1,721,079 research outputs found
Pyrosome corpse observations across the undisturbed and anthropogenically disturbed seafloor of the DISCOL experimental area, Peru Basin
No full textDeep sea food falls of blooms of upper water fauna are rarely observed. During the SO242-2 expedition to the DISCOL experimental area in 2015, a bloom of pyrosome colonial organisms was observed in the upper waters, with the fate of corpses also observed on the deep sea seafloor with the Ocean Floor Observation System (OFOS) towed camera sled, over a period of several weeks. 13,000+ images were inspected and seafloor pyrosome corpses counted in each image. This data set presents these counts for each image, as well as whether the counts were made on undisturbed seafloor, seafloor ploughed in 1989 as part of the DISCOL project or seafloor turned over earlier in 2015 by epibenthic sled. This data represents a rare example of the recording of the onset and decline in a seafllor food abundance over time. An associated manuscript is in preparation
FRAM strait octopus observations with towed camera: MSM95, MSM108, PS126
No full textThe Ocean Floor Observation and Bathymetry System (OFOBS) (Purser et al, 2019) has been used repeatedly to image areas of the deep sea seafloor as part of the FRAM HAUSGARTEN time series observatory. In this dataset, all images collected during the marine expeditions MSM95 (Purser et al., 2020), MSM108 (Soltwedel et al., 2022) and PS126 (Soltwedel, 2021) were inspected for the presence or absence of octopus. This dataset contains every image taken with the OFOBS system under standard operations within which an octopus was observed
Octopus feeding traces from the AURORA seamount, high Arctic
No full textThe Aurora hydrothermal field sits in the westernmost segment of the Gakkel Ridge within the Western Volcanic Zone which extends for 220 km from 7°W to 3°E. The Aurora field was first located associated with one such volcanic mound as part of the InterRidge two-icebreaker AMORE expedition in 2001, at 82°53'N, 6°15'W.During 2019, as part of the 'HACON' research program, the icebreaker RV Kronprins Hakon visited the seamount, using date from previous expeditions to conduct 10 Ocean Floor Observation and Bathymetry System (OFOBS) drift stations across the summit and flanks of the seamount. The Ocean Floor Observation and Bathymetry System (OFOBS) (Purser et al., 2018) is a towed underwater camera sled equipped with both a high resolution photo-camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-camera (iSiTEC, Sony FCB-H11). The cameras are mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers at a distance of 50 cm from each other that were used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOS during deployments. Although the research aim of the OFOBS tows was to investigate hydrothermalism across the Aurora field, the cameras also recorded 106 traces left on the seafloor made by cirrate octopusses during their feeding cycle from within approximately 5100 images of the seafloor. The high abundance of these traces is , at time of writing, unique from arctic research expeditions. This dataset contains a .zip file derived from the full image set collected during the HK19 expedition (and available from the PANGAEA link below). This contains the raw images, processed with Adobe Photoshop CS6.0 to give an exposure offset of +0.2 and a gamma correction of 2.0. At these levels the octagonal traces left by the octopusses on the seafloor during feeding were more apparent. All processed images were examined using the PAPARA(ZZ)I software application (Marcon and Purser, 2017) and "fresh" and "degraded" traces both logged and measured. The output from this stage is provided in the two attached .xlsx documents.FILES WITHIN THIS DATASET:"octotrace.zip" - file contains all seafloor images within which octopus traces were visible"Tracedimensions.xlsx" - file contains as columns the name of each image (image_name), trace type (Trace type) and width of each octogonal trace, in meters (Octo trace width)."OctopusAbundances.xlsx" - file contains as columns image name (image_name), image area captured by each image (imagearea_m2), number of live octopus (Live octopus), number of degraded (Degraded_octopus_trace), Fresh (Fresh octopus trace) and total number of octopus traces (Total octopus traces)
A Time Series Study of Lophelia pertusa and Reef Megafauna Responses to Drill Cuttings Exposure on the Norwegian Margin.
No full textAs hotspots of local biodiversity in the deep sea, preservation of cold-water coral reef communities is of great importance. In European waters the most extensive reefs are found at depths of 300 - 500 m on the continental margin. In Norwegian waters many of these reefs are located in areas of interest for oil and gas exploration and production. In this study drilling was carried out in the Morvin drill field in proximity to a number of small Lophelia pertusa coral reefs (closest reefs 100 m upstream and 350 m downstream of point of waste drill material release). In a novel monitoring study, ROV video surveys of 9 reefs were conducted prior, during, immediately after and >1 year after drilling operations. Behavior of coral polyps inhabiting reefs exposed to differing concentrations of drill cuttings and drilling fluids (waste drilling material) were compared. Levels of expected exposure to these waste materials were determined for each reef by modelling drill cutting transport following release, using accurate in-situ hydrodynamic data collected during the drilling period and drill cutting discharge data as parameters of a dispersal model. The presence / absence of associate reef species (Acesta excavata, Paragorgia arborea and Primnoa resedaeformis) were also determined from each survey video. There were no significant differences in Lophelia pertusa polyp behavior in corals modelled to have been exposed to pulses of >25 ppm drill cutting material and those modelled to be exposed to negligible concentrations of material. From the video data collected, there were no observed degradations of reef structure over time, nor reductions of associate fauna abundance, regardless of modelled exposure concentration at any of the surveyed reefs. This study focused exclusively on adult fauna, and did not assess the potential hazard posed by waste drilling material to coral or other larvae. Video data was collected by various ROV's, using different camera and lighting setups throughout the survey campaign, making comparison of observations prior, during and post drilling problematic. A standardization of video monitoring in future monitoring campaigns is recommended
Time series images taken of each of the monitored reefs throughout the monitoring campaign.
No full text<p>1) prior to drilling, 2) during drilling, 3) Immediately following the drilling period and 4) >1yr after drilling.</p
Percentages of polyps Expanded, Partially expanded or retracted at each of the survey reefs prior, during and after the drilling campaign.
No full textPercentages of polyps Expanded, Partially expanded or retracted at each of the survey reefs prior, during and after the drilling campaign.</p
Modelled suspended concentrations of drill cuttings at times of visual particle concentration assessment.
No full text<p>Three grades of particle concentration were used: 1) no or few particles, 2) particles clearly in suspension, 3) reef partially obscured by high particle densities. The mean, median, maximum, minimum and mean standard deviation in modelled values corresponding to each of these three visual categories is given.</p
ANOVA output of one-way test to assess whether or not percentages of fully extended polyps differed by reef or period of observation.
No full text<p>ANOVA output of one-way test to assess whether or not percentages of fully extended polyps differed by reef or period of observation.</p
Dates on which each of the reefs in the monitoring campaign were visited, and usable video data of the reef collected.
No full text<p>Dates on which each of the reefs in the monitoring campaign were visited, and usable video data of the reef collected.</p
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