Benthic Organisms

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

David D. Hart - One of the best experts on this subject based on the ideXlab platform.

  • physical biological coupling in streams the pervasive effects of flow on Benthic Organisms
    Annual Review of Ecology Evolution and Systematics, 1999
    Co-Authors: David D. Hart, Christopher M. Finelli
    Abstract:

    ▪ Abstract Flowing water has profound effects on a diverse array of ecological processes and patterns in streams and rivers. We propose a conceptual framework for investigating the multiple causal pathways by which flow influences Benthic biota and focus particular attention on the local scales at which these Organisms respond to flow. Flow (especially characteristics linked to the velocity field) can strongly affect habitat characteristics, dispersal, resource acquisition, competition, and predation; creative experiments will be needed to disentangle these complex interactions. Benthic Organisms usually reside within the roughness layer, where the unique arrangement of sediment particles produces strongly sheared and highly three-dimensional flow patterns. Thus, accurate characterization of the local flow environments experienced by Benthic Organisms often requires the use of flow measurement technology with high spatial and temporal resolution. Because flow exhibits variation across a broad range of sca...

  • Physical-Biological Coupling in Streams: The Pervasive Effects of Flow on Benthic Organisms
    Annual Review of Ecology and Systematics, 1999
    Co-Authors: David D. Hart, Christopher M. Finelli
    Abstract:

    Flowing water has profound effects on a diverse array of ecological processes and patterns in streams and rivers. We propose a conceptual framework for investigating the multiple causal pathways by which flow influences Benthic biota and focus particular attention on the local scales at which these Organisms respond to flow. Flow (especially characteristics linked to the velocity field) can strongly affect habitat characteristics, dispersal, resource acquisition, competition, and predation; creative experiments will be needed to disentangle these complex interactions. Benthic Organisms usually reside within the roughness layer, where the unique arrangement of sediment particles produces strongly sheared and highly three-dimensional flow patterns. Thus, accurate characterization of the local flow environments experienced by Benthic Organisms often requires the use of flow measurement technology with high spatial and temporal resolution. Because flow exhibits variation across a broad range of scales, it is also necessary to examine how organism-flow relationships at one scale are linked to those at others. Interdisciplinary approaches are needed in the study of physical-biological coupling; increased collaboration between ecologists and experts in fluid mechanics and hydraulic engineering is particularly desirable. A greater understanding of physical-biological coupling will not only yield deeper insights into the ecological organization of streams and rivers, it will also improve our ability to predict how flow alterations caused by various human activities affect these vital ecosystems.

  • turbulent transport of suspended particles and dispersing Benthic Organisms how long to hit bottom
    Journal of Theoretical Biology, 1997
    Co-Authors: James N. Mcnair, Denis J Newbold, David D. Hart
    Abstract:

    Abstract Turbulence plays an important role in the transport of particles in many aquatic systems. In addition to various types of inorganic sediment (silt, sand, etc.), these particles typically include bacteria, algae, invertebrates, and fine organic debris. In this paper, we focus on one aspect of turbulent particle transport; namely, the average time required for a suspended particle to reach the bottom of a waterbody from a specified initial elevation. This is the mean hitting-time problem, and it is important in determining, for example, the effect of turbulence on downstream transport of organic particles, dispersal times and dispersal propagules. We approach this problem by developing a stochastic diffusion model of particle transport called the Local Exchange Model, which is an extension of a model posed by Denny & Shibata (1989) in an earlier study of the same problem. We show how the mean hitting-time of the Local Exchange Model varies with factors such as a particle's fall velocity an the shape of the vertical profile in turbulent mixing. We also show how the mean hitting-time is related to both the vertical profile in current velocity and the vertical profile in concentration of suspended particles, and how these relationships can be exploited in testing the model. Among other things, our results predict that, with the sole exception of neutrally buoyant particles that do not swim downward, there is always a region of the water-column in which turbulence increases rather than decreases the mean hitting-time. We discuss the significance of this and other results for dispersal by Benthic Organisms.

Christopher M. Finelli - One of the best experts on this subject based on the ideXlab platform.

  • physical biological coupling in streams the pervasive effects of flow on Benthic Organisms
    Annual Review of Ecology Evolution and Systematics, 1999
    Co-Authors: David D. Hart, Christopher M. Finelli
    Abstract:

    ▪ Abstract Flowing water has profound effects on a diverse array of ecological processes and patterns in streams and rivers. We propose a conceptual framework for investigating the multiple causal pathways by which flow influences Benthic biota and focus particular attention on the local scales at which these Organisms respond to flow. Flow (especially characteristics linked to the velocity field) can strongly affect habitat characteristics, dispersal, resource acquisition, competition, and predation; creative experiments will be needed to disentangle these complex interactions. Benthic Organisms usually reside within the roughness layer, where the unique arrangement of sediment particles produces strongly sheared and highly three-dimensional flow patterns. Thus, accurate characterization of the local flow environments experienced by Benthic Organisms often requires the use of flow measurement technology with high spatial and temporal resolution. Because flow exhibits variation across a broad range of sca...

  • Physical-Biological Coupling in Streams: The Pervasive Effects of Flow on Benthic Organisms
    Annual Review of Ecology and Systematics, 1999
    Co-Authors: David D. Hart, Christopher M. Finelli
    Abstract:

    Flowing water has profound effects on a diverse array of ecological processes and patterns in streams and rivers. We propose a conceptual framework for investigating the multiple causal pathways by which flow influences Benthic biota and focus particular attention on the local scales at which these Organisms respond to flow. Flow (especially characteristics linked to the velocity field) can strongly affect habitat characteristics, dispersal, resource acquisition, competition, and predation; creative experiments will be needed to disentangle these complex interactions. Benthic Organisms usually reside within the roughness layer, where the unique arrangement of sediment particles produces strongly sheared and highly three-dimensional flow patterns. Thus, accurate characterization of the local flow environments experienced by Benthic Organisms often requires the use of flow measurement technology with high spatial and temporal resolution. Because flow exhibits variation across a broad range of scales, it is also necessary to examine how organism-flow relationships at one scale are linked to those at others. Interdisciplinary approaches are needed in the study of physical-biological coupling; increased collaboration between ecologists and experts in fluid mechanics and hydraulic engineering is particularly desirable. A greater understanding of physical-biological coupling will not only yield deeper insights into the ecological organization of streams and rivers, it will also improve our ability to predict how flow alterations caused by various human activities affect these vital ecosystems.

Lee P Ferguson - One of the best experts on this subject based on the ideXlab platform.

  • bioaccumulation and toxicity of single walled carbon nanotubes to Benthic Organisms at the base of the marine food chain
    Environmental Toxicology and Chemistry, 2013
    Co-Authors: Ashley N Parks, Lisa M Portis, Ariette P Schierz, Kate M Washburn, Monique M Perron, Robert M Burgess, Kay T Ho, Thomas G Chandler, Lee P Ferguson
    Abstract:

    As the use of single-walled carbon nanotubes (SWNTs) increases over time, so does the potential for environmental release. This research aimed to determine the toxicity, bioavailability, and bioaccumulation of SWNTs in marine Benthic Organisms at the base of the food chain. The toxicity of SWNTs was tested in a whole sediment exposure with the amphipod Ampelisca abdita and the mysid Americamysis bahia. In addition, SWNTs were amended to sediment and/or food matrices to determine their bioavailability and bioaccumulation through these routes in A. abdita, A. bahia, and the estuarine amphipod Leptocheirus plumulosus. No significant mortality to any species via sediment or food matrices was observed at concentrations up to 100 ppm. A novel near-infrared fluorescence spectroscopic method was utilized to measure and characterize the body burdens of pristine SWNTs in nondepurated and depurated Organisms. We did not detect SWNTs in depurated Organisms but quantified them in nondepurated A. abdita fed SWNT-amended algae. After a 28-d exposure to [14C]SWNT-amended sediment (100 µg/g) and algae (100 µg/g), [14C]SWNT was detected in depurated and nondepurated L. plumulosus amphipods at 0.50 µg/g and 5.38 µg/g, respectively. The results indicate that SWNTs are bioaccessible to marine Benthic Organisms but do not appear to accumulate or cause toxicity. Environ Toxicol Chem 2013;32:1270–1277. © 2013 SETAC

Neville S. Barrett - One of the best experts on this subject based on the ideXlab platform.

  • Spatial properties of sessile Benthic Organisms and the design of repeat visual survey transects
    Aquatic Conservation: Marine and Freshwater Ecosystems, 2019
    Co-Authors: Nicholas R. Perkins, Nicole A. Hill, Scott D. Foster, Geoffrey R. Hosack, Neville S. Barrett
    Abstract:

    Monitoring the impacts of pressures, such as climate change, on marine Benthic ecosystems is of high conservation priority. Novel imaging technologies, such as autonomous underwater vehicles (AUVs), remotely operated vehicles (ROVs), and towed systems, now give researchers the ability to monitor Benthic ecosystems over large spatial and temporal scales. The design of monitoring programmes that use such technologies is currently hindered by a lack of information about the typical abundance and spatial distributions of target indicators and the level of sampling required to detect changes. A further complicating factor is that these sampling platforms are often not able to be exactly relocated when conducting repeat surveys. How the spatial properties of Benthic Organisms influence the estimates of cover, given alternative designs that vary in the geolocation precision of transects and the sampling intensity of images, is explored. A geostatistical modelling approach is used to quantify the spatial distribution of 20 key deep-water invertebrate species at a long-term monitoring site. The parameter estimates from these models are then used to simulate repeat transects with geolocation error and different levels of sampling. Results suggest that species with short effective ranges (i.e. those with strong spatial dependence over relatively short distances) and large spatial variance, which suggests strong spatial dependence effects, will require greater sampling effort to achieve a given standard of precision. Spatial offsets of 2 m, typical of an AUV, are unlikely to have dramatic impacts on the precision of estimates when sufficient images are sampled, but offsets of 10 m that are typical of towed systems may require a prohibitively high sampling effort for some species. These findings have important implications for Benthic monitoring programmes, and highlight the importance of considering the interactions between sampling design, the technical limitations of survey equipment, and the spatial properties of indicator species. © 2018 John Wiley & Sons, Ltd.

  • Spatial properties of sessile Benthic Organisms and the design of repeat visual survey transects
    Aquatic Conservation-marine and Freshwater Ecosystems, 2018
    Co-Authors: Nicholas R. Perkins, Nicole A. Hill, Scott D. Foster, Geoffrey R. Hosack, Neville S. Barrett
    Abstract:

    Monitoring the impacts of pressures, such as climate change, on marine Benthic ecosystems is of high conservation priority. Novel imaging technologies, such as autonomous underwater vehicles (AUVs), remotely operated vehicles (ROVs), and towed systems, now give researchers the ability to monitor Benthic ecosystems over large spatial and temporal scales. The design of monitoring programmes that use such technologies is currently hindered by a lack of information about the typical abundance and spatial distributions of target indicators and the level of sampling required to detect changes. A further complicating factor is that these sampling platforms are often not able to be exactly relocated when conducting repeat surveys. How the spatial properties of Benthic Organisms influence the estimates of cover, given alternative designs that vary in the geolocation precision of transects and the sampling intensity of images, is explored. A geostatistical modelling approach is used to quantify the spatial distribution of 20 key deep‐water invertebrate species at a long‐term monitoring site. The parameter estimates from these models are then used to simulate repeat transects with geolocation error and different levels of sampling. Results suggest that species with short effective ranges (i.e. those with strong spatial dependence over relatively short distances) and large spatial variance, which suggests strong spatial dependence effects, will require greater sampling effort to achieve a given standard of precision. Spatial offsets of 2 m, typical of an AUV, are unlikely to have dramatic impacts on the precision of estimates when sufficient images are sampled, but offsets of 10 m that are typical of towed systems may require a prohibitively high sampling effort for some species. These findings have important implications for Benthic monitoring programmes, and highlight the importance of considering the interactions between sampling design, the technical limitations of survey equipment, and the spatial properties of indicator species.

Peter J Wagner - One of the best experts on this subject based on the ideXlab platform.

  • extinction trajectories of Benthic Organisms across the triassic jurassic boundary
    Palaeogeography Palaeoclimatology Palaeoecology, 2007
    Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J Wagner
    Abstract:

    Abstract We analysed diversity and abundance patterns of Benthic Organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macroBenthic groups of the Late Triassic experienced significant extinctions prior to the T-J boundary, a significant end-Triassic extinction peak is evident from PBDB's data. This Rhaetian extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesoBenthic and macroBenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic extinction as a true mass extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass extinctions, evidence for selective extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of extinction risk become evident, suggesting that reef dwellers had a significantly higher extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background extinctions suggesting that the end-Triassic mass extinction represents an intensification of background extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian extinction in reefs and inshore settings.

  • Extinction trajectories of Benthic Organisms across the Triassic–Jurassic boundary
    Palaeogeography Palaeoclimatology Palaeoecology, 2007
    Co-Authors: Wolfgang Kiessling, Martin Aberhan, Benjamin Brenneis, Peter J Wagner
    Abstract:

    Abstract We analysed diversity and abundance patterns of Benthic Organisms across the Triassic–Jurassic (T-J) boundary based on the Paleobiology Database (PBDB), which compiles palaeontological collection data on a global scale. While Sepkoski's [Sepkoski, J.J. Jr., 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363, 1–563] compendium on the stratigraphic ranges of marine animal genera suggests that the dominant macroBenthic groups of the Late Triassic experienced significant extinctions prior to the T-J boundary, a significant end-Triassic extinction peak is evident from PBDB's data. This Rhaetian extinction peak is found in both an analysis of the raw data of stratigraphic ranges and a sample-standardized analysis of occurrence data; 41% of all mesoBenthic and macroBenthic genera crossing the Norian–Rhaetian boundary became extinct within the Rhaetian. Although this rate suffices to characterize the end-Triassic extinction as a true mass extinction against a Middle Triassic to Middle Jurassic background, significantly reduced Rhaetian origination rates add to the strong diversity depletion in the earliest Jurassic. As for other mass extinctions, evidence for selective extinction is meagre when the analysis is limited to the boundary interval alone and when focused on taxonomic and ecological characteristics of individual genera. When taxa are separated by environmental preferences, however, several determinants of extinction risk become evident, suggesting that reef dwellers had a significantly higher extinction risk than level-bottom dwellers, taxa with an inshore preference were more strongly affected than offshore taxa, taxa preferring carbonate substrates were more strongly hit than taxa preferring siliciclastic substrates and taxa preferentially inhabiting low latitudes had higher extinction rates than taxa more common at intermediate and high latitudes. Much of this selectivity is not independent and also seen in the intervals of background extinctions suggesting that the end-Triassic mass extinction represents an intensification of background extinctions but not a qualitatively different macroevolutionary regime. One possible exception is related to preferences for depositional environments suggesting a selective Rhaetian extinction in reefs and inshore settings.