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  • 1
    Publication Date: 2022-08-31
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pease, S. K. D., Brosnahan, M. L., Sanderson, M. P., & Smith, J. L. Effects of two toxin-producing harmful algae, Alexandrium catenella and Dinophysis acuminata (Dinophyceae), on activity and mortality of larval shellfish. Toxins, 14(5), (2022): 335, https://doi.org/10.3390/toxins14050335.
    Description: Harmful algal bloom (HAB) species Alexandrium catenella and Dinophysis acuminata are associated with paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) in humans, respectively. While PSP and DSP have been studied extensively, less is known about the effects of these HAB species or their associated toxins on shellfish. This study investigated A. catenella and D. acuminata toxicity in a larval oyster (Crassostrea virginica) bioassay. Larval activity and mortality were examined through 96-h laboratory exposures to live HAB cells (10–1000 cells/mL), cell lysates (1000 cells/mL equivalents), and purified toxins (10,000 cells/mL equivalents). Exposure to 1000 cells/mL live or lysed D. acuminata caused larval mortality (21.9 ± 7.0%, 10.2 ± 4.0%, respectively) while exposure to any tested cell concentration of live A. catenella, but not lysate, caused swimming arrest and/or mortality in 〉50% of larvae. Exposure to high concentrations of saxitoxin (STX) or okadaic acid (OA), toxins traditionally associated with PSP and DSP, respectively, had no effect on larval activity or mortality. In contrast, pectenotoxin-2 (PTX2) caused rapid larval mortality (49.6 ± 5.8% by 48 h) and completely immobilized larval oysters. The results indicate that the toxic effects of A. catenella and D. acuminata on shellfish are not linked to the primary toxins associated with PSP and DSP in humans, and that PTX2 is acutely toxic to larval oysters.
    Description: This research was partially funded by the National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science Competitive Research, Ecology and Oceanography of Harmful Algal Blooms Program under award #NA19NOS4780182 to J.L.S. (VIMS) and M.L.B (WHOI), and by a William & Mary, School of Marine Science, Student Research Grant to S.K.D.P. (VIMS). This paper is ECOHAB publication number 1022.
    Keywords: saxitoxin ; okadaic acid ; pectenotoxin ; Alexandrium catenella ; Dinophysis acuminata ; Crassostrea virginica ; harmful algae ; harmful algal bloom ; oyster larvae ; shellfish
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 2
    Publication Date: 2022-05-03
    Description: Rocky reefs provide complex structures in the otherwise largely sand-dominated coastal North Sea. Therefore, these reefs are highly important natural habitats for the functioning of coastal ecosystems, as they provide shelter, refuge and nursery grounds for various mobile and sessile species. In the North Sea, the spatial distribution of these habitats has been intensively investigated over recent years. However, these studies generally provide static accounts of the current state of these reef systems, but limited data exist on the temporal variations in sediment dynamics at and around natural rocky reefs. In this study, we provide observations from a multiannual time series of hydroacoustic seafloor surveys conducted at an isolated rocky reef in the North Sea. We use multibeam bathymetry and side-scan sonar backscatter data in combination with video observations, sediment sampling, and sub-bottom profiler data to assess the long-term variations of the rocky reef system. The reef is located in water depths between 11 and 17 m with an areal extent of ~0.5 km2 and is surrounded by mobile sands. The topography of the rocky reef appears to create a distinct hydrodynamic system that permits mobile sands to settle or move into bathymetrical deeper parts of the reef. Our results suggest a very dynamic system surrounding the reef with large scale scouring, sediment reworking and transport, while the shallower central part of the reef remains stable over time. We demonstrate the importance of hydrodynamics and current scouring around reefs for the local variability in seafloor properties over time. These small-scale dynamics are likewise reflected in the spatial distribution of sessile species, which are less abundant in proximity to mobile sands. The hydroacoustic mapping and monitoring of seafloor dynamics at higher spatial and temporal resolutions presents an important future direction in the study of valuable coastal habitats.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
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  • 3
    Publication Date: 2022-10-27
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kalra, T. S., Suttles, S. E., Sherwood, C. R., Warner, J. C., Aretxabaleta, A. L., & Leavitt, G. R. Shoaling wave shape estimates from field observations and derived bedload sediment rates. Journal of Marine Science and Engineering, 10(2), (2022): 223, https://doi.org/10.3390/jmse10020223.
    Description: he shoaling transformation from generally linear deep-water waves to asymmetric shallow-water waves modifies wave shapes and causes near-bed orbital velocities to become asymmetrical, contributing to net sediment transport. In this work, we used two methods to estimate the asymmetric wave shape from data at three sites. The first method converted wave measurements made at the surface to idealized near-bottom wave-orbital velocities using a set of empirical equations: the “parameterized” waveforms. The second method involved direct measurements of velocities and pressure made near the seabed: the “direct” waveforms. Estimates from the two methods were well correlated at all three sites (Pearson’s correlation coefficient greater than 0.85). Both methods were used to drive bedload-transport calculations that accounted for asymmetric waves, and the results were compared with a traditional excess-stress formulation and field estimates of bedload transport derived from ripple migration rates based on sonar imagery. The cumulative bedload transport from the parameterized waveform was 25% greater than the direct waveform, mainly because the parameterized waveform did not account for negative skewness. Calculated transport rates were comparable to rates estimated from ripple migration except during the largest event, when calculated rates were as much as 100 times greater, which occurred during high period waves.
    Description: USGS Coastal and Marine Hazards and Resources Program.
    Keywords: Asymmetric waveform ; Wave shape parameterization ; Sediment transport
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 4
    Publication Date: 2022-10-20
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Dalpe, A. J., Thein, M.-W. L., & Renken, M. . PERFRM: a metric for evaluating autonomous system performance in marine testbed environments using interval type-2 fuzzy logic. Applied Sciences, 11(24), (2021): 11940, https://doi.org/10.3390/app112411940.
    Description: Trust and confidence in autonomous behavior is required to send autonomous vehicles into operational missions. The authors introduce the Performance Evaluation and Review Framework Of Robotic Missions (PERFORM), a framework to enable a rigorous and replicable autonomy test environment, thereby filling the void between that of merely simulating autonomy and that of completing true field missions. A generic architecture for defining the missions under test is proposed and a unique Interval Type-2 Fuzzy Logic approach is used as the foundation for the mathematically rigorous autonomy evaluation framework. The test environment is designed to aid in (1) new technology development (i.e., providing direct comparisons and quantitative evaluations between autonomy algorithms), (2) the validation of the performance of specific autonomous platforms, and (3) the selection of the appropriate robotic platform(s) for a given mission type (e.g., for surveying, surveillance, search and rescue). Three case studies are presented to apply the metric to various test scenarios. Results demonstrate the flexibility of the technique with the ability to tailor tests to the user’s design requirements accounting for different priorities related to acceptable risks and goals of a given mission
    Description: This work was sponsored by the Naval Engineering Education Consortium (NEEC), Naval Sea Systems Command (NAVSEA), and New Hampshire SeaGrant.
    Keywords: Autonomous systems ; Marine vehicles ; Evaluation tools ; Performance metrics ; Fuzzy logic ; Interval Type-2 Fuzzy Logic
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 5
    Publication Date: 2022-10-20
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gomez-Ibanez, D., Kukulya, A. L., Belani, A., Conmy, R. N., Sundaravadivelu, D., & DiPinto, L. Autonomous water sampler for oil spill response. Journal of Marine Science and Engineering, 10(4), (2022): 526, https://doi.org/10.3390/jmse10040526.
    Description: A newly developed water sampling system enables autonomous detection and sampling of underwater oil plumes. The Midwater Oil Sampler collects multiple 1-L samples of seawater when preset criteria are met. The sampler has a hydrocarbon-free sample path and can be configured with several modules of six glass sample bottles. In August 2019, the sampler was deployed on an autonomous underwater vehicle and captured targeted water samples in natural oil seeps offshore Santa Barbara, CA, USA.
    Description: This work was supported by the United States Bureau of Safety and Environmental Enforcement under contract number E18PG00001.
    Keywords: Oil spill ; Water sampling ; Autonomous underwater vehicle ; Autonomous survey ; Organic analysis ; Environmental impact assessment ; Rapid response ; Plume tracking
    Repository Name: Woods Hole Open Access Server
    Type: Article
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