GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2022-05-25
    Description: Author Posting. © Inter-Research, 2006. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 306 (2006): 51-61, doi:10.3354/meps306051.
    Description: Optical imaging samplers are becoming widely used in plankton ecology, but image analysis methods have lagged behind image acquisition rates. Automated methods for analysis and recognition of plankton images have been developed, which are capable of real-time processing of incoming image data into major taxonomic groups. The limited accuracy of these methods can require significant manual post-processing to correct the automatically generated results, in order to obtain accurate estimates of plankton abundance patterns. We present here a dual-classification method in which each plankton image is first identified using a shaped-based feature set and a neural network classifier, and then a second time using a texture-based feature set and a support vector machine classifier. The plankton image is considered to belong to a given taxon only if the 2 identifications agree; otherwise it is labeled as unknown. This dual-classification method greatly reduces the false positive rate, and thus gives better abundance estimation in regions of low relative abundance. A confusion matrix is computed from a set of training images in order to determine the detection and false positives rates. These rates are used to correct abundances estimated from the automatic classification results. Aside from the manual sorting required to generate the initial training set of images, this dual-classification method is fully automatic and does not require subsequent manual correction of automatically sorted images. The resulting abundances agree closely with those obtained using manually sorted results. A set of images from a Video Plankton Recorder was used to evaluate this method and compare it with previously reported single-classifier results for major taxa.
    Description: The work was funded by National Science Foundation Grants OCE-9806498, OCE-9820099, and OCE-0000570.
    Keywords: Plankton ; Video ; Sampling ; Pattern recognition ; Real-time ; Rejection
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2022-05-25
    Description: Author Posting. © Inter-Research, 2008. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 360 (2008): 179-187, doi:10.3354/meps07314.
    Description: Complex 3D biological-physical models are becoming widely used in marine and freshwater ecology. These models are highly valued synthesizing tools because they provide insights into complex dynamics that are difficult to understand using purely empirical methods or theoretical analytical models. Of particular interest has been the incorporation of concentration-based copepod population dynamics into 3D physical transport models. These physical models typically have large numbers of grid points and therefore require a simplified biological model. However, concentration-based copepod models have used a fine resolution age-stage structure to prevent artificially short generation times, known as numerical ‘diffusion.’ This increased resolution has precluded use of age-stage structured copepod models in 3D physical models due to computational constraints. In this paper, we describe a new method, which tracks the mean age of each life stage instead of using age classes within each stage. We then compare this model to previous age-stage structured models. A probability model is developed with the molting rate derived from the mean age of the population and the probability density function (PDF) of molting. The effects of temperature and mortality on copepod population dynamics are also discussed. The mean-age method effectively removes the numerical diffusion problem and reproduces observed median development times (MDTs) without the need for a high-resolution age-stage structure. Thus, it is well-suited for finding solutions of concentration-based zooplankton models in complex biological-physical models.
    Description: This work was supported by US GLOBEC NOAA grant NA17RJ1223.
    Description: 2013-05-22
    Keywords: Plankton ; Copepods ; Modeling ; Marine ecology ; Oceanography ; Limnology ; Methodology ; Mean age
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    Woods Hole Oceanographic Institution
    Publication Date: 2022-05-26
    Description: To enhance collaboration between researchers who model upper ocean biological/physical processes, a workshop was held at WHOI on June 7-12, 1993. The workshop was part of our on-going URIP project entitled "Modeling Biological-Physical Interactions: A Population Biological Approach" sponsored by ONR (Grant N000l4-92-J-1527). The two principal goals of the workshop were to: 1) identify critical problems related to mixed-layer biological-physical models, and 2) develop approaches for solving these problems. The workshop was organized into two parts to address these goals. The first part, held over the first day and a half, included three overview presentations given in plenary followed by working groups, organized along disciplinary lines, to identify critical issues. The second part of the workshop consisted of working groups, organized across disciplines, using "hands-on" modeling to address critical aspects of coupled biological-physical models. Several coupled models were presented and/or developed at the workshop addressing specific aspects of both the biological and physical dynamics. These aspects included the different mixed-layer formulations, a structured grazer population model, and an allometric food-web model including microbial-loop dynamics.
    Description: Funding was provided by the University Research Initiative Program and the Office of Naval Research under Grant No. ONR-URIP N00014-92-J-1527.
    Keywords: Biological/physical modeling ; Upper ocean ; Mixed-layer
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
    Format: 4157061 bytes
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2022-05-26
    Description: This report summarizes the findings of the joint WHOI-NEFC seminar series on recruitment processes in marine fish populations. The seminar series reviewed the status of knowledge of the recruitment process together with on-going research in this field. From the seminars presented it was evident that potentially important biological and physical processes which may control recruitment occur throughout the entire first year of life. It is important to understand the causes of recruitment variability in order to know the degree to which density dependence controls marine fish population dynamics. Future research, therefore, should not focus on a single process or life stage but instead should evaluate all potentially important processes throughout the first year of life.
    Description: Partial funding provided through the National Marine Fisheries Service as part of a cooperative agreement with the the Woods Hole Oceanographic Institution and through a grant to the Center for Analysis of Marine Systems of the Woods Hole Oceanographic Institution.
    Keywords: Fish populations ; Fishes ; Fishery management
    Repository Name: Woods Hole Open Access Server
    Type: Technical Report
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...