Data report: solid-phase major and minor elements and iron and sulfur species in sediments of the Anholt Basin, Baltic Sea, collected during IODP Expedition 347

In this report, we present bulk solid-phase major and minor element contents and Fe and S species in sediments from Site M0060 in the Anholt Basin recovered during Integrated Ocean Drilling Program Expedition 347 to the Baltic Sea. Site M0060 is characterized by alternating sand- and clay-/silt-dominated sediment sequences that indicate deposition under brackish-marine and limnic conditions, respectively. We use Al-normalized elemental ratios and transition metal data to characterize the different sediment sequences and to study the impact of early diagenetic processes on the abundance and reactivity of Fe oxide and Fe sulfide mineral phases across lithologic boundaries. Ratios of Fe/Al and Mn/Al exceed the continental crustal average in the clay-/silt-dominated sequences, whereas low ratios are associated with the sandy units. About 10%–20% of the total bulk Fe content is associated with Fe oxides and Fe sulfides, whereas the major Fe fraction is bound in clay minerals. The transition metals (V, Ni, Cr, and Co) correlate with the depth profile of Fe/Al, which indicates that they are adsorbed onto Fe oxides and concomitantly deposited. Sequential leaching reveals that magnetite is the most abundant Fe oxide phase. Leached contents approach 1 wt% followed by crystalline and easily reducible Fe oxides. Pyrite is the dominant Fe sulfide phase and is enriched at several lithologic boundaries that can likely be associated with the formation of pyrite. Pyrite is formed through the reaction of Fe monosulfides with (1) polysulfides and/or S0 in zones dominated by organoclastic sulfate and Fe oxide reduction and (2) sulfide released during the anaerobic oxidation of methane

Reconstruction of the geochemical history of the Anholt Basin, Southern Kattegat, Baltic Sea

During the Integrated Ocean Drilling Program (IODP) Expedition 347 in 2013, sedimentary records were recovered in the Baltic Sea that cover the Eemian interglacial and Weichselian glacial periods. This non-steady state depositional system was characterized by shifts from limnic to brackish/marine phases over the glacial-interglacial cycle which has subjected the sample location in the Anholt Basin to profound changes in depositional and diagenetic conditions. Here, comprehensive pore-water and solid-phase data of sediments are presented and used to (1) geochemically characterize the different depositional environments, (2) identify key biogeochemical processes and (3) reveal the influence of the abundance and reactivity of metal oxide phases on the cycling of iron, manganese and sulfur and the formation of authigenic iron sulfides across depositional boundaries

Local and temporal variability of biogeochemical trace metal cycling in marine surface sediments

Trace metals such as Mo, U, and V are useful paleo-redox proxies because of their sensitivity to redox conditions and unique incorporation pathways into marine sediments. However, microbial processes can change the primary signal of specific trace metals that can record the environment at the time of deposition. To investigate the impact of microbial activity on trace metals during early diagenesis, geochemical analysis was performed via bag-incubations on samples collected from two giant box corers during RV SONNE Expedition SO260, funded by the MARUM-Center for Marine Environmental Sciences at the University of Bremen. The first core was taken at the head of the Mar del Plata Canyon, consists of mud to fine sand, and was sampled at five depths. The second core was taken on a coral mound, contains larger grains and abundant coral fragments, and was sampled at four depths. Four splits were taken at each depth; the first split was processed on-board, while splits 2-4 were stored in argon flushed aluminum bags at 4°C for processing and analysis every 4 months on-shore. Our data show strong changes in the pore-water trace metal concentrations in the first box core samples, with Mo increasing more than 5000 nM within 8 months. In samples from the second box core, pore-water Mo increases by more than 1000 nM in the first 4 months before decreasing likely due to the onset of sulfate reduction and, consequently, the formation of hydrogen sulfide leading to the (co-)precipitation of Mo. Our data indicate that the dissolution of iron and manganese oxides leads to the release of associated trace metals at different time points for each site. With comparable amounts of organic carbon at both sites, the observed changes are likely related to sediment composition and physical properties. The sediments sampled at the coral mound have a higher overall porosity and thus provide more space for fluid circulation and host microbial communities. This could explain the faster cycling of iron minerals, potential onset of sulfate reduction, and thus changes in the concentration of relevant trace metals. Therefore, our data suggest that trace metal cycling is not only related to the overall sediment composition, but also to physical properties including pore space, permeability, and grain size which affect how much area is available for microbial communities

Impact of physical properties on biogeochemical trace metal cycling in modern marine surface sediments of the Argentine Basin

Specific trace metal contents that can record the environment at the time of deposition are commonly applied as tracers (proxies) to reconstruct ancient oceanic conditions. However, microbial processes can alter the primary trace metal signal of the sediments during sediment burial. To investigate trace metal cycling during early diagenesis, geochemical analyses were performed via bag-incubations on samples collected from two giant box corers retrieved during RV SONNE Expedition SO260, funded by the MARUM-Center for Marine Environmental Sciences at the University of Bremen. The cores were retrieved off-shore Argentina, one from the head of the Mar del Plata Canyon and the other from a coral mound. Collected sediments are dominantly silt to fine grained sand but include dropstones and coral fragments as well. Our data show strong changes in the pore-water trace metal concentrations in the samples from the Mar del Plata Canyon. For example, molybdenum (Mo) increases by more than 5000 nM within 8 months. In samples from the coral mound box core, pore-water Mo increases by more than 1000 nM in the first 4 months before decreasing again likely due to the onset of sulfate reduction and, consequently, the formation of hydrogen sulfide leading to the (co-)precipitation of Mo. Our data indicate that the reductive dissolution of iron and manganese oxides leads to the release of associated trace metals at different time points for each site. The observed changes are likely related to sediment composition and physical properties. Sediments sampled at the coral mound site include coral fragments, increasing overall porosity and permeability providing more space for fluid circulation and to host microbial communities. Therefore, our data suggest that trace metal cycling is closely related to physical properties including pore space, permeability, and grain size that affect how much area is available for microbial communities

Telemedicine and Vascular Surgery: Expanding Access and Providing Care Through the COVID-19 Pandemic.

IntroductionAccess to surgical service is limited by provider availability and geographic barriers. Telemedicine ensures that patients can access medical care.ObjectiveThe objective is to describe our use of telemedicine in delivering vascular surgery services to remote locations before and during the COVID-19 pandemic.MethodsWe conducted a retrospective chart review analyzing care delivered at six vascular surgery telemedicine clinics over a 22-month period. We examined vascular diagnoses, recommended interventions, referrals placed, and emergency department visits within 30 days of evaluation. We calculated travel distance saved for patients between their local clinic and our main hospital.ResultsWe identified 94 patients and 144 telemedicine visits, with an average of 1.5 visits per patient (SD = 0.73). The most common referrals were for peripheral artery disease (20.2%) and abdominal aortic aneurysm (14.9%). Three patients were immediately referred to the emergency department due to concern for acute limb ischemia (2) or questionable symptomatic AAA (1). Telemedicine visit recommendations were distributed between no intervention (n = 30, 31.9%), medical management (n = 41, 43.6%), and surgical intervention (n = 23, 24.5%).The surgical intervention cohort was most commonly referred to arterial revascularization (n = 4), venous ablation (n = 4), and arteriovenous fistula procedures (n = 4). Fourteen patients came to our main hospital for surgery and four to local providers. Average travel distance saved per telemedicine visit was 104 miles (SD = 43.7).ConclusionsTelemedicine provided safe, efficient care during the COVID-19 pandemic and saved patients an average of 104 travel miles per visit

Tropical Pacific climate variability over the last 6000 years as recorded in Bainbridge Crater Lake, Galápagos.

Finely laminated sediments within Bainbridge Crater Lake, Galápagos provide a record of El Niño-Southern Oscillation (ENSO) events over the Holocene. Despite the importance of this sediment record, hypotheses for how climate variability is preserved in the lake sediments have not been tested. Here we present results of long-term monitoring of the local climate and limnology and a revised interpretation of the sediment record. Brown-green, organic rich, siliciclastic laminae reflect warm, wet conditions typical of El Niño events, whereas carbonate and gypsum precipitate during cool, dry La Niña events and persistent dry periods, respectively. Applying this new interpretation, we find ENSO events of both phases were generally less frequent during the mid-Holocene (~6100-4000 cal. years BP) relative to the last ~1500 cal. years. Abundant carbonate laminations between 3500 and 3000 cal. years BP imply that conditions in the Galápagos region were cool and dry during this period when the tropical Pacific E-W SST gradient likely strengthened. The frequency of El Niño and La Niña events then intensified dramatically around 1750-2000 cal. years BP, consistent with a weaker SST gradient and an increased frequency of ENSO events in other regional records. This strong interannual variability persisted until ~700 cal. years BP, when ENSO-related variability at the lake decreased as the SST gradient strengthened. Persistent, dry conditions then dominated between 300 and 50 cal. years BP (AD 1650-1900, ± ~100 years), whereas wetter conditions and frequent El Niño events dominated in the most recent century

The LHCb upgrade I

International audienceThe LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software