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AbstractAccelerated warming and melting of Arctic sea-ice has been associated with significant increases in phytoplankton productivity in recent years. Here, utilizing a multiproxy approach, we reconstruct an annually resolved record of Labrador Sea productivity related to sea-ice variability in Labrador, Canada that extends well into the Little Ice Age (LIA; 1646 AD). Barium-to-calcium ratios (Ba/Ca) and carbon isotopes (δ13C) measured in long-lived coralline algae demonstrate significant correlations to both observational and proxy records of sea-ice variability, and show persistent patterns of co-variability broadly consistent with the timing and phasing of the Atlantic Multidecadal Oscillation (AMO). Results indicate reduced productivity in the Subarctic Northwest Atlantic associated with AMO cool phases during the LIA, followed by a step-wise increase from 1910 to present levels—unprecedented in the last 363 years. Increasing phytoplankton productivity is expected to fundamentally alter marine ecosystems as warming and freshening is projected to intensify over the coming century.

Marine fungi are widely distributed in the ocean, playing an important role in the ecosystems, but only little information is available about their occurrence and activity. Seagrass bleaching is also a neglected phenomenon that seems to be linked to warm environments, even though the causes are still to be defined. In this study, the cultivable mycoflora associated to the leaf conditions (bleached, necrotic and live) and section (from the base to the tip) in the seagrass Posidonia oceanica was investigated in a Mediterranean warm-edge location (Cyprus). A total of 17 Ascomycota species/taxon were identified and results highlighted that mycoflora composition changed significantly in relation to both the leaf condition and section. A few known pathogens of terrestrial plants were detected only on bleached leaves, but it remains unknown whether they have any direct connections with P. oceanica bleaching phenomenon.

Abstract Much CCS research has focused on the injection interval (storage reservoir) and the immediately overlying primary seal. Considerations related to potential long-term leakage have turned attention toward the geologic overburden between the primary seal and shallow intervals containing protected groundwater. Typically the overburden interval is poorly imaged in commercially available seismic data given acquisition and processing optimized for deeper reservoir systems. Recent advances in high-resolution 3D (HR3D) seismic imaging have allowed for more thorough investigation of this critical interval in marine settings, and are well-suited for evaluating potential leakage pathways for prospective CCS sites. HR3D datasets can serve to reduce risks prior to project development as well as provide containment assurance via staggered time-lapse surveys. HR3D is likely to become a fundamental technology in offshore CCS.

Coastal ecosystems are essential for absorbing and bouncing back from the impacts of climate change, yet accelerating climate change is causing anthropogenically-derived stressors in these ecosystems to grow. The effects of stressors are more difficult to foresee when they act simultaneously, however, predicting these effects is critical for understanding ecological change. Spartina alterniflora (Spartina), a foundational saltmarsh plant key to coastal resilience, is subject to biological stress such as herbivory, as well as anthropogenic stress such as chemical pollution. Using saltmarsh mesocosms as a model system in a fully factorial experiment, we tested whether the effects of herbivory and two chemicals (oil and dispersant) were mediated or magnified in combination. Spartina responded to stressors asynchronously; ecophysiology responded negatively to oil and herbivores in the first 2-3 weeks of the experiment, whereas biomass responded negatively to oil and herbivores cumulatively throughout the experiment. We generally found mixed multi-stressor effects, with slightly more antagonistic effects compared to either synergistic or additive effects, despite significant reductions in Spartina biomass and growth from both chemical and herbivore treatments. We also observed an indirect positive effect of oil on Spartina, via a direct negative effect on insect herbivores. Our findings suggest that multi-stressor effects in our model system, 1) are mixed but can be antagonistic more often than expected, a finding contrary to previous assumptions of primarily synergistic effects, 2) can vary in duration, 3) can be difficult to discern a priori, and 4) can lead to ecological surprises through indirect effects with implications for coastal resilience. This leads us to conclude that understanding the simultaneous effects of multiple stressors is critical for predicting foundation-species persistence, discerning ecosystem resilience, and managing and mitigating impacts on ecosystem services.

Insulated aerial bundled cables (ABCs) are preferred over conventional bare conductor cables in electrical distribution system as ABCs are more safe, less prone to electricity pilferage and offers higher reliability. However, the degradation phenomenon of ABCs is sudden as compared to conventional cables especially in coastal areas. Sudden failures of ABCs in coastal areas make the maintenance planning challenging. Hence, accurate reliability estimation is required which can enable timely maintenance planning and in turn reducing the chances of failures. A novel reliability model is reported in this work which is derived from historical failure data of particular type of ABCs coupled with the degradation models. The models are based upon the actual environmental conditions experienced by the cables under study. The actual loading data as well as environmental data of two sites of varying distance from Seashore are used to develop the respective reliability models. The reliability prediction from proposed reliability model is then validated using time to failure computation through comparison of historical infrared thermography based Non-destructive testing (NDT) data, acquired at the sites under study, with reference to NDT measurements acquired from the ruptured/failed cable. The validation indicates the efficacy of the proposed reliability model.

Abstract The use of Autonomous Underwater Vehicles (AUV) is an emerging technology in many fields of marine activity (military, scientific, industrial), offering a significant potential in cost savings and extension of the operational capabilities related to the solutions currently adopted in offshore operations. Commercially available AUVs are mainly used by the oil & gas industry for the execution of seabed surveys and they are not routinely applied for carrying out the environmental monitoring and asset integrity around oil&gas offshore infrastructures. Eni e&p and its subsidiary Eni Norge, in cooperation with Tecnomare, have launched the CLEAN SEA project (Continuous Long-term Environmental and Asset iNtegrity monitoring at SEA) with the objective to use a commercially available AUV, properly upgraded with key enabling technologies, for the execution of environmental monitoring and asset integrity in offshore fields where eni operates. This paper will address how to reach this goal. A custom designed mission payload, arranged as modular and interchangeable pods, has been installed at the AUV. These modules, characterised by a set of sensors, are built to perform different offshore monitoring activities according to specific needs: automatic water samples collection; visual inspection (asset, seabed) and hydrocarbon leakage detection; automatic chemical analyses of trace pollutants and acoustic survey of seabed and pipelines / flowlines. This paper will in addition illustrate the possible future extension of the AUV operational capabilities through the integration and field demonstration of key technologies such as underwater docking, wireless underwater communication for mission data downloading and wireless power recharge for increased autonomy. This may enable a "permanent" operation subsea independently of support from surface. A comprehensive technical overview of the concept will be presented as well as the results of the demonstration tests.

Abstract The global water cycle is predicted to intensify under various greenhouse gas emissions scenarios. Here the nature and strength of the expected changes for the ocean in the coming century are assessed by examining the output of several CMIP5 model runs for the periods 1990–2000 and 2090–2100 and comparing them to a dataset built from modern observations. Key elements of the water cycle, such as the atmospheric vapor transport, the evaporation minus precipitation over the ocean, and the surface salinity, show significant changes over the coming century. The intensification of the water cycle leads to increased salinity contrasts in the ocean, both within and between basins. Regional projections for several areas important to large-scale ocean circulation are presented, including the export of atmospheric moisture across the tropical Americas from Atlantic to Pacific Ocean, the freshwater gain of high-latitude deep water formation sites, and the basin averaged evaporation minus precipitation with implications for interbasin mass transports.