VIRUS DYNAMICS IN HIGH-NUTRIENT, LOW-CHLOROPHYLL MARINE

0,44

MB

SURFACE WATERS

80

stron

5566

ID

University of Tennessee

2005

rok

TABLE OF CONTENTS

BACKGROUND 1

1. The Microbial Food Web 2

2. Viruses in Marine Systems . 4

3. The Iron Hypothesis 8

4. Iron Fertilization Experiments 11

PART ONE: AN ESTIMATION OF VIRAL DYNAMICS IN AN SF6-LABELED HNLC PATCH 16

1. Introduction. 17

2. Materials and Methods 18

2.1 Study site and sampling 18

2.2 Phytoplankton, bacterial, and viral abundance . 18

2.3 Determination of estimated burst size and the frequency of visibly infected cells 20

2.4 Calculating the frequency of infected cells and viral-mediated bacterial mortality 20

2.5 Bacterial and viral production and virus-induced mortality rate estimates 21

3. Results. 24

3.1 Bacterial and viral abundance and production 24

3.2 Chlorophyll a, dissolved iron and iron regeneration. 24

3.3 VMB, burst size other nutrient regeneration. 26

4. Discussion . 28

4.1 Increase in chlorophyll a, dissolved iron, and viral activity (by dilution approach). 28

4.2 VMB, burst size and nutrient remobilization 31

5. Part I Conclusions. 34

PART TWO: A MESOSCALE IRON FERTILIZATION IN THE SUBARCTIC PACIFIC OCEAN AND

ITS EFFECTS ON VIRAL ACTIVITY 35

1. Introduction. 36

2. Materials and Methods 38

2.1 Study site and sampling 38

2.2 Phytoplankton, bacterial and viral abundance, and bacterial production . 38

2.3 Additional viral parameters and tests for significance 40

3. Results. 41

3.1 Dissolved Fe and chlorophyll a. 41

3.2 Bacterial and viral abundance. 41

3.3 Viral production measurements 43

3.4 VMB, burst size and nutrient remobilization 46

4. Discussion . 49

4.1 Dissolved Fe and chlorophyll a. 49

4.2 Bacterial and viral abundance. 49

4.3 Viral production measurements 51

4.4 VMB, burst size and nutrient remobilization 54

5. Part II Conclusions 56

FINAL SUMMARY AND CONCLUSIONS 57

LIST OF REFERENCES 60

Vita. 70