1,720,980 research outputs found
In situ observations of predatory feeding behaviour of the galatheid squat lobster Munida sarsi using a remotely operated vehicle
No full textThe feeding behaviour of a deep-sea holothurian, Stichopus tremulus (Gunnerus) based on in situ observations and experiments using a Remotely Operated Vehicle
No full textUsing a Remotely Operated Vehicle (ROV) to deploy an in situ cage experiment
incorporating fluorescent Luminophore particle tracers, the gut throughput time of the deposit feeding holothurian, Stichopus tremulus (Gunnerus) was determined as 23.73 h (S.D.F2.3). For a range of individuals examined at different depths (350–500 m) and locations, throughput times varied between 19 and 26 h irrespective of animal size or gut tract length. In situ video observations of feeding behaviour showed that this species uses fine oral papillae in a ‘sweeping’ motion to target particles on the seafloor. Following detection of a food source fine-branched digitate tentacles collect a large range of sediment fragments from the seabed. The main types of particles ingested include silica fragments ( < 20 > 500 Am), pelagic foraminifera, benthic
foraminifera, fine phytodetrital remains and occasional larger rock fragments (f1 cm). Ingested sediment consisted mainly of very fine silica fragments (f50 Am) accounting for over 50% of the total gut contents. Frame-by-frame video analysis revealed that the particle handling time (i.e. the time taken for a tentacle insertion and the subsequent collection of food) was found to be f54 s. Only 10 of the 20 feeding tentacles were simultaneously employed during feeding. Use of tentacles appeared to be in sequence, alternating between the reserve and active tentacles. Estimating the rate of movement over the seabed and the total effective capture area of each tentacle, the impact of this animal on the turnover and quality of surface sediment at this deepwater site is potentially substantial. The in situ experiments provided a significant improvement over previous methods used to investigate deep-sea deposit feeders and represent a useful concept for further in situ deep-sea research using an industrial ROV
A review of the uses of work-class ROVs for the benefits of science: lessons learned from the SERPENT project
No full textThis paper reviews the contributions of underwater science in continuing to develop new technology to explore the marine environment and how collaborations taking place between the oil and gas industry and science are facilitating this process. A case study focuses on some of the results and highlights from the SERPENT Project. SERPENT (Scientific and Environmental ROV Partnership using Existing Industrial Technology) is a collaboration programme that was designed to make better use of remotely operated vehicle (ROV) technology and data available through links with marine operations in the oil and gas industry. Oil and gas exploration and production activities in the marine environment are increasing. The amount of global hydrocarbon reserves removed from below the seafloor is set to increase over the next 5–10 years with exploration heading into deeper, more remote waters, many of which have yet to be fully explored. The only way that these remote areas may be documented is through a working relationship with industry, with mutual benefit for both sides, and learning from technology that is already in place for the benefit of science
Seasonality and selectivity in the feeding ecology and reproductive biology of deep-sea bathyal holothurians
No full textChlorophyll and carotenoid pigments were determined from the gut sediments of five species of bathyal holothurian in the NE Atlantic, sampled shortly after the spring/summer phytoplankton bloom in 2001 and prior to the spring bloom in 2002. Three species, Laetmogone violacea, Paroriza pallens and Bathyplotes natans, sampled within a similar depth range (900–1100 m) in the summer of 2001 showed significant differences in their chlorophyll and carotenoid pigment concentrations. This suggests they may select for slightly different components from the available food resource. Four species sampled in early spring 2002, Laetmogone violacea, Paroriza pallens, Benthogone rosea and Benthothuria funebris, also had significant differences in their pigment concentrations. These species were sampled over a wider depth range (1000–3100 m) showing a bathymetric trend in pigment concentrations. There was a distinct seasonal change in the composition and concentration of the pigments, linked to a reduction in the availability of fresh organic material during autumn and winter periods.Ovarian tissue was also examined. The carotenoid pigments found in the ovary also occurred in the OM ingested by the holothurians. The dominant gonadal carotenoid pigments were beta-carotene, echinenone and zeaxanthin. The potential for using these carotenoids to gain a competitive advantage through selectivity of chlorophyll and carotenoid pigment biomarkers are discussed in relation to competition for food resources by deposit-feeders. The results were also compared with selectivity in abyssal species
Snapshot: deep-sea wonders
No full textFrom the whimsical to the downright scary, images featuring creatures from the deep are showcased in the BP Kongsberg Underwater Image Competition being held this week at the 11th International Deep-Sea Biology Symposium, UK. Narelle Towie takes a look at some of the most striking entries.<br/
Feeding behaviour of deep-sea dwelling holothurians: inferences from a laboratory investigation of shallow fjordic species
No full textAn experimental mesocosm was used to investigate the feeding behaviour, particle size selectivity, gut throughput time and dietary selection of two holothurian species, Stichopus tremulus (Gunnerus) and Mesothuria intestinalis (Ascanius). Specimens usually only present at depths > 1000m in the North-eastern Atlantic Ocean were collected from a relatively shallow (< 100 m) cold-water fjordic system in Sweden and maintained in the laboratory. Both species exhibited a similar strategy for retrieving sediment particles from the sediment surface; feeding tentacles were used in a ‘grasping’ motion to pick up sediment particles. The rate at which the feeding tentacles were placed onto the sediment surface, however, differed between species (S. tremulus was three times quicker than M. intestinalis) resulting in a significant difference in gut throughput time. Both species, when offered different sized sediment particles, showed a preference for finer sediment and for nutritionally rich, pigment-enhanced, food patches. <br/
Deepwater observations of monkfish, Lophius piscatorius, in the Northeastern Atlantic Ocean by means of a remotely operated vehicle
No full textIn situ behaviour of anglerfish Lophius piscatorius was observed by a remotely operated vehicle (ROV) in the vicinity of the Schiehallion oil field to the west of the Shetland Isles, Scotland at water depths c. 350 m. Several behaviour patterns associated with the 'sit-and-wait' feeding strategy of L. piscatorius were identified and are described. Concealment behaviour was characterized by recess creation using pectoral and pelvic fins. Sit-and-wait and resting behaviour was typified by relaxed dorsal fin rays and a 34 s exhalation rate. Prey detection responses had a range of c. 5 m and were identified by erection of the fin rays and a reduction in the exhalation rate to once every 65 s. Prey attraction was characterized by lure (illicia) casting, erect dorsal rays and was dependant on both the proximity and position of potential prey. An opportunistic feeding attack is also described. Walking behaviour was also recorded and is described
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