Transcript DIatoms
Nate and Solon DIATOMS Description: •Phylum Bacillariophyta •Unicellular, few in colonies •Cell wall consists of two shells that overlap where they fit together •Silica is deposited in the shell (intricate patterns) •Photosynthetic (chlorophylls a and c and cartenoids) yellow/brown •Important food source for marine organisms. •Estimated to contribute up to 45% of the total oceanic primary production (Photosynthesis) (large numbers) •Energy reserves stored as oils or chrysolaminarin-water-soluble carbohydrate Two Basic Types of Diatoms •With radial symmetry: wheel shaped •With Bilateral Symmetry: Boat shaped Location • Common in Fresh Water but abundant in cool ocean water •Some are part of the floating plankton, others live on rocks and sediments. Movement • Gliding Movement: • Facilitated by the secretion of a slimy material from a small groove along the shell Reproduction •Mostly Asexual Reproduction • By cell division • The two halves of its shell separate and each becomes the larger half of a new diatom shell • Glass shell cannot grow • Smaller and smaller each succeeding generation •Sexual reproduction triggered when diatom is small fraction of original size • Produce shell-less gametes • Zygote, a 2n cell results from the fusion of n gametes, grows before producing a new shell. Miscellaneous At least one species toxic shellfish poisonings, marine mammal strandings, and deaths of over 400 sea lions Pseudo-nitzchia australis When diatoms die, shells trickle down to ocean floor Accumulate in layers Sedimentary rock Diatomaceous earth Refine sugar and process vegetable oils Common ingredient in scouring powders and metal polishes No longer added to toothpaste