Toscano, M., 1996. Late Quaternary Stratigraphy, Sea-Level History, and Paleoclimatology of the Southeast Florida Outer Continental Shelf. PhD thesis, University of South Florida, p. 280.
Toscano, M., and Lundberg, J., 1998. Early Holocene sea-level
record from submerged fossil reefs on the southeast Florida margin. Geology, 26, 255–258.
Toscano, M., and Macintyre, I. G., 2003. Corrected western Atlantic
sea-level curve for the last 11,000 years based on calibrated
14 C
dates from Acropora palmata framework and intertidal mangrove peat. Coral Reefs, 22, 257–270.
Vaughan, T. W., 1916. Some littoral and sublittoral physiographic
features of the Virgin Islands and northern Leeward Islands
and their bearing on the coral reef problem. Washington Academy of Sciences Journal, 6, 53–66.
Cross-references
Barbados
Belize Barrier and Atoll Reefs
Bermuda
Florida Keys
Meltwater Pulses
Reef Classification, Response to Sea Level Rise
West Indian Coral Reef Classification
Western Atlantic/Caribbean, Coral Reefs
EASTERN INDIAN OCEAN – NORTHERN SECTOR
Barbara E. Brown
University of Newcastle, Newcastle upon Tyne, UK
Definition
The northern sector of the eastern Indian Ocean includes
the Andaman Sea where fringing reefs are abundant and
where many corals appear to show some resistance to elevated temperatures and irradiance levels through the possession of thermotolerant symbiotic algae and enhanced
physiological defences.
Background
The northern sector of the eastern Indian Ocean embraces
the Bay of Bengal and also the Andaman Sea, the latter
supporting extensive coral reefs which are both high in
coral cover and coral diversity (Brown, 2007) and comprising approximately 19% of the surface cover of shallow
reefs in the Indian Ocean (Spalding et al., 2001), excluding the reefs of western Australia. Within the Andaman
Sea fringing reefs are extensive in the Andaman and
Nicobar Islands (India), the Mergui Archipelago (Myanmar), west coasts of Thailand and northwest Sumatra
(Indonesia) with limited reef development on the Malaysian coast. Although reefs on the Andaman Sea coast of
Thailand have been well worked the majority of reefs in
the region have never been visited by scientists because
of political restrictions.
The reefs of the Andaman Sea which have been studied
in detail have considerable scientific interest, particularly in
the context of changing climatic conditions. Sea temperatures in the region are generally high and change little over
the year varying from 28
C in January to a maximum of
29.5
C in May. Over the last 50 years sea temperatures have
been rising at a rate of at least 0.126
C per decade (Brown
et al., 1996). However, there have been only two extensive
bleaching events in 1991 and 1995 which have caused any
significant coral mortality – more recent events have been
localised with corals frequently recovering relatively
quickly after the initial bleaching. The most recent mass
bleaching event in the Andaman Sea in May 2010 may
however prove a greater test of the resilience of these corals.
Almost 20% of the 66 genera recorded in western Thailand
host symbiotic algae belonging to Clade D which contains
some of the most thermo-tolerant algal types known
(LaJeunesse et al., 2010) and intertidal corals, which are
abundant throughout the region, boast diverse physiological and biochemical defences to both temperature and light
stresses (Brown et al., 2002a; Brown, 2007). The dynamic
oceanography of the Andaman Sea and the resulting inbuilt stress resistance of many of the shallow water corals
offer potential for the area to be an important ‘refuge’ during a period of climate change.
Geological history and sea floor topography
The Andaman Sea has a complex geological history and
sea floor topography with major rivers draining into the
Bay of Bengal to the north via the Ganges/Bramaputra
delta and also directly into the Andaman basin through
the Irrawaddy delta. The latter river makes a significant
sedimentary contribution to the Andaman Sea with an
annual suspended load of 300,000 Â 10
3 mt and an average discharge at its mouth of 13.6 Â 10
3 m
3 s
À1
. While
sedimentation restricts reef growth in close proximity to
these discharges, reefs flourish in inshore turbid settings
on all islands and mainland areas bordering the Andaman
Sea as well in clearer waters around more offshore islands.
The geological history of the region shapes the topography of the Andaman Sea floor and both the geology and
the plate tectonics are extremely complex (Curry, 2005).
Here the Indian and Eurasian plates collide and other tectonic features include coupling and decoupling of platelets, crustal movement along fault lines, rotation of
continental blocks and the opening of marginal basins,
as in the Andaman Sea. There has been much physical
upheaval over the last 50 million years in the region with
large earthquakes being recorded in the Nicobar islands
in 1847, 1881, 1941 and 2004 and 2005 (Bilham et al.,
2005). The 2004 earthquake was responsible for the devastating Asian tsunami which caused tragic loss of life
across the Indian Ocean together with subsidence of land
and reefs in the Nicobars and on the west coast of the Aceh
province and uplift of land and reefs on the west coast of
Sumatra, and in the Andamans (Meltzner et al., 2006).
The sea floor of the Andaman Sea is dominated by the
Malay continental margin with an outer shelf break that
occurs with increasing depth southward to a maximum at
348
EASTERN INDIAN OCEAN – NORTHERN SECTOR
Toscano, M., and Lundberg, J., 1998. Early Holocene sea-level
record from submerged fossil reefs on the southeast Florida margin. Geology, 26, 255–258.
Toscano, M., and Macintyre, I. G., 2003. Corrected western Atlantic
sea-level curve for the last 11,000 years based on calibrated
14 C
dates from Acropora palmata framework and intertidal mangrove peat. Coral Reefs, 22, 257–270.
Vaughan, T. W., 1916. Some littoral and sublittoral physiographic
features of the Virgin Islands and northern Leeward Islands
and their bearing on the coral reef problem. Washington Academy of Sciences Journal, 6, 53–66.
Cross-references
Barbados
Belize Barrier and Atoll Reefs
Bermuda
Florida Keys
Meltwater Pulses
Reef Classification, Response to Sea Level Rise
West Indian Coral Reef Classification
Western Atlantic/Caribbean, Coral Reefs
EASTERN INDIAN OCEAN – NORTHERN SECTOR
Barbara E. Brown
University of Newcastle, Newcastle upon Tyne, UK
Definition
The northern sector of the eastern Indian Ocean includes
the Andaman Sea where fringing reefs are abundant and
where many corals appear to show some resistance to elevated temperatures and irradiance levels through the possession of thermotolerant symbiotic algae and enhanced
physiological defences.
Background
The northern sector of the eastern Indian Ocean embraces
the Bay of Bengal and also the Andaman Sea, the latter
supporting extensive coral reefs which are both high in
coral cover and coral diversity (Brown, 2007) and comprising approximately 19% of the surface cover of shallow
reefs in the Indian Ocean (Spalding et al., 2001), excluding the reefs of western Australia. Within the Andaman
Sea fringing reefs are extensive in the Andaman and
Nicobar Islands (India), the Mergui Archipelago (Myanmar), west coasts of Thailand and northwest Sumatra
(Indonesia) with limited reef development on the Malaysian coast. Although reefs on the Andaman Sea coast of
Thailand have been well worked the majority of reefs in
the region have never been visited by scientists because
of political restrictions.
The reefs of the Andaman Sea which have been studied
in detail have considerable scientific interest, particularly in
the context of changing climatic conditions. Sea temperatures in the region are generally high and change little over
the year varying from 28
C in January to a maximum of
29.5
C in May. Over the last 50 years sea temperatures have
been rising at a rate of at least 0.126
C per decade (Brown
et al., 1996). However, there have been only two extensive
bleaching events in 1991 and 1995 which have caused any
significant coral mortality – more recent events have been
localised with corals frequently recovering relatively
quickly after the initial bleaching. The most recent mass
bleaching event in the Andaman Sea in May 2010 may
however prove a greater test of the resilience of these corals.
Almost 20% of the 66 genera recorded in western Thailand
host symbiotic algae belonging to Clade D which contains
some of the most thermo-tolerant algal types known
(LaJeunesse et al., 2010) and intertidal corals, which are
abundant throughout the region, boast diverse physiological and biochemical defences to both temperature and light
stresses (Brown et al., 2002a; Brown, 2007). The dynamic
oceanography of the Andaman Sea and the resulting inbuilt stress resistance of many of the shallow water corals
offer potential for the area to be an important ‘refuge’ during a period of climate change.
Geological history and sea floor topography
The Andaman Sea has a complex geological history and
sea floor topography with major rivers draining into the
Bay of Bengal to the north via the Ganges/Bramaputra
delta and also directly into the Andaman basin through
the Irrawaddy delta. The latter river makes a significant
sedimentary contribution to the Andaman Sea with an
annual suspended load of 300,000 Â 10
3 mt and an average discharge at its mouth of 13.6 Â 10
3 m
3 s
À1
. While
sedimentation restricts reef growth in close proximity to
these discharges, reefs flourish in inshore turbid settings
on all islands and mainland areas bordering the Andaman
Sea as well in clearer waters around more offshore islands.
The geological history of the region shapes the topography of the Andaman Sea floor and both the geology and
the plate tectonics are extremely complex (Curry, 2005).
Here the Indian and Eurasian plates collide and other tectonic features include coupling and decoupling of platelets, crustal movement along fault lines, rotation of
continental blocks and the opening of marginal basins,
as in the Andaman Sea. There has been much physical
upheaval over the last 50 million years in the region with
large earthquakes being recorded in the Nicobar islands
in 1847, 1881, 1941 and 2004 and 2005 (Bilham et al.,
2005). The 2004 earthquake was responsible for the devastating Asian tsunami which caused tragic loss of life
across the Indian Ocean together with subsidence of land
and reefs in the Nicobars and on the west coast of the Aceh
province and uplift of land and reefs on the west coast of
Sumatra, and in the Andamans (Meltzner et al., 2006).
The sea floor of the Andaman Sea is dominated by the
Malay continental margin with an outer shelf break that
occurs with increasing depth southward to a maximum at
348
EASTERN INDIAN OCEAN – NORTHERN SECTOR