11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 2: Biotic Response to Ancient Environmental Change in Indo-Pacific Coral Reefs
2-1
Hopping Hotspots: Global Shifts in Marine Biodiversity
Willem RENEMA* 1 , David BELLWOOD 2 , John PANDOLFI 3 , JC BRAGA 4 , K
BROMFIELD 3 , R HALL 5 , KG JOHNSON 6 , Peter LUNT 7 , CP MEYER 8 , L
MCMONAGLE 9 , RJ MORLEY 10 , A. O'DEA 11 , John TODD 6 , FP WESSELINGH 12 , MEJ
WILSON 13
1 Nationaal Natuurhistorisch Museum Naturalis, Leiden, Netherlands, 2 2School of Marine
and Tropical Biology, JCU, Townsville, Australia, 3 Centre for Marine Studies, Brisbane,
Australia, 4 Universidad de Granada, Granada, Spain, 5 SE Asia Research Group, London,
United Kingdom, 6 NHM, London, United Kingdom, 7 Murphy Oil, Kuala Lumpur,
Malaysia, 8 UC Berkeley, San Francisco, CA, 9 University of Durham, Durham, United
Kingdom, 10 Palynova, Cambridge, United Kingdom, 11 STRI, Panama, Panama, 12 NNM
Naturalis, Leiden, Netherlands, 13 Curtin University, Perth, Australia
Hotspots are a dominant feature of global biodiversity patterns. Many coral reef groups
reach their greatest diversity here . Recent fossil and molecular evidence reveal at least
three marine biodiversity hotspots during the past 50 million years. These hotspots have
moved across almost half the globe, with their timing and locations coinciding with major
tectonic events. The birth and death of successive hotspots highlights the link between
environmental change and biodiversity patterns. The molecular and fossil evidence from
a range of taxa rejects the notion of Pleistocene origins of the modern marine IAA fauna
and flora, and point to the presence of a high diversity of extinct and extant lineages from
at least the Miocene onwards. Fossil data further establish that the IAA has not always
been the centre of marine biodiversity, but that earlier ‘centers of marine biodiversity’
occurred in at least two additional places during the past 50 Million years. The future of
modern biodiversity hotspots can now be placed in a historical context.
2-2
Evolution Of Carbonate Factories For The Last 100 Million Years Based On
Investigations On Shallow-Water Carbonate Deposits On Seamounts in The
Northwestern Pacific Ocean
Yasufumi IRYU* 1 , Hideko TAKAYANAGI 1 , Tsutomu YAMADA 1 , Motoyoshi ODA 1 ,
Tokiyuki SATO 2 , Shun CHIYONOBU 1 , Akira NISHIMURA 3 , Tsutomu NAKAZAWA 3 ,
Satoshi SHIOKAWA 4
1 Institute of Geology and Paleontology, Graduate School of Science, Tohoku University,
Sendai, Japan, 2 Institute of Applied Earth Sciences, Faculty of Engineering and Resource
Science, Akita University, Akita, Japan, 3 AIST (Advanced Industrial Science and
Technology ), Tsukuba, Japan, 4 JOGMEC (Japan Oil, Gas and Metals National
Corporation), Kawasaki, Japan
Evolution of carbonate factories for the last 100 million years were delineated by investigating
lithology, biotic and abiotic compositions, and depositional ages of shallow-water carbonates
collected from 25 sites on 21 seamounts in 6 sea areas (Amami Plateau, Daito Ridge, Oki-Daito
Ridge, Urdaneta Plateau, Kyushu-Palau Ridge, and Ogasawara Plateau) in the northwestern
Pacific Ocean. There are significant differences among Cretaceous, Eocene, and Oligocene to
Pleistocene shallow-water carbonates. The shallow-water carbonate deposits examined in the
present study can be roughly divided into three types based on their composition: Cretaceous,
Eocene, and Oligocene to Pleistocene types. The Cretaceous type is characterized by abundant
occurrence of rudists, microencrusters, solenoporacean algae, and calcareous sponges. The
Eocene type includes shallow-water carbonates predominated by Halimeda or nummulitid and
discocyclinid larger foraminifers. The Oligocene to Pleistocene type includes abundant corals,
nongeniculate and geniculate coralline algae, and miogypsinid, lepidocyclinid, and
amphisteginid larger foraminifers. These indicate that carbonate factories comparable with
modern coral reefs were initiated in the Oligocene, which corresponds to the timing of the
transition from Calcite II to Aragonite III. These changes in the composition of the shallowwater
carbonates from the Cretaceous onward is in accordance with those shown in previous
studies, which have been considered to reflect a shift in seawater chemistry. Our investigation
shows that large amounts of shallow-water carbonates were deposited on the seamounts in
Oligocene, although it was a relatively cool period in the Cenozoic. Whereas Early Miocene
shallow-water carbonates are limited, although it was a relatively warm period. These suggest
that deposition of shallow-water carbonates on seamounts in the northwestern Pacific Ocean was
not necessarily controlled by climatic conditions but related with volcanism and tectonics which
served foundations for reef/carbonate-platform formation.
2-3
The Influence Of Global And Regional Environmental Change On Cenozoic Carbonates
in The Indo-Pacific
Moyra WILSON* 1
1 Applied Geology, Curtin University, Perth, Australia
The SE Asian carbonate record allows insight into the poorly known response of equatorial
marine systems to regional and global change during the Cenozoic. There is a marked change
from larger benthic foraminifera to corals as dominant producers in SE Asia around the Oligo-
Miocene boundary. The Early Miocene acme of coral development in SE Asia lags Oligocene
coral development in the Caribbean and Mediterranean. Changing CO2, oceanography, nutrient
input and precipitation patterns are inferred to be the main cause of this lag. Moderate,
although falling level of CO2, Ca 2+ and Ca\Mg when combined with the reduced salinities in
humid equatorial waters probably all contributed to reduced aragonite saturation hindering
reefal development compared with warm more arid regions during the Oligocene. By the Early
Miocene, atmospheric CO2 levels had fallen to pre-industrial levels. Although this was a
relative arid phase globally, in SE Asia palynological evidence indicates the Early Miocene
experienced everwet, but more stable and less seasonal conditions than periods before or after.
Tectonic convergence truncated deep through-flow of cool nutrient-rich currents from the
Pacific to Indian Ocean around the beginning of the Miocene, thereby directly, and perhaps
indirectly (though less seasonal conditions) reducing nutrients. Aragonitic reefs were promoted
where previously the waters had been more acidic, more mesotrophic, more turbid, and less
aragonite saturated. Extensive reefal development resulted in an order of magnitude expansion
of shallow carbonate areas through buildups and pinnacle reefs in the Early Miocene. Tectonics
via increased habitat partitioning and reducing distances to other coral-rich regions may also
have contributed to enhanced reefal development. Implications of this study are that with
anthropogenically induced environmental changes it will be the diverse reefs of SE Asia that are
likely to be amongst the first and hardest hit as oceanic aragonite saturation decreases and
terrestrial nutrient runoff increases.
2-4
Scleractinian Coral Diversity in The Oligocene Of Sabah, Borneo.
Laura MCMONAGLE* 1,2
1 Earth Sciences, Durham University, Durham, United Kingdom, 2 Palaeontology, Natural
History Museum, London, London, United Kingdom
The modern Indo-West Pacific is characterised by the highest global species diversity in reefcorals
and associated biota, but the origins and long-term history of this important biodiversity
hotspot remain poorly studied, with most work on the corals derived from collections made in
the late 19th Century. The extant biota may have appeared during a diversification event that
took place slightly before the Oligocene-Miocene boundary, marked by a change in the style of
carbonate deposition in the region. This may also have coincided with a reduction in the deepwater
throughflow between the Pacific and Indian Oceans and marine incursions in the area. To
better constrain the timing, magnitude, and environmental context for this diversification, a
previously undescribed reef-coral fauna has been documented from extensive new collections
taken from Oligocene patch-reef facies in the Gomantong Formation of Sabah, Malaysia. Study
of nannofossil assemblages suggests that sections range from biozone NP23 (Early Oligocene)
to NP25 (Late Oligocene), with the majority falling within nannofossil zone NP24 (late Early to
early Late Oligocene). This study has more than doubled the number of coral species previously
known from the Oligocene of Borneo, and suggests that the apparent paucity of Paleogene
corals from SE Asia could be a result of sampling bias, rather than true lack of diversity. These
results show that coral diversification was already underway by the Early Oligocene, rather than
occurring at the Oligocene/Miocene boundary. This would indicate that if changes in the
Indonesian Throughflow caused increased diversification, then these changes occurred earlier
than has so far been suggested. Alternatively it could mean that other factors controlled reefcoral
diversification in the Indo-West Pacific during the Oligocene.
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