The chemistry, biology, and vertical flux of oceanic particulate matter

Submitted in partial fulfillment of the requirements for the degree of Doctor of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution January, 1977Particulate matter samples, split into 53 μm size fractions have been obtained using a Large Volume in situ Filtration System (LVFS) during the SOUTHLANT expedition, R/V CHAIN 115. Profiles to 400 m are reported for LVFS Stns. 2 and 4-8. Stns. 4, 5, and 8 (S. E. Atlantic, coastal waters near Walvis Bay and Cape Town, high biological productivity); Stns. 6 and 2 (S.E. Atlantic, Walvis Bay region and equatorial Atlantic, moderate productivity); and Sta. 7 (S.E. Atlantic, edge of central gyre, low productivity) formed a suite of samples for the study of the chemical, biological, morpholigical distributions and of the vertical mass flux of particulate matter as a function of biological productivity. All samples were analysed for Na, K, Mg, Ca, carbonate, opal, Sr, C and N and those from Sta. 2 were further analysed for P, Fe, δ13C, 7Be, 214Bi, 214Pb, (226Ra), 210Po, and 210Pb. Biological distributions of Acantharia, dinoflagellates, coccolithophorids, Foraminifera, diatoms, silicoflagellates, Radiolaria, and tintinnids were made by light microscopy (LM) and augmented by scanning electron microscopy (SEM). Size and morphological distributions of the >53 μm particles, especially Foraminifera, Acantharia, fecal pellets, and fecal matter have been determined by LM and SEM. The particle distributions were controlled at all stations by processes of production, consumption, fragmentation, and aggregation. Maxima in organism abundance and particulate mass were generally coincident. They were found nearest the surface when the mixed layer was absent or poorly developed, and at the base of the mixed layer at the other stations. Organism vertical distributions showed consistent features: Acantharia, and dinoflagellates were always nearest the surface; Foraminifera and diatoms were shallower than or at the base of the mixed layer; Radiolaria and tintinnids were found in the upper thermocline. Coccolithophorids and diatoms were the dominant sources of particulate carbonate and opal in the near surface waters, coccoliths and diatom fragments, deeper. Features of the distributions of particulate matter attributed to the feeding activities of zooplankton were: strong concentration gradients in organisms, mass, and organic matter; enrichment of the >53 μm fraction with coccoliths causing the steady decrease in >53 μm Si/carbonate ratio with depth from values as high as 45 to values near 1.0 at 400 m; the decrease in organic content with depth from values near 100 % near the surface to 50 and 60% at 400 m for the 53 μm size fractions; the fragmentation of most material below 100 m; and the production of fecal pellets and fecal matter which are carriers of fine material to the sea floor. Other features were: the nearly constant organic C/N ratios (7.3±0.5 δ) found for the 1-53 μm fractions at Stns. 4, 5, 6, and 8 compared with the steady increase observed at Stns. 2 and 7 with depth; particulate carbon was rather uniformy distributed below 200 m with concentrations showing a mild reflection of surface productivity; the <1 μC/N and δ13C values are lower and lighter than the 1-53 μm fraction, perhaps indicative of the presence of marine bacteria; the Ca/carbonate ratios in most samples significantly exceeded 1.0, values as high as 2.5 were observed at Sta. 8; the xs Ca and K have shallow regenerative cycles and contrast with Mg which is bound to a refractory component of organic matter; based on a organic C/ xs Ca ratio of 100-200:1 for surfàce samples, the cycling of xs Ca was calculated to be 1-2 x 1013mol/cm2/y compared with the production of carbonate, 7±2 x 1013 mol/cm2/y. Chemical effects noted were: organic matter had both binding capabilities and ion-exchange capacity for major and minor ions present in seawater. Acantharia (SrS04) dissolve most significantly below 200 m at Sta.2. The vertical mass fluxes through 400 m at Stas. 2, 5, 6, and 7 were calculated from size distributions measured in 1 m3 in seawater for Foramifera, fecal pellets, and fecal matter. Two flux models were used together with Junge distributions for these calculations. Fecal matter and Forainifera transported most mass at Stns. 2 and 5 where the fluxes were between 2 and 3, and 5 and 6 gm/cm2/1000y respectively; fècal matter, Foramnifera, and fecal pellets contributed equally to the .9-1.3gm/cm2/1000y flux at Sta. 6; and fecal pellets and Foraminifera were the carriers of 0.1-0.3 gm/cm2/1000y to the sea floor. Corresponding chemical fluxes of organic carbon, carbonate, and opal were: 80-90, 11-24, and ~10 mmol/cm2/1000y at Sta. 5; 15-20, 2.7-5.0 and 1.7-2.5 mmol/cm2/1000y at Sta. 6; 1-4, 0.6-1.5, and 0.1-0.3 mmol/cm2/1000y at Sta. 7, and 40-65, 4.6-7.4, and 4.9-7.9 mmol/cm2/1000y at station 2. Over 90% of the organic matter produced in the euphotic zone is recycled in the upper 400 m. The efficiency is nearly 99% in areas of low productivity; the organic to carbonate carbon ratios are highest at locations where the flux is greatest as are the Si/carbonate ratios. Besides carbonate, opal, celestite, and other mineral phases, organic matter may be a significant carrier of minor and trace elements to the deep ocean.This work was supported by contract N00014-75-C029l from the Office of Naval Research and by the Doherty Foundation

Variations in primary production and particulate carbon flux through the base of the euphotic zone at the site of the Sediment Trap Intercomparison Experiment (Panama Basin)

C primary production data collected during the deployment and recovery cruises of STIE in 1979 showed a simple relationship with light and nutrient concentrations in the euophotic zone. A simple empirical relationship, calibrated using these data, was derived so that weekly averaged observations of fractional cloudiness, sea-surface temperature and mixed layer depth could be used to estimate primary production on a weekly basis for the years 1976–1979. 15N-uptake measurements, which estimate new production, were combined with the 14C data to estimate particulate carbon fluxes from the euphotic zone. Results of calculations showed that production may vary by a factor of three and particulate carbon flux by a factor of ten on a week to week basis with peak values corresponding to times when the mixed layer became enriched in nutrients. Mean euphotic zone production and particulate carbon flux estimated for the STIE deployment cruise were 286 and 138 mg C m–2 d–1, respectively; they were 174 and 59 mg C m–2 d–1 for the recovery cruise. Mean production and flux values were 261 and 122 mg C m–2 d–1, respectively for the duration of STIE. Three high production and particle sedimentation events may have occurred during STIE in September and October 1979. 1979 appeared to be a year of lower than average primary production compared with 1976 and 1977

Data management for JGOFS: Theory and design

The Joint Global Ocean Flux Study (JGOFS), currently being organized under the auspices of the Scientific Committee for Ocean Research (SCOR), is intended to be a decade long internationally coordinated program. The main goal of JGOFS is to determine and understand on a global scale the processes controlling the time-varying fluxes of carbon and associated biogenic elements in the ocean and to evaluate the related exchanges with the atmosphere, sea floor and continental boundaries. 'A long-term goal of JGOFS will be to establish strategies for observing, on long time scales, changes in ocean biogeochemical cycles in relation to climate change'. Participation from a large number of U.S. and foreign institutions is expected. JGOFS investigators have begun a set of time-series measurements and global surveys of a wide variety of biological, chemical and physical quantities, detailed process-oriented studies, satellite observations of ocean color and wind stress and modeling of the bio-geochemical processes. These experiments will generate data in amounts unprecedented in the biological and chemical communities; rapid and effortless exchange of these data will be important to the success of JGOFS

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)

Wintertime phytoplankton bloom in the subarctic Pacific supported by continental margin iron

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 20 (2006): GB1006, doi:10.1029/2005GB002557.Heightened biological activity was observed in February 1996 in the high-nutrient low-chlorophyll (HNLC) subarctic North Pacific Ocean, a region that is thought to be iron-limited. Here we provide evidence supporting the hypothesis that Ocean Station Papa (OSP) in the subarctic Pacific received a lateral supply of particulate iron from the continental margin off the Aleutian Islands in the winter, coincident with the observed biological bloom. Synchrotron X-ray analysis was used to describe the physical form, chemistry, and depth distributions of iron in size fractionated particulate matter samples. The analysis reveals that discrete micron-sized iron-rich hot spots are ubiquitous in the upper 200 m at OSP, more than 900 km from the closest coast. The specifics of the chemistry and depth profiles of the Fe hot spots trace them to the continental margins. We thus hypothesize that iron hot spots are a marker for the delivery of iron from the continental margin. We confirm the delivery of continental margin iron to the open ocean using an ocean general circulation model with an iron-like tracer source at the continental margin. We suggest that iron from the continental margin stimulated a wintertime phytoplankton bloom, partially relieving the HNLC condition.This work was supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (KP1202030) to J. K. B and by NSFATM-9987457 to I. F. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Division of Chemical Sciences, Geosciences, and Biosciences of the U.S. Department of Energy at Lawrence Berkeley National Laboratory under contract DE-AC03-76SF00098

Accuracy and completeness of patient pathways – the benefits of national data linkage in Australia

Background - The technical challenges associated with national data linkage, and the extent of cross-border population movements, are explored as part of a pioneering research project. The project involved linking state-based hospital admission records and death registrations across Australia for a national study of hospital related deaths. Methods - The project linked over 44 million morbidity and mortality records from four Australian states between 1st July 1999 and 31st December 2009 using probabilistic methods. The accuracy of the linkage was measured through a comparison with jurisdictional keys sourced from individual states. The extent of cross-border population movement between these states was also assessed. Results - Data matching identified almost twelve million individuals across the four Australian states. The percentage of individuals from one state with records found in another ranged from 3-5 %. Using jurisdictional keys to measure linkage quality, results indicate a high matching efficiency (F measure 97 to 99 %), with linkage processing taking only a matter of days. Conclusions - The results demonstrate the feasibility and accuracy of undertaking cross jurisdictional linkage for national research. The benefits are substantial, particularly in relation to capturing the full complement of records in patient pathways as a result of cross-border population movements. The project identified a sizeable ‘mobile’ population with hospital records in more than one state. Research studies that focus on a single jurisdiction will under-enumerate the extent of hospital usage by individuals in the population. It is important that researchers understand and are aware of the impact of this missing hospital activity on their studies. The project highlights the need for an efficient and accurate data linkage system to support national research across Australia

The nedd-8 activating enzyme gene underlies genetic resistance to infectious pancreatic necrosis virus in Atlantic salmon

Genetic resistance to infectious pancreatic necrosis virus (IPNV) in Atlantic salmon is a rare example of a trait where a single locus (QTL) explains almost all of the genetic variation. Genetic marker tests based on this QTL on salmon chromosome 26 have been widely applied in selective breeding to markedly reduce the incidence of the disease. In the current study, whole genome sequencing and functional annotation approaches were applied to characterise genes and variants in the QTL region. This was complemented by an analysis of differential expression between salmon fry of homozygous resistant and homozygous susceptible genotypes challenged with IPNV. These analyses pointed to the NEDD-8 activating enzyme 1 (nae1) gene as a putative functional candidate underlying the QTL effect. The role of nae1 in IPN resistance was further assessed via CRISPR-Cas9 knockout of the nae1 gene and chemical inhibition of the nae1 protein activity in Atlantic salmon cell lines, both of which resulted in highly significant reduction in productive IPNV replication. In contrast, CRISPR-Cas9 knockout of a candidate gene previously purported to be a cellular receptor for the virus (cdh1) did not have a major impact on productive IPNV replication. These results suggest that nae1 is the causative gene underlying the major QTL affecting resistance to IPNV in salmon, provide further evidence for the critical role of neddylation in host-pathogen interactions, and highlight the value in combining high-throughput genomics approaches with targeted genome editing to understand the genetic basis of disease resistance

Ground-based measurements of O1D and the H2O production rate from comets

Ground-based high spectral resolution measurements of Comet Halley in the 6300.3 A spectral region establish this technique as a powerful and low cost method for determining cometary H2O production rates. A model on the line profile to be expected from the O1D coma emission indicates that ground-based observations with fields of view on the comet of about 1 x 105 km measure profiles characteristic of O1D from the H2O parent. As the field of view increases, the signature of more energetic O1D ejected by CO2 and CO photolysis may become evident in the wings of the 6300.3 A line profile. The width of the 6300.3 A O1D profile is found to be equal to the ejection speed of O1D following H2O photolysis for fields of view to 1 x 106 km. Halley observations show that cometary NH2 (0,8,0) emissions do not contaminate the cometary O1D signature when the spectral resolution is 2O production rates determined by scaling the measured O1D production rates according to the H2O photolysis branching ratio are in good agreement with other measurements. Minor upgrades in the tracking and spectral resolution capabilities of observatories now dedicated to measurements of the terrestrial airglow would be useful for expansion of the high resolution cometary O1D data base - to include comets that come with less fanfare than did Halley.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28149/1/0000601.pd

LV reverse remodeling imparted by aortic valve replacement for severe aortic stenosis; is it durable? A cardiovascular MRI study sponsored by the American Heart Association

<p>Abstract</p> <p>Background</p> <p>In patients with severe aortic stenosis (AS), long-term data tracking surgically induced effects of afterload reduction on reverse LV remodeling are not available. Echocardiographic data is available short term, but in limited fashion beyond one year. Cardiovascular MRI (CMR) offers the ability to serially track changes in LV metrics with small numbers due to its inherent high spatial resolution and low variability.</p> <p>Hypothesis</p> <p>We hypothesize that changes in LV structure and function following aortic valve replacement (AVR) are detectable by CMR and once triggered by AVR, continue for an extended period.</p> <p>Methods</p> <p>Tweny-four patients of which ten (67 ± 12 years, 6 female) with severe, but compensated AS underwent CMR pre-AVR, 6 months, 1 year and up to 4 years post-AVR. 3D LV mass index, volumetrics, LV geometry, and EF were measured.</p> <p>Results</p> <p>All patients survived AVR and underwent CMR 4 serial CMR's. LVMI markedly decreased by 6 months (157 ± 42 to 134 ± 32 g/m^<b>2</b>, p < 0.005) and continued trending downwards through 4 years (127 ± 32 g/m^<b>2</b>). Similarly, EF increased pre to post-AVR (55 ± 22 to 65 ± 11%,(p < 0.05)) and continued trending upwards, remaining stable through years 1-4 (66 ± 11 vs. 65 ± 9%). LVEDVI, initially high pre-AVR, decreased post-AVR (83 ± 30 to 68 ± 11 ml/m2, p < 0.05) trending even lower by year 4 (66 ± 10 ml/m^<b>2</b>). LV stroke volume increased rapidly from pre to post-AVR (40 ± 11 to 44 ± 7 ml, p < 0.05) continuing to increase non-significantly through 4 years (49 ± 14 ml) with these LV metrics paralleling improvements in NYHA. However, LVmass/volume, a 3D measure of LV geometry, remained unchanged over 4 years.</p> <p>Conclusion</p> <p>After initial beneficial effects imparted by AVR in severe AS patients, there are, as expected, marked improvements in LV reverse remodeling. Via CMR, surgically induced benefits to LV structure and function are durable and, unexpectedly express continued, albeit markedly incomplete improvement through 4 years post-AVR concordant with sustained improved clinical status. This supports down-regulation of both mRNA and MMP activity acutely with robust suppression long term.</p

Representations of sport in the revolutionary socialist press in Britain, 1988–2012

This paper considers how sport presents a dualism to those on the far left of the political spectrum. A long-standing, passionate debate has existed on the contradictory role played by sport, polarised between those who reject it as a bourgeois capitalist plague and those who argue for its reclamation and reformation. A case study is offered of a political party that has consistently used revolutionary Marxism as the basis for its activity and how this party, the largest in Britain, addresses sport in its publications. The study draws on empirical data to illustrate this debate by reporting findings from three socialist publications. When sport did feature it was often in relation to high profile sporting events with a critical tone adopted and typically focused on issues of commodification, exploitation and alienation of athletes and supporters. However, readers’ letters, printed in the same publications, revealed how this interpretation was not universally accepted, thus illustrating the contradictory nature of sport for those on the far left