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Understanding Diatoms: Their Importance, Characteristics, and Environmental Roles

Diatoms are fascinating, single-celled organisms belonging to the Phylum Bacillariophyta, found in diverse habitats such as freshwater, marine environments, and even trees. Characterized by their unique siliceous frustules, they play a crucial role in carbon fixation and contribute significantly to atmospheric oxygen. Diatoms can reproduce asexually and sexually, with varying morphological characteristics across species. They are essential components of the food web, yet can also pose hazards like harmful algal blooms. Understanding diatoms helps us appreciate their ecological significance and impacts on our environment.

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Understanding Diatoms: Their Importance, Characteristics, and Environmental Roles

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  1. Jim Dombroskie • Born in K-W • Attended high school at Eastwood Collegiate • Worked for a couple of years • Attended Sir Sandford Fleming • Hope to graduate from here (someday!) • Work for Crone geophysics

  2. DIATOMS

  3. What are they? • One celled organism • Solitary or colonial • Siliceous • Planktic and Benthic forms • Over 60 000 species • Can be found in almost any moist place • Eukaryotic Grovea pedalis

  4. Environment • Freshwater -puddle -ditch -tree (moss) -lagoon, river, etc • Marine -benthic and planktic areas

  5. Diatom Morphology • Frustule (skeleton) -hypotheca -epitheca -can have varying shapes • Punctae • Raphe (groove) • No flagella

  6. Classification • Phylum Bacillariophyta • Class Diatomatae • Order Centrales • Order Pennales • Although some put it in the phylum Chrysophyta

  7. Order Centrales • Centric • Dominate marine environments • Cret. To Rec. • Radially symmetrical -although they can have varying shapes

  8. Order Pennales • Pennate (elongate) • Dominate non-marine environments • Paleocene to Recent • Bilaterally symmetrical -features perpendicular to long axis

  9. Reproduction • Asexual • Mitosis • Alternation between both • Progressive decrease in size

  10. Reproduction • Sexual • Meiosis • Gametes released and combined with another • Zygote

  11. Importance • Responsible for 20%-25%of all carbon fixation (CO2 + H2O = sugars) • Contribute to atmospheric oxygen • Major component of plankton (source of food for many organisms • Age dating (many have short time ranges) • Dynamite, abrasive, filter, etc. • Grass of the Sea

  12. Hazardous • genus Pseudonitzschia • Domoic acid • binds to the glutamate receptors in the brain where it causes nerve cells to transmit impulses continuously until the cells die • eutrophication processes occurring along our coasts some algae (diatoms!) blooms have caused mass pollution and starvation.

  13. References • http://hjs.geol.uib.no/diatoms/Marbles/index.html-ssi • http://www.microscopy.fsu.edu/primer/techniques/hoffmangallery/diatom.html • http://hjs.geol.uib.no/diatoms/ • http://www.visualsunlimited.com/browse/vu315/vu315607.html • http://earth.leeds.ac.uk/electronoptics/set3/diatom_c.htm • http://www.ucmp.berkeley.edu/chromista/diatoms/diatommm.html

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