Publications by authors named "Holmquist J"

Tidal marshes are threatened coastal ecosystems known for their capacity to store large amounts of carbon in their water-logged soils. Accurate quantification and mapping of global tidal marshes soil organic carbon (SOC) stocks is of considerable value to conservation efforts. Here, we used training data from 3710 unique locations, landscape-level environmental drivers and a global tidal marsh extent map to produce a global, spatially explicit map of SOC storage in tidal marshes at 30 m resolution.

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Article Synopsis
  • Tidal wetlands can absorb greenhouse gases, but methane emissions can vary due to environmental factors and human activities.
  • Land managers require detailed maps of methane properties in these wetlands for effective restoration and greenhouse gas inventories, yet current sampling methods don't align well with broader mapping products.
  • Research involved sampling 27 tidal wetlands, revealing that sulfate concentration is the strongest predictor of methane levels, while salinity also plays a significant role; future studies should focus on understanding local environmental influences on methane variation.
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Article Synopsis
  • * Annual CH fluxes averaged around 26g CH/m²/year; the highest emissions were linked with certain temperature and salinity conditions, particularly in fresh-oligohaline marshes.
  • * The research found that salinity was the main factor affecting annual CH fluxes, while temperature, gross primary productivity, and tidal height influenced shorter-term variability, providing crucial data for better estimating methane emissions in these ecosystems.
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Coastal terrestrial-aquatic interfaces (TAIs) are crucial contributors to global biogeochemical cycles and carbon exchange. The soil carbon dioxide (CO) efflux in these transition zones is however poorly understood due to the high spatiotemporal dynamics of TAIs, as various sub-ecosystems in this region are compressed and expanded by complex influences of tides, changes in river levels, climate, and land use. We focus on the Chesapeake Bay region to (i) investigate the spatial heterogeneity of the coastal ecosystem and identify spatial zones with similar environmental characteristics based on the spatial data layers, including vegetation phenology, climate, landcover, diversity, topography, soil property, and relative tidal elevation; (ii) understand the primary driving factors affecting soil respiration within sub-ecosystems of the coastal ecosystem.

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Quantifying carbon fluxes into and out of coastal soils is critical to meeting greenhouse gas reduction and coastal resiliency goals. Numerous 'blue carbon' studies have generated, or benefitted from, synthetic datasets. However, the community those efforts inspired does not have a centralized, standardized database of disaggregated data used to estimate carbon stocks and fluxes.

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Tidal marshes store large amounts of organic carbon in their soils. Field data quantifying soil organic carbon (SOC) stocks provide an important resource for researchers, natural resource managers, and policy-makers working towards the protection, restoration, and valuation of these ecosystems. We collated a global dataset of tidal marsh soil organic carbon (MarSOC) from 99 studies that includes location, soil depth, site name, dry bulk density, SOC, and/or soil organic matter (SOM).

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Rapid evolution remains a largely unrecognized factor in models that forecast the fate of ecosystems under scenarios of global change. In this work, we quantified the roles of heritable variation in plant traits and of trait evolution in explaining variability in forecasts of the state of coastal wetland ecosystems. A common garden study of genotypes of the dominant sedge , "resurrected" from time-stratified seed banks, revealed that heritable variation and evolution explained key ecosystem attributes such as the allocation and distribution of belowground biomass.

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Unlabelled: Tidal wetlands provide myriad ecosystem services across local to global scales. With their uncertain vulnerability or resilience to rising sea levels, there is a need for mapping flooding drivers and vulnerability proxies for these ecosystems at a national scale. However, tidal wetlands in the conterminous USA are diverse with differing elevation gradients, and tidal amplitudes, making broad geographic comparisons difficult.

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Purpose Of Review: Rates of obesity and reverse total shoulder arthroplasty (rTSA) in the USA have both escalated with time. Obese patients experience arthritis at higher rates than normal weight patients; therefore, these numbers go hand in hand. Obesity has been correlated with health comorbidities such as anxiety, cardiovascular disease, diabetes, and metabolic syndrome as well as poorer outcomes and higher complication rates following lower extremity arthroplasty.

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The aggregation of the amyloid beta (Aβ) protein into plaques is a pathological feature of Alzheimer's disease (AD). While amyloid aggregates have been extensively studied in vitro, their structural aspects and associated chemistry in the brain are not fully understood. In this report, we demonstrate, using infrared spectroscopic imaging, that Aβ plaques exhibit significant heterogeneities in terms of their secondary structure and phospholipid content.

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The objective of this evaluation was to evaluate the integration of behavioral health services at a freestanding birth center. Program evaluation included (1) retrospective health record reviews and (2) provider and client evaluation of satisfaction. In May 2017, an urban freestanding birth center initiated grant-funded integrated behavioral health services.

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Coastal wetlands (mangrove, tidal marsh and seagrass) sustain the highest rates of carbon sequestration per unit area of all natural systems, primarily because of their comparatively high productivity and preservation of organic carbon within sedimentary substrates. Climate change and associated relative sea-level rise (RSLR) have been proposed to increase the rate of organic-carbon burial in coastal wetlands in the first half of the twenty-first century, but these carbon-climate feedback effects have been modelled to diminish over time as wetlands are increasingly submerged and carbon stores become compromised by erosion. Here we show that tidal marshes on coastlines that experienced rapid RSLR over the past few millennia (in the late Holocene, from about 4,200 years ago to the present) have on average 1.

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A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

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Tidal wetlands produce long-term soil organic carbon (C) stocks. Thus for carbon accounting purposes, we need accurate and precise information on the magnitude and spatial distribution of those stocks. We assembled and analyzed an unprecedented soil core dataset, and tested three strategies for mapping carbon stocks: applying the average value from the synthesis to mapped tidal wetlands, applying models fit using empirical data and applied using soil, vegetation and salinity maps, and relying on independently generated soil carbon maps.

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We used a first-of-its-kind comprehensive scenario approach to evaluate both the vertical and horizontal response of tidal wetlands to projected changes in the rate of sea-level rise (SLR) across 14 estuaries along the Pacific coast of the continental United States. Throughout the U.S.

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California has experienced a dry 21(st) century capped by severe drought from 2012 through 2015 prompting questions about hydroclimatic sensitivity to anthropogenic climate change and implications for the future. We address these questions using a Holocene lake sediment record of hydrologic change from the Sierra Nevada Mountains coupled with marine sediment records from the Pacific. These data provide evidence of a persistent relationship between past climate warming, Pacific sea surface temperature (SST) shifts and centennial to millennial episodes of California aridity.

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Assessments of vertebrate disturbance to plant and animal assemblages often contrast grazed versus ungrazed meadows or other larger areas of usage, and this approach can be powerful. Random sampling of such habitats carries the potential, however, for smaller, more intensely affected patches to be missed and for other responses that are only revealed at smaller scales to also escape detection. We instead sampled arthropod assemblages and vegetation structure at the patch scale (400-900 m(2) patches) within subalpine wet meadows of Yosemite National Park (USA), with the goal of determining if there were fine-scale differences in magnitude and directionality of response at three levels of grazing intensity.

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Grazing management necessarily emphasizes the most spatially extensive vegetation assemblages, but landscapes are mosaics, often with more mesic vegetation types embedded within a matrix of drier vegetation. Our primary objective was to contrast effects of equine grazing on both subalpine vegetation structure and associated arthropods in a drier reed grass (Calamagrostis muiriana) dominated habitat versus a wetter, more productive sedge habitat (Carex utriculata). A second objective was to compare reed grass and sedge as habitats for fauna, irrespective of grazing.

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Conclusions regarding disturbance effects in high elevation or high latitude ecosystems based solely on infrequent, long-term sampling may be misleading, because the long winters may erase severe, short-term impacts at the height of the abbreviated growing season. We separated a) long-term effects of pack stock grazing, manifested in early season prior to stock arrival, from b) additional pack stock grazing effects that might become apparent during annual stock grazing, by use of paired grazed and control wet meadows that we sampled at the beginning and end of subalpine growing seasons. Control meadows had been closed to grazing for at least two decades, and meadow pairs were distributed across Sequoia National Park, California, USA.

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Background: Fairy shrimps (Anostraca), tadpole shrimps (Notostraca), clam shrimps (Spinicaudata), algae (primarily filamentous blue-green algae [cyanobacteria]), and suspended organic particulates are dominant food web components of the seasonally inundated pans and playas of the western Mojave Desert in California. We examined the extent to which these branchiopods controlled algal abundance and species composition in clay pans between Rosamond and Rogers Dry Lakes. We surveyed branchiopods during the wet season to estimate abundances and then conducted a laboratory microcosm experiment, in which dried sediment containing cysts and the overlying algal crust were inundated and cultured.

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Large dams degrade the integrity of a wide variety of ecosystems, yet direct downstream effects of dams have received the most attention from ecosystem managers and researchers. We investigated indirect upstream effects of dams resulting from decimation of migratory freshwater shrimp and fish populations in Puerto Rico, USA, in both high- and low-gradient streams. In high-gradient streams above large dams, native shrimps and fishes were extremely rare, whereas similar sites without large dams had high abundances of native consumers.

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A 20-year-old man developed a complete facial nerve paralysis following surgical reconstruction of the posterior ear canal with ionomeric cement. The paralysis developed gradually during the second and third postoperative weeks. Six weeks following the complete removal of the cement, the facial nerve recovered completely.

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The efficacy of hyaluronic acid when utilized in tympanoplasty was investigated in a multicenter, randomized, prospective patient blinded study. Of the 117 patients who completed the study, a majority (76) were treated with myringoplasty, 26 with myringoplasty combined with ossiculoplasty, and 15 with ossiculoplasty alone. The patients were evaluated by the operating surgeon up to 3 months following surgery, when the final assessment was made.

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Eustachian tube function and tympanoplasty.

Acta Otorhinolaryngol Belg

August 1991

104 ears with preoperative poor Eustachian tube (ET) function were analyzed 1-2 years after surgery in order to find out whether or not the ET function improves as a result of the surgical procedure. The majority of ears with poor preoperative ET function (77%) continue to have poor ET function after surgery as judged by tympanometry and ET function testings.

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