Life Sciences Commons^™

Evaluation Of Automated Threshold Selection Methods For Accurately Sizing Microscopic Fluorescent Cells By Image-Analysis, Me Sieracki, Se Reichenbach, Kl Webb

VIMS Articles

The accurate measurement of bacterial and protistan cell biomass is necessary for understanding their population and trophic dynamics in nature. Direct measurement of fluorescently stained cells is often the method of choice. The tedium of making such measurements visually on the large numbers of cells required has prompted the use of automatic image analysis for this purpose. Accurate measurements by image analysis require an accurate, reliable method of segmenting the image, that is, distinguishing the brightly fluorescing cells from a dark background. This is commonly done by visually choosing a threshold intensity value which most closely coincides with the outline …

Ingestion Of Gametes By Protists: Fate Of Surplus Reproductive Energy In The Sea, Hm Galvao, At Fritz, R Schmaljohann

VIMS Articles

No abstract provided.

Evidence Of A Semiannual Reproductive Cycle For The Sea Scallop, Placopecten Magellanicus (Gmelin, 1791), In The Mid-Atlantic Region, William D. Dupaul, James E. Kirkley, Anne C. Schmitzer

VIMS Articles

The reproductive cycle of the sea scallop, Placopecten magellanicus in the mid-Atlantic region was studied over a 15 month period. One to 15 samples a month were collected from commercial vessels fishing from Long Island to Cape Hatteras in water depths of 37-68 m. Gonad weights were determined for four shell size intervals as an indicator of the reproductive cycle. A sharp decline in mean gonad weights between April-May 1987 and a subsequent increase and decrease in weights between SeptemberNovember 1987 indicated reproductive processes were occurring on a semiannual cycle. A major spring spawning season was reconfirmed in 1988 by …

Algorithm To Estimate Cell Biovolume Using Image Analyzed Microscopy, Me Sieracki, Cl Viles, Kl Webb

VIMS Articles

This paper describes an algorithm for calculating the biovolume of cells with simple shapes, such as bacteria, flagellates, and simple ciliates, from a 2-dimensional digital image. The method can be adapted to any image analysis system which allows access to the binary cell image-( i.e., the pixels, or (x,y) points, composing the cell. The cell image is rotated to a standard orientation (horizontal), inand a solid of revolution is calculated by digital integration. Verification and a critical assessment of the method are presented. The algorithm accounts for irregularities in cell shape that conventional methods based on length, width, and geometrical …

Autotrophic Picoplankton Dynamics In A Chesapeake Bay Sub-Estuary, Rt Ray, Lw Hass, Me Sieracki

VIMS Articles

No abstract provided.

A Comparison Of The Utermohl And Epifluorescent Microscopic Techniques For Quantifying Natural Picophytoplankton : Final Report, Leonard W. Haas, Harold G. Marshall

Reports

The phytoplankton monitoring program in the Virginia portion of the Chesapeake Bay was initiated in July 1985. A total of 13 stations (7 in the lower Chesapeake Bay and 6 in the major trtbutaries) are sampled on a regular basis to quantify phytoplankton (Birdsong et al., 1987; 1988). A primary objective of the monitoring program is to document longterm trends in phytoplankton abundance and species composition and use this information as one means of evaluating the effectiveness of pollution abatement strategies, particularly related to the reduction of nutrients to the Chesapeake Bay.

The philosophy of monitoring programs is to consistently …