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• Processing of three different kinds of drifters to extract the geostrophic component. • The use of drifters leads to a higher improvement than an additional altimeter. • Improvement is of 1% in SLA and 10% in meridional velocities. • Both components of the velocity vector have similar accuracy. Knowledge of ocean surface geostrophic circulation has been greatly improved due to satellite observations. However, it is essential to use different observation sources (satellites and in situ data) in order to improve accuracy and resolution. This study combines along-track Sea Level Anomalies (SLA) with geostrophic velocity estimated from surface drifters to map SLA and associated geostrophic current anomalies in the Gulf of Mexico. Firstly, substantial pre-processing is needed on the drifter data to extract the geostrophic component of the signal in order to be consistent with the physical content provided by altimetry. This step includes estimating and removing the Ekman current, Stokes drift and wind slippage. Three kinds of drifters are used: – Drifters belonging to Woods Hole Group, a CLS Group company that launches their own drifters in the Gulf of Mexico. – Drifters launched in the framework of the Lagrangian Submesoscale ExpeRiment (LASER) campaign (January-April 2016). – Drifters from Atlantic Oceanographic and Meteorological Laboratory (AOML). Secondly, drifters and along-track SLA from Jason2, HY2, SARAL and Cryosat-2 are combined through multivariate objective analysis to map a daily time series of SLA and associated geostrophic current anomalies from 01/09/2015 to 30/04/2016. Finally, comparisons with independent data reveal the improved agreement of maps combining both altimetry and drifter data, especially for the meridional component of geostrophic current. [ABSTRACT FROM AUTHOR]

Four cruises were conducted in Jiaozhou Bay from January to November in 2008 to study carbon monoxide (CO) distribution, diurnal variation, seasonal variation, and sea-to-air flux. Surface water CO concentration exhibited strong diurnal variations at an anchor station in both April and November, with highest CO concentration 3–5 times higher than minimum values. Diurnal variation (sampling time) exerts an overall pattern on CO distribution, spatially distributed factors impose extra influence. High CO concentrations and fluxes were observed in the eastern, northern, and western parts of the bay, which are close to areas of estuaries, dense population, and high industrialization, reflecting the impact of human activities on CO distribution. Both surface water CO concentrations and sea-to-air fluxes showed seasonal variations, with the highest values in summer and the lowest values in winter. Sea-to-air CO flux in Jiaozhou Bay ranged from 0 to 34.66 μmol m − 2 d − 1 with a mean flux of 4.96 μmol m − 2 d − 1 . [ABSTRACT FROM AUTHOR]

The hull–propeller interaction of autonomous underwater vehicle (AUV) in straight and oblique flow is numerically studied. The study is performed based on computational fluid dynamics (CFD) and the general commercial software ANSYS Workbench. The multiple reference frames (MRF) method and the shear stress transport (SST) k − ω turbulence model are adopted. Firstly, the drag of Suboff AUV and the open water performance of the Wageningen B-3-50 propeller are simulated numerically. The errors are all within 5%, validating the reliability of the method in this paper. Then, the Sailfish AUV and B-3-35 propeller developed by the Underwater Vehicle Laboratory (UVL) of Ocean University of China are simulated. The maximum incremental drag produced by the appendages reaches even more than 1.5 times the hull drag. Propeller rotation causes an additional hull drag increment of over 25%. With an inlet velocity of 1.5 m/s, the thrust and torque behind the bare hull increase by 16.7% and 6.4%, respectively. The effect of angle of attack on drag is more significant at high velocity. Finally, the numerical simulation result 1.825 m/s and experimental result 1.75 m/s are compared. This study has implications for guidance on AUV integration analysis. • The hull–propeller interaction of autonomous underwater vehicle in straight and oblique flow is numerically studied. • The wake changes the propulsion performance of the propeller while the propeller modifies the pressure distribution. • The self-propulsion point is predicted, and the wake fraction and thrust deduction factor are calculated. • The appendages seriously affect the flow distribution around the hull, and quantitative conclusions are given. [ABSTRACT FROM AUTHOR]

Intercomparison of trace metal data is a key aspect of the International GEOTRACES program, allowing data from multiple laboratories and countries to be combined to produce high-resolution datasets for the oceans. The use of crossover stations by the GEOTRACES program provides the opportunity both for comparison of analytical techniques and assessment of temporal variability in the cycling of trace metals such as iron (Fe). Here, we present the first comparison of dissolved Fe stable isotope ratio (δ 56 Fe; relative to IRMM-014) profiles in the oceans, from reoccupations of three locations in the Atlantic Ocean; (1) the Bermuda Atlantic Time Series station (31.75°N 64.17°W) during the US GEOTRACES IC1 cruise (June 2008) and the US GEOTRACES GA03 cruise (Nov. 2011); (2) the Tenatso Time Series station near Cape Verde (17.4°N 24.5°W) during the U.S GEOTRACES GA03 cruises (2010; 2011), and (3) a station in the Cape Basin close to South West Africa (31.1–31.4°S 36.5°W) during the French GEOTRACES GIPY4 Bonus Good Hope Cruise (Feb. 2008) and the UK GEOTRACES GA10 D357 cruise (Oct. 2010). These datasets provided us with the opportunity not only to compare sampling and analysis techniques by two different laboratories (USC and LEGOS), but also the temporal variability of δ 56 Fe at these locations on a 1–3 year timescale. We found that a good agreement between data and profiles generated by different laboratories does allow assessment of temporal variation of δ 56 Fe in the water column, as well as spatial variability and synthesis of datasets from different regions of the ocean. In fact, comparison of δ 56 Fe at the three locations in this study demonstrates a remarkable consistency between the shapes of ocean δ 56 Fe profiles measured 1–3 years apart, pointing to the overall stability of Fe cycling at all three locations on these timescales, despite the expected dynamic nature of the Fe cycle. This consistency is highlighted by strong agreement in δ 56 Fe throughout the whole water-column at Bermuda, and in waters deeper than 500 m in the Cape Basin, which suggests that different water masses may carry distinct δ 56 Fe signatures. In contrast to these stable δ 56 Fe, we did observe apparent temporal variability in δ 56 Fe between cruises at other locations and in surface waters, both throughout the water column at Cape Verde, and in Agulhas-leakage influenced surface waters in the Cape Basin. Such temporal variability may thus provide information about changes in internal Fe cycling or external Fe sources on these timescales. Overall, this study highlights the usefulness of repeat δ 56 Fe measurements to provide information on the variability of Fe cycling throughout the oceans. [ABSTRACT FROM AUTHOR]

Dissolved organic carbon (DOC) was measured weekly in five coastal upwelling Galician rías (Ría de Vigo, Ría de Pontevedra, Ría de Arousa, Ría de Muros and Ría de Ares–Betanzos) and the first decadal DOC series was examined in these rías. The temporal variability of DOC was assessed by considering biweekly values at 10 oceanographic stations for the decade 2002–2011. Seasonal variability in surface DOC concentrations was observed, with higher values (101 ± 8 μmol L − 1 ; average ± STD) during the accumulation period (DOC b ; May–October) in all inner and outer stations. During the rest of the year (DOC c ; November–April) surface DOC concentrations decreased to 88 ± 6 μmol L − 1 . The temporal distribution of DOC and temperature were comparable, with a marked seasonal variability, suggesting that the temperature was the main proxy for DOC. The average decadal seasonal increase in surface DOC (ΔDOCs = DOC b − DOC c ) was between 7 and 18 μmol L − 1 for all stations. The interannual variability of surface DOC ranged between 0 and 18 μmol L − 1 ; 0 and 11% of the average DOC of each station. Decadal DOC trends were slightly positive in middle-inner areas of the Rías Baixas (Ría de Vigo, Ría de Pontevedra, Ría de Arousa and Ría de Muros) in agreement with positive temperature trends. The outer area of the Rías Baixas showed positive DOC trends in the stations of Ría de Vigo and Ría de Arousa and negative DOC trends in the stations of Ría de Pontevedra and Ría de Muros, although temperature presented positive trends in these four stations. The Ría de Ares–Betanzos exhibited negative trends in DOC and temperature. [ABSTRACT FROM AUTHOR]

The distribution of hydrogen peroxide was determined at 28 stations in four transects across the No rthern So uth C hina Sea S helf-sea (NoSoCS) in June 2010. The average concentration in the top 10 m ranged between 0.063 and 0.231 µM. Among the hydrographic regimes: the inner shelf outside the influence of upwelling, the inner shelf under the influence of upwelling, the middle shelf, the outer shelf and the open South China Sea, the highest concentration was found in the day-time in the inner shelf outside of the influence of upwelling and the lowest concentration was found in the night-time in the inner shelf under the influence of upwelling. The average concentration at the day-time stations in each hydrographic regime was invariably higher than the corresponding concentration at the night-time stations. Across the shelf, the concentration was the highest in the inner shelf. The variations in the concentrations of hydrogen peroxide and total organic carbon (TOC) in the different hydrographic regimes followed a similar pattern. All these behaviors are consistent with the photochemical production of hydrogen peroxide, using dissolved organic matter as the chromophore, as a primary control on its occurrence in the surface waters. Moreover, at day-time stations at different locations in the NoSoCS and at a single location sampled through the day, the relationship between the concentration of hydrogen peroxide and the product of the concentration of TOC and the time-integrated irradiance at the time of sample collection fell on two distinct linear lines with different slopes and intercepts: one for mostly the inner and middle shelf waters and the other for mostly the water in the open northern SCS. These relationships suggest that the light history, the pre-existing concentration of hydrogen peroxide, and, the concentration and the photochemical efficiency of the dissolved organic matter in the production of hydrogen peroxide play major roles in determining the temporal and spatial variations in the concentration of hydrogen peroxide in the surface waters in the day-time. In the sub-surface, a notably large fraction, about one-third, of the profiles of hydrogen peroxide did not follow the typical distribution of a quasi-exponential decrease in concentration with depth. Almost all the profiles at the stations in the slope where the internal waves were most active were atypical. At these stations, the concentration of hydrogen peroxide was generally elevated down to about 100 m, well beyond the depths where solar irradiance was plentiful. Superimposed on these elevated concentrations was a persistent sub-surface maximum, with concentrations reaching about 0.5 µM, at 80 m. While the origin of these atypical distributions is not yet clear, dark biological production and the action of internal waves conceivably could have contributed to their occurrence. [ABSTRACT FROM AUTHOR]

Abstract: In this study we have performed a baseline characterisation of sediment properties in four depositional areas of the Ingøydjupet trough in order to investigate the sediment transport and deposition by ocean currents in the SW Barents Sea. Sedimentation rates, by the 210Pb method, were 1.0–2.4mm/yr and decreasing with distance offshore. Stronger and more variable bottom currents associated with the Norwegian coastal current operate nearshore based on the down-core distribution of sortable silt ( ) and sediment fractions (clay and silt). These nearshore stations exhibit a trend of decreasing fine sediment supplies and increasing sand content toward present day. The most stable bottom currents are associated with the farthest offshore station which is under the influence of the North Atlantic Current as indicated by the distribution of ( ) and also higher TOC contents (0.6–0.9%) compared to nearshore stations (0.4–0.8%). These baseline findings are of relevance for the petroleum industry in planning environmental assessment and monitoring programs connected to the future expansion of industry activities in this region. [Copyright &y& Elsevier]

Abstract: Macrofouling is a common problem when deploying underwater instrumentation for long periods of time. It is a problem which can effect scientific experiments and monitoring missions though the creation of artificial reefs (thus increasing local biological activity) and reduce the quality of scientific data. Macrofouling is an issue typically considered to be restricted to the photic zones and is absent or negligible in the deep sea. To the contrary, the recovery of an accidentally lost deep-sea lander after 3 years submergence at 3960m on the Mid-Atlantic Ridge (North Atlantic) revealed dense colonisation of macrofouling organisms. These organisms were found attached to all surfaces of the lander regardless of orientation and materials. The occurrence of such deep-sea macrofouling should be carefully investigated given the recent developments in long-term deep-sea observatory networks. [Copyright &y& Elsevier]

Abstract: Hyperspectral remote-sensing reflectance (Rrs) from above-surface (ir)radiance measurements is derived using a new, automated method that is suitable for use on moving platforms. The sensors are mounted on a rotating platform that compensates for changing solar and ship azimuth angles, optimizing the sensor azimuth for minimal contribution of sky radiance to measured water-leaving radiance. This sea-surface reflectance (ρs ) lies in the order of 2.5–8% of sky radiance, and is determined through spectral optimization, minimizing the propagation of atmospheric absorption features to Rrs. Up to 15 of these gas absorption features are frequently recognized in (ir)radiance spectra under clear and overcast skies. Rrs was satisfactorily reproduced for a wide range of simulated Case 2 waters and clear sky conditions. A set of 13,784 in situ measurements collected with optimized viewing angles on the high-absorption, low-scattering Baltic Sea was collected in April and July 2010–2011. The processing procedure yielded a 22% retrieval rate of ρs for the field data. The shape of the subsurface irradiance reflectance measurements (R(0−)) measured at anchor stations was well reproduced in above-surface Rrs in those cases where the algorithm converged on a solution for ρs , except under unstable or weak illumination conditions. Clear-sky conditions resulted in the best correspondence of Rrs and R(0−) and gave the highest (>50%) retrieval rates of ρs . Two indices, derived from the available sensor data, are given to describe illumination conditions, and are shown to predict the ability of the algorithm to retrieve Rrs. [Copyright &y& Elsevier]

Abstract: Port Blair is the capital city of Andaman & Nicobar Islands, the union territory of India. More than 50% of the population of these islands lives around Port Blair Bay. Therefore the anthropogenic effects in the bay water were studied for monitoring purpose from seven stations. Physico-chemical parameters of seawater were analyzed in samples collected once in every 3months for 2years from seven sampling stations located in Port Blair Bay, South Andaman Island to evaluate the spatial and tidal variation. Cluster analysis and factor analysis were applied to the experimental data in an attempt to understand the sources of variation of physico-chemical parameters. In cluster analysis, the stations Junglighat Bay and Phoenix Bay having high anthropogenic influence formed a separate group. The factors obtained from factor analysis indicated that the parameters responsible for physico-chemical variations are mainly related to land run-off, sewage outfall and tidal flow. [Copyright &y& Elsevier]

Abstract: A suite of physical–biological models was used to explore the importance of mortality and fluid dynamics in controlling concentrations of fecal indicator bacteria (FIB) at Huntington Beach, CA. An advection–diffusion (AD) model provided a baseline to assess improvements in model skill with the inclusion of mortality. Six forms of mortality were modeled. All mortality models performed better than the AD model, especially at offshore sampling stations, where model skill increased from <0.18 to >0.50 (Escherichia coli) or <−0.14 to >0.30 (Enterococcus). Models including cross-shore variable mortality rates reproduced FIB decay accurately (p <0.05) at more stations than models without. This finding is consistent with analyses that revealed cross-shore variability in Enterococcus species composition and solar dose response. No best model was identified for Enterococcus, as all models including cross-shore variable mortality performed similarly. The best model for E. coli included solar-dependent and cross-shore variable mortality. [Copyright &y& Elsevier]

Abstract: The distribution and abundance of dinoflagellate cysts in recent sediments from Visakhapatnam harbour, east coast of India was investigated and compared with sediment characteristics and physico-chemical variables of the overlying water column. The cyst abundance varied from 11 to 1218cystsg–1 dry sediment. Changes in the cyst assemblages from phototrophic to heterotrophic forms were observed from inner to outer harbour stations, and related to changes in environmental characteristics. Enhanced cyst production of potentially harmful dinoflagellate Protoceratium reticulatum was recorded in the inner harbour stations with higher nutrient concentrations. Protoperidinium cysts were the most diversified group, and were dominant in the outer harbour stations having improved water conditions and circulation. This study points out the potential use of dinoflagellate cyst populations in providing information on environmental conditions. [Copyright &y& Elsevier]

Abstract: A wave-averaged process-based one-dimensional model for beach profile change was developed to predict the cyclic evolution of longshore bars. The cross-shore sediment transport was assumed to be composed of suspended load due to wave breaking and bed load due to velocity skewness, acceleration skewness, and beach slope. The model''s performance was investigated using the beach profile data obtained every weekday during a 12-year period from 1989 to 2000 along a 400-m long pier at the Hazaki Oceanographical Research Station, located on the Hasaki coast of Japan, where the mean duration of bar evolution is approximately 1year. The model was unable to reproduce bar development from a rather flat profile, possibly because some sediment movement process was missing in the model. However, the model calibrated with a 1-year data set, including the bar evolution cycle consisting of bar generation, seaward migration, decay, and new bar generation, can be used to predict the first cycles of bar evolution at Hasaki. [Copyright &y& Elsevier]

Abstract: The collective terminology used in a community of interest identifies the important concepts used by that community. These concepts are related to the research activities of the community and therefore to the types of data that the community creates and uses. Such data may be obtained through direct measurement, through laboratory analysis, or through the numerical or physical modeling conducted by community members. The terminology associated with the data, collectively referred to as a vocabulary, often develops within subgroups of a larger community. When these subgroups are brought together, the disjointed nature of the vocabularies must be addressed for the data to be consolidated into a single, consistent data resource. This consolidation represents a critical challenge for the construction of an ocean observing system. The work presented here describes a semantic mediation framework, which is used to relate multiple oceanographic vocabularies, thereby allowing data consolidation. The framework is described in terms of capabilities required to manage the diverse vocabularies from the organizations that support an ocean observing system. The framework implementation then illustrates the required semantic mediation between the oceanographic vocabularies of the smaller communities, allowing an ocean observing system to appear as a coherent single system, producing coherent data resources from the originally disjoint systems. [Copyright &y& Elsevier]

Abstract: Free-drifting icebergs in the Weddell Sea are expected to affect the surrounding marine ecosystem. Sampling associated with iceberg C-18a, a large tabular, free-drifting iceberg in the NW Weddell Sea, carried out from 10 March to 7 April 2009, was designed to test the hypothesis that the iceberg''s presence modified phytoplankton composition and abundance. Areas that define a gradient of possible iceberg influence were sampled for phytoplankton: stations close (<1km) and far (18km) from iceberg C-18a, an area with numerous small icebergs, Iceberg Alley, and a control site 74km away. Quantitative samples were obtained from Niskin bottles and counted with an inverted microscope for species abundance. Qualitative samples were collected with nets from the ship''s seawater intake. Taxonomic determinations were performed with light and electron microscopy. Overall, diatoms dominated in the mixed layer (surface-∼40m) and unidentified small flagellated and coccid cells at depth (∼100m). Fragilariopsis nana, a diatom 2.4–15.5μm in length, dominated numerically the phytoplankton and was most abundant at the control area. The iceberg''s effect on phytoplankton composition was consistent with the hypothesis that they facilitate phytoplankton communities enriched in diatoms, as found in other productive areas of Antarctica. Near the iceberg, diatoms were most abundant, principally at depth, while small flagellate concentration diminished. However, total phytoplankton abundance was lowest at Iceberg Alley in the area of highest meltwater contribution, as indicated by low mean temperature in the mixed layer, and highest at the control site. These results suggest that during austral fall, low growth or high zooplankton grazing could be counteracting the positive effect by icebergs on phytoplankton biomass, otherwise observed in summer months. [Copyright &y& Elsevier]

Abstract: We report on the late winter oceanography observed beneath the Antarctic sea ice offshore from the Sabrina and BANZARE coast of Wilkes Land, East Antarctica (117–128°E) in September–October 2007 during the Sea Ice Physics and Ecosystem eXperiment (SIPEX). A pilot program using specifically designed ‘through-ice’ conductivity-temperature-depth (CTD) and acoustic Doppler current profiling (ADCP) systems was conducted to opportunistically measure water mass properties and ocean currents at major ice stations. Additional water mass properties across the survey region were collected from Ice-Argo floats deployed during the voyage north of the 3000m isobath. The mean drift of the floats was along the slope to the west with the Antarctic Slope Current. Vertical profiles of the potential temperature reveal the deepest winter mixed layer (WML) in the western sector of the survey northwest of the Dalton Iceberg Tongue polynya. The meridional structure of the Antarctic Slope Front, i.e. the monotonic shoaling of the WML across the upper continental slope, is found to be similar to the previous observations in summer. A strong bottom-intensified intrusion of modified Circumpolar Deep Water (mCDW) as warm as 0°C was detected beneath the fast ice south of the continental shelf break at 118°E. An mCDW intrusion of similar strength was detected near this location in the austral summer of 1996. We hypothesise that there is a persistent supply of mCDW and associated ocean heat flux to this region of the continental shelf that is capable of migrating to the grounding lines of the nearby Totten Glacier and Moscow University Ice Shelf. There was no detection of locally formed dense shelf water capable of forming Antarctic Bottom Water at the shelf break locations sampled despite the number of minor polynyas across this region. Ocean current measurements, limited to a maximum period of 24h and 50–100m depth by the relative scarcity of backscatter, found increased mean vertical speeds at the offshore stations (6–17cms−1) relative to the shelf break (2.3–6.4cms−1). The diurnal variation in the ADCP range reflected the diel migration of zooplankton occurring beneath the sea ice in late winter, with greater range/abundance offshore. Concurrent time series of wind, ocean current and their influence on sea ice drift from global positioning system (GPS) compass measurements were examined but the length of data acquisitions limited the applicability of this analysis. [Copyright &y& Elsevier]

Abstract: This work considers a first order approximation to the dependability analysis of complex large scale installations. The dependability criterion used here is quantitative unavailability, and an appropriate unavailability model is presented. The model assumes that the system is symmetrical, has various levels of hierarchy, and components found in the same level are similar and function independently. The application example comes from very large volume neutrino telescopes installed under water or ice, consisting of several thousands of optical modules. The readout architecture of the detector has several levels of multiplexing including optical detection towers, branches and tower sectors. The paper presents results for various alternative detector layouts and distances of the detector from the onshore facilities. It also develops dependability requirements for major components and/or subsystems consistent with an overall system performance target. The results depict the dependence of the system unavailability on the number of optical modules and the alternative deep sea infrastructure configurations for transferring the measured signals. [ABSTRACT FROM AUTHOR]

Abstract: Five photographic transects, covering some 830m2 of seafloor in total, were analyzed to characterize the megabenthic community along a bathymetric gradient covering water depths from 1200 to 5500m in the eastern Fram Strait. Megafaunal densities ranged between 11 and 38 ind.m−2. The highest densities were found at 1650m and the lowest densities occurred at 3000m depth. The number of taxa and morphotypes ranged between 4 at 5500m and 27 at 1650m water depth. Ophiocten gracilis, a small white unidentified amphipod, Kolga hyalina, and Bathycrinus carpenteri were the dominant and characteristic species on the slope and continental rise. Elpidia heckeri dominated in the Molloy Hole, the deepest depression known in the Arctic Ocean. Megafaunal zonation patterns appeared to be mainly controlled by food availability, as indicated by phytodetrital matter measured at the seafloor, and by benthic biomass in the sediments, as indicated by sediment-bound particulate proteins and phospholipids. By contrast, physical factors, including water depth and seabed properties such as sediment porosity and hard substrata (e.g., dropstones), appear to play a secondary role in determining megabenthic zonation patterns along the bathymetric HAUSGARTEN gradient. [Copyright &y& Elsevier]

Abstract: This paper presents an optical classification of station L4 south of Plymouth in the western English Channel based on satellite and in situ observations. Weekly-sampled in situ data from 2003 and 2004 are presented on temperature and salinity with depth, together with surface measurements of absorption by phytoplankton, coloured dissolved organic matter (CDOM) and non-algal particles (NAP), phytoplankton counts, HPLC chl-a concentrations and suspended particulates. Measured absorption values are compared with a published optical model used to estimate the magnitude and natural variability of absorption by in-water optically active constituents in case 1 waters. Satellite retrievals of remote sensing reflectance, R rs, are compared with model-based limits. L4 is found to be classed as turbid for ~35% of the year (in winter) related to the vertical stability and suspended particulate matter. In situ absorption data reveal an excess of CDOM absorption over that expected in modelled case 1 waters, while phytoplankton and NAP absorption are more consistent with case 1. Time series of satellite and in situ surface chl-a and vertical diffuse attenuation coefficient at 490 nm agree well statistically, probably as a result of the range of chl-a encountered and the use of R rs ratio based satellite algorithms. There was no evidence of coastal adjacency effects upon the chl-a retrievals. L4 can be considered as case 1 or case 2 depending upon the time period, the optical parameter or even the wavelength. This suggests that simple labelling of the site as case 1 or 2 is misleading and instead the station should be characterised in terms of the individual inherent optical property of interest. [Copyright &y& Elsevier]

Abstract: The morphology, stability and duration of seasonal landfast sea ice in Alaska''s coastal zone is changing alongside large-scale ice thinning and retreat. The extent and complexity of change at the local level requires an integrated observing approach to assess implications of such change for coastal ecosystems and communities that rely on or make use of the sea-ice cover. Barrow, Alaska is an example of a community that experiences and utilizes a broad range of sea-ice types and conditions. The local population is increasingly forced to adapt to less stable sea ice, loss of multiyear ice and a shorter ice season. We are working toward an integrated coastal ice observatory to monitor landfast and adjacent pack ice and to maximize the usefulness of information to the community. The observatory includes: (1) satellite remote-sensing datasets distributed in near real-time; (2) a coastal sea-ice radar and webcam that monitor ice movement and evolution; (3) a mass-balance site that provides temperature profiles and thickness information for ice and snow; (4) sea-level measurements; (5) periodic ice thickness surveys using direct drilling and electromagnetic induction sounding; and (6) a program of regular, undirected observations by Iñupiat sea-ice experts. We examine two significant landfast ice breakout events off Barrow in spring of 2007. During these events, Barrow''s subsistence whaling community partook in a successful hunting season observing and responding to these breakout events and their impacts on ice stability. Using local expert knowledge to parse geophysical datasets obtained from the observatory has provided deeper insight into different approaches for assessing ice stability, and integrating information on ice growth, origin, morphology, and dynamics, as well as winds, weather, and currents. [Copyright &y& Elsevier]

Abstract: EMSO has been identified by the ESFRI Report 2006 as one of the Research Infrastructures that European members and associated states are asked to develop in the next decades. It will be based on a European-scale network of multidisciplinary seafloor observatories from the Arctic to the Black Sea with the aim of long-term real-time monitoring of processes related to geosphere/biosphere/hydrosphere interactions. EMSO will enhance our understanding of processes, providing long time series data for the different phenomenon scales which constitute the new frontier for study of Earth interior, deep-sea biology and chemistry, and ocean processes. The development of an underwater network is based on past EU projects and is supported by several EU initiatives, such as the on-going ESONET-NoE, aimed at strengthening the ocean observatories’ scientific and technological community. The EMSO development relies on the synergy between the scientific community and industry to improve European competitiveness with respect to countries such as USA, Canada and Japan. Within the FP7 Programme launched in 2006, a call for Preparatory Phase (PP) was issued in order to support the foundation of the legal and organisational entity in charge of building up and managing the infrastructure, and coordinating the financial effort among the countries. The EMSO-PP project, coordinated by the Italian INGV with participation by 11 institutions from as many European countries, started in April 2008 and will last four years. [Copyright &y& Elsevier]

The Mapping and Modeling Subcommittee of the US National Tsunami Hazard Mitigation Program convened a workshop in January 2017 to evaluate the present state of numerical models for the simulation of tsunamis generated by submarine or subaerial landslides. A range of benchmark tests were provided to participants, with three tests emphasized: (i) a laboratory submarine solid slide in a 2D horizontal tank, (ii) a laboratory submarine granular slide in a 1D flume, and (iii) a field case based on submarine slides which occurred in Port Valdez, AK during the 1964 Alaska earthquake. Nine landslide tsunami models configured with 21 different combinations of physical options were benchmarked, including: (1) hydrostatic models with no frequency dispersion, which include the nonlinear shallow equation models traditionally used for modeling coseismic tsunamis; (2) Boussinesq or one-layer weakly dispersive models; (3) Multi-layer or non-hydrostatic (i.e., dispersive) models; and (4) Full Navier–Stokes models. Model/data comparison indicates that the inclusion of frequency dispersion in model formulations is critical to obtaining physically reasonable results for the test cases considered. Because the importance of dispersive effects is unknown a priori for any given simulated event, the central recommendation from this work is that a model with at minimum a leading-order representation of frequency dispersion effects be used whenever possible for landslide tsunami simulations. • A benchmark exercise for models of landslide tsunami generation is described. • Hydrostatic, weakly- and fully-dispersive and Navier–Stokes models were tested. • Slides used imposed bottom motion, viscous/granular layers and 3D multiphase models. • Hydrostatic models predicting tsunami propagation away from generation region poorly. [ABSTRACT FROM AUTHOR]

Abstract: Amino acids, neutral sugars and amino sugars were analyzed to investigate the chemical composition and diagenetic processing of suspended particulate organic matter (POM, >100 nm), high-molecular-weight dissolved organic matter (HMW DOM, 1–100 nm) and low-molecular-weight dissolved organic matter (LMW DOM, <1 nm) at the time-series stations near Bermuda (BATS) and Hawaii (HOT). Differences between BATS and HOT were principally related to location-specific biogeochemical processes and water mass ventilation ages. Concentrations of amino acids, neutral sugar and amino sugars in unfiltered seawater sharply declined with depth at both stations, indicating an upper ocean source and rapid turnover of these components. The size distribution of organic matter was heavily skewed to smaller molecular sizes. Depth comparisons showed that larger size classes of organic matter were more efficiently removed than smaller size classes. Carbon-normalized yields of amino acids, neutral sugars and amino sugars decreased rapidly with depth and molecular size. Together these biochemicals accounted for 55% of organic carbon in surface POM but only 2% of the organic carbon in LMW DOM in deep water. Chemical compositions showed distinct differences between organic matter size classes indicating the extent of diagenetic processing increased with decreasing molecular size. These findings are consistent with the size-reactivity continuum model for organic matter in which bioreactivity decreases with decreasing molecular size and diagenetic processes lead to the formation of smaller components that are resistant to biodegradation. The data also provided evidence for a size-composition continuum. Carbon-normalized yields of amino acids, neutral sugars and amino sugars were sensitive indicators of diagenetic alterations. Diagenetic indicators based on amino acid compositions revealed distinct patterns for the North Pacific and Sargasso Sea possibly indicating the influence of varying sources or diagenetic processing. [Copyright &y& Elsevier]

This paper presents a review of sediment dispersal processes in the Strait of Georgia, based on marine geological studies. Sediment from the Fraser River is dispersed around the Strait through a variety of transport pathways. Most sand and coarser silt fractions settle out and are deposited within a few 100m of the channel mouths. Both channelled and non-channelled gravity flows probably transport sediment downslope and onto the basin floor. Asymmetric tidal currents force a predominantly northward sediment drift, resulting in a reworked slope off Roberts Bank and a finer-grained depositional slope off Sturgeon Bank. Far-field sediment accumulation is controlled by local morphology and sediment dynamics. Multibeam mapping and seismic profiling reveal that some parts of the basin floor are characterized by bottom sediment reworking and erosion. Given the complexities of sediment dispersal and seafloor reworking, generalizations about sediment dispersal paths and sedimentation rates are difficult. Future understanding will be advanced by the cabled observatory, VENUS, which will enable near real-time monitoring of key processes. [Copyright &y& Elsevier]

Abstract: A comprehensive set of bio-optical measurements collected at the Acqua Alta Oceanographic Tower site in the northern Adriatic Sea is used to assess satellite derived optical properties and concentrations of optically significant constituents. These include normalized water leaving radiance spectra L WN , absorption spectra due to phytoplankton, non-pigmented particles and chromophoric dissolved organic matter, back-scattering spectra, concentrations of chlorophyll a, Chla, and total suspended matter, TSM, and diffuse attenuation coefficients, K d, obtained with a diverse set of algorithms. A total of 81 and 21 match-ups are found for SeaWiFS and MODIS L WN , respectively. For both sensor products, the match-ups show mean absolute percentage differences of approximately 30% at 412 nm, 20% at 443 nm, and 14% from 490 to 555 nm. Some dependence of these differences has been found with respect to the aerosol optical thickness and the single scattering albedo associated with the in-water constituents. However, the performance of the atmospheric correction scheme appears relatively robust with respect to angular and environmental conditions. The different Chla products generally show quite large uncertainties whereas a TSM product shows encouraging results. Three algorithms produce K d (490) with a RMS uncertainty of 0.13 for log-transformed data. The comparison between in situ data and satellite derived absorption values yields varying levels of uncertainties for the three bio-optical algorithms considered here and for the different wavelengths. Preliminary improvements could be reached by reducing biases affecting the total absorption coefficient at various wavelengths. Another general result is that the bio-optical models are able to represent a larger part of the observed variability for phytoplankton absorption than for the absorption by dissolved and non-pigmented particulate matter. The assumed spectral shape of the latter absorption term appears logically as a strong determinant of the partition of the total absorption. The three sets of satellite derived back-scattering spectra compare favorably with in situ optical measurements, with mean RMS differences between 0.12 and 0.18. Importantly, the uncertainties obtained here for satellite match-ups of absorption coefficients are comparable to published estimates of the inherent uncertainties associated with the bio-optical algorithms. [Copyright &y& Elsevier]

A number of coastal and ocean observation systems exist throughout the Gulf of Mexico (GOM), but the network of systems is not currently linked or integrated and at present not fully implemented. The network of local systems are diverse, typically involving unique mandates and several different funding sources at various levels of permanence. The purpose of this paper is to describe the ocean observation systems that currently exist in the GOM, and to identify and quantify the expected economic benefits that may result from the implementation of an integrated regional network. Improved ocean observation systems are expected to reduce the uncertainty of ocean/weather forecasting and to enhance the value of ocean/weather information throughout the Gulf region. The source of benefits and the size of activity from which improved ocean observation benefits may be derived are estimated for private sector, non-market, and public sector activities categorized according to marine transportation, commercial fishing, recreational fishing, search and rescue operations, and pollution management. The benefits of improved ocean observation systems to energy exploration, development, and production activities are estimated, and a discussion of potential benefits to lightering activities, environmental monitoring, royalty payments, and engineering design are highlighted. [Copyright &y& Elsevier]

Focuses on a study that determined the call densities of total coccolithophore ecology at the HOT station ALOHA in Hawaii. Materials and methods used; Oceanographic conditions during 1994-1996; Total coccolithopore abundances; Ecological analyses and interpretation.

Presents information on a study that provided annual and seasonal averages for migrant-mediated export fluxes at Station ALOHA in Hawaii, a time-series sampling site in North Pacific. Materials and methods used; Results on migrant biomass; Composition of the migratory community.

Deals with a study that examined the seasonal and interannual variability in mesozooplankton biomass structure at Ocean Station ALOHA in Hawaii. Materials and methods used; Error estimates; Seasonal patterns at the station.

Deals with a study that investigated the errors in total particulate organic carbon (POC) measurements in the Bermuda Atlantic Time-series Study (BATS) site. Materials and methods; Biogeochemical results of the POC measurements at the BATS site; Potential errors in POC estimates and test of viable bacterial cells passing a GF/F filter.

Deals with a study that presented an overview of patterns in ocean biology and biogeochemistry over a decade at the Bermuda Atlantic Time-series Study (BATS) site. Purpose of the United States Joint Global Ocean Flux Study; Methodology; Hydrographic and biogeochemical variability at BATS.

Deals with a seasonal study that examined the significance of nitrogen fixation by Trichodesmium specie at the Bermuda Atlantic Time-series Study site (BATS). Materials and methods used; Abundance of Trichodesmium species at BATS.

Focuses on a study that examined the seasonal and interannual variability in deep ocean particle fluxes at the Oceanic Flux Program and Bermuda Atlantic Time Series sites in the western Sargasso Sea. Description of the study area; Methodology; Mass fluxes at different depths; Seasonality of mass flux.

Focuses on the Canadian Joint Global Ocean Flux Study in the northeast subarctic Pacific. High Nitrate Low Chlorophyll regions; Characteristics of the regions; Analyses of long-time series data sets from Ocean Station Papa and other stations in the coastal and open ocean.

Presents a review of the oceanographic properties in the vicinity of Ocean Station Papa (OSP) in Canada. Description of the physical and chemical properties of the upper ocean both at OSP and along Line P, a series of oceanographic stations; Impacts of the 1982 El Nio; Possible effects of physical and chemical variability on ecology.

Editorial. Focuses on the interpretations of biogeochemical processes from the United States Joint Global Ocean Flux Study (US JGOFS) in the Bermuda and Hawaii time-series sites. Creation of time-series oceanography studies; Contribution of the US JGOFS to oceanographic experiments.

Abstract: The shore station of a deep-sea neutrino telescope hosts the on-shore DAQ system and any other system required for sustained operation and control of the telescope. We present design choices of the on-shore DAQ system, which is independent of the actual implementations in the deep-sea readout systems. The realization of this design is possible with commercially available components only. [ABSTRACT FROM AUTHOR]