The Microbial WorldChapter 5

Prokaryotic MetabolismAutotrophsHeterotrophs

AutotrophsSome bacteria and archaea make their own

organic compounds Primary producers If they do photosynthesis it takes place in on

folded membranes in the bacteria cellPhotosynthetic bacteria account for much of

the primary production of open oceanOther bacterial autotrophs- chemosynthetic

bacteria

HeterotrophsMost marine bacteria are heterotrophsHeterotrophs obtain energy from organic

matter by respirationRespiration in aerobic bacteria and archaea

use oxygenIn Anoxic sediments bacteria use anaerobic

respiration

Nitrogen FixationBottom dwelling and planktonic

cyanobacteria carry out nitrogen fixation

Nitrogen fixation N2 NH4 (covert nitrogen to ammonium)

Ammonium is then transferred into NO3- (nitrate) and other N compoundsThese N sources can be used by primary

producers

Unicellular Algae Algae – very diverse group (mostly aquatic,

mostly photosynthetic) Eukaryotic- cells have a nucleus, organellesPhotosynthesis- ChloroplastLack true leaves, stems, roots

Have plant and animal characteristics- Protista

DiatomsUnicellular but they can be colonial or form

groups or chainsIn a shell made of silica frustule (2 halves) The perforations allow dissolved gases and

nutrients to enter and exitColoration- carotenoid pigments (few are

colorless) Photosynthetic factoriesSome are toxic

Diatom ReproductionAsexual reproductionAuxospores- resistant stages that eventually

give rise to larger cells that display the frustule characteristic of the species **get smaller each division**

Favorable conditions- bloomDiatomaceous ooze- dead diatoms sink and

form thick deposits of siliceous material

DinoflagellatesLarge group of planktonic unicellular

organisms2 flagella, cell wall, platesPhotosynthesize and ingest Reproduction is almost exclusively by cell

divisionBioluminescence Toxic

Protozoans (animal like protists)Eukaryotic Structure is simpleAnimal likeProtozoans comprise several groups of

unrelated originsHeterotrophs and some photosynthesize

ForaminiferansType of marine protozoanHave a shell (test) made of CaCO3Pseudopodia- extensions of the cytoplasmLive on the bottom either free or attached

Shells of bottom forams are important contributors to calcarious material

White cliffs of Dover

RadiolariansPlanktonic marine protozoansSecrete shells of glass and other materials Typical shells are spherical with radiating

spines Sausage shaped coloniesWhen they die and sink to the bottom they

become silicious ooze Resistant to dissolving under pressure

CiliatesProtozoansLots of hair like extentions

Locomotion and feedingFound all over seaweeds and in bottom

sedimentsLive in gills of clams, urchin intestines,skin of

fish

FungiEukaryotic and mostly multicellular

Molds, yeasts are unicellular They are heterotrophs that lack chloroplasts500 species of marine fungi (most are

microscopic)Decompose detritusSome are parasitesSome form symbiotic relationships with algae

lichens

Microbial worldProkaryotes EukaryotesBacteria

Cyanobacteria (stromatolites)

ArchaeaExtremophiles

DiatomsDinoflagellatesProtozoans (animal like)

ForaminieransRadiolarians

Fungi

PresentationRow 1 –DiatomsRow 2- DinoflagellatesRow 3- Foraminiferans-Row 4 RadiolariansRow 5- CiliatesRow 6- Fungi

Row 7: Cyanobacteria

Poster RubricImageDefinitionAt least 5 facts Importance to marine environment/role in

marine environment

** this will be a graded assignment**