190 research outputs found

    Spatial distribution of water level impacting back-barrier bays

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aretxabaleta, A. L., Ganju, N. K., Defne, Z., & Signell, R. P. Spatial distribution of water level impacting back-barrier bays. Natural Hazards and Earth System Sciences, 19(8), (2019): 1823-1838, doi: 10.5194/nhess-19-1823-2019.Water level in semi-enclosed bays, landward of barrier islands, is mainly driven by offshore sea level fluctuations that are modulated by bay geometry and bathymetry, causing spatial variability in the ensuing response (transfer). Local wind setup can have a complementary role that depends on wind speed, fetch, and relative orientation of the wind direction and the bay. Bay area and inlet geometry and bathymetry primarily regulate the magnitude of the transfer between open ocean and bay. Tides and short-period offshore oscillations are more damped in the bays than longer-lasting offshore fluctuations, such as a storm surge and sea level rise. We compare observed and modeled water levels at stations in a mid-Atlantic bay (Barnegat Bay) with offshore water level proxies. Observed water levels in Barnegat Bay are compared and combined with model results from the Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) modeling system to evaluate the spatial structure of the water level transfer. Analytical models based on the dimensional characteristics of the bay are used to combine the observed data and the numerical model results in a physically consistent approach. Model water level transfers match observed values at locations inside the bay in the storm frequency band (transfers ranging from 50 %–100 %) and tidal frequencies (10 %–55 %). The contribution of frequency-dependent local setup caused by wind acting along the bay is also considered. The wind setup effect can be comparable in magnitude to the offshore transfer forcing during intense storms. The approach provides transfer estimates for locations inside the bay where observations were not available, resulting in a complete spatial characterization. An extension of the methodology that takes advantage of the ADCIRC tidal database for the east coast of the United States allows for the expansion of the approach to other bay systems. Detailed spatial estimates of water level transfer can inform decisions on inlet management and contribute to the assessment of current and future flooding hazard in back-barrier bays and along mainland shorelines.This work was supported by the US Geological Survey, Coastal and Marine Hazards/Resources Program

    Observations and a linear model of water level in an interconnected inlet-bay system

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 2760–2780, doi:10.1002/2016JC012318.A system of barrier islands and back-barrier bays occurs along southern Long Island, New York, and in many coastal areas worldwide. Characterizing the bay physical response to water level fluctuations is needed to understand flooding during extreme events and evaluate their relation to geomorphological changes. Offshore sea level is one of the main drivers of water level fluctuations in semienclosed back-barrier bays. We analyzed observed water levels (October 2007 to November 2015) and developed analytical models to better understand bay water level along southern Long Island. An increase (∼0.02 m change in 0.17 m amplitude) in the dominant M2 tidal amplitude (containing the largest fraction of the variability) was observed in Great South Bay during mid-2014. The observed changes in both tidal amplitude and bay water level transfer from offshore were related to the dredging of nearby inlets and possibly the changing size of a breach across Fire Island caused by Hurricane Sandy (after December 2012). The bay response was independent of the magnitude of the fluctuations (e.g., storms) at a specific frequency. An analytical model that incorporates bay and inlet dimensions reproduced the observed transfer function in Great South Bay and surrounding areas. The model predicts the transfer function in Moriches and Shinnecock bays where long-term observations were not available. The model is a simplified tool to investigate changes in bay water level and enables the evaluation of future conditions and alternative geomorphological settings.New York State Department of Environmental Conservation Grant Number: (NYS-DEC); U.S. Geological Survey (USGS

    Hydrologic controls of methane dynamics in Karst subterranean estuaries

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    Author Posting. © American Geophysical Union, 2019. 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 32(12), (2019): 1759-1775, doi:10.1029/2018GB006026.Karst subterranean estuaries (KSEs) extend into carbonate platforms along 12% of all coastlines. A recent study has shown that microbial methane (CH4) consumption is an important component of the carbon cycle and food web dynamics within flooded caves that permeate KSEs. In this study, we obtained high‐resolution (~2.5‐day) temporal records of dissolved methane concentrations and its stable isotopic content (δ13C) to evaluate how regional meteorology and hydrology control methane dynamics in KSEs. Our records show that less methane was present in the anoxic fresh water during the wet season (4,361 ± 89 nM) than during the dry season (5,949 ± 132 nM), suggesting that the wet season hydrologic regime enhances mixing of methane and other constituents into the underlying brackish water. The δ13C of the methane (−38.1 ± 1.7‰) in the brackish water was consistently more 13C‐enriched than fresh water methane (−65.4 ± 0.4‰), implying persistent methane oxidation in the cave. Using a hydrologically based mass balance model, we calculate that methane consumption in the KSE was 21–28 mg CH4·m−2·year−1 during the 6‐month dry period, which equates to ~1.4 t of methane consumed within the 102‐ to 138‐km2 catchment basin for the cave. Unless wet season methane consumption is much greater, the magnitude of methane oxidized within KSEs is not likely to affect the global methane budget. However, our estimates constrain the contribution of a critical resource for this widely distributed subterranean ecosystem.Funding for T. M. I. and D. B. was provided by TAMU‐CONACYT (project 2015‐049). D. B. was supported by the Research‐in‐Residence program (NSF award 1137336, Inter‐university Training in Continental‐scale Ecology), the Boost Fellowship (Texas A&M University at Galveston), and the Postdoctoral Scholar Program by Woods Hole Oceanographic Institution and U.S. Geological Survey. We thank Jacob Pohlman and István Brankovits for assistance with field expeditions. Special thanks to the late Bil Phillips (Speleotech) for the support and expertise provided us during field operations. We also thank Pete van Hengstum for productive discussions and guidance during the development of the manuscript. Michael Casso and Adrian Green helped with laboratory analyses. The manuscript was greatly improved by helpful comments from an anonymus reviewer, Jeff Chanton, and Meagan Gonneea. This work is contribution number UMCES 5541. Any use of trade names is for descriptive purposes and does not imply endorsement by the U.S. Government. The authors declare no competing financial interests. Archival data are available through the USGS ScienceBase‐Catalog at https://doi.org/10.5066/P9U0KRVM

    Tidal and groundwater fluxes to a shallow, microtidal estuary : constraining inputs through field observations and hydrodynamic modeling

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    This paper is not subject to U.S. copyright. The definitive version was published in Estuaries and Coasts 35 (2012): 1285-1298, doi:10.1007/s12237-012-9515-x.Increased nutrient loading to estuaries has led to eutrophication, degraded water quality, and ecological transformations. Quantifying nutrient loads in systems with significant groundwater input can be difficult due to the challenge of measuring groundwater fluxes. We quantified tidal and freshwater fluxes over an 8-week period at the entrance of West Falmouth Harbor, Massachusetts, a eutrophic, groundwater-fed estuary. Fluxes were estimated from velocity and salinity measurements and a total exchange flow (TEF) methodology. Intermittent cross-sectional measurements of velocity and salinity were used to convert point measurements to cross-sectionally averaged values over the entire deployment (index relationships). The estimated mean freshwater flux (0.19 m3/s) for the 8-week period was mainly due to groundwater input (0.21 m3/s) with contributions from precipitation to the estuary surface (0.026 m3/s) and removal by evaporation (0.048 m3/s). Spring–neap variations in freshwater export that appeared in shorter-term averages were mostly artifacts of the index relationships. Hydrodynamic modeling with steady groundwater input demonstrated that while the TEF methodology resolves the freshwater flux signal, calibration of the index– salinity relationships during spring tide conditions only was responsible for most of the spring–neap signal. The mean freshwater flux over the entire period estimated from the combination of the index-velocity, index–salinity, and TEF calculations were consistent with the model, suggesting that this methodology is a reliable way of estimating freshwater fluxes in the estuary over timescales greater than the spring– neap cycle. Combining this type of field campaign with hydrodynamic modeling provides guidance for estimating both magnitude of groundwater input and estuarine storage of freshwater and sets the stage for robust estimation of the nutrient load in groundwater.Funding was provided by the USGS Coastal and Marine Geology Program and by National Science Foundation Award #0420575 from the Biocomplexity/Coupled Biogeochemical Cycles Program

    Sediment transport-based metrics of wetland stability

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    Despite the importance of sediment availability on wetland stability, vulnerability assessments seldom consider spatiotemporal variability of sediment transport. Models predict that the maximum rate of sea level rise a marsh can survive is proportional to suspended sediment concentration (SSC) and accretion. In contrast, we find that SSC and accretion are higher in an unstable marsh than in an adjacent stable marsh, suggesting that these metrics cannot describe wetland vulnerability. Therefore, we propose the flood/ebb SSC differential and organic-inorganic suspended sediment ratio as better vulnerability metrics. The unstable marsh favors sediment export (18mgL(-1) higher on ebb tides), while the stable marsh imports sediment (12mgL(-1) higher on flood tides). The organic-inorganic SSC ratio is 84% higher in the unstable marsh, and stable isotopes indicate a source consistent with marsh-derived material. These simple metrics scale with sediment fluxes, integrate spatiotemporal variability, and indicate sediment sources

    Progress and challenges in coupled hydrodynamic-ecological estuarine modeling

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    © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Estuaries and Coasts 39 (2016): 311-332, doi:10.1007/s12237-015-0011-y.Numerical modeling has emerged over the last several decades as a widely accepted tool for investigations in environmental sciences. In estuarine research, hydrodynamic and ecological models have moved along parallel tracks with regard to complexity, refinement, computational power, and incorporation of uncertainty. Coupled hydrodynamic-ecological models have been used to assess ecosystem processes and interactions, simulate future scenarios, and evaluate remedial actions in response to eutrophication, habitat loss, and freshwater diversion. The need to couple hydrodynamic and ecological models to address research and management questions is clear because dynamic feedbacks between biotic and physical processes are critical interactions within ecosystems. In this review, we present historical and modern perspectives on estuarine hydrodynamic and ecological modeling, consider model limitations, and address aspects of model linkage, skill assessment, and complexity. We discuss the balance between spatial and temporal resolution and present examples using different spatiotemporal scales. Finally, we recommend future lines of inquiry, approaches to balance complexity and uncertainty, and model transparency and utility. It is idealistic to think we can pursue a “theory of everything” for estuarine models, but recent advances suggest that models for both scientific investigations and management applications will continue to improve in terms of realism, precision, and accuracy.NKG, ALA, and RPS acknowledge support from the USGS Coastal and Marine Geology Program. DKR gratefully acknowledges support from NSF (OCE-1314642) and NIEHS (1P50-ES021923-01). MJB and JMPV gratefully acknowledge support from NOAA NOS NCCOS (NA05NOS4781201 and NA11NOS4780043). MJB and SJL gratefully acknowledge support from the Strategic Environmental Research and Development Program—Defense Coastal/Estuarine Research Program (RC-1413 and RC-2245)

    Innovations in mental health services implementation: a report on state-level data from the U.S. Evidence-Based Practices Project

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    BACKGROUND: The Evidence-Based Practice (EBP) Project has been investigating the implementation of evidence-based mental health practices (Assertive Community Treatment, Family Psychoeducation, Integrated Dual Diagnosis Treatment, Illness Management and Recovery, and Supported Employment) in state public mental health systems in the United States since 2001. To date, Project findings have yielded valuable insights into implementation strategy characteristics and effectiveness. This paper reports results of an effort to identify and classify state-level implementation activities and strategies employed across the eight states participating in the Project. METHODS: Content analysis and Greenhalgh et al's (2004) definition of innovation were used to identify and classify state-level activities employed during three phases of EBP implementation: Pre-Implementation, Initial Implementation and Sustainability Planning. Activities were coded from site visit reports created from documents and notes from key informant interviews conducted during two periods, Fall 2002 – Spring 2003, and Spring 2004. Frequency counts and rank-order analyses were used to examine patterns of implementation activities and strategies employed across the three phases of implementation. RESULTS: One hundred and six discreet implementation activities and strategies were identified as innovative and were classified into five categories: 1) state infrastructure building and commitment, 2) stakeholder relationship building and communications, 3) financing, 4) continuous quality management, and 5) service delivery practices and training. Implementation activities from different categories were employed at different phases of implementation. CONCLUSION: Insights into effective strategies for implementing EBPs in mental health and other health sectors require qualitative and quantitative research that seeks to: a) empirically test the effects of tools and methods used to implement EBPs, and b) establish a stronger evidence-base from which to plan, implement and sustain such efforts. This paper offers a classification scheme and list of innovative implementation activities and strategies. The classification scheme offers potential value for future studies that seek to assess the effects of various implementation processes, and helps establish widely accepted standards and criteria that can be used to assess the value of innovative activities and strategies

    Principles and processes behind promoting awareness of rights for quality maternal care services: a synthesis of stakeholder experiences and implementation factors

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    BACKGROUND: Promoting awareness of rights is a value-based process that entails a different way of thinking and acting, which is at times misunderstood or deemed as aspirational. METHODS: Guided by the SURE framework, we undertook a secondary analysis of 26 documents identified by an earlier systematic review on promoting awareness of rights to increase use of maternity care services. We thematically analysed stakeholder experiences and implementation factors across the diverse initiatives to derive common elements to guide future efforts. RESULTS: Interventions that promote awareness of rights for maternal health varied in nature, methodological orientation, depth and quality. Materials included booklets, posters, pamphlets/ briefs and service standards/charters. Target populations included women, family members, communities, community structures, community-based and non governmental organizations, health providers and administrators, as well as elected representatives. While one initiative only focused on raising awareness, most were embedded within larger efforts to improve the accountability and responsiveness of service delivery through community monitoring and advocacy, with a few aiming to change policies and contest elections. Underlying these action oriented forms of promoting awareness of rights, was a critical consciousness and attitudinal change gained through iterative capacity-building for all stakeholders; materials and processes that supported group discussion and interaction; the formation or strengthening of community groups; situational analysis to ensure adaptation to local context; facilitation to ensure common ground and language across stakeholders; and strategic networking and alliance building across health system levels. While many positive experiences are discussed, few challenges or barriers to implementation are documented. The limited documentation and poor quality of information found indicate that while various examples of promoting awareness of rights for maternal health exists, research partnerships to systematically evaluate their processes, learning and effects are lacking. CONCLUSION: Rather than being aspirational, several examples of promoting awareness of women’s rights for quality maternity care services exist. More than mainly disseminate information, they aim to change stakeholder mindsets and relationships across health system levels. Due to their transformatory intent they require sustained investment, with strategic planning, concrete operationalization and political adeptness to manage dynamic stakeholder expectations and reactions overtime. More investment is also required in research partnerships that support such initiatives and better elucidate their context specific variations.ScopusIS

    Phase II study of the dual EGFR/HER3 inhibitor duligotuzumab (MEHD7945A) vs. cetuximab in combination with FOLFIRI in RAS wild-type metastatic colorectal cancer

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    PURPOSE: Duligotuzumab is a dual-action antibody directed against EGFR and HER3. EXPERIMENTAL DESIGN: mCRC patients with KRAS ex2 wild-type received duligotuzumab or cetuximab and FOLFIRI until progression or intolerable toxicity. Mandatory tumor samples underwent mutation and biomarker analysis. Efficacy analysis was conducted in patients with RAS exon 2/3 wild-type tumors. RESULTS: Of 134 randomized patients, 98 were RAS ex2/3 wild-type. Duligotuzumab provided no PFS or OR benefit compared to cetuximab; though there was a trend for lower ORR in the duligotuzumab arm. No relationship was seen between PFS or ORR and ERBB3, NRG1, or AREG expression. There were fewer skin rash events for duligotuzumab but more diarrhea. Although the incidence of grade ≥ 3 AEs was similar, the frequency of serious AEs was higher for duligotuzumab. CONCLUSIONS: Duligotuzumab plus FOLFIRI did not appear to improve the outcomes in patients with RAS exon 2/3 wild-type mCRC compared to cetuximab + FOLFIRI
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