This page intentionally left blank Light and Photosynthesis in Aquatic Ecosystems Third edition Beginning systematically with the fundamentals, the fully updated third edition of this popular graduate textbook provides an understanding of all the essential elements of marine optics It explains the key role of light as a major factor in determining the operation and biological composition of aquatic ecosystems, and its scope ranges from the physics of light transmission within water, through the biochemistry and physiology of aquatic photosynthesis, to the ecological relationships that depend on the underwater light climate This book also provides a valuable introduction to the remote sensing of the ocean from space, which is now recognized to be of great environmental significance due to its direct relevance to global warming An important resource for graduate courses on marine optics, aquatic photosynthesis, or ocean remote sensing; and for aquatic scientists, both oceanographers and limnologists joh n t o k ir k began his research into ocean optics in the early 1970s in the Division of Plant Industry of the Commonwealth Scientific & Industrial Research Organization (CSIRO), Canberra, Australia, where he was a chief research scientist, and continued it from 1997 in Kirk Marine Optics He was awarded the Australian Society for Limnology Medal (1981), and besides the two successful previous editions of this book, has also co-authored The Plastids: Their Chemistry, Structure, Growth and Inheritance (Elsevier, 1978), which became the standard text in its field Beyond his own scientific research interests, he has always been interested in the broader implications of science for human existence, and has published a book on this and other issues, Science and Certainty (CSIRO Publishing, 2007) Light and Photosynthesis in Aquatic Ecosystems Third edition JOHN T O KIRK Kirk Marine Optics CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sa˜o Paulo, Delhi, Dubai, Tokyo, Mexico City Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521151757 # John T O Kirk 2011 This publication is in copyright Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press First published 1983 Second edition 1994 Printed in the United Kingdom at the University Press, Cambridge A catalogue record for this publication is available from the British Library Library of Congress Cataloging-in-Publication Data Kirk, John T O (John Thomas Osmond), 1935– Light and photosynthesis in aquatic ecosystems / John T O Kirk – 3rd ed p cm Includes bibliographical references and indexes ISBN 978-0-521-15175-7 (Hardback) Photosynthesis Plants–Effect of underwater light on Aquatic plants– Ecophysiology Underwater light I Title QK882.K53 2010 5720 46–dc22 2010028677 ISBN 978-0-521-15175-7 Hardback Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate Contents page ix Preface to the third edition PART I THE UNDERWATER LIGHT FIELD Concepts of hydrologic optics 1.1 Introduction 1.2 The nature of light 1.3 The properties defining the radiation field 1.4 The inherent optical properties 1.5 Apparent and quasi-inherent optical properties 1.6 Optical depth 1.7 Radiative transfer theory 3 14 Incident solar radiation 2.1 Solar radiation outside the atmosphere 2.2 Transmission of solar radiation through the Earth’s atmosphere 2.3 Diurnal variation of solar irradiance 2.4 Variation of solar irradiance and insolation with latitude and time of year 2.5 Transmission across the air–water interface 28 28 Absorption of light within the aquatic medium 3.1 The absorption process 3.2 The measurement of light absorption 3.3 The major light-absorbing components of the aquatic system 50 50 53 v 21 24 24 30 38 42 44 61 vi Contents 3.4 3.5 Optical classification of natural waters Contribution of the different components of the aquatic medium to absorption of PAR 92 95 Scattering of light within the aquatic medium 4.1 The scattering process 4.2 Measurement of scattering 4.3 The scattering properties of natural waters 4.4 The scattering properties of phytoplankton 98 98 104 116 128 Characterizing the underwater light field 5.1 Irradiance 5.2 Scalar irradiance 5.3 Spectral distribution of irradiance 5.4 Radiance distribution 5.5 Modelling the underwater light field 133 133 143 144 147 149 The 6.1 6.2 6.3 6.4 6.5 6.6 nature of the underwater light field Downward irradiance – monochromatic Spectral distribution of downward irradiance Downward irradiance – PAR Upward irradiance and radiance Scalar irradiance Angular distribution of the underwater light field 6.7 Dependence of properties of the field on optical properties of the medium 6.8 Partial vertical attenuation coefficients 153 153 159 159 168 178 Remote sensing of the aquatic environment 7.1 The upward flux and its measurement 7.2 The emergent flux 7.3 Correction for atmospheric scattering and solar elevation 7.4 Relation between remotely sensed reflectance and the scattering/absorption ratio 7.5 Relation between remotely sensed reflectances and water composition 199 200 215 181 188 197 218 225 228 Contents PART II PHOTOSYNTHESIS IN THE AQUATIC ENVIRONMENT vii 263 The 8.1 8.2 8.3 8.4 8.5 Light capture by aquatic plants 9.1 Absorption spectra of photosynthetic systems 9.2 The package effect 9.3 Effects of variation in cell/colony size and shape 9.4 Rate of light absorption by aquatic plants 9.5 Effect of aquatic plants on the underwater light field 308 308 311 314 319 325 Photosynthesis as a function of the incident light 10.1 Measurement of photosynthetic rate in aquatic ecosystems 10.2 Photosynthesis and light intensity 10.3 Efficiency of utilization of incident light energy 10.4 Photosynthesis and wavelength of incident light 330 330 339 360 380 11 Photosynthesis in the aquatic environment 11.1 Circulation and depth 11.2 Optical characteristics of the water 11.3 Other limiting factors 11.4 Temporal variation in photosynthesis 11.5 Photosynthetic yield per unit area 388 388 397 400 430 440 12 Ecological strategies 12.1 Aquatic plant distribution in relation to light quality 12.2 Ontogenetic adaptation – intensity 12.3 Ontogenetic adaptation – spectral quality 12.4 Ontogenetic adaptation – depth 12.5 Significance of ontogenetic adaptation of the photosynthetic system 12.6 Rapid adaptation of the photosynthetic system 453 453 469 479 488 10 photosynthetic apparatus of aquatic plants Chloroplasts Membranes and particles Photosynthetic pigment composition Reaction centres and energy transfer The overall photosynthetic process 265 265 268 275 298 300 503 514 viii Contents 12.7 12.8 The microphytobenthos Highly productive aquatic ecosystems References and author index Index to symbols Index to organisms Index to water bodies Subject index The colour plates appear between pages 212 and 213 528 532 539 626 628 632 638