form, and process are the essential ingredients in the earth
science recipe for understanding coral reefs as well as
most other landforms.
During the last 100 years, coral reefs have attained new
values beyond the support of local subsistence economies.
They have provided sites for navigational aids and in days
of aircraft with limited range, stopover refuelling sites.
During World War II many mid-oceanic atolls had strategic importance and following the war, some became testing sites for nuclear weapons. Ironically, the drilling
associated with this testing did much to extend the knowledge of the origin of reefs and in particular, support
Charles Darwin. Reefs are important sites for commercial
as well as subsistence fishing, and further economic value
has been added by tourism.
Unfortunately, the future for coral reefs is very uncertain. They are one of the ecosystems most at risk from
global climate change and because of this have achieved
much prominence in recent times. They have been compared to canaries in coal mines, providing early warning
of increasing risks! Both public and scientific perspectives
on the impacts of global warming on coral reefs have
changed over the last 20 years. Initially a rise in sea level
was seen as positive, encouraging new coral growth over
largely dead reef flats, although at the other extreme were
forecasts of reefs being drowned, all reef islands
disappearing and even the reefs themselves being eroded
away and tropical coastlines losing their protection. More
balanced responses have come as scientists working on
processes opened up a range of possibilities. Earth science
has played a major role in these revisions especially where
cooperation with other disciplines has provided balanced
assessments. Impacts will be severe with bleaching from
temperature rise and calcification rates declining in
response to acidified oceans, leading to unsustainable
growth rates of corals and many other important organisms. The earth science focus here is on the impact on sediment budgets and the transportational ability of waves.
Many scenarios are possible including an increase in
available sediment over the reef top, and, with deeper
water greater ability of waves to move both this new sediment and that which may have rested on the reef top for
several thousand years, towards any preexisting reef
island. At least in the foreseeable future, the actual volume
of reef islands may increase, though new areas added will
lack vegetation and soils and may be at the expense of the
areas which have supported subsistence agriculture for
millennia.
What is becoming more apparent, as further research
into the impact of climate change on reefs is carried out,
is that in many instances there are important thresholds
which determine the severity of response. Climate
change impact is undoubtedly the most important focus
of coral reef research in all disciplines at present. To some
extent, the situation is similar to that of the nineteenth
century when conflicting hypotheses on the formation
of coral reefs were the highlight. Then, as further research
revealed the depth and lithology of the foundations, ideas
on glacially controlled sea levels became accepted and
the whole new scenario of plate tectonics was revealed,
it became clear that as in many areas of science, there
may be more than one correct answer to a problem. As
more thresholds are determined, different options for
coral reefs to move into the future will become apparent.
Unfortunately, these will mostly be under adverse
conditions.
Climate change and coral reefs form one of the major
foci of this encyclopedia. Although entries are presented
in alphabetical order, they have been organized under
major compilation headings which should become particularly obvious when the reader uses the cross-references
with each entry. Theories and hypotheses, from Darwin
to climate change, also provide a substantial number of
entries, together with some of the major methodologies
used in the hypothesis testing. Short biographies are given
of some of the major contributors to the study of coral reefs
in the earth science field, including organizations. Classifications of various features are given, which again show that
there may be more than one critical approach to features
or processes. Although the encyclopedia does not contain
a formal glossary, there are many short entries explaining
specific features or processes. As coral reefs vary around
the world, a significant number of entries have been devoted
to geographical areas. Finally, the past contribution to modern reefs is not forgotten with contributions on specific reef
complexes of the geological past, whilst the future, however
fragile, is assessed through a number of contributions on
conservation.
This is not an exhaustive list but hopefully, it gives
a structure to the encyclopedia’s contents. Of equal value
are the many references given with the entries. These
range from some of the most classical to material only
published in the last 12 months. The interest in coral reefs
is such that, over the next few years, further interesting
material will be published and updates may be required,
but the 260 entries within the present volume, written by
authors from 15 different countries, give a wide perspective of earth science’s interest in an increasingly fragile
ecosystem.
David Hopley
September 2010
xxviii
PREFACE
science recipe for understanding coral reefs as well as
most other landforms.
During the last 100 years, coral reefs have attained new
values beyond the support of local subsistence economies.
They have provided sites for navigational aids and in days
of aircraft with limited range, stopover refuelling sites.
During World War II many mid-oceanic atolls had strategic importance and following the war, some became testing sites for nuclear weapons. Ironically, the drilling
associated with this testing did much to extend the knowledge of the origin of reefs and in particular, support
Charles Darwin. Reefs are important sites for commercial
as well as subsistence fishing, and further economic value
has been added by tourism.
Unfortunately, the future for coral reefs is very uncertain. They are one of the ecosystems most at risk from
global climate change and because of this have achieved
much prominence in recent times. They have been compared to canaries in coal mines, providing early warning
of increasing risks! Both public and scientific perspectives
on the impacts of global warming on coral reefs have
changed over the last 20 years. Initially a rise in sea level
was seen as positive, encouraging new coral growth over
largely dead reef flats, although at the other extreme were
forecasts of reefs being drowned, all reef islands
disappearing and even the reefs themselves being eroded
away and tropical coastlines losing their protection. More
balanced responses have come as scientists working on
processes opened up a range of possibilities. Earth science
has played a major role in these revisions especially where
cooperation with other disciplines has provided balanced
assessments. Impacts will be severe with bleaching from
temperature rise and calcification rates declining in
response to acidified oceans, leading to unsustainable
growth rates of corals and many other important organisms. The earth science focus here is on the impact on sediment budgets and the transportational ability of waves.
Many scenarios are possible including an increase in
available sediment over the reef top, and, with deeper
water greater ability of waves to move both this new sediment and that which may have rested on the reef top for
several thousand years, towards any preexisting reef
island. At least in the foreseeable future, the actual volume
of reef islands may increase, though new areas added will
lack vegetation and soils and may be at the expense of the
areas which have supported subsistence agriculture for
millennia.
What is becoming more apparent, as further research
into the impact of climate change on reefs is carried out,
is that in many instances there are important thresholds
which determine the severity of response. Climate
change impact is undoubtedly the most important focus
of coral reef research in all disciplines at present. To some
extent, the situation is similar to that of the nineteenth
century when conflicting hypotheses on the formation
of coral reefs were the highlight. Then, as further research
revealed the depth and lithology of the foundations, ideas
on glacially controlled sea levels became accepted and
the whole new scenario of plate tectonics was revealed,
it became clear that as in many areas of science, there
may be more than one correct answer to a problem. As
more thresholds are determined, different options for
coral reefs to move into the future will become apparent.
Unfortunately, these will mostly be under adverse
conditions.
Climate change and coral reefs form one of the major
foci of this encyclopedia. Although entries are presented
in alphabetical order, they have been organized under
major compilation headings which should become particularly obvious when the reader uses the cross-references
with each entry. Theories and hypotheses, from Darwin
to climate change, also provide a substantial number of
entries, together with some of the major methodologies
used in the hypothesis testing. Short biographies are given
of some of the major contributors to the study of coral reefs
in the earth science field, including organizations. Classifications of various features are given, which again show that
there may be more than one critical approach to features
or processes. Although the encyclopedia does not contain
a formal glossary, there are many short entries explaining
specific features or processes. As coral reefs vary around
the world, a significant number of entries have been devoted
to geographical areas. Finally, the past contribution to modern reefs is not forgotten with contributions on specific reef
complexes of the geological past, whilst the future, however
fragile, is assessed through a number of contributions on
conservation.
This is not an exhaustive list but hopefully, it gives
a structure to the encyclopedia’s contents. Of equal value
are the many references given with the entries. These
range from some of the most classical to material only
published in the last 12 months. The interest in coral reefs
is such that, over the next few years, further interesting
material will be published and updates may be required,
but the 260 entries within the present volume, written by
authors from 15 different countries, give a wide perspective of earth science’s interest in an increasingly fragile
ecosystem.
David Hopley
September 2010
xxviii
PREFACE