UV Effects in Aquatic Organisms and Ecosystems

600 Pages·2003·43.49 MB·English

by  E Walter Helbling

COMPREHENSIVE SERIES IN PHOTOCHEMISTRY
& PHOTOBIOLOGY
Series Editors
Donat P. Hader
Professor of Botany
and
Giulio Jori
Professor of Chemistry
European Society for Photobiology
COMPREHENSIVE SERIES IN PHOTOCHEMISTRY
& PHOTOBIOLOGY
Series Editors: Donat P. Hader and Giulio Jori
Titles in this Series
Volume 1 UV Effects in Aquatic Organisms and Ecosystems
Edited by E.W. Helbling and H. Zagarese
COMPREHENSIVE SERIES IN PHOTOCHEMISTRY
& PHOTOBIOLOGY - VOLUME 1
UV Effects in Aquatic Organisms
and Ecosystems
Editors
E. Walter Helbling
Estacion de Fotobiologia Playa Union
Playa Union, Rawson, Chubut
Argentina
and
Horacio Zagarese
Centro Regional Universitario Bariloche
Universidad Nacional del Comahue
Bariloche
Argentina
RSmC
advancing the chemical sciences
ISBN 0-85404-301-2
A catalogue record for this book is available from the British Library
0T he Royal Society of Chemistry 2003
All rights reserved
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Preface for the ESP series in photochemical
and photobiological sciences
“Its not the substance, it’s the dose which makes something poisonous!” When
Paracelsius, a German physician of the 14th century, made this statement he
probably did not think about light as one of the most obvious environmental.
But his statement applies as well to light. While we need light, for example for
vitamin D production, too much light might cause skin cancer. The dose makes
the difference. These diverse findings of light effects have attracted the attention
of scientists for centuries. The photosciences represent a dynamic multidiscip-
linary field which includes such diverse subjects as behavioral responses of single
cells, cures for certain types of cancer and protective potential of tanning lotions.
It includes photobiology and photochemistry, photomedicine as well as the
technology for light production, filtering and measurement. Light is a common
theme in all these areas. In recent decades a more molecular centered approach
has changed both the depth and the quality of the theoretical as well as the
experimental foundation of photosciences.
An example of the relationship between global environment and the biosphere
is the recent discovery of ozone depletion and the resulting increase in high
energy ultraviolet radiation. The hazardous effects of high energy ultraviolet
radiation on all living systems is now well established. This discovery of the result
of ozone depletion put photosciences in the center of public interest with the
result that in an unparalleled effort scientists and politicians worked closely
together to come to international agreements to stop the pollution of the
atmosphere.
The changed recreational behavior and the correlation with several diseases in
which sunlight or artificial light sources play a major role in the causation of
clinical conditions (e.g. porphyrias, polymorphic photodermatoses, Xeroderma
pigmentosum and skin cancers) have been well documented. As a result, in some
countries (i.e. Australia) public services inform people about the potential risk of
extended periods of sun exposure. The problems are often aggravated by the
phototoxic or photoallergic reactions produced by a variety of environmental
pollutants, food additives or therapeutic and cosmetic drugs. On the other hand,
if properly used, light-stimulated processes can induce important beneficial
vi PREFACE FOR THE ESP SERIES
effects in biological systems, such as the elucidation of several aspects of cell
structure and function. Novel developments are centered around photodiagnos-
tic and phototherapeutic modalities for the treatment of cancer, artherosclerosis,
several autoimmune diseases, neonatal jaundice and others. In addition, classic
research areas like vision and photosynthesis are still very active. Some of these
developments are unique to photobiology, since the peculiar physico-chemical
properties of electronically excited biomolecules often lead to the promotion of
reactions which are characterized by high levels of selectivity in space and time.
Besides the biologically centered areas, technical developments have paved the
way for the harnessing of solar energy to produce warm water and electricity or
the development of environmentally friendly techniques for addressing problems
of large social impact (e.g. the decontamination of polluted waters). While also in
use in Western countries, these techniques are of great interest for developing
countries.
The European Society for Photobiology (ESP) is an organization for develop-
ing and coordinating the very different fields of photosciences in terms of public
knowledge and scientific interests. Due to the ever increasing demand for a
comprehensive overview over the photosciences the ESP decided to initiate an
encyclopedic series, the “Comprehensive Series in Photochemical and Photo-
biological Sciences”. This series is intended to give an in-depth coverage of all the
very different fields related to light effects. It will allow investigators, physicians,
students, industry and laypersons to obtain an updated record of the state-of-
the-art in specific fields, including a ready access to the recent literature. Most
importantly, such reviews give a critical evaluation of the directions that the field
is taking, outline hotly debated or innovative topics and even suggest a redirec-
tion if appropriate. It is our intention to produce the volumes at a sufficiently
high rate to generate a timely coverage of both well established and emerging
topics. As a rule, the individual volumes are commissioned; however, comments,
suggestions or proposals for new subjects are welcome.
Donat-P. Hader and Giulio Jori
Spring 2002
Volume preface
The surge in the systematic study of UV effects on aquatic habitats is contempor-
ary with the discovery of the ozone hole in the 1980s. Since then, and for the last
two decades, the number of publications on UV related issues has grown
virtually exponentially. Paralleling the explosive development of this new “field”,
a number of reviews have attempted to summarize the available knowledge in
the primary literature. These works have evolved from environmental agencies’
reports to symposia volumes to multi-authored edited books, many of which are
excellent, some of which are reasonably comprehensive, and a few of which are
quite recent. Thus, as soon as we were offered the opportunity of producing a
new book on UV effects on aquatic ecosystems, we wondered how a new book
on this subject could provide new insights or a different perspective, and perhaps
the stimulus or inspiration for future research. In this book, we have attempted
to bridge the gap between the environmental studies of UVR effects and the
broader, traditional fields of ecology, oceanography and limnology. Our purpose
has been to provide evidence to persuade a general ecologist that UV driven
processes are relevant to aquatic ecosystems. But, at the same time, we wanted to
adopt the point of view that UV is only one of several important ecological
processes operating synchronously in the natural environment. If we have suc-
ceeded, the message from this book should be that the search for environmental
UV effects must be framed within a wider ecological context.
What’s in the book
The book is divided into five sections, which are intended to cover the most
salient aspects of UV research. The introductory chapter provides an overview of
the role of UVR in aquatic systems with a strong emphasis on the interaction
between UVR and DOM. This interaction will be a recurrent subject in subse-
quent chapters, and reflects the contemporary perception of UV researchers
about the key role played by DOM in controlling UV optics, and directly or
indirectly regulating chemical and biological processes.
vii
...
Vlll VOLUME PREFACE
The Physics section provides information and discussions on global UVR
climatology at the Earth’s surface level and the factors controlling the transmit-
tance of UVR through the atmosphere (Chapter 2), and the penetration into the
water column (Chapter 3). The last chapter within this section (Chapter 4)
introduces basic notions of mixing and advection and outlines the implications
of vertical water motion for photochemical and photobiological processes.
The four chapters within the Chemistry section discuss the effects of UVR on
biogeochemical cycles of various elements (Chapter 5), the photochemistry of
DOM (Chapter 6), the photo-activated toxicity of several natural and an-
thropogenic substances (Chapter 7) and the environmental implications of
photoinduced formation of reactive oxygen species (Chapter 8). Once again, the
central role of DOM emerges as a unifying theme.
The fourth section focuses on individual and sub-individual effects and re-
sponses. The first chapter within this section (Chapter 9) reviews the effects of
UVR on DNA, which has long been identified as one of the primary targets of
UVR in biological systems. It is followed by a discussion of the main physiologi-
cal photoprotective mechanisms in aquatic organisms (Chapter 10). Chapter 11
reviews the available literature on UVR effects on autotrophs, while Chapters 12
and 13 present two different and complementary perspectives on the effects of
UVR on heterotrophs. This section ends with an extensive review on the role of
sensory systems and behavioral responses to UVR (Chapter 14).
Three chapters within the last section address the effects of UVR from the
community and ecosystem perspective that has been anticipated in the introduc-
tory section. Chapter 15 provides a thorough review of the effects of UVR on
species interactions, including predation, competition, parasitism and diseases.
Chapter 16 discusses the methods for reconstructing the radiation history of
aquatic ecosystems and presents evidence for different UVR paleoclimates.
Chapter 17 speculates on potential future UVR scenarios in a world that is
experiencing several climatic changes from regional acidification to global
warming and the also global depletion of stratospheric ozone.
Acknowledgements
Many people have contributed to make this book possible. First, we would like
to thank all the authors for their time and commitment, and for their great
disposition to help us out in every way. It has been a pleasure and a honour to
work with them. We are deeply indebted to Ruben Sommaruga, who “volun-
teered” to work as Associate Editor for the chapters authored by either one of us.
His help has been essential to assure the impartial review process of our chapters.
Virginia Villafaiie helped us at every stage of the editing process and her inputs,
comments and criticisms have been fundamental.
The contribution of the external reviewers deserves a separate paragraph. We
cannot overemphasize how much this book benefited from the comments, opin-
ions and generous suggestions made by the many reviewers: Maria Marta
Bianchi, J. Platt Bradbury, Howard Browman, Cynthia Carey, Ron Douglas,