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Research mentoring programs are limited in many low- and middle-income countries (LMICs). The TDR Global initiated a global crowdsourcing open call soliciting proposals on how to improve research mentorship in LMICs. The purpose of this study is to examine ideas submitted to this open call to identify the ways to improve research mentorship in LMICs. Open calls have a group of individuals solve all or part of a problem and then share solutions. A WHO/TDR/SESH crowdsourcing guide was used to structure the open call. Each submission was judged by three independent individuals on a 1-10 scale. Textual submissions were extracted from eligible proposals and qualitatively analyzed via inductive and deductive coding techniques to identify themes. The open call received 123 submissions from 40 countries in Asia (49), Africa (38), Latin America (26), and Europe (10). Among all participants, 108 (87%) had research experience. A total of 21 submissions received a mean score of 7/10 or higher. Our thematic analysis identified three overarching themes related to prementoring, facilitation, and evaluation. Prementoring establishes mentor-mentee compatibility to lay foundations for mentorship. Facilitation involves iterative cycles of planning, communication, and skill improvement. Evaluation creates commitment and accountability within a framework of monitoring. This global crowdsourcing open call generated numerous mentorship ideas, including LMIC-contextualized facilitation tools. The open call demonstrates a need for greater focus on mentorship. Our data may inform the development of formal and informal mentoring programs in LMIC settings. Published version This study received support from the Special Programme for Research and Training in Tropical Diseases (TDR) and the US NIH (NIAID K24AI143471).

The current pandemic has generated the search for new reliable and economic alternatives for the detection of SARS-CoV-2, which produces the COVID-19 disease, one of the recommendations by the World Health Organization, is the detection of the virus by RT-qPCR methods from upper respiratory tract samples. The discomfort of the pharyngeal nasopharyngeal swab described by patients, the requirement of trained personnel, and the generation of aerosols, are factors that increase the risk of infections in this type of intake. It is known that the main means of transmission of SARS-CoV-2 is through aerosols or small droplets, which is why saliva is important as a relevant means of detecting COVID-19. In this study, a modified method based on SARS-CoV-2 RNA release from saliva is described, avoiding the isolation and purification of the genetic material and its quantification of viral copies; the results are compared with paired pharyngeal/nasopharyngeal swab samples (EF/EN). Results showed good agreement in saliva samples compared to EF/EN samples. On average, a sensitivity for virus detection of 80% was demonstrated in saliva samples competing with EF/EN samples. The use of saliva is a reliable alternative for the detection of SARS-CoV-2 by means of RT-PCR in the first days of infection, having important advantages over the conventional method. Saliva still needs to be studied completely to evaluate the detection capacity of the SARS-CoV-2 nucleic acid, however, the described process is viable, due to the decrease in materials and supplies, process times, the increment in the sampling and improvement of laboratory performance.

The experience of a lack of time due to an increasing burden of urgent tasks is one of the more common challenges created by digital communication media in the network society. This study develops the concept of chronemic urgency to explore urgent messaging using digital media. Chronemic urgency is the urgency users assign to messages received via a specific communication medium. Consistent with a communication perspective, the urgency is a function of both the relationship and the media. This study uses social entrainment theory and expectancy violations theory to conceptualize the chronemic urgency construct. This construct is then examined in a pilot study of the chronemic urgency 773 US-based participants assign to the communication media they use at least on a weekly basis. High chronemic urgency is assigned to messages received through media that (1) are used for urgent communication, (2) are checked more often, (3) are likely to be used by others who wish to contact the user urgently, and (4) are likely to lead to a quicker response. Despite the increasing centrality of urgency in everyday communication in the digital age, researchers and practitioners lack reliable methods to measure chronemic urgency in populations. The findings provide initial indications of levels of chronemic urgency in the US population’s everyday digital communication and create a foundation to better understand contemporary temporal phenomena.

Sea ice, an intrinsic component of the Arctic system, is undergoing rapid change. Sea ice dynamics play a role in the distributions of trace metals in Arctic waters through the incorporation, trans...

Atmospheric dust is an important source of the micronutrient Fe to the oceans. Although relatively insoluble mineral Fe is assumed to be the most important component of dust, a relatively small yet highly soluble anthropogenic component may also be significant. However, quantifying the importance of anthropogenic Fe to the global oceans requires a tracer which can be used to identify and constrain anthropogenic aerosols in situ. Here, we present Fe isotope (δ56Fe) data from North Atlantic aerosol samples from the GEOTRACES GA03 section. While soluble aerosol samples collected near the Sahara have near-crustal δ56Fe, soluble aerosols from near North America and Europe instead have remarkably fractionated δ56Fe values (as light as −1.6‰). Here, we use these observations to fingerprint anthropogenic combustion sources, and to refine aerosol deposition modeling. We show that soluble anthropogenic aerosol Fe flux to the global surface oceans is highly likely to be underestimated, even in the dusty North Atlantic., The relative importance of crustal vs. anthropogenic dust deposition for iron cycling in the surface ocean is unclear. Based on analysis of iron isotope data from North Atlantic aerosol samples, the authors can reveal the relative importance of anthropogenic iron emissions and its impact on marine biogeochemistry.

Atmospheric deposition is an important source of bioactive trace elements to the open ocean, but observations of this flux are sparse. Atmospheric deposition of aerosol iron is of particular interest as it can play an important role in supporting primary production in the global ocean, yet it represents a key uncertainty that hampers accurate numerical modeling of the marine iron cycle. We report concentrations of atmospheric trace elements from samples collected as part of the 2013 US GEOTRACES GP16 zonal transect of the eastern Pacific Ocean. The cruise transected a relatively dusty region which coincided with the Peruvian upwelling zone before entering the much less dusty region of the subtropical gyre. The aerosol chemical composition and elemental ratios indicate crustal sources for Al, Ti, V, Mn, and Fe while the analyses suggest that Cu, Cd, and Pb originate from anthropogenic emissions. Dry deposition fluxes were calculated by applying characteristic deposition velocities based on the expected particle size associated with each element. Bulk deposition, which includes wet and dry deposition, was calculated using the inventory of 7Be in the upper water column. Soluble aerosol iron flux estimates were compared with vertical iron fluxes within the water column to assess the relative importance of atmospheric deposition to the marine iron cycle in the region. Atmospheric deposition was insignificant relative to the upwelling input of iron in the areas near the continental sources but increased in relative importance seaward of the coastal upwelling zone even as the magnitude of deposition decreased away from the coast. This article is part of a special issue entitled: “Cycles of trace elements and isotopes in the ocean – GEOTRACES and beyond” - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. Gonzalez.

Data collected during the US Arctic GEOTRACES expedition in 2015 are used to estimate the mean residence time of dissolved trace elements (Fe, Mn, Ni, Cd, Zn, Cu, Pb, V) in surface water with respect to atmospheric deposition . The calculations utilize mixed layer trace element (TE) inventories, aerosol solubility determinations, and estimates of the atmospheric trace element flux into the upper ocean. The trace element flux is estimated by the product of the 7Be flux (determined by the ocean 7Be inventory) and the TE/7Be ratio of aerosols. This method has been established elsewhere and is tested here by comparing 7Be-derived TE flux to the measured TE accumulation in recently deposited snow. Given the variability in snow and aerosol TE concentration observed over the expedition, and the limited timescale of the observations, agreement between the two methods is reasonable. While there are assumptions in these calculations, the distribution of residence times with respect to atmospheric input across the expedition track informs us of additional sources or sinks for each element. The residence time of dissolved Fe was ~ 20–40 y for most stations. However, several stations that display a longer, oceanographically inconsistent apparent Fe residence time of ~300–500 years are likely influenced by additional input from the Transpolar Drift (TPD), which has been shown to convey shelf water properties to the central Arctic. This was seen for Cu, Ni and Zn as well. The flux of Fe delivered by the TPD was ~ 10 nmol/m2 /d for these stations, an order of magnitude greater than the soluble atmospheric input. On the other hand, V and Pb show a decrease in the apparent residence times within TPD water, suggesting removal of these elements from the source region of the TPD. For Mn, there is no obvious trend in residence time among the stations; however the apparent residence time (400–1400 y) is significantly greater than the ~20 y calculated for atmospheric input elsewhere, signifying appreciable input from other sources. It has been suggested that about 90% of Mn input to the Arctic Ocean originates from Arctic rivers, shelf sediments , and coastal erosion. Results here suggest a flux from these sources of ~30 nmol/m 2/d which is significantly greater than the atmospheric input of Mn in the Arctic.

Pacing structures are inherent in formal organizing, as R. McPhee and P. Zaug describe activity coordination as one of the several constitutive flows of organizing. This chapter considers how time scale and organizational temporality, more broadly, can function to include or exclude certain types of natural processes inherent in members’ experiences, particularly those processes that arise in and through their work. They do this through applying a temporal stewardship perspective to the question of inclusion/exclusion in contemporary work and consider each of the three components of their model, in turn: organizational effectiveness versus efficiency, wider participation, and more cognizant agency. When organizational norms and policies privilege exploration over exploitation and individuals tend toward processing (as opposed to avoiding) the physiological demands they face, slow processes will be included. In these cases, reintegration to homeostasis can be expected and even resilient reintegration is possible.

Melt ponds are a prominent feature of Arctic sea ice during the summer and play a role in the complex interface between the atmosphere, cryosphere and surface ocean. During melt pond formation and development, micronutrient and contaminant trace elements (TEs) from seasonally accumulated atmospheric deposition are mixed with entrained sedimentary and marine-derived material before being released to the surface ocean during sea ice melting. Here we present particulate and size-fractionated dissolved (truly soluble and colloidal) TE data from five melt ponds sampled in late summer 2015, during the US Arctic GEOTRACES (GN01) cruise. Analyses of salinity, δ18O, and 7Be indicate variable contributions to the melt ponds from snowmelt, melting sea ice, and surface seawater. Our data highlight the complex TE biogeochemistry of late summer Arctic melt ponds and the variable importance of different sources for specific TEs. Dissolved TE concentrations indicate a strong influence from seawater intrusion for V, Ni, Cu, Cd, and Ba. Ultrafiltration methods reveal dissolved Fe, Zn, and Pb to be mostly colloidal (0.003–0.2 μm), while Mn, Co, Ni, Cu, and Cd are dominated by a truly soluble (

International audience; Certification of trace metals in seawater certified reference materials (CRMs) NASS-7 and CASS-6 is described. At the National Research Council Canada (NRC), column separation was performed to remove the seawater matrix prior to the determination of Cd, Cr, Cu, Fe, Pb, Mn, Mo, Ni, U, V, and Zn, whereas As was directly measured in 10-fold diluted seawater samples, and B was directly measured in 200-fold diluted seawater samples. High-resolution inductively coupled plasma mass spectrometry (HR-ICPMS) was used for elemental analyses, with double isotope dilution for the accurate determination of B, Cd, Cr, Cu, Fe, Pb, Mo, Ni, U, and Zn in seawater NASS-7 and CASS-6, and standard addition calibration for As, Co, Mn, and V. In addition, all analytes were measured using standard addition calibration with triple quadrupole (QQQ)-ICPMS to provide a second set of data at NRC. Expert laboratories worldwide were invited to contribute data to the certification of trace metals in NASS-7 and CASS-6. Various analytical methods were employed by participants including column separation, co-precipitation, and simple dilution coupled to ICPMS detection or flow injection analysis coupled to chemiluminescence detection, with use of double isotope dilution calibration, matrix matching external calibration, and standard addition calibration. Results presented in this study show that majority of laboratories have demonstrated their measurement capabilities for the accurate determination of trace metals in seawater. As a result of this comparison, certified/reference values and associated uncertainties were assigned for 14 elements in seawater CRMs NASS-7 and CASS-6, suitable for the validation of methods used for seawater analysis.

The Northern Gulf of Alaska (NGA) shelf is a productive high-latitude environment where nutrient dynamics are greatly impacted by the seasonal variability in freshwater input. Iron is a key nutrient on the NGA shelf that directly modulates primary production, and freshwater is a major input of iron to the NGA shelf. However, variability in the input of dissolved iron from freshwater sources is obscured by high biological uptake and by the concentration of organic ligands, which bind iron and help maintain it in solution. Riverine inputs of other lithogenic elements such as aluminum and manganese are expected to behave quasi-conservatively on the NGA shelf and could help provide insight into the variability of iron input in this region. Here we present the seasonal (spring, summer, and fall) distribution of dissolved aluminum (dAl) and manganese (dMn) observed during 2018 and 2019 in the NGA region. Data were obtained during the NGA Long Term Ecological Research (LTER) site cruises and include several surface transects from Kayak Island to Kodiak Island, vertical profiles at several locations sparsely distributed throughout the shelf, and surface information from a Copper River plume study. We find that seasonal patterns in the surface concentrations of dMn and dAl mirrored annual glacial melt cycles, with the lowest values observed in spring and higher values in summer and fall. Sharp cross-shelf gradients were observed for both metals particularly in summer and fall. Surface concentrations decreased (by 1–2 orders of magnitude) away from the outflow of the Copper River, the major point source of freshwater within the NGA LTER site. Extremely high concentrations in the Copper River plume (≤1395 nM dAl, ≤128 nM dMn) and strong correlations with salinity (p = 7.9E-14 for dAl, 1.4E-14 for dMn) highlight the quasi-conservative nature of these metals within the plume. Enhanced dAl and dMn concentrations within nepheloid layers in subsurface waters indicate regions where a sedimentary source of iron could also be important. Residence times for dAl and dMn in surface waters over the NGA shelf were estimated to be 31 days (dAl) and 42 days (dMn) on average based on summer and fall data from both years.

The Gulf of Alaska (GoA) shelf is a highly productive regime bordering the nitrate-rich, iron (Fe)-limited waters of the central GoA. The exchange between nitrate-limited, Fe-replete coastal waters and nitrate-rich, Fe-deplete offshore waters, amplified by mesoscale eddies, is key to the productivity of the region. Previous summer field studies have observed the partitioning of Fe in the coastal GoA as being heavily dominated by the particulate phase due to the high suspended particulate loads carried by glacial rivers into these coastal waters. Here we present new physico-chemical iron data and nutrient data from the continental shelf of the GoA during spring and late summer 2011. The late summer data along the Seward Line showed variable surface dissolved iron (DFe) concentrations (0.052 nM offshore to 4.87 nM inshore), within the range of previous observations. Relative to available surface nitrate, DFe was in excess (at Fe:C=50 μmol:mol) inshore, and deficient (at Fe:C=20 μmol:mol) offshore. Summer surface total dissolvable iron (TDFe, acidified unfiltered samples) was dominated by the acid-labile particulate fraction over the shelf (with a median contribution of only 3% by DFe), supporting previously observed Fe partitioning in the GoA. In contrast, our spring data from southeast GoA showed TDFe differently partitioned, with surface DFe (0.28–4.91 nM) accounting on average for a much higher fraction (~25%) of the TDFe pool. Spring surface DFe was insufficient relative to available nitrate over much of the surveyed region (at Fe:C=50 μmol:mol). Organic Fe-binding ligand data reveal excess concentrations of ligands in both spring and summer, indicating incomplete titration by Fe. Excess concentrations of an especially strong-binding ligand class in spring surface waters may reflect in-situ ligand production. Due to anomalous spring conditions in 2011, river flow and phytoplankton biomass during our spring sampling were lower than the expected May average. We argue our samples are likely more representative of early spring pre-bloom conditions, providing an idea of the possible physico-chemical partitioning of Fe in coastal GoA waters relevant to initial spring bloom dynamics.

Trace element (TE) fluxes and their residence times (Fe, Mn, Cu, Pb, Cd, and V) within the surface ocean were determined along the GEOTRACES East Pacific Zonal Transect (GP16/EPZT) and found to reflect the diverse physical and geochemical conditions encountered across the track. The TE flux from atmospheric deposition, vertical mixing, and upwelling into the mixed layer and into the particle production zone (PPZ) along the GEOTRACES EPZT transect were evaluated with 7Be-based methods developed in earlier works. A horizontal input flux is driven from east to west by the South Equatorial Current (SEC), and estimated advection velocities were applied to horizontal gradients in the distributions of several TEs to approximate this term. There is a minimum in atmospheric deposition in the central gyre, with higher fluxes to the east due to large near-shore aerosol TE loadings, and higher to the west due to greater precipitation-driven deposition velocities (Vb). The 7Be-derived vertical diffusion (Kz) values range from 2.5 to 39 m2/d (0.29 × 10−4 to 4.5 × 10−4 m2/s) with higher values generally within the nearshore upwelling region and the lowest values within the stratified central gyre. Manganese displayed a well-defined gradient extending from the nearshore stations into the central gyre such that the advective term is a major component of the total input flux, particularly within the central gyre. Relative to other inputs the atmospheric input of soluble Mn is only of minor importance. Unlike Mn, there is no discernable horizontal gradient in the dissolved Fe data and therefore, there is no horizontal component of flux. Nearshore removal processes are more intense for dissolved Fe than for dissolved Mn and as a result, dissolved Mn remains elevated much farther offshore than does dissolved Fe. For the stratified mid-ocean gyre stations, the total input of Fe from all sources is relatively small compared to the inshore stations, and atmospheric deposition becomes the dominant mode of input. Aerosol Fe solubility determined by a 25% acetic acid leach with hydroxylamine hydrochloride was much greater than that derived from a leach using ultra-pure deionized water. This led to significant differences in the residence time of Fe calculated for the mid-ocean gyre using these different solubilities. Generally, each element displays relatively short (weeks–months) residence times within the nearshore region of robust upwelling, reflecting large input terms and rapid removal. Moving offshore, total input fluxes decrease and the residence times of the TEs increase markedly until the western edge of the transect. There, relaxation of ocean stratification permits greater upward turbulent flux and greater rainfall leads to greater atmospheric input of TEs.

The concentration of dissolved iron (DFe) and suspended leachable particulate iron (LPFe) in the water column of the western Beaufort Sea were investigated during the late summer of 2010. Elevated concentrations of surface DFe (0.49–1.42 nM) were similar to those reported in resent studies, likely reflecting input from melting sea ice and river discharge. The rapid decrease in DFe (5.20–0.48 nM) and LPFe (88.2–1.83 nM) values observed from inshore to offshore in Pacific influenced waters, suggest scavenging processes limit the input of DFe from the shelf to the deep basin. However, frequent eddies found in this region are likely important in promoting lateral advection, as suggested by higher surface DFe concentrations at an offshore station in the vicinity of a warm-core eddy. Within the Atlantic layer, relatively homogeneous DFe (0.69–0.80 nM) and LPFe (1.18–2.13 nM) concentrations were observed at all the stations, reflecting a balance in the interplay between input and removal processes within this watermass. An input of DFe east of the Lomonosov Ridge was inferred by comparing DFe values within the core of Atlantic water between the Eastern and Western Arctic.

Atmospheric deposition of trace elements and isotopes (TEI) is an important source of trace metals to the open ocean, impacting TEI budgets and distributions, stimulating oceanic primary productivity, and influenc ing biological community structure and function. Thus, accurate sampling of aerosol TEIs is a vital component of ongoing GEOTRACES cruises, and standardized aerosol TEI sampling and analysis procedures allow the com parison of data from different sites and investigators. Here, we report the results of an aerosol analysis intercal ibration study by seventeen laboratories for select GEOTRACES-relevant aerosol species (Al, Fe, Ti, V, Zn, Pb, Hg, NO 3 ‐ , and SO 4 2‐ ) for samples collected in September 2008. The collection equipment and filter substrates are appropriate for the GEOTRACES program, as evidenced by low blanks and detection limits relative to analyte concentrations. Analysis of bulk aerosol sample replicates were in better agreement when the processing proto col was constrained (± 9% RSD or better on replicate analyses by a single lab, n = 7) than when it was not (gen erally 20% RSD or worse among laboratories using different methodologies), suggesting that the observed vari ability was mainly due to methodological differences rather than sample heterogeneity. Much greater variabil ity was observed for fractional solubility of aerosol trace elements and major anions, due to differing extraction methods. Accuracy is difficult to establish without an SRM representative of aerosols, and we are developing an SRM for this purpose. Based on these findings, we provide recommendations for the GEOTRACES program to

Surface transects and vertical profiles of total and leachable particulate Fe, Mn, Al and P, along with dissolved and soluble Fe were obtained during August 2003 in the southeastern Bering Sea. High concentrations of leachable particulate Fe were observed in the bottom waters over the Bering Sea shelf with an unusually high percentage of the suspended particulate Fe being leachable. Leachable particulate Fe averaged 81% of total particulate Fe, and existed at elevated concentrations that averaged 23 times greater than dissolved Fe in the isolated cool pool waters over the mid shelf where substantial influence of sedimentary denitrification was apparent. The elevated leachable particulate Fe is suggested to be a result of sedimentary Fe reduction in surficial sediments, diffusion of Fe(II) from the sediments to the bottom waters, and subsequent oxidation and precipitation of reduced Fe in the overlying bottom waters. Eddies and meanders of the Bering Slope Current can mix this Fe-rich water into the Green Belt at the outer shelf-break front. Elevated levels of leachable particulate Fe were observed in surface waters near the Pribilof Islands where enhanced vertical mixing exists. Storm events and/or cooling during fall/winter with the resultant destruction of the thermally stratified two-layer system can also mix the subsurface water into surface waters where the elevated leachable particulate Fe is a substantial source of biologically available Fe.

Surface transects and vertical profiles of macronutrients, dissolved iron (D-Fe), and dissolved manganese (D-Mn) were investigated during August 2003 in the southeastern Bering Sea. We observed iron-limited, HNLC surface waters in the deep basin of the Bering Sea (15–20 μmol/kg nitrate, ∼0.07 nmol/kg D-Fe, and ⩽1.0 nmol/kg D-Mn); nitrate-limited, iron-replete surface waters over the shelf (

A sensitive flow injection method for determining iron in seawater developed by Measures et al. (1995) has been substantially modified to allow the direct preconcentration of dissolved iron in acidified seawater samples (pH 1.7) onto a nitrilotriacetic acid (NTA) chelating resin. This removes the need to adjust the pH and buffer samples before the preconcentration step, and the low pH eliminates potential interference from the presence of strong iron-binding organic ligands. As part of an international intercalibration exercise for the Sampling and Analysis of Fe (SAFe), we investigated at sea the precision and accuracy of this flow injection method with its preconcentration step plus catalytic spectrophotometric detection with N,N-dimethyl-p-phenylenediamine dihydrochloride (FI-NTA-DPD). Acidified seawater samples analyzed using FI-NTA-DPD were shown to be in excellent agreement with other shipand lab-based methods. The acidification of seawater samples to pH 1.7 is an important protocol if total dissolved iron in seawater is to be determined within hours of collection. A ship- and lab-based analytical intercomparison of two flow injection methods (FI-NTA-DPD and FI-NTA-ICP-SFMS) for the determination of total dissolved iron in seawater was carried out on SAFe samples collected from surface waters and at 1000 m depth from the North Pacific Ocean. For the two methods, total dissolved iron concentrations in surface samples were 0.101 ± 0.009 and 0.098 ± 0.009 nM, respectively, and in samples from 1000 m, 0.93 ± 0.04 and 0.92 ± 0.08 nM. No statistical difference between the FI-NTA-DPD and FI-NTA-ICP-SFMS methods was observed (P = 0.05).

The sensitive, laboratory- and ship-based, flow-injection (FI) method for the determination of dissolved manganese in seawater developed by Resing and Mottl (Anal. Chem. 1992;64:2682-2687) has been significantly modified and improved by incorporating five significant changes. The three major changes are the use of a commercially available iminodiacetate (IDA) resin (Toyopearl AF-chelate 650M) in place of 8-hydroxyquinoline for on-line preconcentration of manganese and matrix removal, the addition of nitrilotriacetic acid as an activator ligand which increases sensitivity by a factor of 7 and decreases the limit of detection, and the on-line buffering of acidified samples before column loading. Two minor improvements include use of the more soluble sodium periodate in place of potassium periodate and elimination of Brij-35 surfactant. To accommodate these changes, the pH of samples was adjusted to 8.5 (vs. 7.8), a higher acid concentration was required to elute the Mn from the IDA resin, and stronger reaction buffer was required to neutralize the acid. The accuracy of the method was evaluated with the use of NASS-4 standard seawater and by a comparison study of samples from the California coast that were analyzed by this method and an FI method coupled to inductively coupled plasma sector field mass spectrometry detection. The detection limit and precision of the method depend on the amount of sample preconcentrated onto the column. By preconcentrating 1.6 mL of sample, a detection limit of 0.03 nM (3 times the standard deviation of a blank) and precision of 3.2% (as percent relative standard deviation) were obtained. The method was used on board ship to determine dissolved manganese in coastal waters off Oregon and Washington.

The use of a commercially available chelating resin with NTA-type functional groups for concentration of trace metals from seawater is described. Trace metal recoveries from this NTA Superflow chelating resin are pH dependent. At a pH of ≤2 only iron(III) and copper are quantitatively recovered from the resin. Iron(II) cannot be quantitatively recovered from this resin below a pH of 5. However, oxidation of acidified seawater samples (pH 1.7) with H2O2 prior to loading onto the resin has been demonstrated to allow quantitative recovery of total dissolved iron. Deferrioxamine and Rhodoturlic Acid, two commercially available siderophores were used to investigate the effect of strong Fe(III)-binding organic ligands on the ability to retain iron at different pH values. Acidification of seawater samples to pH 1.7 dissociates the iron complexed to these organic ligands, thereby allowing total dissolved iron and copper to be determined. Acidified samples from Monterey Bay were analyzed by a flow injection method coupled to ICP-SFMS detection using the NTA Superflow resin in the pre-concentration step. Results from this study show that when seawater samples are stored acidified (pH 1.7) over time, a portion of iron(III) is reduced to iron(II), thus necessitating the use of H2O2 to reoxidize the Fe(II) to Fe(III) prior to analysis. Total dissolved concentrations of iron and copper can be directly obtained on seawater samples at pH 1.7 with this method, eliminating the need to buffer the sample to a higher pH prior to column loading. This resin has the potential to be used in shipboard or in situ flow injection methods.

[1] The Ross Sea polynya is among the most productive regions in the Southern Ocean and may constitute a significant oceanic CO2 sink. Based on results from several field studies, this region has been considered seasonally iron limited, whereby a “winter reserve” of dissolved iron (dFe) is progressively depleted during the growing season to low concentrations (∼0.1 nM) that limit phytoplankton growth in the austral summer (December–February). Here we report new iron data for the Ross Sea polynya during austral summer 2005–2006 (27 December–22 January) and the following austral spring 2006 (16 November–3 December). The summer 2005–2006 data show generally low dFe concentrations in polynya surface waters (0.10 ± 0.05 nM in upper 40 m, n = 175), consistent with previous observations. Surprisingly, our spring 2006 data reveal similar low surface dFe concentrations in the polynya (0.06 ± 0.04 nM in upper 40 m, n = 69), in association with relatively high rates of primary production (∼170–260 mmol C m−2 d−1). These results indicate that the winter reserve dFe may be consumed relatively early in the growing season, such that polynya surface waters can become “iron limited” as early as November; i.e., the seasonal depletion of dFe is not necessarily gradual. Satellite observations reveal significant biomass accumulation in the polynya during summer 2006–2007, implying significant sources of “new” dFe to surface waters during this period. Possible sources of this new dFe include episodic vertical exchange, lateral advection, aerosol input, and reductive dissolution of particulate iron.

[1] Concentrations of soluble ( 0.4 μm) and colloidal (0.025–0.4 μm) Fe size fractions were removed from surface waters within the inner and mid shelf. As a result the contribution of soluble Fe to the total Fe concentration increased from the inner shelf to the shelf break/slope waters. Surface water dissolved Fe concentrations on the northern GoA continental slope were higher than those previously observed in the central GoA gyre. Variations in surface water Fe concentrations from spring through summer appear to result from the changes in freshwater discharge and physical processes on the shelf.

[1] Factors influencing concentrations of nitrate, silicic acid, dissolved Fe, and dissolved Mn in the near-field Columbia River plume were examined during late spring and summer from 2004 to 2006 as part of the River Influences on Shelf Ecosystems program. Under upwelling-active phases, cold, high-nitrate coastal seawater was entrained in the plume, and nitrate concentrations of 16–19 μM were observed with as much as 90% from a coastal seawater origin. Under downwelling-relaxation phases, warm, nutrient-depleted coastal seawater was entrained forming a near-field plume with nitrate concentrations of 2.5–6 μM, with the river as the only source. Elevated silicic acid in the river is the dominant source, with concentrations of 60–80 μM in the near-field plume. During upwelling-active phases, high concentrations of dissolved Fe (as high as 40 nM) in the cold, low-oxygen, nutrient-rich coastal seawater were entrained to form a near-field plume with 15–20 nM dissolved Fe. During downwelling-relaxation phases, dissolved Fe in the intruding underlying warm coastal seawater was 1–3 nM, producing plume concentrations of 2–13 nM, with higher concentrations during the high river flow of May 2006. Dissolved Mn in the near-field plume covaried markedly as a function of increased tidal flushing in the estuary. The use of CORIE (pilot environmental observation and forecasting system for the Columbia River) time series conductivity-temperature-depth data within the estuary, along with data presented in this study, allows extrapolation of the near-field plume chemistry throughout the spring and summer seasons to provide insight into this important source of nutrients to the coastal waters in this region.

[1] Observational and modeling studies in the Bering Sea indicate that changes in the seasonal ice cover and time of ice retreat influence open-water productivity. In particular, the timing of the spring bloom and its phytoplankton community composition are affected. Dissolved iron (DFe) data in the water column and ice cores collected during the 2007- Bering Ecosystem Study (BEST) cruise indicate that the melting ice provided substantial DFe to the water column. The additional DFe input from melting sea ice could be biologically important along the outer shelf and shelf break where in ice-free areas insufficient DFe ( 20 μM). Variability in sea ice dynamics are likely to result in a varying supply of DFe to the outer shelf and shelf break in early spring, and to contribute to the observed changes in the timing and community composition of the spring phytoplankton bloom.

The aims of this study were to calculate concordance among results of the assessment of a population of neonates by using a screening version of neurologic assessment developed by our group with the Amiel-Tison examination, to evaluate distribution of the findings for each item in the studied population, and to develop an optimality score to aid in the detection of possible deviations in infants. Infants in this report include 107 infants born consecutively; they were mainly at-term infants, or preterm infants who, when reaching at-term corrected age, were suspected to be abnormal with a wide spectrum of complications. Newborns were tested by neurologic screening and neurologic examination. Agreement, correlations among tests, sensitivity, and specificity were calculated. Correlation among results from Neurological Screening and Neurological Examination was significant (rho = 0.759, p = 0.01), and Cronbach’s alpha concordance had an acceptable value (0.83). Sensitivity and specificity of neurologic screening after Amiel-Tison examination comparison were 0.98 and 0.82, respectively. Our results support the use of the neurologic screening proposed.