This document summarizes different types of microbes found in the microbial world. It describes prokaryotes like bacteria that come in different shapes and have a variety of metabolic functions. Archaea are also described as single-celled microorganisms that lack organelles. The document outlines different types of microbial metabolisms including autotrophs that produce their own food and heterotrophs that obtain energy through respiration. It also summarizes various protists like algae, diatoms, dinoflagellates, foraminiferans, radiolarians, and ciliates. Fungi are also briefly discussed as eukaryotic decomposers and parasites.

1. THE MICROBIAL WORLD

3. Prokaryotes
 Structurally simple
 Have a great range of metabolic activities

4. Prokaryotes
 three main shapes: spheres, rods and spiral
 (coccus, bacillus, spirillum)

5. Prokaryotes
 Study of bacteria is known as bacteriology, a branch of
microbiology

7. Archaea
 Group of single-celled
microorganisms
 Among the simplest, most
primitive forms of life
 No cell nucleus or
organelles

8. Archaea
 Archaeon: an individual or species from the domain
Archaea
 Some types of archaea were recently discovered at
extreme temperatures around hydrothermal vents
were thought to only be extremophiles
 Common in marine environments, including sediment

10. Prokaryote Metabolism
 Metabolism: All the chemical reactions that take place
inside an organism

11. Prokaryote Metabolism
 Autotrophs are primary producers which make their
own organic compounds
 Photoautotrophs
 Chemoautotrophs

12. Photoautotrophs
 make organic compounds using photosynthesis
 contain chlorophyll and other photosynthetic
pigments

13. Photoautotrophs
 Photosynthesis occurs within the folded membranes
of the bacterial cell
 No chloroplasts
 Accounts for much of the primary production in open-
ocean areas

14. Chemoautotrophs
 Gain energy from chemical
compounds instead of from
light
 Including hydrogen sulfide
(H2S) and other sulfur,
nitrogen and iron
compounds

15. Heterotrophs
 obtain energy from respiration
 some use aerobic and some use anaerobic respiration

16. Heterotrophs
 Anaerobic bacteria do not grow when oxygen is
present and thrive when oxygen is absent
 Especially in sediments deprived of oxygen (anoxic)

18. Unicellular Algae
 Algae: (s. alga) are a very diverse group of simple,
mostly aquatic, mainly photosynthetic organisms

19. Unicellular Algae
 Eukaryotic
 Photosynthesis occurs
in chloroplasts
 Color results from
pigments and their
concentrations
 Range in size and
complexity

20. Unicellular Algae
 Algae lack true roots, stems, and leaves
 Multicellular seaweeds are considered protists,
because they lack the specialized tissues of plants

22. Diatoms
 Unicellular, many aggregate into
chains or star-shaped groups
 round, two-piece frustule: glassy shell
 Diatom cells are enclosed by cell walls
made mainly of silica (SiO2)
 allows light to pass through so golden-
brown chloroplasts can capture light
energy for photosynthesis

23. Diatoms
 Many frustules have intricate perforations or
ornaments such as spikes or spines
 perforations allow gases and nutrients to pass in and
out
 Their sinking is often slowed by oil present in their
cells or in the spines of the frustule
 Carotenoids give diatoms their characteristic yellow-
brown color

24. Diatoms
 The frustules of dead
diatoms contribute to
biogeneous sediment
known as diatomaceous
ooze
 This siliceous material or
diatomaceous earth is
mined and used in
products for filtering
swimming pools,
clarifying beer, and mild
abrasives in toothpaste

25. Dinoflagellates
 1,200 living species
 Important primary
producers
 Possess 2 flagella
 One along the groove
in the center
 One floating along
freely

26. Dinoflagellates
 Most have a cell wall
armored with plates made
of cellulose called a theca
 Most photosynthesize
 Many also ingest food
particles
 A few have a light-
sensitive spot that acts as
a crude eye

27. Algal Blooms
 Sometimes form
blooms that color the
water red, yellow or
another unusual shade
 Algal bloom: a rapid,
sudden growth in the
number of algae

28. Algal Blooms
 Under favorable conditions, dinoflagellates can divide
every 8-12 hours
 Some dinoflagellates use bioluminescence - emit light

29. Red Tide
 Some release toxic substances and seafood
collected during these “red-tide” periods may be
poisonous
 certain dinoflagellates produce a neurotoxins called
saxitoxin and brevetoxin
 concentrated in the tissues of filter feeders such as clams
and mussels

30. Red Tide
 when these shellfish are
consumed by humans and
they ingest high
concentrations of
brevetoxin or saxitoxin,
paralytic shellfish poisoning
(PSP)results
 in severe cases death can
result in 12-24 hours

31. Red Tide
 saxitoxin is over 100,000 times more potent than
cocaine and concentrations sufficient to cause
poisoning may be present in shellfish when “red tide”
is not noticeable

32. Red Tide

33. Red Tide

35. Zooxanthellae
 Zooxanthellae: A group of round, golden-brown
dinoflagellates that live in close proximity to animals

36. Zooxanthellae
 Animals that harbor zooxanthellae include sponges,
sea anemones, and giant clams

38. Other Unicellular Algae
 Three additional
groups are very
significant primary
producers
 All three groups are so
small 100s could fit
inside a large diatom
or dinoflagellate cell

39. Other Unicellular Algae
 1. Silicoflagellates
 Characterized by a star-shaped internal skeleton made
of silica and two flagella of different lengths
 Can be used to date sediment

40. Other Unicellular Algae
 2. Coccolithophorids
 Flagellated, spherical cells
 Covered with button-like ornamental structure
 Coccoliths may be found in sediment as fossils

41. Other Unicellular Algae
 3. Cryptophytes
 Have two flagella and lack a skeleton
 Have a chloroplast

43. Protozoans
 Protozoan - structurally simple and very diverse
eukaryotic organisms that are traditionally considered
animal-like

44. Foraminiferans
 Foraminiferans: often called
forams, are marine protozoans
that usually have a shell or test
made of calcium carbonate
 Have long, thin, retractable
pseudopodia (false feet),
extensions of the cytoplasm
 Most live on the ocean bottom
either free or attached

45. Foraminiferans
 Foraminiferan Ooze: A form of calcareous ooze
consisting mainly of the shells of deceased forams

46. Foraminiferans
 Shells of warm water
species are larger and more
porous than those from
colder waters
 distribution of shells can
be used to determine past
water temperatures
 Good indicator of the right
type of environment for
the formation of oil and
the age of the sediment

47. Radiolarians
 radiolarians: Planktonic marine protozoans that
secrete elaborate and delicate shells made of glass
(silica) and other materials

48. Radiolarians
 Typical shells are spherical with radiating spines
 Thin needle like pseudopodia capture food particles,
like forams

49. Radiolarians
 Microscopic but form large colonies that reach 3m
(9ft) in length
 Inhabit open oceans

50. Ciliates
 Ciliates: Protozoans with many hair-like cilia used in
locomotion and feeding

51. Ciliates
 A familiar ciliate is the
paramecium - freshwater
 Many ciliates live in unusual
places
 On the gills of clams,
intestines of sea urchins, or
the skin of fish

53. Fungi
 Fungi: eukaryotic and mostly multicellular plant-like
heterotrophs
 Molds and yeasts - unicellular
 At least 500 species of marine fungi
 mostly microscopic

54. Fungi
 Important decomposers
 Many are parasitic
 Some are symbiotic, such
as lichens
 Lichen provides support,
plant provides food