Quantifying pursuit-diving seabirds’ associations with fine-scale physical features in tidal streamenvironments

Acknowledgements James J. Waggitt was funded by a NERC Case studentship supported by OpenHydro Ltd and Marine Scotland Science (NE/J500148/1). Vessel-based transects were funded by a NERC (NE/J004340/1) and a Scottish National Heritage (SNH) grant. FVCOM modelling was funded by a NERC grant (NE/J004316/1). Marine Scotland Science provided time on the FRV Alba-na-Mara as part as the Marine Collaboration Research Forum (MarCRF). The bathymetry data used in hydrodynamic models (HI 1122 Sanday Sound to Westray Firth) was collected by the Maritime & Coastguard Agency (MCA) as part of the UK Civil Hydrography Programme. We wish to thank Christina Bristow, Matthew Finn and Jennifer Norris at the European Marine Energy Centre (EMEC); Marianna Chimienti, Ciaran Cronin, Tim Sykes and Stuart Thomas for performing vessel-based transects; Marine Scotland Science staff Eric Armstrong, Ian Davies, Mike Robertson, Robert Watret and Michael Stewart for their assistance; Shaun Fraser, Pauline Goulet, Alex Robbins, Helen Wade and Jared Wilson for invaluable discussions; Thomas Cornulier, Alex Douglas, James Grecian and Samantha Patrick for their help with statistical analysis; and Gavin Siriwardena, Leigh Torres, Mark Whittingham and Russell Wynn for their constructive comments on earlier versions of this manuscript.

Benthic–pelagic links and rocky intertidal communities: Bottom-up effects on top-down control?

Insight into the dependence of benthic communities on biological and physical processes in nearshore pelagic environments, long considered a “black box,” has eluded ecologists. In rocky intertidal communities at Oregon coastal sites 80 km apart, differences in abundance of sessile invertebrates, herbivores, carnivores, and macrophytes in the low zone were not readily explained by local scale differences in hydrodynamic or physical conditions (wave forces, surge flow, or air temperature during low tide). Field experiments employing predator and herbivore manipulations and prey transplants suggested top-down (predation, grazing) processes varied positively with bottom-up processes (growth of filter-feeders, prey recruitment), but the basis for these differences was unknown. Shore-based sampling revealed that between-site differences were associated with nearshore oceanographic conditions, including phytoplankton concentration and productivity, particulates, and water temperature during upwelling. Further, samples taken at 19 sites along 380 km of coastline suggested that the differences documented between two sites reflect broader scale gradients of phytoplankton concentration. Among several alternative explanations, a coastal hydrodynamics hypothesis, reflecting mesoscale (tens to hundreds of kilometers) variation in the interaction between offshore currents and winds and continental shelf bathymetry, was inferred to be the primary underlying cause. Satellite imagery and offshore chlorophyll-a samples are consistent with the postulated mechanism. Our results suggest that benthic community dynamics can be coupled to pelagic ecosystems by both trophic and transport linkages.

Balkan Peninsula, 1908 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Die Balkan-Halbinsel in 4 Blättern : Türkei, Rumänien, Griechenland, Serbien, Montenegro, Bulgarien, entworfen von C. Vogel ; bearbeitet von B. Domann ; gestochen von Kern, Kühn u. Weiler. It was published by Justus Perthes in 1908. Scale 1:1,500,000. Covers the Balkan Peninsula. Map in German. The image inside the map neatline is georeferenced to the surface of the earth and fit to the a modified 'Europe Lambert Conformal Conic' projection with a central meridian of 24 degrees East projection. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, railroads,canals, fortifications, ports, ruins, territorial boundaries, shoreline features, and more. Relief shown by hachures. Depths shown by bathymetry. Includes insets: Constantinopel (Scale 1:150,000) -- Athens und Piraeus (Scale 1:150,000) -- Das Nördliche Rümanien im Anschluss and die Hauptkarte (Scale 1:1,500,000) -- Strasse der Dardanellen (Scale 1:150,000) -- Der Bosporus (Scale 1:150,000). This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection as part of the Open Collections Program at Harvard University project: Islamic Heritage Project. Maps selected for the project represent a range of regions, originators, ground condition dates, scales, and purposes. The Islamic Heritage Project consists of over 100,000 digitized pages from Harvard's collections of Islamic manuscripts and published materials. Supported by Prince Alwaleed Bin Talal and developed in association with the Prince Alwaleed Bin Talal Islamic Studies Program at Harvard University.

Tunis Region, Tunisia, 1902 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Environs de Tunis. It was published by Service géographique de l'Armée in 1902. Scale 1:50,000. Covers the Tunis region, Tunisia. Map in French.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator (UTM Zone 32N, meters, WGS 1984) projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and towns, villages, roads, railroads and stations, selected buildings and built-up areas, shoreline features, and more. Relief shown by contours, shading, and spot heights; bathymetry shown by isolines.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Die Balkan-Halbinsel in 4 Blättern: Türkei, Rumänien, Griechenland, Serbien, Montenegro, Bulgarien

entworfen von C. Vogel ; bearbeitet von B. Domann ; gestochen von Kern, Kühn u. Weiler.

Late-Holocene Mass Movements in High Arctic East Lake, Melville Island (Western Canadian Arctic Archipelago)

East Lake, located at Cape Bounty (Melville Island, Canadian High Arctic), was mapped using a high-resolution swath bathymetric sonar and a 12 kHz sub-bottom profiler, allowing for the first time the imaging of widespread occurrence of mass movement deposits (MMDs) in a Canadian High Arctic Lake. Mass movements occurred mostly on steep slopes located away from deltaic sedimentation. The marine to lacustrine transition in the sediment favours the generation of mass movements where the underlying massive mud appears to act as a gliding surface for the overlying varved deposits. Based on acoustic stratigraphy, we have identified at least two distinct events that triggered failures in the lake during the last 2000 years. The synchronicity of multiple failures and their widespread distribution suggest a seismic origin that could be related to the nearby Gustaf-Lougheed Arch seismic zone. Further sedimentological investigations on the MMDs are however required to confirm their age and origin.

Asentamiento y reclutamiento de poliquetos bentónicos en la plataforma continental frente a Callao desde verano a invierno de 2015

La diversidad en los estadios de desarrollo de los poliquetos bentónicos fue estudiada en un perfil batimétrico de la plataforma continental central frente a Callao (Perú, 12°S) del verano al invierno del 2015, con el objetivo de determinar el asentamiento de larvas y reclutamiento de poliquetos bentónicos, bajo la influencia de los factores abióticos del agua y sedimento: temperatura, salinidad, oxígeno disuelto de fondo, sulfuro de hidrógeno en agua intersticial, fitopigmentos totales, materia orgánica total y biopolímeros lábiles. Se encontró un total de 25 especies, pertenecientes a 15 familias. La familia Spionidae presentó la mayor diversidad de larvas (06 especies), seguida de la familia Pilargidae (03 especies). Las larvas de Magelonidae fueron dominantes en verano y otoño. La disponibilidad larval en la capa de fondo estuvo asociada al régimen de oxigenación en el gradiente batimétrico. El número de larvas de poliquetos disminuyó desde el ambiente somero hacia la plataforma externa. Asimismo, la abundancia total de larvas de poliquetos y la abundancia de larvas de Magelona phyllisae se redujeron con el aumento de la temperatura y de la profundidad de la oxiclina durante el período de estudio, caracterizado por la influencia del evento El Niño 2015 - 2016. Por otro lado, se encontró que el número de especies de poliquetos juveniles y adultos fue mayor en ambientes someros, con mayor grado de oxigenación pero también condiciones más reductoras en el sedimento. No obstante, el éxito del reclutamiento, inferido a partir de la abundancia de individuos adultos y la proporción entre el número de especies en estadio adulto y el estadio juvenil fueron mayores en la plataforma externa deficiente en oxígeno, lo cual fue explicado principalmente por la contribución de Paraprionospio pinnata, especie dominante y típica de sedimentos de la plataforma continental.

Age determination of sediment cores of the southeastern Weddell Sea, Antarctica

On the continental margin of the southeastern Weddell Sea, Antarctica, several channel-ridge systems can be traced on the eastern side of the Crary Fan. Swath mapping of the bathymetry reveals three southwest-northeast trending ridges up to 300 m high with channels on their southeastern side. The structures occur on a terrace of the continental slope in water depths of 2000 - 3300 m. We carried out sedimentological studies on cores from three sites. Two of the studied cores are from ridges, one is from the northwestern part of the terrace. The stratigraphy of the recovered sediments is based on accelerator mass spectrometer 14C determinations, stable oxygen and carbon isotopes analyses and paleomagnetic measurements. The sediments represent a period from the last glacial maximum (LGM) to recent time. They are composed predominantly of terrigenous components. We distinguish four different sedimentary facies and assign them to processes controlling sedimentation. Microlaminated muds and cross-stratified coarse-silty sediments originated from contour currents. Bioturbated sediments reflect the increasing influence of hemipelagic sedimentation. Structureless sediments with high contents of ice-rafted debris characterize slumps. The inferred contour currents shaping the continental slope during the LGM were canalized within the channels and supplied microlaminated mud to the western sedimentary ridges due to deflection to the left induced by the Coriolis force. The lamination of the sediments is attributed to seasonal variations of current velocities. The thermohaline bottom currents were directed to the northeast and hence opposite to the Weddell Gyre. Cross-stratified coarse-silty contourites on the ridges are intercalated with the muds and indicate spillover of faster thermohaline flows. Average sedimentation rates on the terrace of the continental slope were unusually high (250 cm/ka) during the LGM, indicating active growth phases of the Crary Fan during glacial intervals. A substantial environmental change at 19.5 - 20 ka is documented in the sediments by a gradual change from lamination to bioturbation. During the recent interglacial, bioturbated sediments were deposited in all parts of the terrace. Because of a reduction of the contour current velocities (4-7 cm/s), the water masses of the Weddell Gyre, supplying fine-grained sediments from northeast, gain a greater influence on sedimentation on the continental slope. Higher percentages of microfossils indicate enhanced biogenic productivity. Increased iceberg activity is documented by greater amounts of ice-rafted debris. The interglacial sedimentation rates decrease to a few cm/ka and indicate that the Crary Fan became relatively sediment-starved during interglacial intervals.

Bellingshausen Sea bathymetric compilation

The southern Bellingshausen Sea (SBS) is a rapidly-changing part of West Antarctica, where oceanic and atmospheric warming has led to the recent basal melting and break-up of the Wilkins ice shelf, the dynamic thinning of fringing glaciers, and sea-ice reduction. Accurate sea-floor morphology is vital for understanding the continued effects of each process upon changes within Antarctica's ice sheets. Here we present a new bathymetric grid for the SBS compiled from shipborne echo-sounder, spot-sounding and sub-ice measurements. The 1-km grid is the most detailed compilation for the SBS to-date, revealing large cross-shelf troughs, shallow banks, and deep inner-shelf basins that continue inland of coastal ice shelves. The troughs now serve as pathways which allow warm deep water to access the ice fronts in the SBS. Our dataset highlights areas still lacking bathymetric constraint, as well as regions for further investigation, including the likely routes of palaeo-ice streams. The new compilation is a major improvement upon previous grids and will be a key dataset for incorporating into simulations of ocean circulation, ice-sheet change and history. It will also serve forecasts of ice stability and future sea-level contributions from ice loss in West Antarctica, required for the next IPCC assessment report in 2013.

AWI Bathymetric Chart of the Fram Strait (BCFS) (Scale 1:100,000)

Based on data from R/V Polarstern multibeam sonar surveys between 1984 and 1997 a high resolution bathymetry has been generated for the central Fram Strait. The area ensonified covers approx. 36,500 sqkm between 78°N - 80°N and 0°E - 7.5°E. Basic outcome of the investigation is a Digital Terrain Model (DTM) with 100 m grid spacing which was utilized for contouring and generation of a new series of bathymetric charts at a scale of 1:100,000, the AWI Bathymetric Chart of the Fram Strait (AWI BCFS).

Sedimentology of the southern Bellingshausen Sea

A major trough ('Belgica Trough') eroded by a palaeo-ice stream crosses the continental shelf of the southern Bellingshausen Sea (West Antarctica) and is associated with a trough mouth fan ('Belgica TMF') on the adjacent continental slope. Previous marine geophysical and geological studies investigated the bathymetry and geomorphology of Belgica Trough and Belgica TMF, erosional and depositional processes associated with bedform formation, and the temporal and spatial changes in clay mineral provenance of subglacial and glaciomarine sediments. Here, we present multi-proxy data from sediment cores recovered from the shelf and uppermost slope in the southern Bellingshausen Sea and reconstruct the ice-sheet history since the last glacial maximum (LGM) in this poorly studied area of West Antarctica. We combined new data (physical properties, sedimentary structures, geochemical and grain-size data) with published data (shear strength, clay mineral assemblages) to refine a previous facies classification for the sediments. The multi-proxy approach allowed us to distinguish four main facies types and to assign them to the following depositional settings: 1) subglacial, 2) proximal grounding-line, 3) distal sub-ice shelf/subsea ice, and 4) seasonal open-marine. In the seasonal open-marine facies we found evidence for episodic current-induced winnowing of near-seabed sediments on the middle to outer shelf and at the uppermost slope during the late Holocene. In addition, we obtained data on excess 210Pb activity at three core sites and 44 AMS 14C dates from the acid-insoluble fraction of organic matter (AIO) and calcareous (micro-)fossils, respectively, at 12 sites. These chronological data enabled us to reconstruct, for the first time, the timing of the last advance and retreat of the West Antarctic Ice Sheet (WAIS) and the Antarctic Peninsula Ice Sheet (APIS) in the southern Bellingshausen Sea. We used the down-core variability in sediment provenance inferred from clay mineral changes to identify the most reliable AIO 14C ages for ice-sheet retreat. The palaeo-ice stream advanced through Belgica Trough after ~36.0 corrected 14C ka before present (B.P.). It retreated from the outer shelf at ~25.5 ka B.P., the middle shelf at ~19.8 ka B.P., the inner shelf in Eltanin Bay at ~12.3 ka B.P., and the inner shelf in Ronne Entrance at ~6.3 ka B.P.. The retreat of the WAIS and APIS occurred slowly and stepwise, and may still be in progress. This dynamical ice-sheet behaviour has to be taken into account for the interpretation of recent and the prediction of future mass-balance changes in the study area. The glacial history of the southern Bellingshausen Sea is unique when compared to other regions in West Antarctica, but some open questions regarding its chronology need to be addressed by future work.

Clay mineralogy and shear strength of subglacial and glaciomarine sediments in the southern Bellingshausen Sea

The Belgica Trough and the adjacent Belgica Trough Mouth Fan in the southern Bellingshausen Sea (Pacific sector of the Southern Ocean) mark the location of a major outlet for the West Antarctic Ice Sheet during the Late Quaternary. The drainage basin of an ice stream that advanced through Belgica Trough across the shelf during the last glacial period comprised an area exceeding 200,000 km**2 in the West Antarctic hinterland. Previous studies, mainly based on marine-geophysical data from the continental shelf and slope, focused on the bathymetry and seafloor bedforms, and the reconstruction of associated depositional processes and ice- drainage patterns. In contrast, there was only sparse information from seabed sediments recovered by coring. In this paper, we present lithological and clay mineralogical data of 21 sediment cores collected from the shelf and slope of the southern Bellingshausen Sea. Most cores recovered three lithological units, which can be attributed to facies types deposited under glacial, transitional and seasonally open-marine conditions. The clay mineral assemblages document coinciding changes in provenance. The relationship between the clay mineral assemblages in the subglacial and proglacial sediments on the shelf and the glacial diamictons on the slope confirms that a grounded ice stream advanced through Belgica Trough to the shelf break during the past, thereby depositing detritus eroded in the West Antarctic hinterland as soft till on the shelf and as glaciogenic debris flows on the slope. The thinness of the transitional and seasonally open-marine sediments in the cores suggests that this ice advance occurred during the last glacial period. Clay mineralogical, acoustic sub-bottom and seismic data furthermore demonstrate that the palaeo-ice stream probably reworked old sedimentary strata, including older tills, on the shelf and incorporated this debris into its till bed. The geographical heterogeneity of the clay mineral assemblages in the sub- and proglacial diamictons and gravelly deposits indicates that they were eroded from underlying sedimentary strata of different ages. These strata may have been deposited during either different phases of the last glacial period or different glacial and interglacial periods. Additionally, the clay mineralogical heterogeneity of the soft tills recovered on the shelf suggests that the drainage area of the palaeo-ice stream flowing through Belgica Trough changed through time.

A 20 m spatial resolution seamless multisource Digital Elevation/Depth Model for Lizard Island, northern Great Barrier Reef

Hydrographers have traditionally referred to the nearshore area as the "white ribbon" area due to the challenges associated with the collection of elevation data in this highly dynamic transitional zone between terrestrial and marine environments. Accordingly, available information in this zone is typically characterised by a range of datasets from disparate sources. In this paper we propose a framework to 'fill' the white ribbon area of a coral reef system by integrating multiple elevation and bathymetric datasets acquired by a suite of remote-sensing technologies into a seamless digital elevation model (DEM). A range of datasets are integrated, including field-collected GPS elevation points, terrestrial and bathymetric LiDAR, single and multibeam bathymetry, nautical chart depths and empirically derived bathymetry estimations from optical remote sensing imagery. The proposed framework ranks data reliability internally, thereby avoiding the requirements to quantify absolute error and results in a high resolution, seamless product. Nested within this approach is an effective spatially explicit technique for improving the accuracy of bathymetry estimates derived empirically from optical satellite imagery through modelling the spatial structure of residuals. The approach was applied to data collected on and around Lizard Island in northern Australia. Collectively, the framework holds promise for filling the white ribbon zone in coastal areas characterised by similar data availability scenarios. The seamless DEM is referenced to the horizontal coordinate system MGA Zone 55 - GDA 1994, mean sea level (MSL) vertical datum and has a spatial resolution of 20 m.