Algal Photosynthesis

268 Pages·1992·6.335 MB·English

by  Richard J. Geider, Bruce A. Osborne (auth.)

ALGAL
P
HOTO
SYNTHESIS
Current Phycology
Series editors: M. J. Dring, Queen's University Belfast
Michael Melkonian, Universitat Koln
Also published
Ralph A. Lewin and Lanna Cheng, eds. Prochloron: A Microbial Enigma
Michael Melkonian, ed. Algal Cell Motility
HOTO
SYNTHESIS
Richard J. Geider
and Bruce A. Osborne
Springer-Science+Business Media, B.V.
© 1992 Springer Science+Business Media Dordrecht
Originally published by Routledge, Chapman & Hall, Inc. in 1992
Softcover reprint of the hardcover 1s t edition 1992
All rights reserved. No part of this book may be reprinted or reproduced or
utilized in any form or by any electronic, mechanical or other means, now
known or hereafter invented, including photocopying and recording, or by an
information storage or retrieval system, without permission in writing from the
publishers.
Library of Congress Cataloging in Publication Data
Geider, Richard J., 1955-
Algal photosynthesis : the measurement of algal gas exchange /
Richard J. Geider, Bruce A. Osborne.
p. cm.-(Current phycology)
Includes bibliographical references and index.
ISBN 978-1-4757-2155-3 ISBN 978-1-4757-2153-9 (eBook)
DOI 10.1007/978-1-4757-2153-9
1. Photosynthesis-Measurement. 2. Algal gas exchange
-Measurement. 3. Algae-Physiology. I. Osborne, Bruce A., 1952-.
II. Title. III. Series.
QK565.G45 1991 91-7596
589.3/13342-dc20 CIP
British Library Cataloguing in Publication Data
Osborne, Bruce 1952-
Algal photosynthesis : the measurement of algal gas
exchange.
1. Algae. Photosynthesis
1. Title II. Geider, Richard 1955-III. Series
581.13342
ISBN 978-1-4757-2155-3
To Clare, Kath, and our parents.
Contents
Preface xi
Acknowledgments xv
1 NET GAS EXCHANGE
Factors influencing the distribution of O2 and CO2 2
Oxygen determinations 5
Winkler method 5
Oxygen electrodes 7
Inorganic carbon determinations 10
Measuring CO2 exchange in air 14
Measuring net gas exchange 14
Sampling and subsampling 18
Comparison of O2 and CO2 exchange 20
Changes in biomass 24
Coupling of growth and photosynthesis 24
Community metabolism 26
Abiological oxygen consumption 29
2 USING ISOTOPES TO MEASURE GAS EXCHANGE
14C-C02 Assimilation 32
Dissolved organic 1~ production 34
Problems with the 14C method 38
What does 14C uptake measure? 41
Zooplankton grazing and 14C assimilation 48
Comparisons of net gas exchange and 14C assimilation 51
Modifications to the 14C method 52
Single cell rates of photosynthesis of microalgae 55
Microautoradiography 56
Isolation of individual cells 57
Tritium as a tracer 58
VIII Contents
Stable isotopes as tracers 59
Particulate organic J3C production 60
180 measurements 62
Isotope discrimination and natural abundance 66
3 FLUORESCENCE TECHNIQUES
Deexcitation processes and the origins
of chlorophyll fluorescence 72
Fluorescence kinetics 75
The Kautsky curve 76
Fluorescence quenching components 80
Fluorescence techniques 84
Relationship between photosynthesis and fluorescence 88
4 LIGHT SOURCES AND RELATED ACCESSORIES
Incandescent lamps 94
Discharge lamps 95
Light-emitting diodes 97
Lasers 98
Optical filters 101
Monochromators 104
5 MEASURING PHOTOSYNTHETIC PIGMENTS
Extraction of chlorophylls and carotenoids 107
Quantification of chlorophylls and carotenoids 109
Chromotographic separation of pigments 113
Extraction and quantification of phycobiliproteins 115
In vivo fluorescence for estimating chlorophyll a 118
Fluorescence microscopy 119
Use of derivative spectra in pigment analysis 120
6 LIGHT UTILIZATION AND OPTICAL PROPERTIES OF ALGAE
Characterization of the light environment 125
Optical properties of cells and tissues 130
Theoretical treatment of the optical properties of cells
and tissues 136
Spectrophotometric techniques for measuring the optical
properties of cells and tissues 139
Assessment of the package effect 147
Theory and measurement of action spectra 150
7 THE PHOTOSYNTHESIS-LIGHT RESPONSE CURVE
Mathematical descriptions of the photosynthesis-irradiance
curve 157
Contents IX
Alternative forms of the photosynthesis-light response curve 161
Mechanistic interpretation of the photosynthesis-light
response curve 163
Photosynthesis at irradiances near the light compensation point 166
Models that include photoinhibition 168
Interspecific and intraspecific variations in Pm and a 169
Genetic variability 180
Problems in measuring parameters of the photosynthesis-light
response curve 188
8 REMOTE SENSING OF ALGAL PHOTOSYNTHESIS
Estimating surface water chlorophyll a 195
Empirical relationships between primary production and
chlorophyll a 198
Mechanistic descriptions of the relationship between
primary production and chlorophyll a 203
References 205
Index 252
Preface
The algae are a diverse group of organisms with forms that range in
size from less than a micron in diameter to over ten meters in length.
Small « 1 JLm diam) unicellular forms dominate the open waters of the
oceans and large lakes. Large multicellular forms often form a large
component of the autotrophic biomass of shallow waters at the periphery
of lakes and oceans but have also been found on seamounts in clear open
ocean waters at depths up to several hundred meters (Littler and Littler,
1985). Phytoplankton in the sea probably account for more than 50% of
global photosynthesis, although there is considerable uncertainty about
this estimate. In addition, many symbiotic associations between unicellu
lar algae and heterotrophic or autotrophic organisms have been identi
fied, and algae can be found in a diverse range of terrestrial environ
ments, ranging from polar to desert regions. The most important
common biochemical attribute that unites the algae is their ability to split
water, producing molecular oxygen during photosynthesis and concomi
tantly assimilating carbon dioxide. This attribute is shared with the terres
trial plants, cyanobacteria and chloroxybacteria. Although vascular
plants are excluded from this review, we employ a broad definition of
algae that includes the photosynthetic, oxygenic procaryotes.
Measurements of gas exchange are fundamental to most biochemical,
physiological and ecological investigations of the algae. Information on
the gas exchange characteristics of algae has progressed steadily over the
past 80 years following the introduction of the unicellular green alga
Chlorella to photosynthesis research by Otto Warburg. Already by the
1930's, gas exchange measurements carried out by Robert Emerson had
led to such fundamental concepts as the photosynthetic unit. Adversaries
for many years, Warburg and Emerson laid much of the groundwork for
subsequent investigations in photosynthesis research.
xii Preface
Only under restricted conditions can photosynthetic reactions be com
pletely separated from overall algal metabolism. For example, very short
flashes of light « 1 JLs) have been used to investigate photosynthetic
water splitting (oxygen evolution), and nutrient-starved "resting" cells
have been used to investigate the biochemical pathway of carbon dioxide
fixation (i.e., the Calvin or photosynthetic carbon reduction cycle) and
the formation of simple sugars and starch. In general, however, gas
exchanges due to photosynthetic reactions cannot be completely isolated
from other metabolic gas exchanges and growth processes. Mitochon
drial respiration proceeds at variable rates in illuminated cells, as do
other oxygen-consuming and inorganic carbon-consuming and evolving
reactions. An understanding of these other metabolic processes is neces
sary for interpreting measurements of gas exchange by algae.
The study of algal photosynthesis has progressed greatly during the
last decade. Improvements and refinements in methodology have led to
increases in our basic knowledge of photosynthetic and other gas ex
change reactions. This information, however, is dispersed in the primary
literature. In this book, we review the conceptual background, available
methodology, and interpretation of the results of algal photosynthesis
research. This review is not a technical manual but rather a summary
and appraisal of the available methods for measuring photosynthetic gas
exchange, including a discussion of some applications of these tech
niques. Our choice of subject matter covered reflects our background
and research interests. We hope that there are no major omissions,
although other investigations might have approached this review with a
different emphasis.
In reviewing the methods available for measuring gas exchange by
algae, we have included an overview of measurement techniques, an
assessment of their sensitivity and accuracy, and a description of their
limitations and applications. Wherever possible, the different techniques
are compared, and potential explanations for any apparent differences
are examined. Although algae can be separated from heterotrophs under
controlled laboratory conditions, autotrophic and heterotrophic organ
isms coexist in the same environment in the real world. Determining the
rate of photosynthesis by algal assemblages in nature requires corrections
for the activity of heterotrophs, and experimental manipulations that
allow these problems to be overcome are considered. Using fluorescence
measurements to probe photosynthetic reactions is described also. In
Chapters 1 and 2, we consider the problems encountered in manipulating
organisms over the extreme size range, from less than 1 JLm to more than
10 m, that is found in algae. Methods for determining the concentrations
of photosynthetic pigments, the optical properties of algae, and the light
field in which algae are suspended are also included, because these