Coral Triangle vs. Climate Change: How Rising CO2 Levels Threaten Reefs

Coral Triangle vs. Climate Change
Hanny Tioho, coloqium PS. IPA, Pasca-Sarjana UNSRAT, 13 Juni 2012, Manado

Coral Triangle (Segitiga Karang)
(1) Indonesia, (2) East Timor, (3) Philippines, (4) Malaysia (Sabah),
(5) Papua New Guinea, (6) Solomon Islands.
 583 km2
Ocean teritory
 >100.000 km2
Coral Reefs

Sejarah “Segitiga Karang”
Spatial Database Coral Geographic
(Peta Orijinal Spesies terkini by Veron, 2000)
798 peta spesies dalam 141 ecoregion
Coral Ecoregions of the World (Veron et al. 2009a)

Global Biodiversity of Zooxanthellate corals (Veron, 2011)
Ecoregions and spesies richness of Zooxanthellate corals of the CT (Veron, 2011)

Tropical Ecosystems in CT region
(Burke et al., 2001; Spalding et al., 2002, WWF Australia 2009)

Karakteristik “Segitiga Karang”
CT Area: The ‘Amazon’ of Seas
Food security, income and coastal
protection for over 225 million people
Significant Marine Based Tourism
($ 9.6B/yr, Cesar et al., 2003)
Supports World’s largest tuna fishery
($ 5B/yr, Bell et al., 2009)
Habitat & Migration route for some
threatened species
A Mega-diversity in CT Area

Aktivitas MC : burning of
fossil fuels, deforestation
and changing land use
meningkatkan konsentrasi
gas rumah kaca di atmosfer
(CO2 dan Metan)
global warming and
ocean acidification
both of which pose serious threats to
coral reef ecosystems through
increased thermal stress and
ocean acidity as well as declining
carbonate ion concentrations
Perubahan Iklim (Climate Change)

Perubahan Iklim (Climate Change)
Peningkatan yg cepat konsentrasi CO2 dan gas-gas rumah kaca lainnya di
atmosfer sejak mulainya periode industri yg mengakibatkan perubahan
lingkungan fisika-kimia dan sistem biological di bumi (IPCC, 2007)
Variation in planetary conditions as a result
of natural and anthropogenic climate change.
(a) Variation in atmospheric carbon dioxide
over the past 420,000 years (Petit et al.
1999). Arrows indicate atmospheric
concentrations today, as well as for three
key scenarios from the fourth assessment
report of the Intergovernmental Panel on
Climate Change (IPCC 2007).
(b) Anomalies in global temperature of
relative to 1999 calculated from isotope
proxies.
(c) Changes in key greenhouse gases over the
past 2,000 years (IPCC 2007).
(d) Changes in sea level measured using
satellite altimeters (Courtesy of Colorado
Center for Astrodynamics
Research, University of Colorado)
(O. Hoegh-Guldberg dalam Z. Dubinsky and N. Stambler, 2011)

Faktor-Faktor Penyebab Stres pada Terumbu Karang

G R L
Stress Factors Scale Comments
Faktor-Faktor Penyebab Stres pada Terumbu Karang

Impacts of Thermal Stress
on Coral Reefs
large-scale ‘mass’ coral bleaching began to
occur in the early 1980s in
Panama, Florida, and at other Caribbean
sites (Glynn 1983; Lessios et al. 1983; Glynn
1996) with corals across large areas of reef
literally turned white over a number of
weeks
The whitening of coral tissues during bleaching events is primarily due
to the loss of pigments and/or cells of their essential symbiotic
dinoflagellates (Symbiodinium) (Hoegh-Guldberg 1999).
Climate Change
Coral Bleaching

mass bleaching is highly likely on a coral reef if sea temperatures rise
by 1°C above the long-term summer maximum temperatures (Strong
et al. 1996; Toscano et al. 2000)
These measurements have been further extended by incorporating
the length of time that a coral reef region is exposed to a particular
anomaly. In this respect, analysis of the “degree heating weeks”
(DHW = anomaly size ×
length of exposure)
Climate Change
Impacts of Thermal Stress on Coral Reefs

 DHW diatas 4, karang akan memutih tapi cepat pulih dgn sedikit atau
tanpa kerusakan.
 DHW diatas 8, karang akan memutih diikuti kematian yg signifikan
 DHW diatas 12 seluruh sistem terumbu akan mati
In 1998, many sites across the Western Indian Ocean experienced DHW
values of over 12, with as much as 95% of corals on some reef systems
being killed (Hoegh-Guldberg 1999).
Almost 50% of all corals died across the region by the end of the very
long warm summers associated with this period (Hoegh-Guldberg
1999; Wilkinson and Hodgson 1999; Wilkinson et al. 1999).
Climate Change
Impacts of Thermal Stress on Coral Reefs

Coral Bleaching (pemutihan karang)
Coral Bleaching :
Keluarnya/hilangnya zoox dari jaringan
hewan karang, yg mengakibatkan
hewan karang menjadi berwarna putih
The number and severity of coral
bleaching events has been described as
a “biological signal” (Hughes 2000) for
the consequences of global climate
change on coral reefs

Coral Bleaching (pemutihan karang)
Penyebab Coral Bleaching :
 magnitude of temperature elevation,
 duration of exposure,
 salinity changes,
 sedimentation,
 exposure to supra-optimal irradiances
of visible radiation,
 exposure to ultraviolet radiation, and
 low-temperature thermal stress.
 diseases

Akibat Coral Bleaching
pada sistem terumbu
normal
bleached
dead

Impacts of Ocean Acidification on Coral Reefs
“ocean acidification”: is a consequence of the increasing flux of
carbon dioxide into ocean waters as a result of increasing atmospheric
carbon dioxide concentrations
When CO2 level in seawater is elevated or when seawater is
acidified, corals slow down their calcification rates (Andersson et al.
2009)
Climate Change

This series of photographs depict a series of sites on the Great Barrier
Reef (GBR) that are analogous to reef states expected under the rapid
buildup of atmospheric CO2
Impacts of Ocean Acidification on Coral Reefs
Climate Change

What next ???? (tindakan aksi …..)
Kurangi (hentikan) tekanan ke terumbu karang
Kurangi (aktivitas) pemicu peningkatan CO2
Political : CTI ------- done !!!
Masyarakat ????????????

Coral Triangle vs. Climate Change: How Rising CO2 Levels Threaten Reefs

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