Hydrological and ecological observations along the eastern Beaufort Sea coast of Alaska

The US Beaufort Sea coast is fringed by barrier islands, which enclose numerous bays and lagoons that provide habitat for migratory fish and waterfowl that are essential to the subsistence and culture of Iñupiat communities of northern Alaska. In the eastern Beaufort, in particular, residents of Kaktovik rely heavily on the high benthic productivity of these lagoon systems to support the fish and bird populations that they depend on for subsistence. We monitored aspects of hydrology and ecology in several lagoons in the eastern Alaskan Beaufort Sea coast from 2011 to 2014. Our hydrographic data from continuous in situ measurements of temperature and salinity revealed that lagoons possess unique regimes that vary seasonally and reflect unique hydrologic and geomorphic characteristics. H2O-δ18O and salinity measurements revealed that meteoric water is the dominant source of low-salinity water in all lagoons in June and August, though sea ice melt water was also present. Most differences among lagoons were caused by variation in circulation and connection to adjacent marine waters. We also used stable C and N isotopic analysis to determine trophic structure and assess dependence of fauna on terrestrial (CT) vs. marine sources of carbon, with particular focus on animals widely used by local subsistence hunters. Our mixing model results suggest that terrestrial carbon (CT) may be assimilated by upper trophic level consumers, though marine-derived C sources dominate. For example, 15 - 70% of polar bear and 0 - 60% of beluga whale carbon was of terrestrial origin. Our results suggest that 1) CT assimilated by benthic omnivorous invertebrates is transferred to the highest trophic levels in the Beaufort Sea, and 2) arctic cod are the most likely intermediary for transferring CT from lower to upper trophic levels.Marine Scienc

Lack of Correlation Between Pulmonary Disease and Cystic Fibrosis Transmembrane Conductance Regulator Dysfunction in Cystic Fibrosis: A Case Report

Introduction: Mutations in both alleles of the cystic fibrosis transmembrane conductance regulator gene result in the disease cystic fibrosis, which usually manifests as chronic sinopulmonary disease, pancreatic insufficiency, elevated sodium chloride loss in sweat, infertility among men due to agenesis of the vas deferens and other symptoms including liver disease. Case presentation: We describe a pair of African-American brothers, aged 21 and 27, with cystic fibrosis. They were homozygous for a rare frameshift mutation in the cystic fibrosis transmembrane conductance regulator 3791delC, which would be expected to cause significant morbidity. Although 80% of cystic fibrosis patients are colonized with Pseudomonas aeruginosa by eight years of age, the older brother had no serum opsonic antibody titer to P. aeruginosa by age 13 and therefore would have failed to mount an effective antibody response to the alginate (mucoid polysaccharide) capsule of P. aeruginosa. He was not colonized with P. aeruginosa until 24 years of age. Similarly, the younger brother was not colonized with P. aeruginosa until age 20 and had no significant lung disease. Conclusion: Despite a prevailing idea in cystic fibrosis research that the amount of functional cystic fibrosis transmembrane conductance regulator predicts clinical status, our results indicated that respiratory disease severity in cystic fibrosis exhibits phenotypic heterogeneity. If this heterogeneity is, in part, genetic, it is most likely derived from genes outside the cystic fibrosis transmembrane conductance regulator locus

Forces associated with launch into space do not impact bone fracture healing

Segmental bone defects (SBDs) secondary to trauma invariably result in a prolonged recovery with an extended period of limited weight bearing on the affected limb. Soldiers sustaining blast injuries and civilians sustaining high energy trauma typify such a clinical scenario. These patients frequently sustain composite injuries with SBDs in concert with extensive soft tissue damage. For soft tissue injury resolution and skeletal reconstruction a patient may experience limited weight bearing for upwards of 6 months. Many small animal investigations have evaluated interventions for SBDs. While providing foundational information regarding the treatment of bone defects, these models do not simulate limited weight bearing conditions after injury. For example, mice ambulate immediately following anesthetic recovery, and in most cases are normally ambulating within 1-3 days post-surgery. Thus, investigations that combine disuse with bone healing may better test novel bone healing strategies. To remove weight bearing, we have designed a SBD rodent healing study in microgravity (µG) on the International Space Station (ISS) for the Rodent Research-4 (RR-4) Mission, which launched February 19, 2017 on SpaceX CRS-10 (Commercial Resupply Services). In preparation for this mission, we conducted an end-to-end mission simulation consisting of surgical infliction of SBD followed by launch simulation and hindlimb unloading (HLU) studies. In brief, a 2 mm defect was created in the femur of 10 week-old C57BL6/J male mice (n = 9-10/group). Three days after surgery, 6 groups of mice were treated as follows: 1) Vivarium Control (maintained continuously in standard cages); 2) Launch Negative Control (placed in the same spaceflight-like hardware as the Launch Positive Control group but were not subjected to launch simulation conditions); 3) Launch Positive Control (placed in spaceflight-like hardware and also subjected to vibration followed by centrifugation); 4) Launch Positive Experimental (identical to Launch Positive Control group, but placed in qualified spaceflight hardware); 5) Hindlimb Unloaded (HLU, were subjected to HLU immediately after launch simulation tests to simulate unloading in spaceflight); and 6) HLU Control (single housed in identical HLU cages but not suspended). Mice were euthanized 28 days after launch simulation and bone healing was examined via micro-Computed Tomography (µCT). These studies demonstrated that the mice post-surgery can tolerate launch conditions. Additionally, forces and vibrations associated with launch did not impact bone healing (p = .3). However, HLU resulted in a 52.5% reduction in total callus volume compared to HLU Controls (p = .0003). Taken together, these findings suggest that mice having a femoral SBD surgery tolerated the vibration and hypergravity associated with launch, and that launch simulation itself did not impact bone healing, but that the prolonged lack of weight bearing associated with HLU did impair bone healing. Based on these findings, we proceeded with testing the efficacy of FDA approved and novel SBD therapies using the unique spaceflight environment as a novel unloading model on SpaceX CRS-10

The MOSAiC ice floe: Sediment-laden survivor from the Siberian shelf

In September 2019, the research icebreaker Polarstern started the largest multidisciplinary Arctic expedition to date, the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) drift experiment. Being moored to an ice floe for a whole year, thus including the winter season, the declared goal of the expedition is to better understand and quantify relevant processes within the atmosphere-ice-ocean system that impact the sea ice mass and energy budget, ultimately leading to much improved climate models. Satellite observations, atmospheric reanalysis data, and readings from a nearby meteorological station indicate that the interplay of high ice export in late winter and exceptionally high air temperatures resulted in the longest ice-free summer period since reliable instrumental records began. We show, using a Lagrangian tracking tool and a thermodynamic sea ice model, that the MOSAiC floe carrying the Central Observatory (CO) formed in a polynya event north of the New Siberian Islands at the beginning of December 2018. The results further indicate that sea ice in the vicinity of the CO ( \u3c 40 km distance) was younger and 36 % thinner than the surrounding ice with potential consequences for ice dynamics and momentum and heat transfer between ocean and atmosphere. Sea ice surveys carried out on various reference floes in autumn 2019 verify this gradient in ice thickness, and sediments discovered in ice cores (so-called dirty sea ice) around the CO confirm contact with shallow waters in an early phase of growth, consistent with the tracking analysis. Since less and less ice from the Siberian shelves survives its first summer (Krumpen et al., 2019), the MOSAiC experiment provides the unique opportunity to study the role of sea ice as a transport medium for gases, macronutrients, iron, organic matter, sediments and pollutants from shelf areas to the central Arctic Ocean and beyond. Compared to data for the past 26 years, the sea ice encountered at the end of September 2019 can already be classified as exceptionally thin, and further predicted changes towards a seasonally ice-free ocean will likely cut off the long-range transport of ice-rafted materials by the Transpolar Drift in the future. A reduced long-range transport of sea ice would have strong implications for the redistribution of biogeochemical matter in the central Arctic Ocean, with consequences for the balance of climate-relevant trace gases, primary production and biodiversity in the Arctic Ocean

The MOSAiC ice floe: sediment-laden survivor from the Siberian shelf

In September 2019, the research icebreaker Polarstern started the largest multidisciplinary Arctic expedition to date, the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) drift experiment. Being moored to an ice floe for a whole year, thus including the winter season, the declared goal of the expedition is to better understand and quantify relevant processes within the atmosphere–ice–ocean system that impact the sea ice mass and energy budget, ultimately leading to much improved climate models. Satellite observations, atmospheric reanalysis data, and readings from a nearby meteorological station indicate that the interplay of high ice export in late winter and exceptionally high air temperatures resulted in the longest ice-free summer period since reliable instrumental records began. We show, using a Lagrangian tracking tool and a thermodynamic sea ice model, that the MOSAiC floe carrying the Central Observatory (CO) formed in a polynya event north of the New Siberian Islands at the beginning of December 2018. The results further indicate that sea ice in the vicinity of the CO (<40 km distance) was younger and 36 % thinner than the surrounding ice with potential consequences for ice dynamics and momentum and heat transfer between ocean and atmosphere. Sea ice surveys carried out on various reference floes in autumn 2019 verify this gradient in ice thickness, and sediments discovered in ice cores (so-called dirty sea ice) around the CO confirm contact with shallow waters in an early phase of growth, consistent with the tracking analysis. Since less and less ice from the Siberian shelves survives its first summer (Krumpen et al., 2019), the MOSAiC experiment provides the unique opportunity to study the role of sea ice as a transport medium for gases, macronutrients, iron, organic matter, sediments and pollutants from shelf areas to the central Arctic Ocean and beyond. Compared to data for the past 26 years, the sea ice encountered at the end of September 2019 can already be classified as exceptionally thin, and further predicted changes towards a seasonally ice-free ocean will likely cut off the long-range transport of ice-rafted materials by the Transpolar Drift in the future. A reduced long-range transport of sea ice would have strong implications for the redistribution of biogeochemical matter in the central Arctic Ocean, with consequences for the balance of climate-relevant trace gases, primary production and biodiversity in the Arctic Ocean

On the origins of crenarchaeol: environmental controls on an enigmatic archaeal lipid in hot springs

Glycerol dibiphytanyl glycerol tetraethers (GDGTs) are membrane-spanning lipids of archaea that are ubiquitous in hot spring, ocean, lake, and soil environments. These lipids allow for microbial acclimatization to environmental stress and serve as the basis for important paleotemperature proxies. The number of cyclopentyl rings in the core structure of archaeal GDGTs change in response to temperature, pH, and oxidant load in both environmental samples and in cultured marine and acidophilic hot spring strains. Archaea from acidic hot springs can produce GDGT moieties with up to eight cyclopentyl rings (GDGT-0 to -8). Biophysical models show that synthesizing more cyclopentyl rings promotes tighter membrane packing and decreased permeability, enabling archaea to occupy hotter, more acidic, and more oxidizing environments. A unique GDGT found in both marine and hot spring archaea, crenarchaeol, contains four cyclopentyl and one cyclohexyl ring. While the function of this lipid in archaeal membranes is not well understood, it has been proposed that the cyclohexyl ring allowed archaea adapted to acidic, high temperature hot springs to adapt to cooler and circumneutral waters, eventually allowing for diversification into oceanic environments. To improve the understanding of crenarchaeol’s function in membranes, its role in archaeal evolution, and its distribution in the geologic record, we quantify the relationship between pH, temperature, redox, and other parameters with crenarchaeol abundance in the natural thermal springs of Yellowstone National Park, where these parameters vary widely. We evaluate our data in the context of a comprehensive compilation of previously reported GDGT data from hot spring environments, focusing particularly on crenarchaeol, to examine the environmental factors that likely control its distribution. These results shed new light on the role of crenarchaeol in the diversification of archaea into lower temperature, circumneutral environments.https://digitalcommons.dartmouth.edu/wetterhahn_2023/1003/thumbnail.jp

Nutrient gradients in Panamanian estuaries : effects of watershed deforestation, rainfall, upwelling, and within-estuary transformations

Author Posting. © Inter-Research, 2013. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 492 (2013): 1-15, doi:10.3354/meps10358.To test whether deforestation of tropical forests alters coupling of watersheds, estuaries, and coastal waters, we measured nutrients in 8 watershed-estuarine systems on the Pacific coast of Panama where watershed forest cover ranged from 23 to 92%. Watersheds with greater forest cover discharged larger dissolved inorganic nitrogen concentrations and higher N/P into estuary headwaters. As freshwater mixed with seawater down-estuary, within-estuary biogeochemical processes erased the imprint of watershed deforestation, increased ammonium, lowered nitrate concentrations, and otherwise altered down-estuary water column composition. As estuarine water left mangrove estuaries, ammonium, nitrate, and phosphate, but not dissolved organic nitrogen, were exported to receiving near-shore waters. Mangrove estuaries in this region thus provide important ecological services, by uncoupling coastal waters from changes in terrestrial land covers, as well as by subsidizing adjoined receiving coastal waters by providing nutrients. The pattern of land-sea coupling and exports was disrupted during La Niña-influenced conditions. In one instance when La Niña conditions led to upwelling of deeper layers, high concentrations of marine-derived ammonium were inserted into estuaries. In another instance, La Niña-associated high rainfall diluted nutrient concentrations within estuaries and lowered salinity regionally, and the fresher upper layer impaired coastal upwelling. Regional rainfall has increased during the last decade. If La Niña rainfall continues to increase, disruptions of current land-estuary-sea couplings may become more frequent, with potentially significant changes in nutrient cycles and ecological services in these coupled ecosystems.This work was made possible by US NSF grant BIO-0842413

Searching for the impact of participation in health and health research: challenges and methods

Internationally, the interest in involving patients and the public in designing and delivering health interventions and researching their effectiveness is increasing. Several systematic reviews of participation in health research have recently been completed, which note a number of challenges in documenting the impact of participation. Challenges include working across stakeholders with different understandings of participation and levels of experience in reviewing; comparing heterogeneous populations and contexts; configuring findings from often thin descriptions of participation in academic papers; and dealing with different definitions of impact. This paper aims to advance methods for systematically reviewing the impact of participation in health research, drawing on recent systematic review guidance. Practical examples for dealing with issues at each stage of a review are provided based on recent experience. Recommendations for improving primary research on participation in health are offered and key points to consider during the review are summarised

Increased rainfall remarkably freshens estuarine and coastal waters on the Pacific coast of Panama: Magnitude and likely effects on upwelling and nutrient supply.

Increased intensity of rainfall events during late 2010 led to a remarkable freshening of estuarine, near- and off-shore waters in coastal Pacific Panama. The increased rain intensity during the wet season of 2010 lowered salinity of estuarine and coastal waters to levels unprecedented in previous years. Fresher conditions were most marked within estuaries, but even at 6 km from shore, salinities were 8–13‰ lower during the 2010 wet season, compared to a lowering of up to 2‰ during previous wet seasons. Freshwater added to surface waters by rain had major biological, hydrodynamic, and biogeochemical consequences, increasing stream erosion, uprooting stream-edge terrestrial and mangrove trees, increasing mortality of benthic fauna, damping upwelling of denser, nutrient-rich water that was expected given the contemporaneous most intense La Niña in decades, as well as by enriching surface seawater by direct deposition and by horizontal advection of nutrients from land. It appears that wet season rainfall is slowly increasing in the region, and if the level of rainfall reported here is a harbinger of future climate change effects on land-sea couplings in tropical coastal ecosystems, the resulting freshening could significantly shift biogeochemistry and coastal food webs in the region and elsewhere.Fil: Valiela, Ivan. Marine Biological Laboratory; Estados UnidosFil: Camilli, Luis. Woods Hole Oceanographic Institution; Estados UnidosFil: Stone, Thomas. Woods Hole Research Center; Estados UnidosFil: Giblin, Anne. Marine Biological Laboratory; Estados UnidosFil: Crusius, John. University of Washington; Estados UnidosFil: Fox, Sophia. No especifíca;Fil: Barth Jensen, Coralie. Marine Biological Laboratory; Estados UnidosFil: Oliveira Monteiro, Rita. Marine Biological Laboratory; Estados UnidosFil: Tucker, Jane. Marine Biological Laboratory; Estados UnidosFil: Martinetto, Paulina Maria del Rosario. 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: Harris, Carolynn. Marine Biological Laboratory; Estados Unido