RV Pelagia Cruise 64PE219, 05 Nov – 24 Nov 2003. TOBI surveys of Setubal and Nazarre Canyons and of the MV Prestige wreck site, west of Iberia

The main objective of the cruise was to collect TOBI sidescan sonar imagery over three areas of the continental margin west of Iberia, where sediment transport studies are being undertaken as part of the EC funded ‘EUROSTRATFORM’ project. The three study areas were:1. The Setubal Canyon, between 38° to 38° 20’N on the continental margin. Here it wasplanned to image the canyon with a single 6 km-wide swath from the shelf edge near200m to the abyssal plain at depths exceeding 4800m2. The Nazarre Canyon, between 39° 30’ and 40°N on the continental margin. The survey plan was similar to that for Setubal Canyon, but with two parallel swaths over the lower reaches of the canyon, where it broadens into a 10 km wide channel crossing the continental rise.3. The Prestige tanker wreck site, at 42°N, 12°W, on the west flank of Galicia Bank, offnorthwest Spain. Here the aim was to investigate the stability of the slope where thetanker was lying. This part of the project was carried out jointly with UTM-CMIMA(CSIC), Barcelona, Spain.Although some time was lost to bad weather and equipment problems, excellent TOBI images were obtained over all three of the areas studied during Pelagia cruise 219. The cruise objectives were fully completed in areas 1 and 3, and about 60% of the expected area was surveyed in area 2, where almost three days were lost to bad weather

RRS Charles Darwin Cruise 126, 11 Mar-20 Mar 2001. Piston coring of debris flows and turbidites west and south of the Canary Islands

The major cruise objective was to obtain sediment cores at various locations to the west and southwest of the Canary Islands with the aims of :· Sampling debris flow sediments in the Canary and Saharan debris flows· Obtaining dateable sediments immediately above and below the debris flow sediments· Sampling turbidite sediments associated with the debris flows· Sampling sediments on either flank of a sediment wave west of La PalmaIn addition, it was planned to:· obtain seabed video footage, using the SHRIMP towed camera station, at several localities where downslope sediment transport was believed to be active at the present day, and undertake some test deployments of the SOC Scatterometer syste

RRS James Cook Cruise 36, 19 Jul-28 Jul 2009. The Geobiology of Whittard Submarine Canyon

The biological and geological research programme for James Cook cruise 36 was built around a series of ROV video transects to determine variations in species and community structure and composition in different geological and topographic settings down the canyon. ROV transects were planned to undertake detailed studies of recognised biological hotspots on both hard and soft substrates, to collect specimens for taxonomic studies, including molecular genetics, and to carry out biological experiments, including the use of in situ incubation chambers and tracer feeding experiments to study the physiology of deep-water fauna. Additional coring, CTD and water column particulate sampling programmes were planned to investigate the recent geological history of the canyon, and, in particular, to investigate whether significant sediment is currently accumulating in any part of the canyon, to sample macro- and meiofauna in areas of soft substrate, and to investigate the fate of organic carbon in the canyon. JC36 was highly successful. The cruise built on the successful mapping of the canyon, using swath bathymetry and 30 kHz sidescan sonar, undertaken during JC35. The main achievements of JC36 included the completion of 26 ROV dives, totalling 340 hr. Seafloor video and photographs along 12 transects from the eastern and western canyon branches between 500 and 3600 m waterdepth were collected. A collection of over 240 biological specimens was collected to verify species identification from the video transects. Pushcores for sedimentology, organic geochemistry, biology and microbiology were also collected. Ultra high-resolution swath bathymetry of the canyon floor using the multibeam system mounted on the ROV was collected on 8 dives. A total of 10 dives were dedicated to placing, initiating and recovering a variety of biological experiments on the seafloor, mainly to examine respiration rates of individual animals or animal communities. The coring programme completed 19 successful piston core stations and 29 successful megacore stations. Most of the latter were processed for macrofauna and meiofauna but some were subsampled for sedimentology and geochemistry. A preliminary assessment suggests that most of the sediment recovered is late glacial in age, and that little Holocene sediment has been deposited in the canyon. 6 CTD profiles and 5 SAPS (stand-alone pump) stations were completed to characterise the suspended particulate matter above the canyon floor. A total of 30 pushcores and megacores also sampled for organic geochemistry

RRS Discovery Cruise 248, 07 Jul-10 Aug 2000. A multidisciplinary study of the environment and ecology of deep-water coral ecosystems and associated seabed facies and features (The Darwin Mounds, Porcupine Bank and Porcupine Seabight)

RRS Discovery Cruise 248 aimed to carry out a multidisciplinary study of the environment and ecology of deep-water coral ecosystems and associated seabed features in the northeast Atlantic. The study was primarily focused on the Darwin Mounds area, northern Rockall Trough (59° 49’N, 07° 22’W), but also examined a number of sites in the Porcupine Seabight area. The cruise was divided into two legs (Govan-Stornoway, 8 Jul-21 Jul 2000; Stornoway-Southampton, 22 Jul-10 Aug 2000). Leg 1 focused on the ecology of the Darwin Mounds area, with seabed photographic surveys (SOC SHRIMP system), coring (Box and Multiple cores) and trawling (Agassiz) forming the main activities. Leg 2 began with detailed geological investigations of the Darwin Mounds area, concentrating on piston coring and sidescan sonar surveys. Leg 2 concluded with combined ecological and geological studies of carbonate mound sites on the Porcupine Bank and in the Porcupine Seabight.Observations in the Darwin Mounds area confirmed the common occurrence of deep-water corals on these Mounds. The mounds themselves do not appear to be carbonate formations but may be better characterised as sand volcanoes. Numerous xenophyophores were observed in association with the mounds; however, no live specimens were recovered in any of the samples collected. Sidescan sonar images and seabed photography both suggested that the Darwin Mounds area had been subject to considerable commercial trawling with resultant apparent damage to the deep-water coral ecosystems.The various operations undertaken in the Porcupine Seabight area were also successful in imaging giant carbonate mounds and their associated coral communities with both sidescan sonar and seabed photography, and in recovering biological sample material from these areas. In common with the Darwin Mounds area, the observations made suggested that deep-water fishing impacts on coral ecosystems were also evident in this region

Of sands and corals : the sedimentary environment of the Darwin Mounds, N. Rockall Trough

The Darwin Mounds, small mounded features colonised by deep-water coral species such as Lophelia pertusa and Madrepora oculata, are found in the Northern Rockall Trough, at water depths between 900 and 1100 m. They were discovered in 1998 during a TOBI (Towed Ocean Bottom Instrument) 30 kHz sidescan sonar survey, where they appeared as circular to oval high-backscatter features on a generally lowbackscatter background. A typical mound can be up to 75 m across and 5 m high, and may have a scoured ‘tail’ feature of moderate backscatter in the down-current direction. High-resolution sidescan sonar and video imagery confirmed the presence of deep-water corals, and their confinement to the mounds. However, it also illustrated damage caused by deep-water trawling activities. As a result of these findings, the European Commission adopted a regulation in March 2004 to permanently ban bottom trawling from the area, while the UK government has the intention to designate the province as Special Area of Conservation under the Habitats Directive.The specific setting in which the Darwin Mounds occur, just south of the Wyville Thomson Ridge (WTR), creates a particular oceanographic regime : while most of the Continental Slope Current of the eastern Rockall margin continues its northward course across the WTR, the lower parts (<500 m) of the current are deflected to the south-west. This resulted in the formation of a sediment drift complex in the area, including a broad sheeted drift upon which upstream flank the Darwin Mounds are located. Further to the southwest, on the down-stream flank, a large field of pockmarks has also been discovered. Piston and box cores indicate that the general sedimentary sequence in the area consists of a thin upper layer of Holocene contourite sands overlying glacigenic muds. Cores in the mounds however show several meters of homogeneous sands. Masson et al. (2003) therefore proposed that the mounds might have a genetic relationship to the pockmarks, suggesting that the mounds formed as a result of fluid escape and the eruption of sand on the seafloor. Their higher elevation above the seafloor would subsequently have attracted coral colonisation. Alternatively, it is often suggested that small coral mounds can be formed through the baffling of sand by the coral framework.Detailed grainsize and mineralogical analyses of the piston and box cores reveal the nature of the sands in the area, and show a sorting effect in the down-current (SW-ly) direction throughout the Darwin Mound Province. However, they are less effective in discriminating clearly between the on-mound and off-mound sands, or between the sands of different depths within the mounds themselves. New information from highresolution TOPAS profiles and from foraminifera studies gives more insight in the mound origin and in the position of the mounds/corals within the contourite system, including the change of current regime related to the last deglaciation

RRS Charles Darwin Cruise 101C Leg 1, 05 Jun-13 Jul 1996. TOBI surveys of the continental slope west of Shetland

This was the first of two cruises, the overall objective of which was to undertake an integrated baseline environmental survey of the continental slope west of Shetland. The major objective of this cruise was to obtain TOBI (30 kHz) and 100 kHz sidescan sonar imagery of the designated survey area west of Shetland. All the objectives of the cruise were achieved in full or exceeded. Over 14000 km2 of seafloor was imaged with the TOBI system during 25 days of survey and 650 line km of 100 kHz data were obtained in 3.5 days of survey. Twelve sample stations were occupied during trials of the multicorer, box corer and Day grab. As anticipated, the mapped sediment facies variations are strongly related to waterdepth. Iceberg ploughmarks dominate the seafloor structure to depths of about 500 m. At mid slope depths, sediment bedforms and erosion due to current activity can be seen. At greater depths, less energetic depositional conditions prevail. Highlights of the sonar survey include the discovery of a field of barchan sand-dunes at a waterdepth of 300 m, a small sediment slide at 900-1000 m waterdepth, and an extensive sandy contourite sheet between the 850 and 1000 m depth contours between 61° and 61°20’N. The second cruise of the two cruises, mainly devoted to seabed sampling, is described in Southampton Oceanography Centre Cruise Report No. 7

RRS Charles Darwin Cruise 108, 14 Sep-16 Oct 1997. TOBI and MULTIBEAM surveys of submarine landslides around the Canaries

The overall objective of the cruise was to examine the contribution of large-scale landsliding to the evolution of the western Canary Islands. Aims included the production of a comprehensive assessment of the effects of catastrophic landslides, including analysis of their frequency, triggering mechanisms and volumes, as well as studies of landsliding processes. The main tools used included swath bathymetry, TOBI high-resolution sidescan sonar and 3.5 kHz and seismic profiling. The survey programme concentrated on three areas where landsliding was believed to be most active: the northern flank of Tenerife, the flanks of the island of La Palma and the flanks of the island of El Hierro. The cruise was highly successful, obtaining swath bathymetry and EM12 sidescan sonar data covering much of the flanks of Tenerife, El Hierro and La Palma. Large-scale slope failures are more abundant on these island flanks than had previously been recognised and at least ten slope failure events can be recognised from the new data. TOBI sidescan sonar images from key areas show varied flow processes including debris avalanche, sediment slide and debris flow

Effectiveness of a deep-sea cold-water coral Marine Protected Area, following eight years of fisheries closure

Pressure on deep-sea ecosystems continues to increase as anthropogenic activities move into ever deeper waters. To mitigate impacts on vulnerable habitats, various conservation measures exist, such as the designation of Marine Protected Areas (MPAs). So far, however, little evidence is available about their effectiveness. This paper presents a unique follow-up study assessing the status and recovery of a deep-sea fisheries closure and MPA at ~1000 m water depth in the NE Atlantic, eight years after designation. The Darwin Mounds cold-water coral ecosystem was discovered in 1998, and closed to all bottom contact fisheries, especially trawling, in 2003. Our repeat survey in 2011 used both high-resolution sidescan sonar data collected by Autonomous Underwater Vehicle (AUV) and video footage from a Remotely Operated Vehicle (ROV) to evaluate recovery. The results demonstrate that (1) protection was successful and fishing impact was largely avoided in the Western Darwin Mounds, which contained similar proportions of live cold-water coral occurrence in 2011 as observed in 1998-2000; however (2) the Eastern Darwin Mounds suffered severe damage pre-closure, and by 2011 showed no coral recolonisation and very little regrowth. These results are further evidence for the low resilience and slow recovery potential of deep-sea ecosystems, and underline once again the importance of the precautionary principle in deep-sea conservation

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil