Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 5 The Microbial World

2 Microorganisms are the most important primary producers in many marine environment

Viruses

4 Particle not make up of a cell -- consist of small chain of nucleic acid (genetic material) -- protected by a outer coat (capsid( 衣殼 )) Parasites and reproduce after infest a living cell Small: ~20 to 200 nm

5 Viruses type  Retroviruses( 反轉病毒 )  Lysogenic viruses( 溶原病毒 )

6 Retroviruses Store genetic information in the RNA, no DNA Responsible for deadly human disease (e.g. AIDs and leukemia) Reproduction: -- attach into a living cell, inject nucleic acids into the cell -- command the cell to deuplicate the virus -- release as infected cell burst -- infect other cell or infect new host

7 Lysogenic viruses Reproduction: -- inducing nucleic acid become part of the genome of the host cell -- directs the production of new viruses -- viruses released as the infected cell destroyed Bacteriophages

8 Role of viruses in marine ecosystem  Most abundant life-like particles in the ocean -- abundance directly related to the abundance of microbial life; bacteria  Viruses infect bacteria and phytoplankton  Important to “Microbial Loop” -- causing release large quantity of DOM -- release large quantity of essential nutrients  Responsible for diseases of marine life: shellfish, fishes, turtles, even human

9 Prokaryotes

10 Prokaryotes The smallest, structurally simplest and oldest form of life Different from eukaryotes

12 Differences from viruses Cell wall Plasma membranes Cellular machinery Genetic information

13 Two domains  Bacteria  Archaea

15 Bacteria Branched out very early on the tree of life Have many shape Decay bacteria

-- Among the first photosynthetic organisms on earth Cyanobacteria (blue-green algae)

17 Photosynthetic bacteria 3 kinds of photopigments -- phycocyanin ( 藻藍素 ) -- phycoerythrin( 藻紅素 ) -- chlorophyll a

Fossil stromatolites ( 層疊石墊藻岩 )

19 -- Almost everywhere in marine environment -- Epiphytes and endophytes

20 Archaea (archaebacteria)

21 Archaea (archaebacteria) Among the simplist, most primitive form of life -- estimated at least 3.8 billion(38 億 ) years old Characters; (1) small, (2) prokaryotic (3) extremophiles( 極端生 物 )

22 Prokaryote metabolism metabolism metabolism autotrophs; photoautotrophs; chemoautotrophs autotrophs; photoautotrophs; chemoautotrophs

23 Autotrophs  Photoautotrophy -- energy obtained from sun -- e.g. photosynthesis  Chemoautotrophy -- energy obtained from other sources -- e.g. hydrothermal vent; from earth

Hydrothermal vent

25 Heterotrophs  Obtain energy by respiration  bacteria  Decomposer  Aerobic and anaerobic bacteria

Nitrogen fixation covert gases nitrogen to ammonium --

28 Unicellular alga  Characters: (1) aquatic, (2) eukaryotes, (3) chloroplast  Belongs to Protista ( 原生生物 )

29 Unicellular alga Color depends on the pigments and their concentration Lack true leaves, stems and roots

30 Diatom Phylum (or Division) Bacillariophyta Characters: (1) unicellular, (2) frustules

31 Life history characters frustule( 硅藻細胞 ) minute perforation sinking is slow by oil droplet in cells and spines

32 -- Photopigments; carotenoid; chlorophyll a and c -- Important primary producers in temperature and polar regions -- Half of estimated species are marine -- Both pelagic and benthic forms

Asexual reproduction; auxospore( 增大細胞 )

34 Bloom( 藻華 ) Mechanims Mechanims Cells are smaller; asexual reproduction, depletion of silicate from the water column Cells are smaller; asexual reproduction, depletion of silicate from the water column

Biogenous sediment -- Diatomaceous (siliceous) ooze -- diatomaceous earth

36 Dianoflagellates Phylum (or Division) Dinophyra

37 Characters possession two flagella cellulose plate photosynthesis and heterotrophs

38 -- About 1200 species; all marines -- Reproduction almost exclusively by simple cell division -- Produce “red tides”, bioluminance -- Zooxanthellae( 蟲黃藻 ); and function -- Especially bright when disturb by boat or wave crash on shore

39 Other unicellular algaes

40 Silicoflatellates( 硅鞭藻 ) Phylum (or Division) Chryosphytes( 金藻門 ) -- common in marine sediment; used to date the sediment

41 Coccolithophorids, or coccoliths( 球石藻 ) Phylum Haptophyta :

42 Coccoliths Made of calcium carbonate Found in sediment as fossils

43 Cryptomonads( 隱藻 ) Phylum Cryptophyta -- has two flagella -- lack a skeleton

44 Protozoans: animal-like protists  Structurally simple and animal- like  Characters: (1) photosynthesis and heterotrophs, (2) most single- celled, (3) microscope  About species  everywhere and parasites

45 Forminiferans( 有孔蟲 ) Phylum Granuloreticulosa

48 Forminiferans  Forams  Characters; (1) test (calcium carbonate), (2) possess pseudopodia, (3) benthos  Spines to aid in floatation  Shells of bottom-living foram  Foraminiferan ooze

49 Applications  Geological temperature variation  Oil distribution  Determine the age of sediment

50 Radiolarians Phylum Polycystina

51 Radiolarians Planktonic marine protozoans Shell and pseudopodia Inhabit in open ocean throughout the world Radiolarian ooze

52 Ciliates Phylum Ciliophora

53 Ciliates cilia for locomotion and feeding creeping over seaweeds, in bottom sediments, in the intestine and skin of marine animals Important in the microbial loop of open-water; facilitate energy flow

54 Fungi Kingdom Fungi Eukaryotic and most multicellular Multicellular fungi form long filaments called hyphae( 菌絲 ) Heterotrophic life style Fungi have cell walls

Fungi At least 1500 species of marine fungi Characters: (1) mostly microscopic, (2) decompose organic matter, some parasite, some symbiotes 55

Marine Lichens( 苔鮮 )

57 Marine Lichens Cyanobacteria are nitrogen fixers Few types live on the shells of rocky shore barnacles and limpets