1. Coral Bleaching Events In India: A Quaternary Chronicle
Afreen Hussain and Baban Ingole
CSIR-National Institute of Oceanography
Dona Paula-Goa
Quaternary climate :Recent findings and future challenges, CSIR-NIO, Goa

2. Introduction Coral reefs are complex and productive ecosystem.
Highest biodiversity of any marine ecosystem.
Home to 25% of all marine species although it covers less than 2 % of surface area.
 Coral reefs support > 800 hard coral species and > 4,000 species of fish (NOAA ).
1 to 9 million species of living organism yet undiscovered in and around coral reefs (NOAA).

3. Coral Reef & Climate change
Rising Sea temperature- main causes of coral death. Expected to increase by 4°C by turn of 21st century.
Ocean acidification- weakens the coral skeleton
Sea level rise
Storms and rainfall- (Unusual weathers) physical damage & less time between events to recover.

5. Coral Reef : Past and Present
Richest paleoclimate archives in the world (Gagan et al.2000:Quaternary science reviews)
widely distributed,
accurately dated,
Contain broad array of geochemical tracers within their skeletons
Modern studies (Present )
Biological traits
Ecological processes
Coral core (

6. Coral Reefs Of India Gulf of Kutuchh Angria Bank Malvan Grand Island
Andaman &Nicobar
Lakshadweep
Gulf of Mannar

7. Case study :Malvan Marine Sanctuary
15% coral colonies were effected/bleached in the survey area (MMS).
SSTs showed 1.02°C and 1.61°C increase above normal in summer and winter respectively in the Malvan Sanctuary area during 2014.
(Giovanni Ocean colour radiometry (NASA); Goddard Earth Science Data and Information Service Centre (GES DISC)
Average summer and winter SST time series data (11 micron/day at 4 km level) analysed during past 4 years (data courtesy: NASA).
De et al. Current Science,2015

8. Case Study: Grande Island, Goa
Underwater surveys were conducted during November- December, 2015.
20m X 1m Bleaching belt transect, triplicate
Bleaching severity and bleaching percentage recorded (Marshall and Schuttenberg, 2006).
Map showing Grande Island

9. Coral composition: Grande Island

10. Coral bleaching: Grande Island
Decadal SST around Grande island
(Source: NOAA/OAR/ESRL)
Bleaching frequency of different Coral genera
Bleaching frequency(%)
Mean percentage of bleaching ~41.5%.
Highest in Porites sp. (88.67%) followed by Coscinaria (73.9%).
Elevated SST is considered the main trigger for coral bleaching (Cantin et al., 2010), )
Rise of 0.75°C SST above normal in 2014.

11. Coral bleaching: Grande Island
Bleached colonies at Grande Island (A-C) Porites, (D-F) Faviidae, G Coscinaria, (H-J) Goniopora, (K-L) Soft Coral .

12. Trait-based assessment of corals
Porites (massive): resistant
Turbinaria (foliose):resistant
Acropora (branching)-sensitive (nanoreef.com)
Malvan – Massive and Foliose form dominant
Grande Island – Massive form dominant
Acc. To van Woesik et al. Proc. R. Soc. B doi: /rspb (2012) , survival depends on the morphology of corals.

13. History of Global Coral bleaching events
About 60 coral bleaching events from 1979 to
First major global coral bleaching : Triggered by the El Niño resulted in 16% mortality of the corals on reefs around the world
Second global bleaching- triggered by El Niño
Third global bleaching -October (NOAA).

14. Bleaching events in India
LOCATION
YEAR
CAUSE
REMARKS
Andaman and Nicobar’s
Lakshadweep island
2002
2005
2010
2015
Multiple
Widespread bleaching
Gulf of Mannar & Palk Bay
April-June 2002
April-May 2010.
2015-UNPUBLISHED
El Nino
elevated SST & failure of South-West monsoon
89% bleaching & 23% mortality.
> 80 % bleaching
Gulf of Kutch
Increase SST, sedimentation & delayed monsoon in 2014
82% bleaching
Malvan and Grande island
2014 and 2015 respectively
Increase SST, multiple stressors
~15 % bleaching in Malvan and 41.5% in Grande Island
29 bleaching events from 1998 to 2005

15. Mass extinction and coral reef growth
Mesozoic
Cenozoic
Palaezoic
Ordocvician
Silurian
Devonian
Carboniferous
Permian
Triassic
Jurassic
Cretaceous
490
434
410
354
298
251
205
141 65
First reefs
First Scleractinia
End Ordovician
Late Devonian
End Permian
End Triassic
K/T
Mass extinction
Reef gap
Rapid reef growth
Million of years ago
Timeline of mass extinction events (Veron 2008)
Reefs are particularly impacted in mass extinctions.
Many millions of years to recover
Mass extinction correspond to increase CO2
Currently- CO2 is rapidly increasing influenced by anthropogenic activities.
May be the 6th mass extinction?

16. Conclusion Coral reefs in India are under threat.
Studies on effect of climate changes on coral reefs in India are few.
Corals as proxy for paleoclimate are under- studied in India.
Future studies- integrating biology and paleoclimate to predict future changes .

17. Thank You
Benthos group, NIO