity. The Fly River system also has very high soil organic carbon content and conditions favorable to perennially high production, oxidation, and discharge within the watershed. We used stable and radiogenic isotopes (δ13C, Δ14C, and δ15N), lignin phenols, and X-ray photoelectron spectroscopy to examine the organic and inorganic composition of particulate and dissolved carbon at several lowland sites in the Fly and Strickland rivers and on the Strickland River floodplain. Isotopic, elemental, and biomarker results suggest that organic carbon in the Strickland River was more degraded than in the Fly River, with a greater input of ancient organics from upland sources, and that aquatic production constituted a larger source in the Fly River. Radiocarbon results indicate that all carbon fractions were older in the Strickland than in the Fly and that Strickland floodplain sediments were also depleted in radiocarbon. Collectively, these results suggest that rivers of New Guinea export a comparable amount of particulate organic carbon to the Amazon, with a significant contribution from radiocarbon-depleted sources

Terrigenous organic matter in sediments from the Fly River delta-clinoform system (Papua New Guinea)

Although an inordinate fraction of the global sediment flux to the ocean occurs in tropical mountainous river margins, little is known regarding the sources and fate of organic matter in these systems. To address these knowledge gaps, the distribution and composition of organic matter in sediments from the Fly River delta-clinoform were examined in the context of the source-to-sink study of the Papuan Continuum. The significant contrasts in the texture of seabed sediments measured across the study area coincided with stark contrasts in concentration and composition of the sedimentary organic matter. Coarser sediments displayed significantly lower organic carbon and nitrogen contents, more enriched stable carbon and nitrogen compositions, lower lignin product yields, and distinctly different lignin and nonlignin product compositions than their fine-textured counterparts. Compositional differences were also measured between high- and low-density fractions of selected sediment samples. Subsurface sediments showed marked compositional variations that were predominantly associated with changes in the texture of the deposits. Most sediments were characterized by moderate carbon loadings (0.5–1.0 mg C m–2), although several samples from the outer topset region, an area of sediment bypass, were characterized by lower carbon loadings indicative of enhanced carbon losses. Overall, the organic matter in both surface and subsurface sediments appeared to have predominantly a terrigenous origin, with no evidence for dilution and/or replacement by marine carbon. The measured compositions were consistent with contributions from modern vascular plant detritus, aged soil organic matter, and very old or fossil organic matter devoid of recognizable biochemicals

Arginine catabolism metabolites and atrial fibrillation or heart failure risk: 2 case-control studies within the Prevención con Dieta Mediterránea (PREDIMED) trial

Background Arginine-derived metabolites are involved in oxidative and inflammatory processes related to endothelial functions and cardiovascular risks. Objectives We prospectively examined the associations of arginine catabolism metabolites with the risks of atrial fibrillation (AF) or heart failure (HF), and evaluated the potential modifications of these associations through Mediterranean diet (MedDiet) interventions in a large, primary-prevention trial. Methods Two nested, matched, case-control studies were designed within the Prevención con Dieta Mediterránea (PREDIMED) trial. We selected 509 incident cases and 547 matched controls for the AF case-control study and 326 cases and 402 matched controls for the HF case-control study using incidence density sampling. Fasting blood samples were collected at baseline and arginine catabolism metabolites were measured using LC-tandem MS. Multivariable conditional logistic regression models were applied to test the associations between the metabolites and incident AF or HF. Interactions between metabolites and intervention groups (MedDiet groups compared with control group) were analyzed with the likelihood ratio test. Results Inverse association with incident AF was observed for arginine (OR per 1 SD, 0.83; 95% CI: 0.73–0.94), whereas a positive association was found for N1-acetylspermidine (OR for Q4 compared with Q1 1.58; 95% CI: 1.13–2.25). For HF, inverse associations were found for arginine (OR per 1 SD, 0.82; 95% CI: 0.69–0.97) and homoarginine (OR per 1 SD, 0.81; 95% CI: 0.68–0.96), and positive associations were found for the asymmetric dimethylarginine (ADMA) and symmetric dimethlyarginine (SDMA) ratio (OR per 1 SD, 1.19; 95% CI: 1.02–1.41), N1-acetylspermidine (OR per 1 SD, 1.34; 95% CI: 1.12–1.60), and diacetylspermine (OR per 1 SD, 1.20; 95% CI: 1.02–1.41). In the stratified analysis according to the dietary intervention, the lower HF risk associated with arginine was restricted to participants in the MedDiet groups (P-interaction = 0.044). Conclusions Our results suggest that arginine catabolism metabolites could be involved in AF and HF. Interventions with the MedDiet may contribute to strengthen the inverse association between arginine and the risk of HF. This trial was registered at controlled-trials.com as ISRCTN35739639

Representing the function and sensitivity of coastal interfaces in earth system models

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ward, N. D., Megonigal, J. P., Bond-Lamberty, B., Bailey, V. L., Butman, D., Canuel, E. A., Diefenderfer, H., Ganju, N. K., Goni, M. A., Graham, E. B., Hopkinson, C. S., Khangaonkar, T., Langley, J. A., McDowell, N. G., Myers-Pigg, A. N., Neumann, R. B., Osburn, C. L., Price, R. M., Rowland, J., Sengupta, A., Simard, M., Thornton, P. E., Tzortziou, M., Vargas, R., Weisenhorn, P. B., & Windham-Myers, L. Representing the function and sensitivity of coastal interfaces in earth system models. Nature Communications, 11(1), (2020): 2458, doi:10.1038/s41467-020-16236-2.Between the land and ocean, diverse coastal ecosystems transform, store, and transport material. Across these interfaces, the dynamic exchange of energy and matter is driven by hydrological and hydrodynamic processes such as river and groundwater discharge, tides, waves, and storms. These dynamics regulate ecosystem functions and Earth’s climate, yet global models lack representation of coastal processes and related feedbacks, impeding their predictions of coastal and global responses to change. Here, we assess existing coastal monitoring networks and regional models, existing challenges in these efforts, and recommend a path towards development of global models that more robustly reflect the coastal interface.Funding for this work was provided by Pacific Northwest National Laboratory (PNNL) Laboratory Directed Research & Development (LDRD) as part of the Predicting Ecosystem Resilience through Multiscale Integrative Science (PREMIS) Initiative. PNNL is operated by Battelle for the U.S. Department of Energy under Contract DE-AC05-76RL01830. Additional support to J.P.M. was provided by the NSF-LTREB program (DEB-0950080, DEB-1457100, DEB-1557009), DOE-TES Program (DE-SC0008339), and the Smithsonian Institution. This manuscript was motivated by discussions held by co-authors during a three-day workshop at PNNL in Richland, WA: The System for Terrestrial Aquatic Research (STAR) Workshop: Terrestrial-Aquatic Research in Coastal Systems. The authors thank PNNL artist Nathan Johnson for preparing the figures in this manuscript and Terry Clark, Dr. Charlette Geffen, and Dr. Nancy Hess for their aid in organizing the STAR workshop. The authors thank all workshop participants not listed as authors for their valuable insight: Lihini Aluwihare (contributed to biogeochemistry discussions and development of concept for Fig. 3), Gautam Bisht (contributed to modeling discussion), Emmett Duffy (contributed to observational network discussions), Yilin Fang (contributed to modeling discussion), Jeremy Jones (contributed to biogeochemistry discussions), Roser Matamala (contributed to biogeochemistry discussions), James Morris (contributed to biogeochemistry discussions), Robert Twilley (contributed to biogeochemistry discussions), and Jesse Vance (contributed to observational network discussions). A full report on the workshop discussions can be found at https://www.pnnl.gov/publications/star-workshop-terrestrial-aquatic-research-coastal-systems

Evaluation of a multiplex PCR assay (Bruce-ladder) for molecular typing of all <i>Brucella</i> species, including the vaccine strains

An evaluation of a multiplex PCR assay (Bruce-ladder) was performed in seven laboratories using 625 Brucella strains from different animal and geographical origins. This robust test can differentiate in a single step all of the classical Brucella species, including those found in marine mammals and the S19, RB51, and Rev.1 vaccine strains

Species differential regulation of COX2 can be described by an NFκB-dependent logic AND gate

Cyclooxygenase 2 (COX2), a key regulatory enzyme of the prostaglandin/eicosanoid pathway, is an important target for anti-inflammatory therapy. It is highly induced by pro-inflammatory cytokines in a Nuclear factor kappa B (NFκB)-dependent manner. However, the mechanisms determining the amplitude and dynamics of this important pro-inflammatory event are poorly understood. Furthermore, there is significant difference between human and mouse COX2 expression in response to the inflammatory stimulus tumor necrosis factor alpha (TNFα). Here, we report the presence of a molecular logic AND gate composed of two NFκB response elements (NREs) which controls the expression of human COX2 in a switch-like manner. Combining quantitative kinetic modeling and thermostatistical analysis followed by experimental validation in iterative cycles, we show that the human COX2 expression machinery regulated by NFκB displays features of a logic AND gate. We propose that this provides a digital, noise-filtering mechanism for a tighter control of expression in response to TNFα, such that a threshold level of NFκB activation is required before the promoter becomes active and initiates transcription. This NFκB-regulated AND gate is absent in the mouse COX2 promoter, most likely contributing to its differential graded response in promoter activity and protein expression to TNFα. Our data suggest that the NFκB-regulated AND gate acts as a novel mechanism for controlling the expression of human COX2 to TNFα, and its absence in the mouse COX2 provides the foundation for further studies on understanding species-specific differential gene regulation

Displacement of phenyl and styryl ligands by benzophenone imine and 2-vinylpyridine on ruthenium and osmium

8 pages, 4 figures, 4 tables.The phenyl complexes MPhCl(CO)(PiPr3)2 (M = Ru (3), Os (4)) have been prepared by reaction of MHCl(CO)(PiPr3)2 (M = Ru (1), Os (2)) with HgPh2. In solution the phenyl ligand of these compounds rotates around the M−Ph bond. The activation parameters for the process are ΔH = 13.0 ± 0.6 kcal·mol-1 and ΔS = 1.5 ± 1.3 cal·mol-1·K-1 for 3 and ΔH = 11.7 ± 0.5 kcal·mol-1 and ΔS = −5.4 ± 1.2 cal·mol-1·K-1 for 4. The addition of benzophenone imine to dichloromethane solutions of 3 and 4 and the related styryl complexes M{(E)-CHCHPh}Cl(CO)(PiPr3)2 (M = Ru (7), Os (8)) leads to equilibrium mixtures between the starting compounds and the six-coordinate derivatives MPhCl(NHCPh2)(CO)(PiPr3)2 (M = Ru (5): ΔH° = −8.6 ± 0.4 kcal·mol-1, ΔS° = −42.5 ± 1.6 cal·mol-1·K-1; M = Os (6): ΔH° = −9.1 ± 0.8 kcal·mol-1, ΔS° = −31.0 ± 2.6 cal·mol-1·K-1) and M{(E)-CHCHPh}Cl(NHCPh2)(CO)(PiPr3)2 (M = Ru (9): ΔH° = −9.5 ± 0.3 kcal·mol-1, ΔS° = −39.4 ± 1.1 cal·mol-1·K-1; M = Os (10): ΔH° = −8.8 ± 0.8 kcal·mol-1, ΔS° = −27.3 ± 2.6 cal·mol-1·K-1). In toluene under reflux complexes 3, 4, 7, and 8 react with benzophenone imine and 2-vinylpyridine to afford the metalated derivatives (M = Ru (11), Os (12)) and (M = Ru (13), Os (14)), releasing benzene and styrene. Complexes 9, 12, and 13 have been characterized by X-ray diffraction analysis. The structure of 9 shows a Cl···H−N hydrogen bond (2.47 Å) between the NH hydrogen atom of the imine and the chloride ligand.Financial support from the MCYT of Spain (Project CTQ2005-00656) is acknowledged. M.L.B. thanks the Spanish MCYT/Universidad de Zaragoza for funding through the “Ramón y Cajal” program.Peer reviewe