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The shallow marine environment represents a region of high biological productivity, ecological diversity, and complex oceanographic conditions, and often supports various human activities and industries. Mapping of the seafloor in shallow marine environments reveals seafloor features in detail, shedding light on a range of natural and anthropogenic processes. We present a high-resolution (2-m) multibeam dataset, combined with geologic samples that reveals a complete map of the seafloor from the land-water interface to ∼350 m water depth within Queen Charlotte Sound/Tōtaranui (QCS) and Tory Channel/Kura Te Au (TC), Marlborough Sounds, New Zealand. These data reveal that the seafloor geomorphology and distribution of natural and anthropogenic features varies spatially from the inner QCS to the Cook Strait. Tidal currents play a large role in the erosion, transport, and deposition of sediments in QCS and TC. The distribution and depth of seafloor scouring suggests that tidal flow is locally intensified by coastal geometry and bathymetric barriers, resulting in concentrated scouring where tidal flow is restricted or redirected. In addition, superimposed bedforms reflect localized variations in flow direction that have likely developed across a range of spatial and temporal scales. Evidence for extensive seafloor fluid expulsion is preserved in > 8500 pockmarks mainly located within the inner and central QCS. The size and spatial distribution of pockmarks suggest multiple fluid sources in the region. The cumulative anthropogenic footprint on the seafloor within QCS represents 6.4 km2 (∼1.5%) of the total seafloor area and is predominantly related to maritime activities including anchor dragging (47.5%) and mooring blocks (24%). This study provides a unique example of the information that can be revealed by a comprehensive survey programme that mapped from the land-water interface to the subtidal zone. Results presented in this study form a robust basis upon which to develop improved hydrodynamic models and benthic habitat maps and to assess the full extent of anthropogenic activities in the shallow marine realm.

Submerged paloeshorelines preserved on the continental shelf indicate the depths of the most frequent (modal) low sea-levels within the glacial stages of the Late Quaternary. Here we have determined the south-east Australian shelf configuration when sea level was 40 m and 60 m below present-day sea-level (depths of the most persistent paleoshorelines within the last 120 ka), and we resolve the wave climate variations influencing the sediment transport pathways over this period. We present evidence demonstrating that the combination of shelf morphological evolution, changes in sea-level and variations in wave climate is responsible for latitudinal changes in sediment transport and deposition during the interglacial states. The paleoshoreline and shelf evolution is key to understanding the distribution of present-day shelf sand deposits and the contemporary sand budget response to future wave climate changes.

13 pages, 12 figures, 2 tables, supplementary material https://doi.org/10.1016/j.margeo.2020.106377, Three instrumented lines were installed on the continental slope and the basin of the Gulf of Valencia for thirteen months (May 2010 to June 2011) aiming to study particle fluxes and their relationship with environmental parameters. Total mass flux varied between 52 mg m−2 d−1 in the central part of the basin and 7199 mg m−2 d−1 in the northern slope sector. The main biogenic constituent was calcium carbonate (estimated fraction) representing more than 26% of the total flux, whereas organic matter and biogenic silica add together 400 m−3 s−1 can be detected at least 155 km to the southwest. The temporal variation of satellite-derived chlorophyll-a abundance and organic matter flux indicated that biogenic material collected in the Gulf of Valencia is related to sea surface spring phytoplankton blooms developing in the northwestern Mediterranean. However, the temporal variation of biogenic silica corresponded better with the usual pattern of deep chlorophyll-a maxima reached during the fall season, suggesting that diatoms are a main component in subsurface phytoplankton blooms, This research was supported by the Spanish Ministry of Economy and Competitiveness research project COSTEM (CTM2009–07806), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

16 pages, 13 figures, 1 table, Detailed analysis of recently acquired swath bathymetry, together with high-resolution seismic profiles and bottom sediment samples, revealed the presence of large-scale fine-grained sediment waves over the Gulf of Valencia continental slope. As many other deep-water sediment waves, these features were previously attributed to gravitational slope failure, related to creep-like deformation, and are here reinterpreted as sediment wave fields extending from 250m depth to the continental rise, at ~850m depth. Geometric parameters were computed from the high-resolution multibeam dataset. Sediment wave lengths range between 500 and 1000m, and maximum wave heights of up to 50m are found on the upper slope, decreasing downslope to minimum values of 2m high. Sediment waves on the lower part of the slope are quasi-stationary vertically accreting, whereas they show an upslope migrating pattern from the mid-slope to the upper part of the continental slope. High-resolution seismic profiles show continuous internal reflectors, with sediment waves merging down-section and sediment wave packages decreasing in thickness downslope. These sediment packages are thicker on the crest of each individual sediment wave and thinner on the downslope flank. 210Pb analyses conducted on sediment cores collected over the sediment wave fields also indicate slightly higher sediment accumulation rates on the wave crests. Sediment wave formation processes have been inferred from contemporary hydrodynamic observations, which reveal the presence of near-inertial internal waves interacting with the Gulf of Valencia continental slope. Internal wave activity is suggested to be the preferential mechanism for the transport and deposition of sediment, and the maintenance of the observed sediment wave fields. © 2015 Elsevier B.V., This work was funded by the project COSTEM (CMT2009-07806) and FORMED (CGL2012-33989). [...] The author M. Ribó is supported by a FPI grant (Ref. BES-2010-029949) fromthe Spanish Ministry of Economy and Competitiveness. P. Masqué acknowledges the financial support through the ICREA Academia award and by a Gledden Visiting Fellowship from the Institute of Advanced Studies, The University of Western Australia

13 pages, 8 figures, 2 tables, Large sediment waves have been observed over the Gulf of Roses (GoR) continental slope (NW Mediterranean), developed between ~200 and ~400 m water depth. Geometric parameters computed from the acquired swath bathymetry revealed mean wave lengths of ~2000 m, and maximum wave heights of ~60 m. Single-channel reflection seismic profiles provided information on the sediment wave internal structure and the Quaternary stratigraphic architecture of the GoR outer shelf and slope. Seven main seismic units could be identified, with continuous development of sediment waves over the outer continental shelf and upper slope, showing differences in wave height and length. The seismic units are differentiated by erosional surfaces that can be followed from the outer shelf down the slope, and which have been correlated with Pleistocene eustatic oscillations. Sediment cores were collected over the sediment wave crests and troughs, and grain size distribution and sediment accumulation rates were analysed. Results show a dominant fraction of fine sediments, allowing classifying the observed bedforms as mud waves. Calculated sediment accumulation rates ranged between 0.08 and 0.18 cm/y, with no clear sedimentation pattern (e.g. differential sediment deposition rates) observed between wave crests and troughs. Nevertheless, the presence of thick surface mixed layers and the increase of the sand fraction in the upper sections of the cores indicate that the surface sediments are affected by bottom trawling activities, since the area is highly impacted by this human activity. The sediment waves observed over the GoR slope are most likely to be formed by bottom currents generated by overflows of dense water originated in the Gulf of Lions shelf, which cascade downslope in an oblique angle with respect the main bathymetric contours. This study offers new insights on the role of dense shelf water cascading processes and associated off-shelf sediment transport reshaping the morphology of the open-slope regions, This work was funded by the Spanish grants FORMED (CGL2012-33989) and ABIDES (CTM2015-65142-R) and by the Generalitat de Catalunya supporting grants 2014 SGR-1642 and 2014 SGR-1356

6 pages, 3 figures, Recently acquired swath bathymetry and seismic datasets on the Gulf of Roses continental slope revealed the presence of large sediment waves that have developed between ~200 and ~400 m water depth. Geometric parameters were computed from the multibeam dataset and the obtained results showed mean sediment wave lengths of ~2000 m and maximum heights of ~60 m. The analysis of seismic profiles showed the general architecture of the Late Quaternary deposits over the Gulf of Roses outer shelf and slope. The outer continental shelf is characterized by morphological erosional features affecting the upper part of the most recent seismic unit. Over the continental slope five main unconformity-bounded seismic units are differentiated, with sediment waves developed in all of them. The sediment waves observed over the continental slope are presumably generated by bottom currents intensified during major dense shelf water cascading events flowing downslope at an oblique angle with respect to the main bathymetry

Special issue The contourite log-book: significance for palaeoceanography, ecosystems and slope instability.-- 15 pages, 10 figures, High-resolution single channel sparker reflection seismic data revealed the presence of large-scale sediment waves nearby DSDP Site 548, located on Goban Spur. They developed in a gentle terraced environment which contrasts with the canyon-incised Celtic margin, and the relatively smooth Porcupine Seabight to the north. Based upon the morphological characteristics of the observed seabed and buried sediment waves, energetic alongslope bottom currents are thought to be the driving mechanism for the sediment wave development. These currents are driven on their turn by an enhanced internal tide regime that could be attributed to the introduction of the Mediterranean Outflow Water. The DSDP Site 548 downhole geophysical data and the seismic stratigraphic analysis allowed the differentiation of three sequences that relate to evolutionary stages since the lower Pliocene. The sequences are bounded by local erosional events, associated with mass wasting events, which seem to occur roughly synchronously to major northern hemisphere glaciations, respectively during the Lower Pleistocene (~ 2.5 to 2.15 Ma), and the Middle Pleistocene (~ 0.45 Ma). The lower sequence (from ~ 4.5 to ~ 2.15 Ma) shows no morphological evidence of bottom-current driven sedimentation. It is however settled over a smooth erosional surface which could indicate the introduction of the Mediterranean Outflow Water. The intermediate sequence is characterised by large-scale sediment waves that have gradually developed in close association with palaeo-seafloor irregularities. It is inferred that the sedimentation resumed with a relative bottom current energy increase. The youngest sequence recorded active sediment wave formation, similar to the previous sequence. Although the Goban Spur sediment waves cannot be regarded as contourite drifts as such, their stratigraphic evolution corresponds to other well-documented contourite depositional systems, influenced by the Mediterranean Outflow Water, This study was carried out within the framework of a Ghent University BOF “Starting Grant”. [...] These research cruises were carried out within the framework of the EC FP6 IP HERMES and EC FP7 IP HERMIONE projects

Special issue The contourite log-book: significance for palaeoceanography, ecosystems and slope instability.-- 16 pages, 8 figures.-- This research is a contribution to the INQUA commission for Coastal and Marine Processes, Several fields of large-scale sediment waves have been observed along the Gulf of Valencia continental margin (NW Mediterranean). The largest sediment waves develop on the continental slope, extending from 250 to 850 m water depth, with wavelengths ranging between 500 m and 1000 m and wave heights from ~ 2 m to ~ 50 m. On the lower part of the slope, sediment waves are quasi-stationary “vertically accreting”, becoming up-slope migrating towards the mid- and upper part of the slope. A second group of sediment waves have developed over the outer continental shelf, with wavelengths of 400 to 800 m and heights of 2 to 4 m, also displaying an up-slope migrating pattern. Multi-channel seismic lines crossing the continental margin show that the sediment waves over the continental slope region have been continuously developed on the foreset region of the prograding margin clinoform. Several units of sediment waves have been identified in the sedimentary record, evolving in accordance with the margin progradation. Detailed analysis of single-channel (sparker) seismic profiles revealed the presence of several sediment depositional subunits over the outer continental shelf, some of them with successive development of sediment waves being truncated by erosive surfaces, likely related to Quaternary eustatic sea-level oscillations. These erosional surfaces can be followed downslope into paraconformable strata of the sediment waves on the continental slope, where constant bedform growth is observed, without being affected by sea level changes. Based on geophysical data, the thickness of the sediment waves mapped units show that the largest sediment waves (in wave ratio, length and height) develop where sediment deposition rates are the highest, coinciding with the upper part of the continental slope (foreset clinoforms), confined by the presence of structural highs. The development of these sediment waves has been previously explained by the interaction of internal waves over the continental slope. Because sediment waves are preserved in the sedimentary record since the Lower/Pliocene, internal waves activity could have been present in this part of the margin shortly after the Zanclean reflooding of the Mediterranean Basin, following the Messinian desiccation event ~ 5.6 My ago. Deep water hydrodynamic conditions were re-established at that time, modulating sediment transport and deposition over the continental slope and outer continental shelf, This research was supported by the Spanish Projects COSTEM (Ref. CMT2009-07806) and FORMED (CGL2012e-33989)

25 pages, 15 figures, 5 tables, Clinoform depositional features along the Iberian Mediterranean margin are investigated in this study, with the aim of establishing the causes of their varied shapes and other characteristics. We have analyzed the broad-scale margin physiography and seismic stratigraphic patterns based on high-resolution bathymetric data and previously interpreted seismic data. In addition, we have evaluated regional supply conditions and the uplift-subsidence regime of the different shelf sectors. The upper Quaternary record is strongly dominated by shelf-margin regressive wedges affected by the prevailing 100 ka cyclicity. However, the margins exhibit considerable lateral variability, as the result of the balance between the amount of sediment supply and the uplift-subsidence relationship. Three major shelf sectors with distinct morpho-sedimentary features have been defined. The relatively narrow northern shelves (Roses, La Planassa and Barcelona) are supplied by discrete river outlets that collectively constitute a linear source and are mainly affected by tectonic tilting. The wide middle shelves (Ebro Shelf, the Gulf of Valencia, and the Northern Arc) receive the sediment supply from the large Ebro River and other medium rivers. Although the tectonic regime changes laterally (strong subsidence in the north and uplift in the south), shelf growth is maintained by lateral advection of sediments. The southern shelves (the Southern Arc and the northern Alboran Shelf) are very abrupt and narrow because of the uplifting Betic Cordillera, and the torrential fluvial regimes that determine a very efficient sediment by-pass toward the deep basin. Submarine canyons deeply incised in the continental margin constitute a key physiographic feature that may enhance the transport of sediment to the deep sea or individualize shelf sectors with specific sedimentation patterns, as occurs in the Catalan margin, This research was funded by the Spanish Ministry of Economy, Industry and Competitiveness projects CGL2011-30302-C02-02, CGL2015-74216-JIN, CTM2015-65142-R and CTM2017-88237-P

13 pages, 4 figures, 2 tables, The Cap de Creus continental shelf and Cap de Creus canyon are located in the southernmost sector of the Gulf of Lions, in the northwestern Mediterranean. The Cap de Creus continental shelf contains sandy and muddy sediments and an abrupt morphology, with rocky outcrops, relict bioherms, erosive features, and planar bedforms. The Cap de Creus canyon breaches the shelf at a depth of 110 m and denotes a marked difference in the morphology between the northern and the southern flank, reflecting a different depositional regime. The most common substrates correspond to coarse and medium sands (28%) and silty sediments (40%). The most common megabenthic assemblages of the shelf correspond to the communities of “offshore detritic” (31.95%) and “coastal terrigenous muds” (36.99%), mostly dominated by sea pens, alcyonaceans, and ceriantharians. The northern flank of the Cap de Creus canyon is predominantly depositional, whereas the southern flank is erosional. Rocky outcrops provide the substratum for cold-water coral (CWC) communities’ development, in which the white coral Madrepora oculata is the most abundant species, This research was supported by the European projects INDEMARES (Life + NAT/E/000732), HERMES (Goce-CT-2005-511234-I), HERMIONE (Contract number: 226354), INTERREG (“Pirineus Mediterrànis: La muntanya que uneix”), and the Spanish national projects DEEPCORAL (CTM2005-07756-C02-02/MAR) from the Spanish Ministry of Science and Technology and SHAKE (CGL2011-30005-C02-02) of the Spanish Ministry of Science and Innovation. Some bathymetric data has been kindly provided by the Spanish Fishery General Secretary (“Secretaria General de Pesca”). We are grateful to Dan Orange (AOA Geophysics Inc.) for having provided the bathymetric data set of the Cap de Creus canyon