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These web pages, though created for anyone interested in phytoplankton, are aimed toward the technician and the student who look at water samples daily and must count and identify the phytoplankton species under normal working conditions. Though some textbooks and websites display stunning micrographs of phytoplankton species, few environmental laboratories use electron microscopes to make routine identifications. Consequently, identifying phytoplankton can be a long and arduous duty depending on the complexity and the condition of the sample. It is our hope that students as well as seasoned technicians will view this collection and find photos of species that are representative of what they encounter in their own samples

The photos presented include phytoplankton species encountered in the Chesapeake Bay and its tributaries since 1988. As a tidal estuary, the Chesapeake Bay and its tributaries offer a multitude of both saline and freshwater phytoplankton varieties. Also included are phytoplankton species collected from other areas such as Antarctica, Belize, Abu Dhabi UAE, Panama, Vietnam and India. The photos and data will be updated as additional species are found and photographed. Films used in the photography were Kodak ASA 40, Kodak ASA 25, Fuji ASA 50, Agfa ASA 50, and Kodachrome 64. Beginning September 2002, all photo micrographs of algae have been taken on an Olympus DP12 digital camera attached to an Olympus IX71 inverted phase microscope. Beginning in July 2011 the DP12 was upgraded to DP12 using cellSens 1.5 software. Photographs were taken by taxonomist Sharyn Hedrick unless otherwise noted.

Samples are fixed with a variety of preservatives, any of which can distort the appearance of certain species, or even destroy those with soft bodies that are often in the same sample. Frequently, preserved samples sit on shelves for long periods of time prior to analysis using light microscopy methods. Distortion may also occur due to the physical parameters of the water from which the phytoplankton was taken.
Unusually high temperature and salinity in an estuarine environment can stress ambient species so that when collected and fixed, species that preserve well under normal circumstances may distort and rupture. Mineral deposits and detritus also hinder the identification process. Lastly, the species themselves may fall in a position that the technician has never encountered before, which can lead to misidentification. There is more than one photo included of some species in an attempt to show the different shapes a species may assume when under stress. There are estuarine, oceanic, and freshwater species in the collection along with microzooplankton and miscellaneous items frequently found in water samples.

Viewing the pages on this website may be delayed due to the size and number of photographs. We apologize for any inconvienence this may cause.
Funding for this project is provided by the Smithsonian Environmental Science Program.
Comments and suggestions are welcome. Email to