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  • Articles  (17)
  • 1
    Electronic Resource
    Electronic Resource
    An in situ experiment to investigate the modification of particulate matter and urea above a benthic sandy silt community in the Baltic Sea (1998)
    Springer
    Hydrobiologia 375-376 (1998), S. 353-361 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During two cruises to the Baltic (Mecklenburg Bight) in September 1993 and November 1994 bottom water and sediment samples were taken from 5 stations on a 2.0 km long transect above a benthic sandy silt community. Profiles of total particulate matter, particulate organic carbon, chlorophyll equivalents and urea were taken in the benthic boundary layer (5–40 cm height above sea floor) on the downstream stations across an area occupied by macrofauna feeding at the sediment-water interface at 26 m water depth. Particulate matter concentration profiles varied under the two different flow conditions in September ( u* = 0.7 cm s-1) and November (u* = 0.2 cm s-1). In September 1993 resuspension of total particulate matter (TPM) of 22 to 130 mg m-2 h-1 occurred while particulate organic carbon (POC) and chlorophyll (CPE) were deposited with a rate of 9 mg m-2 h-1 and 0.11 mg m-2 h-1 respectively at the station of highest macrofauna abundance. In November 1994 physical sedimentation and biological deposition of up to 388 mg m-2 h-1 TPM, 7.4 mg m-2 h-1 POC and 0.07 mg m-2 h-1 CPE occurred. Urea was released into the water column. Data suggest that in shallow water environments local sediment and benthic boundary layer characteristics prevent large scale calculations of fluxes of particulate matter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017019932033
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Do physical and chemical factors structure the macrobenthic community at a continental slope in the NE Atlantic? (1998)
    Springer
    Hydrobiologia 375-376 (1998), S. 265-285 
    Details
    ISSN: 1573-5117
    Keywords: Macrobenthos ; community structure ; continental slope ; flow velocity ; C/N ; NE Atlantic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Macrofauna density, biomass and community structure together with several characteristics of the sediment and flow velocity were estimated in May 1994 and August 1995 at seven stations ranging from 208 m to 4470 m water depth along the OMEX-transect in the Goban Spur area (NE Atlantic). In 1994 four additional stations were sampled at a parallel transect about 40 km SSE of the OMEX-transect. In 1995 two additional transects were sampled, one in the Porcupine Seabight ∼ 100 km NNW and one along the slope at ∼ 3500 m water depth situated ∼ 200 km SSE of the OMEX-transect. An overall trend in decrease in density and biomass with increasing water depth was found, but no depth related pattern in mean individual weight could be observed. Mean individual weight, however, did show a negative relationship with flow velocities. Correspondence-analyses and single linkage clustering of the community structure showed three more or less depth related clusters, representing a shelf community, an upper-slope and a lower-slope community. These clusters coincided with differences in grain-size, % organic C and total N within the sediment and differences in flow velocities. However, some of the stations at similar depths were not clustered together. Grain-size did not differ at stations with similar depth, but the % of C and N and flow velocities could differ markedly. Stations at similar depth, but with different physical and/or chemical conditions showed differences in density, biomass, mean individual weight and in macrobenthic community structure. More filter-feeding taxa were observed at stations with higher flow velocities, whereas more subsurface deposit-feeders were found at stations with higher sedimentation rates. Thus, besides the effects of water depth on macrobenthic community structure, other physical and chemical factors (such as flow velocities and organic matter supply) can be important structuring factors as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017009409743
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  • 3
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    Plastic microbeads from cosmetic products: an experimental study of their hydrodynamic behaviour, vertical transport and resuspension in phytoplankton and sediment aggregates (2018)
    In:  EPIC3Elem Sci Anth, 6(1), pp. 61, ISSN: 2325-1026
    Details
    Publication Date: 2018-09-11
    Description: Hydrodynamic behaviour and the transport pathways of microplastics within the ocean environment are not well known, rendering accurate predictive models for dispersal management of such pollutants difficult to establish. In the natural environment, aggregation between plastic microbeads and phytodetritus or suspended sediments in rivers and oceans further complicate the patterns of dispersal. In this laboratory study, the physical characteristics and hydrodynamic behaviour of a selection of common plastic microbeads, as used in exfoliation skincare cosmetic products, were investigated. Additionally, the potential for aggregation of these microbeads with phytodetritus and suspended sediments, as well as the subsequent sinking and resuspension behaviour of produced aggregates, were investigated with roller tanks, settling columns and erosion chamber. Physical characteristics of the plastic microbeads showed great heterogeneity, with various densities, sizes and shapes of plastic material being utilised in products designed for the same purpose. The majority of the plastics investigated were positively buoyant in both freshwater and seawater. Aggregation between plastic microbeads and phytoplankton was observed to be swift, with even extremely high concentrations of plastics being rapidly scavenged by suspended algal material. Following aggregation to sizes of 300 to 4400 μm diameter, some formerly buoyant plastics were observed to settle through the water column and enter the benthic boundary layer with settling velocities ranging between 32 and 831 m day–1. These aggregates could be resuspended in the laboratory under critical shear velocities of 0.67–1.33 cm s–1 (free stream velocities of 〉 10 cm s–1). This rapid aggregation and subsequent settling indicates a potentially important transport pathway for these waste products, a pathway that should be considered when modelling discharge and transport of plastic microbeads and determining the ecosystems that may be at risk from exposure.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 4
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    5 Year-long Monitoring of Barkley Canyon Cold-seeps with the Internet Operated Deep-sea Crawler “Wally” (2016)
    In:  EPIC37th MARTECH workshop on marine technology, Barcelona, Spain, 2016-10-26-2016-10-28
    Details
    Publication Date: 2017-01-20
    Description: Despite the technological advances of the last decades (e.g. ROVs, AUVs, cabled observatories), our knowledge of most deep-sea environments is still strongly limited by spatio-temporal sampling and observational capabilities. The novel Internet Operated Deep-Sea Crawler technology can provide high-frequency, multi-sensor data, during long-term deployments, 24/7 communication with researchers and broader spatial coverage (i.e. mobile platform) than fixed instrument installations. The crawler “Wally” is deployed at the Barkley Canyon methane hydrates site (NE Pacific, Canada; ~890 m depth) and connected to the Ocean Networks Canada NEPTUNE cabled observatory network (ONC; www.oceannetworks.ca). Here we present the environmental and biological datasets obtained from Wally instruments and cameras, during the first deployment phase (September 2010 to January 2015), as well as new features and preliminary results obtained since it was re-deployed (May 2016 – present). In addition to data provided by the standard payload of the crawler (i.e. ADCP, CTD, methane sensor, turbidity sensor and fluorometer), the hydrates community was video-monitored at different frequencies and timespans. Photomosaics were generated at two distinct locations, in order to map chemosynthetic bacterial mats and vesicomyid clam colonies covering the ~2-3 m high hydrate mounds, and document their temporal dynamics. The crawler followed the development of a deep-sea shell taphonomic experiment aiming to quantify biogenic carbon fluxes at the hydrates environment. The composition and diel activity patterns of the hydrates megafaunal community were studied with the use of linear video-transects conducted from February 2013 to April 2014. Since the summer of 2016, video-frames recorded at different locations of the site are analyzed for a biodiversity study and photomosaicing of the hydrate mounds continues, with 3D modelling of the mound structures also available as a new feature of the crawler deployed in May 2016. All data are archived in real-time and can be accessed online on the Ocean Networks Canada database. As deep-sea crawler technology and similar mobile, benthic platform technologies progress towards full operational autonomy, they will provide an even greater capacity for future monitoring and understanding of dynamic, extreme environments such as methane hydrate fields.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 5
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    Leben am Meeresboden (2017)
    SPRINGER
    In:  EPIC3Faszination Meeresforschung, Faszination Meeresforschung, Heidelberg, SPRINGER, pp. 179-210, ISBN: 978-3-662-49714-5
    Details
    Publication Date: 2017-01-18
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 6
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    Cutting the umbilical - new technological perspectives in benthic deep-sea research (2016)
    MDPI
    In:  EPIC3Journal of Marine Science and Engineering, MDPI, 4, ISSN: 2077-1312
    Details
    Publication Date: 2016-05-20
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 7
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    Seasonal monitoring of deep-sea megabenthos in Barkley Canyon cold seep by internet operated vehicle (IOV) (2017)
    In:  EPIC3PLOS ONE, 12(5), pp. e0176917, ISSN: 1932-6203
    Details
    Publication Date: 2018-02-23
    Description: Knowledge of the processes shaping deep-sea benthic communities at seasonal scales in cold-seep environments is incomplete. Cold seeps within highly dynamic regions, such as submarine canyons, where variable current regimes may occur, are particularly understudied. Novel Internet Operated Vehicles (IOVs), such as tracked crawlers, provide new techniques for investigating these ecosystems over prolonged periods. In this study a benthic crawler connected to the NEPTUNE cabled infrastructure operated by Ocean Networks Canada was used to monitor community changes across 60 m2 of a cold-seep area of the Barkley Canyon, North East Pacific, at ~890 m depth within an Oxygen Minimum Zone (OMZ). Short video-transects were run at 4-h intervals during the first week of successive calendar months, over a 14 month period (February 14th 2013 to April 14th 2014). Within each recorded transect video megafauna abundances were computed and changes in environmental conditions concurrently measured. The responses of fauna to environmental conditions as a proxy of seasonality were assessed through analysis of abundances in a total of 438 video-transects (over 92 h of total footage). 7698 fauna individuals from 6 phyla (Cnidaria, Ctenophora, Arthropoda, Echinodermata, Mollusca, and Chordata) were logged and patterns in abundances of the 7 most abundant taxa (i.e. rockfish Sebastidae, sablefish Anoplopoma fimbria, hagfish Eptatretus stoutii, buccinids (Buccinoidea), undefined small crabs, ctenophores Bolinopsis infundibulum, and Scyphomedusa Poralia rufescens) were identified. Patterns in the reproductive behaviour of the grooved tanner crab (Chionnecetes tanneri) were also indicated. Temporal variations in biodiversity and abundance in megabenthic fauna was significantly influenced by variabilities in flow velocity flow direction (up or down canyon), dissolved oxygen concentration and month of study. Also reported here for the first time are transient mass aggregations of grooved tanner crabs through these depths of the canyon system, in early spring and likely linked to the crab's reproductive cycle.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 8
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    The Oceanic Biological Pump: Rapid carbon transfer to depth at Continental Margins during Winter (2017)
    In:  EPIC3Scientific Reports, 7(1), ISSN: 2045-2322
    Details
    Publication Date: 2018-02-23
    Description: The oceanic biological pump is responsible for the important transfer of CO2-C as POC “Particulate Organic Carbon” to the deep sea. It plays a decisive role in the Earth’s carbon cycle and significant effort is spent to quantify its strength. In this study we used synchronized daily time-series data of surface chlorophyll-a concentrations from the NASA’s MODIS satellite in combination with hourly to daily observations from sea surface buoys and from an Internet Operated Vehicle (IOV) on the seafloor within Barkley Canyon (Northeast Pacific) to investigate the importance of winter processes in the export of fresh phytodetritus. The results indicate that phytoplankton pulses during winter can be as important in POC transfer to depth as the pulses associated with spring and summer blooms. Short winter phytoplankton pulses were observed to disappear from surface waters after low-pressure systems affected the area. Pulses of chlorophyll reached the IOV, at 870 m depth on the canyon seafloor, 12–72 hours later. These observed short pulses of biological carbon production regularly observed in the region from December to March have not been considered a significant component of the biological pump when compared with the denser summer productivity blooms.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 9
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    High-Frequency Patterns in the Abundance of Benthic Species near a Cold-Seep – An Internet Operated Vehicle Application (2016)
    In:  EPIC3PLOS ONE, 11(10), pp. e0163808, ISSN: 1932-6203
    Details
    Publication Date: 2017-01-27
    Description: Three benthic megafaunal species (i.e. sablefish Anoplopoma fimbria; pacific hagfish Eptatretus stoutii and a group of juvenile crabs) were tested for diel behavioral patterns at the methane hydrates site of Barkley Canyon (890 m depth), off Vancouver Island (BC, Canada). Fluctuations of animal counts in linear video-transects conducted with the Internet Operated Deep-Sea Crawler ªWallyº in June, July and December of 2013, were used as proxy of population activity rhythms. Count time series and environmental parameters were analyzed under the hypothesis that the environmental conditioning of activity rhythms depends on the life habits of particular species (i.e. movement type and trophic level). Nonlinear least squares modeling of biological time series revealed significant diel periods for sablefish in summer and for hagfish and crabs in December. Combined cross-correlation and redundancy (RDA) analyses showed strong relationships among environmental fluctuations and detected megafauna. In particular, sablefish presence during summer months was related to flow magnitude, while the activity of pacific hagfish and juvenile crabs in December correlated with change in chemical parameters (i.e. chlorophyll and oxygen concentrations, respectively). Waveform analyses of animal counts and environmental variables confirmed the phase delay during the 24 h cycle. The timing of detection of sablefish occurred under low flow velocities, a possible behavioral adaptation to the general hypoxic conditions. The proposed effect of chlorophyll concentrations on hagfish counts highlights the potential role of phytodetritus as an alternative food source for this opportunistic feeder. The juvenile crabs seemed to display a cryptic behavior, possibly to avoid predation, though this was suppressed when oxygen levels were at a minimum. Our results highlight the potential advantages such mobile observation platforms offer in multiparametric deep-sea monitoring in terms of both spatial and temporal resolution and add to the vastly understudied field of diel rhythms of deep-sea megafauna.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 10
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    Physical and hydrodynamic properties of deep sea mining-generated, abyssal sediment plumes in the Clarion Clipperton Fracture Zone (eastern-central Pacific) (2019)
    In:  EPIC3Elementa, 7(1)
    Details
    Publication Date: 2019-09-16
    Description: The anthropogenic impact of polymetallic nodule harvesting in the Clarion-Clipperton Fracture Zone is expected to strongly affect the benthic ecosystem. To predict the long-term, industrial-scale impact of nodule mining on the deep-sea environment and to improve the reliability of the sediment plume model, information about the specific characteristics of deep-sea particles is needed. Discharge simulations of mining-related fine-grained (median diameter ≈ 20 μm) sediment plumes at concentrations of 35–500 mg L–1 (dry weight) showed a propensity for rapid flocculation within 10 to 135 min, resulting in the formation of large aggregates up to 1100 μm in diameter. The results indicated that the discharge of elevated plume concentrations (500 mg L–1) under an increased shear rate (G ≥ 2.4 s–1) would result in improved efficiency of sediment flocculation. Furthermore, particle transport model results suggested that even under typical deep-sea flow conditions (G ≈ 0.1 s–1), rapid deposition of particles could be expected, which would restrict heavy sediment blanketing (several centimeters) to a smaller fall-out area near the source, unless subsequent flow events resuspended the sediments. Planning for in situ tests of these model projections is underway
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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