501 research outputs found

    Value Based Outline: Transitioning from features and output to impact and outcome

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    USNH 2022 Virtual Lean Summit presentation

    Benthic oxygen exchange in a live coralline algal bed and an adjacent sandy habitat: an eddy covariance study

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    Coralline algal (maerl) beds are widespread, slow-growing, structurally complex perennial habitats that support high biodiversity, yet are significantly understudied compared to seagrass beds or kelp forests. We present the first eddy covariance (EC) study on a live maerl bed, assessing the community benthic gross primary productivity (GPP), respiration (R), and net ecosystem metabolism (NEM) derived from diel EC time series collected during 5 seasonal measurement campaigns in temperate Loch Sween, Scotland. Measurements were also carried out at an adjacent (~20 m distant) permeable sandy habitat. The O2 exchange rate was highly dynamic, driven by light availability and the ambient tidally-driven flow velocity. Linear relationships between the EC O2 fluxes and available light indicate that the benthic phototrophic communities were lightlimited. Compensation irradiance (Ec) varied seasonally and was typically ~1.8-fold lower at the maerl bed compared to the sand. Substantial GPP was evident at both sites; however, the maerl bed and the sand habitat were net heterotrophic during each sampling campaign. Additional inputs of ~4 and ~7 mol m-2 yr-1 of carbon at the maerl bed and sand site, respectively, were required to sustain the benthic O2 demand. Thus, the 2 benthic habitats efficiently entrap organic carbon and are sinks of organic material in the coastal zone. Parallel deployment of 0.1 m2 benthic chambers during nighttime revealed O2 uptake rates that varied by up to ~8-fold between replicate chambers (from -0.4 to -3.0 mmol O2 m-2 h-1; n = 4). However, despite extensive O2 flux variability on meter horizontal scales, mean rates of O2 uptake as resolved in parallel by chambers and EC were typically within 20% of one another

    Dynamics of rising CO\u3csub\u3e2\u3c/sub\u3e bubble plumes in the QICS field experiment: Part 1 - The experiment

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    © 2015 The Authors. Published by Elsevier Ltd. The dynamic characteristics of CO2 bubbles in Scottish seawater are investigated through observational data obtained from the QICS project. Images of the leaked CO2 bubble plume rising in the seawater were captured. This observation made it possible to discuss the dynamics of the CO2 bubbles in plumes leaked in seawater from the sediments. Utilising ImageJ, an image processing program, the underwater recorded videos were analysed to measure the size and velocity of the CO2 bubbles individually. It was found that most of the bubbles deform to non-spherical bubbles and the measured equivalent diameters of the CO2 bubbles observed near the sea bed are to be between 2 and 12 mm. The data processed from the videos showed that the velocities of 75% of the leaked CO2 bubbles in the plume are in the interval 25-40 cm/s with Reynolds numbers (Re) 500-3500, which are relatively higher than those of an individual bubble in quiescent water. The drag coefficient C d is compared with numerous laboratory investigations, where agreement was found between the laboratory and the QICS experimental results with variations mainly due to the plume induced vertical velocity component of the seawater current and the interactions between the CO2 bubbles (breakup and coalescence). The breakup of the CO2 bubbles has been characterised and defined by Eötvös number, Eo, and Re

    Marine baseline and monitoring strategies for Carbon Dioxide Capture and Storage (CCS)

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    The QICS controlled release experiment demonstrates that leaks of carbon dioxide (CO2) gas can be detected by monitoring acoustic, geochemical and biological parameters within a given marine system. However the natural complexity and variability of marine system responses to (artificial) leakage strongly suggests that there are no absolute indicators of leakage or impact that can unequivocally and universally be used for all potential future storage sites. We suggest a multivariate, hierarchical approach to monitoring, escalating from anomaly detection to attribution, quantification and then impact assessment, as required. Given the spatial heterogeneity of many marine ecosystems it is essential that environmental monitoring programmes are supported by a temporally (tidal, seasonal and annual) and spatially resolved baseline of data from which changes can be accurately identified. In this paper we outline and discuss the options for monitoring methodologies and identify the components of an appropriate baseline survey

    Local perceptions of the QICS experimental offshore CO2 release: results from social science research.

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    This paper explores the social dimensions of an experimental release of carbon dioxide (CO2) carried out in Ardmucknish Bay, Argyll, United Kingdom. The experiment, which aimed to understand detectability and potential effects on the marine environment should there be any leakage from a CO2 storage site, provided a rare opportunity to study the social aspects of a carbon dioxide capture and storage-related event taking place in a lived-in environment. Qualitative research was carried out in the form of observation at public information events about the release, in-depth interviews with key project staff and local stakeholders/community members, and a review of online media coverage of the experiment. Focusing mainly on the observation and interview data, we discuss three key findings: the role of experience and analogues in learning about unfamiliar concepts like CO2 storage; the challenge of addressing questions of uncertainty in public engagement; and the issue of when to commence engagement and how to frame the discussion. We conclude that whilst there are clearly slippages between a small-scale experiment and full-scale CCS, the social research carried out for this project demonstrates that issues of public and stakeholder perception are as relevant for offshore CO2 storage as they are for onshore

    Phosphorus behavior in sediments during a sub-seabed CO\u3csub\u3e2\u3c/sub\u3e controlled release experiment

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    © 2015 Elsevier Ltd. The CO2 controlled release experiment Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS) assessed the impacts of potential CO2 leakage from sub-seabed carbon capture and storage reservoirs to the marine environment. During QICS, CO2 gas was released into shallow sediment in Ardmucknish Bay, Scotland, in the spring and summer of 2012. As part of this project, we investigated the effects of CO2 leakage on sedimentary phosphorus (P), an essential nutrient for marine productivity. We found no statistically significant effects during QICS, as the solid-phase P content in the sediment was constant before, during, and after exposure to CO2. However, laboratory experiments using marine sediment standard materials as well as QICS sediment revealed substantial differences among these different sediment types in their potential for P release during CO2 exposure. Employing the SEDEX sequential extraction technique to determine the sizes of the major P pools in the sediments, we showed that calcium-bound P can be easily released by CO2 exposure, whereas iron-bound P is a major sink of released P. The overall impacts of CO2 leakage on sediment P behavior appear to be low compared to natural variability

    Cyclone Shaheen: the exceptional tropical cyclone of October 2021 in the Gulf of Oman

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    Early October 2021 saw Cyclone Shaheen track westward across the far northern Arabian Sea, penetrate the Gulf of Oman and strike the northeast Oman coastline – the first storm to make such a unique landfall in more than 130 years. This paper describes how the unusual cyclogenesis location, favourable initial trajectory and steering, conducive environmental conditions and anomalously warm sea‐surface temperatures were the main influences responsible for Shaheen\u27s extraordinary genesis, intensification and remarkable geographical landfall
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