NUTRIENTS AND EUTROPHICATION IN DANISH MARINE WATERS

12,4

MB

66

stron

3699

ID

Danish Environmental Protection Agency

2003

rok

CONTENTS

Preface 3

Contents . 5

1 Background, defi nition, causes and effects 7

1.1 Defi nition 8

1.2 Causes. 10

1.3 Effects and consequences 12

2 Technical-scientifi c assessment .19

2.1 Climate 24

2.2 Hydrography 26

2.3 Inputs from land-based sources, the atmosphere and adjacent seas . 28

2.4 Nutrient concentrations, nutrient ratios and nutrient limitation 36

2.5 Phytoplankton and harmful algal blooms . 46

2.6 Zooplankton 54

2.7 Oxygen depletion 58

2.8 Degradation of organic matter in estuarine sediments . 62

2.9 Submerged aquatic vegetation 68

2.10 Soft-bottom macrozoobenthos 76

2.11 Fish kills in coastal waters 80

3 Responses and adaptive management 85

3.1 Principles . 86

3.2 Nutrient reduction strategies in Denmark. 88

3.3 International co-operation to abate marine eutrophication . 96

4 Summary, conclusions and the future101

Glossary and abbreviations . 111

Where can I read more?. 116

List of contributors. 117

References. 118

Annexes .. 123