responding to the 2016 and 2017 mass coral bleaching ... · more than 70% of coral reefs around the...

AIMS: Australia’s tropical marine research agency.

Responding to the 2016 and 2017 Mass Coral

Bleaching events on the Great Barrier Reef: from

Observations to Modelling

Craig Steinberg & Claire SpillmanN. Cantin, J. Benthuysen, H. Tonin, S. Bainbridge, F. McAllister,

R. Brinkman, M. Herzfeld, M. Baird, C. Sun, W. Skirving, R. Pears,

T. Simpson, C. Pattiaratchi E. Klein Salas

EMatson@aims

Recent marine heatwave

NOAA Coral Reef Watch; Liu et al 2014

Alert Level 1: Significant coral bleaching

Alert Level 2: Widespread coral bleaching and significant mortality

More than 70% of coral reefs around the world have experienced heat stress that

can cause bleaching and/or mortality since January 2014.

Mean Monthly Observed SST: GBR

Monthly GBR SST

ERSSTv4 data set: 1961-1990 climatology

23.0

24.0

25.0

26.0

27.0

28.0

29.0

30.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Climatology

2015

2016

2017

January–March 2016

SST percentiles

January–March 2017

SST percentiles

2016 2017

ENSO El Niño Neutral

CloudinessLess cloudy than

normalNormal

SST

January, February,

March and April

hottest since 1900

March second hottest

since 1900

Tropical

cyclones

None over GBR (TCs

Tatiana and Winston

in Coral Sea)

Severe TC Debbie

late March

2016 vs 2017

Climate change a factor in both events through rising ocean temperatures

Seasonal forecasting

• POAMA current Bureau global operational dynamical seasonal forecast system

• POAMA assimilates Argo, XBT, buoy, satellite SST and altimetry data

• POAMA GBR forecasts first operational dynamical forecasts of coral bleaching risk in the world

• ACCESS-S1 to replace POAMA operationally in 2018• UKMO collaboration• ACCESS-S1 assimilates satellite & in situ SST, in situ

T&S profiles, altimetry & satellite sea ice• New operational seasonal GBR products March 2018• New operational Australia-wide SST and thermal

stress products June 2019

POAMA

ACCESS-S

Ocean model grid resolutions

20151001 20151101 20151203

20151217 20160103 20160114

20160131 20160214 20160228

Did POAMA predict 2016?

Forecasts for March 2016

Predictions in Oct/Nov 2015: • Strong El Niño• Warmer than normal summer SST• 40% probability of DHM > 1 on GBR

Predictions in Feb/March 2017: • Local weather impacts in February

increased SST predictions for March • Warmer that average SST conditions

predicted for GBR for March• Very high probability of DHM > 1

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http://poama.bom.gov.au/

Predictions in November 2016: • La Niña WATCH status • Near average SST conditions predicted

for GBR for summer months• Low probability of DHM > 1 over GBR

Predictions in February/March 2017: • Warmer that average SST conditions

predicted for GBR for March• Very high probability of DHM > 1

Did POAMA predict 2017?

20161120 20161201 20161229

20170119 20170202 20170216

2017226 20170312 20170323

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Forecasts for March 2017


• ReefTemp Next Gen: Operational high resolution (2km x 2km) daily satellite SST monitoring tool

• IMOS L3S night-only daily SST • Developed under eReefs• Accumulation of daily thermal

stress (Degree Heating Days):• Green = ok• Yellow = watch• Orange = worry

• Upgrade planned for 2018/19

Monitoring the events

Garde et al (2014)


AIMS reef weather stations& IMOS sensor networks

Monitoring Reef Weather

NOAA Degree Heating Weeks (DHW’s)


Great Barrier Reef

• > 2000km (1200miles) long• ~ 3000 individual reefs and islands• Coastal Barrier ecosystem

Spatial size = challenging ecosystem to monitor & fully document major change

AIMS Long-term monitoring began systematic repetitive surveys between 1980-1992

Co-ordinated approaches are key


RESPONDING TO A CORAL BLEACHING EVENT

AERIAL SURVEYS


"Based on combined survey results so far, the overall mortality is 22% — and about 85% of that die-off has occurred in the far north between the tip of Cape York and just north of Lizard Island, 250 km north of Cairns."

Great Barrier Reef Marine Park Authority (GBRMPA), June 2016

Coral mortality in 2016


A second successive bleaching in 2017


RESPONDING TO A CORAL BLEACHING EVENT

IN WATER SCUBA SURVEYS

NO/MINOR BLEACHINGSEVERELY

BLEACHED AND DEAD

• 50 m x 1m belt transects• Bleaching severity of all corals within the 1m quadrat

scored for bleaching severity • Community bleaching severity (%) • Live coral cover using Line Intercept methods

• Flat• Crest• Slope

5 x 10mTransects per site.


RECENT MORTALITY

NO BLEACHINGMAJOR: 50-95%

MINOR:1 - 50%

SEVERE: 95-100% white & fluorescent

BLEACHING SEVERITY


Bleached Porites

June 2016

ncantin_AIMS

• Long-lived, old individuals 100-400 yrs• Tolerant coral species• Bleached and Partial mortality of tissue• Surviving tissue overgrows sections of partial mortality

ncantin_AIMS

June 2016


Sentinel-2 captures coral bleaching

processed by J. Hedley; conceptual model by C. RoelfsemaImages from the Copernicus Sentinel-2A satellite captured on 8 June 2016 and 23 February 2017 for Adelaide Reef, Central GBR.

AIMS: Australia’s tropical marine research agency.Hughes et al., 2017; Berkelmans et al. 2004

16 & 17 dramatic increase in both heat stress and bleaching severity

1998 2002 2016 2017

BleachingSeverity

SSTAnomaly


Slocum gliders track sub-surface warming in the Great Barrier Reef

IMOS OceanCurrent News, 24 May 2016°E

°S

Cooktown

Cairns

0 m 50 m

200 m100 m

March 2016 Sea Surface Temperature Anomaly

22 Mar 2016

12 Apr 2016

(°C)

North

East


Slocum gliders track sub-surface warming in the Great Barrier Reef

°E

°S

Townsville

Cairns200 m 100 m

March 2017 Sea Surface Temperature

22 Mar 2016

(°C)

North

East


Palm Passage mooring: bottom intrusions2009-2010 2010-2011

2012-2013

30

28

26

24

22

2013-2014 2014-2015

-15

-60

z (m)

-15

-60

z (m)

-15

-60

z (m)

-15

-60

z (m)

-15

-60

z (m)

T (oC)2011-2012-15

-60

z (m)

October - April

Temperature

2015-2016-15

-60

z (m)


ex TC Tatiana and TC Winston in 2016

Distant or low end tropical cyclones can have a silver lining


eReefs 3D captures cooling mechanisms


Differential heating on drying reefs

200m downscaled model

4km modelGBR4

GBR1

Mongin, CSIRO


eReefs RECOM DHW

Elofer & Baird, CSIRO & Cantin AIMS


TC Debbie led to cooling of surface waters over the mid and southern GBR in late March. This is reflected in cooler mean observed SST for April 2017 as well as seasonal outlooks for April.

TC Debbie

http://poama.bom.gov.au


Mean Monthly Observed SST: GBR

Oceancurrent 95m below the surface TC Debbie March 29, 2007

Courtesy Gary Brassington, BoM


Bleaching Thresholds in a warming ocean

• Can corals adapt and keep pace with the rising trend in temperature?

Frieler et al. 2012, Nature Climate Change

• Increased frequency of extreme thermal anomalies influence bleaching thresholds?


Dr Claire Spillman(03) 9669 [email protected]

Craig [email protected]

• OceanCurrenthttp://oceancurrent.imos.org.au

• ReefTemp Next Generation: http://www.bom.gov.au/environment/activities/ reeftemp/reeftemp.shtml

• POAMA seasonal forecastshttp://poama.bom.gov.au

• eReefshttp://ereefs.org.au/ereefs

• AIMS Weatherhttp://weather.aims.gov.au/

Thank you

http://www.bom.gov.au/environment/doc/marine-heatwave-2016.pdf

mailto:[email protected]

mailto:[email protected]

http://oceancurrent.imos.org.au/

http://www.bom.gov.au/environment/activities/reeftemp/reeftemp.shtml


http://ereefs.org.au/ereefs

http://weather.aims.gov.au/

http://www.bom.gov.au/environment/doc/marine-heatwave-2016.pdf

responding to the 2016 and 2017 mass coral bleaching ... · more than 70% of coral reefs around the...

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