Global Coral Bleaching 2014-2017: Status and an Appeal for Observations

Global Coral Bleaching 2014-2017: Status and an Appeal for Observations
NOAA Coral Reef Watch Program
DOC
NOAA
NESDIS
STAR
CRW
USCRTF
CRCP
NCRMP
CoRIS
Coral Bleaching During & Since the 2014-2017 Global Coral Bleaching Event
Status and an Appeal for Observations
(Last Updated: March 19, 2018)
In 2014, NOAA Coral Reef Watch wrote in
Reef Encounter
about the prospect for a 2014-15 El Niño
Eakin
et al
. 2014
).
While that El Niño never fully formed, it did help set off a three-year global coral bleaching event -- the third ever documented. A subsequent
2015-16 strong El Niño formed, spreading and worsening the bleaching
Eakin
et al
. 2016
), and
a La Niña reared its head thereafter, further extending the event into 2017, as predicted by Coral Reef Watch. Multiple coral reef ecosystems around the world
experienced severe bleaching in back-to-back years, including areas like Guam, where corals bleached every year from 2013 to 2017.
As of the end of May 2017, the third global coral bleaching event most likely ended
National Oceanic and Atmospheric Administration (NOAA) 2017
but will remain the
longest, most widespread, and possibly the
most damaging coral bleaching event on record
. It affected more reefs than any previous global bleaching event and was worse in some
locales (e.g., Great Barrier Reef, Kiribati, Jarvis Island).
Heat stress during this event also caused mass bleaching in several reefs that never bleached before (e.g., northernmost Great Barrier Reef).
Coral Reef Watch's Analysis of Current Thermal Conditions and Four-Month Outlook
NOAA Coral Reef Watch's most recent daily global 5km satellite Coral Bleaching Alert Area is below. This figure shows the regions currently
experiencing high levels of heat stress that can cause coral bleaching and mortality.
NOAA Coral Reef Watch's most recent
Four-Month Coral Bleaching Heat Stress Outlook
is below. This figure shows the distribution of the
lowest heat stress levels predicted by at least 60% of the model ensemble members. In other words,
there is a 60% chance that the displayed heat stress levels will occur.
NOAA Coral Reef Watch's satellite Coral Bleaching Alert Area below shows the maximum heat stress during the Third Global Coral Bleaching Event.
Regions that experienced the high heat stress that can cause coral bleaching, from June 1, 2014 to May 31, 2017, are displayed.
Alert Level 2 heat stress indicates widespread coral bleaching and significant mortality. Alert Level 1 heat stress indicates significant coral bleaching.
Lower levels of stress may have caused some bleaching as well. More than 70% of coral reefs around the world experienced the heat stress that can cause
bleaching and/or mortality during the three-year long global event.
NOAA Coral Reef Watch's (CRW)
daily global 5km satellite coral bleaching heat stress monitoring products
indicate that in the eastern Pacific Ocean, cooler waters continue
and all of CRW's 5km Regional Virtual Stations are experiencing low-level or no heat stress conducive to coral bleaching. The
Galapagos, Ecuador
is currently at a level of Bleaching Warning, but that is expected to return to
and remain at a Bleaching Watch in the next 1-4 weeks.
In the central equatorial Pacific, heat stress is building at multiple of CRW's
5km Regional Virtual Stations
. This includes
the
Samoas
, which suffered many weeks of Alert Level 2 heat stress
(associated with widespread coral bleaching and significant mortality) in 2015 and early 2017, with confirmed reports of bleaching of
both shallow and deeper corals. As of this writing, the
Austral Islands
are at Alert Level 1 heat stress
(associated with significant bleaching), which is expected to continue for the next 1-4 weeks. Also within the coming 1-4 weeks,
Southern Tonga
is expecting Alert Level 1 conditions; a short burst of high heat stress is
expected in the
Pitcairn Islands
(Alert Level 2) and in the
Southern Cook Islands
(Alert Level 1); and multiple other Polynesian islands should
elevate to a Bleaching Warning.
The
Main Hawaiian Islands (MHI)
, which observed record levels of
bleaching in 2014 and static Alert Level 2 bleaching heat stress in October and November 2015, experienced only low-level heat stress during its
2016 and 2017 summers, although there had been concerns in August, September, and October 2017 that Alert Level 2 stress would again develop.
The
Northwestern Hawaiian Islands (NWHI)
, which sustained high, prolonged levels of bleaching heat stress
in 2014 and some subsequent coral death, returned to Alert Level 1 bleaching conditions from mid-September to mid-October 2017 but then decreased
to a level of No Stress. CRW continues to collect data from
field partners, including Hawai'i's
Eyes of the Reef (EOR)
volunteer community reef monitoring program,
concerning the extent and severity of coral bleaching and mortality in the MHI and NWHI since 2014.
CRW's
5km Regional Virtual Stations
in Micronesia all have returned to Bleaching Watch or No Stress status, which is expected
to continue for the next 9-12 weeks. Micronesian reefs overall were impacted by severe heat stress
and widespread bleaching in multiple years of the 2014-2017 global coral bleaching event, leaving corals little to no time to recover between repeat stress events.
Guam
, in particular, experienced severe, widespread coral bleaching in 2013, 2014, 2016, and 2017
(its worst bleaching on record), as well as localized bleaching due to El Niño-associated low sea level in 2015. In
the
Northern Line Islands, Kiribati
, as noted in multiple articles below and by numerous news outlets worldwide,
persistent elevated ocean temperatures (as high as 31.4-degrees Celsius) in 2015-2016 killed most of the corals in the region. Photos taken by scientists surveying
the reef damage, especially around Kiritimati (Christmas Island), where more than 80% coral mortality has been documented, were gruesome.
The high bleaching heat stress in Kiribati was tied to the very strong El Niño that dissipated in late 2016 but
whose effects lasted for multiple additional months in the southern hemisphere. It is estimated that only 1-5% of Kiribati's reefs will survive
and recover from the 2014-2017 global coral bleaching event.
Continuing further west, in Melanesia, Alert Levels 1 and 2 bleaching stress returned to the area at the end of November 2017. Multiple coral reef regions
are currently getting slight relief (in the form of a Bleaching Watch) from the severe, prolonged heat stress that lasted for months, but
Papua New Guinea
remains at Alert Level 2. In addition, Alert Level 1 conditions are predicted
to return to
Fiji
and
Vanuatu
in 1-4 weeks' time and to
Papua New Guinea
and the
Solomon Islands
in 9-12 weeks.
In the Coral Triangle, besides the high heat stress that remains in
Papua New Guinea
, cooler waters are present
throughout. The Philippines (which suffered severe Alert Levels 1 and 2 bleaching stress throughout much of June and July 2017) appears to
have escaped this last round of high heat stress. However, Alert Level 1 conditions are expected again in the next 9-12 weeks, bringing
high heat stress back to much of the Coral Triangle.
CRW continues communicating with local field partners to try and assess the status of local reefs throughout the Coral Triangle impacted
by severe bleaching heat stress during and since the 2014-2017 global coral bleaching event.
Severe heat stress (Alert Levels 1 and 2) persisted for many weeks in East Asia in summer 2016. Significant coral bleaching was reported
in multiple reef areas, including
Hainan Island, China
Northern Vietnam
Dongsha, Taiwan
, and the
Ryukyu Islands, Japan
, where,
as of July 2016, extensive (over 90%) bleaching was observed in the region's largest coral reef (Sekiseishoko Reef),
resulting in 70% mortality
Prolonged, severe Alert Levels 1 and 2 heat stress returned to the Ryukyu Islands, Japan, Taiwan, Vietnam, and China from mid-August to mid-October 2017. The
heat dissipated with the onset of late Autumn throughout the region, and as of this writing, all of CRW's
5km Regional Virtual Stations
in East Asia
are registering No Stress. Note however that Alert Level 1 heat stress is predicted to return to China's and Vietnam's
5km Regional Virtual Stations
in the next 9-12 weeks. CRW continues communicating with local coral reef management and research partners
to determine the extent of the damage to the region's coral reefs during and since the 2014-2017 global coral bleaching event.
In Southeast Asia, CRW's
5km Regional Virtual Stations
all are at a level of either Bleaching Watch or No Stress, excluding
Southern Java
, which has elevated to a Bleaching Warning. With approaching
heat stress from the south, however, Alert Level 1 heat stress is predicted at most of the CRW
5km Regional Virtual Stations
throughout Southeast Asia in 9-12 weeks' time.
As reported in multiple articles below and by news sources around the world, sustained, high ocean temperatures in early 2016 (especially in March) did significant damage to
Australia's Great Barrier Reef (GBR). Per the Australian National Coral Bleaching Taskforce, the Australian Research
Council Centre of Excellence for Coral Reef Studies, and the Great Barrier Reef Marine Park Authority, the event turned out to be the worst bleaching in the GBR's history.
This was especially true in the northernmost portion of the GBR, which experienced massive die-offs of coral. A NOAA CRW co-authored
Nature
cover story
on the 2016 GBR bleaching was published on March 15, 2017. Click
here
for additional information.
After multiple weeks of severe (Alert Levels 1 and 2) heat stress along much of the GBR, especially the central GBR, in March 2017
(the Reef's unprecedented, second consecutive year of confirmed mass bleaching), cooler waters finally arrived in the region in mid-April.
All of CRW's
5km Regional Virtual Stations
for the GBR region returned to a level of No Stress.
As of January 2018, high heat stress returned to the GBR and persisted throughout the month. Cooler waters arrived along the GBR at the start of
February, but by the end of the month, high heat stress had returned to the
Torres Strait
and
Far Northern GBR
and persisted for multiple weeks. As of this writing in late March 2018, with the onset of Autumn,
the entirety of the GBR is under Bleaching Watch conditions. CRW's
near real-time satellite monitoring
and
modeled predictions
of environmental stress during and since the
third-documented global coral bleaching event have been critical in helping local management and research partners plan effectual in-water and aerial surveys of the GBR.
We recommend coral reef managers and other stakeholders continue to closely monitor CRW's website for the most up-to-date information
on environmental conditions on the GBR.
In mid-May 2017, cooler waters arrived along the western coast of Australia, in the Indian Ocean. Since that time,
CRW's
5km Regional Virtual Stations
throughout the region had registered No Stress. However, as of early December 2017,
Alert Level 1 bleaching heat stress returned to Australia's northern and western coasts. Now in late March 2018, Alert Level 2 stress remains in
Hamelin Pool
(after many weeks) and Alert Level 1 heat stress in
Central Western Australia
. Cooler waters have arrived at the other
5km Regional Virtual Stations
along the northern and western coasts of Australia. However, Alert Level 1 heat stress is expected again
in the coming 9-12 weeks at
Christmas Island
and
Pulu Keeling
and from
Shark Bay
south to
Marmion and Rottnest Island
Bleaching heat stress developed again in early March 2017 in the Western Indian Ocean. However, since moderate bleaching was confirmed in only one
area of the Indian Ocean in April 2017 - in
Southwestern Madagascar
- and not basin-wide, this provided the first hint
that the
Third Global Coral Bleaching Event was likely coming to an end
By mid-April, CRW's
5km Regional Virtual Stations
throughout the Western Indian Ocean region had returned to a level of No Stress.
Low-level heat stress did return to the Western Indian Ocean as of late February 2018; however, as of this writing in late March 2018, most
of CRW's
5km Regional Virtual Stations
have returned to either a Bleaching Watch or No Stress status, with only
Western Madagascar
remaining at Alert Level 1.
It is important to note that even though widespread coral bleaching was not confirmed throughout the Indian Ocean in the first half of 2017,
in the Middle East, severe Alert Level 2 bleaching heat stress was present throughout September 2017 in multiple coral reef areas, including in
the
Western Persian Gulf
and
Bahrain
As of this writing in late March 2018, CRW's
5km Regional Virtual Stations
throughout the Middle East all remain at a level of No Stress.
In South Asia, however, Alert Level 1 heat stress is expected again in
Kerala, India
and in the
Chagos Archipelago, UK
, in the next 5-8 weeks.
In the Atlantic Ocean, substantial bleaching was observed by local coral reef managers and monitoring networks in southeastern Florida
and the Florida Keys in August and September 2014. Then in September and October 2015, moderate to severe coral bleaching (and disease) and low to
moderate mortality were observed along the Florida Reef Tract (including in the National Marine Sanctuary) for the second year in a row.
In mid-July 2016, a Bleaching Warning was issued for both the
Florida Keys
and
Southeast Florida
5km Regional Virtual Stations. However, significant bleaching heat stress
(Bleaching Alert Levels 1 and 2) did not develop in Florida in 2016, providing much needed relief to corals and other reef
organisms that were still recovering from severe back-to-back bleaching. Additionally, although Alert Level 1 heat stress was predicted
for the
Florida Keys
and
Southeast Florida
5km Regional
Virtual Stations througout most of July and into early August 2017, it did not materialize. Only low-level bleaching heat stress developed, and it dissipated as of mid-September 2017.
In the Gulf of America, multiple months of high heat stress in the
Flower Garden Banks, Texas
and
Yucatan Peninsula
dissipated in mid-September and late-October 2016, respectively. Again in 2017, Alert Level 1 heat stress was predicted at
all three
5km Regional Virtual Stations
for the Gulf region through early August; however it only
materialized in the
Yucatan Peninsula
. In mid-September, the high heat stress increased further, elevating to Alert Level 2
bleaching conditions, which remained until the end of October 2017.
A strong bleaching season in 2015 impacted coral reefs throughout the Caribbean. Bleaching of Caribbean corals at a number of
reef locations (e.g., Cuba, the Turks and Caicos, the Bahamas, Haiti, the Dominican Republic, and Mexico) in 2015, as reported by partner organizations
with divers working on affected reefs, including the
XL Catlin Seaview Survey
and
Reef Check
, led to
NOAA's declaration of the Third
Global Coral Bleaching Event on record
(after the 1998 and 2010 global events). In early November 2016, high levels of bleaching heat stress returned to the eastern
and southern portions of the Caribbean basin. These potential bleaching conditions remained until late December 2016. As of early October 2017, Alert Levels 1 and 2 heat stress
were present at more than one-half of CRW's
5km Regional Virtual Stations
in the Caribbean, especially in the southern portion
of the basin; this severe heat stress remained throughout the month. As of early December 2017, Alert Level 2 bleaching stress remained only
in
Nearshore Venezuela
. As of this writing in late March 2018,
CRW's
5km Regional Virtual Stations
in the Caribbean all are at a level of No Stress. Continuing further south and east, along the coast of
Brazil, all
5km Regional Virtual Stations
in the region also remain at Bleaching Watch or No Stress status, excluding
Maracajau
Abrolhos Reefs
, and
Buzios, Brazil
which are at a Bleaching Warning.
CRW continues seeking data and observations from field partners throughout the Caribbean and Brazil
concerning the extent and severity of coral bleaching and mortality during and since the 2014-2017 global coral bleaching event.
Click
here
to access NOAA CRW's Pacific Climate Update from February 2018.
For more information about the Top 10 Things Resource Managers and Other Coral Reef Stakeholders Can Do Before, During, and After a Bleaching Event,
please visit:
Click
here
to access a
presentation, given by the NOAA CRW Coordinator on March 17, 2017, as part of the
Virginia Institute of Marine Science Spring Seminar Series, on the Third Global Coral Bleaching Event.
Official Bleaching Announcements and Select Media Stories
2017 June 29
About the Reef: Reef Health
source article
2017 June 19
Global Coral Bleaching Event Likely Ending
2017 April 10
Scientists Just Confirmed the Great Barrier Reef Bleached
source article
2017 April 8
Australia Floats Plan To Keep Corals Cool In A Warming World
source article
2017 March 16
Great Barrier Reef's future looks grim
source article
2017 March 16
'Are we there yet?': Fears that 'significant' coral mortality still to come
source article
2017 March 15
Large Sections of Australia's Great [Barrier] Reef Are Now Dead, Scientists Find
source article
2017 March 13
Scientists race to prevent wipeout of world's coral reefs
source article
2017 March 10
Great Barrier Reef bleached for unprecedented second year running
source article
2017 March 10
Warm ocean temperatures cause another bleaching event on Great Barrier Reef
source article
2017 March 10
Second wave of mass bleaching unfolding on Great Barrier Reef
source article
2017 February 17
Variable levels of bleaching reported in Great Barrier Reef Marine Park
source article
2016 November 12
In graveyard of dead coral in Pacific hope and life bloom
source article
2016 November 12
In Singapore: Coral bleaching getting worse
source article
2016 November 10
Majority of Sekisei shoko coral reef dies with 97% extremely severely bleached
source article
2016 November 5
Scientists: Flower Garden Banks coral bleaching part of global problem
Link to photos
2016 September 9
Summary of Findings for 2015 Coral Bleaching Surveys: South Kohala, North Kona
2016 September 9
Hawaii Division of Aquatic Resources Coral Bleaching Recovery Plan
source article
2016 June 20
U.S. coral reefs facing warming waters, increased bleaching
2016 June 8
As coral bleaching goes global, scientists fear worst is yet to come
source article
2016 June 8
World oceans day: healthy oceans - healthy planet
source article
2016 June 7
Maldives warns coral bleaching could prompt reef closure
2016 June 2
Updated Map of observed coral mortality for the Great Barrier Reef
2016 June 2
Updated Map of observed bleaching for the Great Barrier Reef
2016 June 2
Coral bleaching update on the Great Barrier Reef
source article
2016 June 1
El Niño Warming Turns Coral Garden in Marine National Monument to Graveyard
2016 May 30
Coral death toll climbs on Great Barrier Reef
source article
2016 May 27
Update on coral bleaching and mortality in the Great Barrier Reef
source article
2016 May 26
Thailand closes dive sites over coral bleaching crisis
source article
2016 May 13
Update on coral bleaching in the Great Barrier Reef
source article
2016 May 13
Updated Map of observed bleaching for the Great Barrier Reef
source article
2016 May 6
Update on coral bleaching in the Great Barrier Reef
source article
2016 April 20
Press release: Only 7% of Great Barrier Reef has avoided coral bleaching
source article
2016 April 20
Map of reef survey results accompanying Great Barrier Reef press release
source article
2016 April 20
Statement on Great Barrier Reef coral bleaching surveys
source article
2016 April 12
Dead Kiribati reefs mark potential arrival at "dangerous" climate change threshold
source article
2016 April 12
Updated Map of observed bleaching for the Great Barrier Reef
source article
2016 April 12
Update on coral bleaching in the far northern Great Barrier Reef
source article
2016 April 11
ABC-TV News
interview with Mark Eakin about Great Barrier Reef bleaching
source video
2016 April 9
Climate-Related Coral Bleaching and Death - A Global Update
source article
2016 April 6
Intense bleaching thermal stress continues devastating reefs of Kiribati
source article
2016 April 5
National Coral Bleaching Taskforce unleashes an armada of experts
source article
2016 April 1
Map of observed bleaching for the Great Barrier Reef
source article
2016 April 1
Update on coral bleaching in the far northern Great Barrier Reef
source article
2016 April 1
El Niño continues devastating reefs worldwide, including the Great Barrier Reef
source article
2016 March 29
Appeal for underwater photographers and videographers to document bleaching
source video
2016 March 29
Coral Bleaching Taskforce documents most severe bleaching on record
source article
2016 March 21
Scientist witnesses severe coral bleaching at Lizard Island
source article
2016 March 20
Coral mortality rises in remote far northern Great Barrier Reef
source article
2016 March 14
Australian National Coral Taskforce puts plan into effect as bleaching intensifies
source article
2016 March 14
Coral Bleaching Intensifies in the Far Northern Great Barrier Reef
source article
2016 March 8
Marine Reserve in Reunion Alerts of Coral Bleaching
source article
2016 March 1
Widespread Low Level Coral Bleaching on the Great Barrier Reef
source article
2016 February 25
New Caledonia Mass Bleaching
source article
2016 February 23
El Niño Prolongs Longest Global Coral Bleaching Event
2015 October 8
NOAA Declares Third Ever Global Coral Bleaching Event
2015 September 11
Record Ocean Temperatures Causing Coral Bleaching Across Hawaii
2015 July 6
Coral Bleaching Threat Increasing in Western Atlantic and Pacific Oceans
Progression of the Third Global Coral Bleaching Event (June 2014-May 2017)
The following content was drafted from the Eakin
et al
. article, "Ding, Dong, The Witch is Dead (?) - Three Years of Global Coral Bleaching 2014-2017",
published in
Reef Encounter
in August 2017:
In 2016, we wrote in
Reef Encounter
about the ongoing Third Global Coral Bleaching Event, which was forecast to continue into 2017
Eakin
et al
. 2016
).
As predicted, the 2015-16 strong El Niño formed, worsening the bleaching, and was followed by a La Niña event. Despite the end of the
La Niña, high temperatures persisted into 2017. At least half of the world's coral reef areas bleached in two or all three years of the event,
and many suffered the worst bleaching ever documented. As of June 2017, the three-year-long, Third Global Coral Bleaching Event has most likely ended
National Oceanic and Atmospheric Administration (NOAA) 2017
but remains the longest, most widespread, and probably the most destructive ever recorded.
Recap: Bleaching in 2014
In
June 2014
coral bleaching began in
Guam and the Commonwealth of the Northern Mariana Islands (CNMI,
Heron
et al
. 2016
), and
it looked like an El Niño was predicted to form but never did.
Papaha̅naumokua̅kea Marine National Monument
, the Main Hawaiian Islands
DAR 2014
Bahr
et al
. 2015
), southeastern Florida and the Florida Keys
FRRP 2015a
) saw bleaching in August and September, while the
Republic of the Marshall Islands (Fellenius 2014,
Eakin
et al
. 2016
saw bleaching from September-November.
Recap: Bleaching in 2015
Bleaching worsened as heat stress moved into the southern hemisphere in late 2014/early 2015, striking in the South Pacific, large areas of the
Indian Ocean, and parts of Southeast Asia - including severe localized bleaching in Dongsha Atoll in June 2015
DeCarlo
et al
. 2017
). With the onset of the
2015-16 El Niño, the heat stress focused on the central and eastern Tropical Pacific. The heat stress spread northward,
causing the worst bleaching on record in the Main Hawaiian Islands in October 2015
TNC 2015
Eakin
et al
. 2016
Kramer
et al
. 2016
Rodgers
et al
. 2017
Rosinski
et al
. 2017
).
In the Atlantic, September-October brought moderate to severe coral bleaching (and
disease) and low to moderate mortality to Florida's coral reefs for the second year in a row
FRRP 2015b
FRRP 2016a
); bleaching at varying severities and scales was then
reported from multiple locations across the eastern and western Caribbean through October. As of October 2015, with widespread bleaching in each
of the Indian, Pacific, and Atlantic basins,
NOAA
declared that the Third Global Coral Bleaching Event was underway
. By the end of 2015, 41% of global coral reefs had been exposed to heat stress of
4°C-weeks or more (measured by NOAA Coral Reef Watch's
daily global 5km satellite Degree Heating Week [DHW] product)
and almost all of the world's reefs had exceeded their normal warm-season temperatures.
Figure 1. NOAA Coral Reef Watch Maximum Bleaching Alert Area map for January-December 2016. Severe coral bleaching was reported in all areas
circled in white on map and listed below the map. Data from Coral Reef Watch Daily Global 5km Coral Bleaching Heat Stress Monitoring Product Suite version 3
Liu
et al
. 2017
).
Bleaching in 2016
As the El Niño continued to strengthen, heat stress and bleaching returned to the Southern Hemisphere. Heat stress in 2016 was much
more widespread than in 2015, encompassing 51% of global coral reefs (measured by Coral Reef Watch's DHW product). Even more important was the severity. The El
Niño resulted in continuous heat stress in the Central Pacific from April 2015 to May 2016. The
Northern Line Islands
heat stress values
were the highest Coral Reef Watch has ever documented (DHW > 25°C-weeks) and caused the worst bleaching-related mortality ever reported.
By May 2016, this included 80% of total coral cover dead and an additional 15% bleached in Kiritimati
Harvey 2016
), as well as 98% total coral
cover dead at
Jarvis Island
with
substantial reduction to reef structural complexity (investigation into the mechanism of this rapid erosion is underway). Severe heat stress in Fiji's
lagoons caused sudden and widespread coral death in February just weeks before Cyclone Winston cooled ocean temperatures. Bleaching in New Caledonia
in March caused wide swaths of lagoon corals, especially
Acropora
, to fluoresce in
multi-colored pastels
The first major bleaching ever documented on the Northern and Far Northern sectors of the Great Barrier Reef (GBR) peaked in March
Hughes
et al
. 2017
). This was the worst bleaching
ever seen in the GBR resulting in 29% mortality of shallow-water corals across the entire reef
GBRMPA 2017
). Coral bleaching started in the
Western Indian Ocean in January and peaked by May
CORDIO-EA
),
with bleaching in the Seychelles ranging from 69-99% resulting in a subsequent 50% reduction in hard coral cover (SIF 2017).
Bleaching in Southeast Asia caused Thailand to close many of its coral reefs to recreational diving activities in May
AFP 2016
).
Bleaching in Guam, especially Tumon Bay, returned for the fourth year in a row.
In the boreal summer, bleaching returned to the Northern Hemisphere, with extensive (over 90%) bleaching observed in the largest coral reef in the
Ryukyu Islands, Japan starting in July, resulting in 70% mortality
Harvey 2017
). The heat stress then brought
bleaching back to the western Atlantic, Gulf of America, and Caribbean from September through November, with the western Caribbean hit hardest.
Florida suffered only mild to moderate bleaching in summer 2016 but was struck by another round of coral disease, including the loss of 95% of pillar coral
Dendrogyra cylindrus
) across the state
FRRP 2016b
). October brought
the worst bleaching ever to the Flower Garden Banks, while patchy bleaching was reported from the eastern Caribbean. Moderate to severe
bleaching (generally more severe than in 2015) also was reported in parts of the Mesoamerican Barrier Reef in October and November,
with deeper reefs being impacted moreso than shallow. The year culminated in a return of bleaching to the Republic of the Marshall Islands
by November 2016. Figure 1 (above) shows the total extent of heat stress in 2016 and regions with confirmed coral bleaching reports.
Figure 2. NOAA Coral Reef Watch Maximum Bleaching Alert Area map for January-May 2017, with coral reef areas with reports of bleaching
circled in white. Data from Coral Reef Watch Daily Global 5km Coral Bleaching Heat Stress Monitoring Product Suite version 3
Liu
et al
. 2017
).
Bleaching in the First Half of 2017
Mild coral bleaching started in Fiji in January 2017, but stormy conditions cooled the water, averting severe thermal stress and bleaching.
However, severe bleaching was reported in Niue in February and by March, bleaching returned to American Samoa and Samoa. This time, bleaching
was much more extensive on the outer reefs than in 2015. The first-ever consecutive bleaching was confirmed on the GBR in March
Hughes and Kerry 2017
).
This time, the Northern (again) and Central sectors were most impacted in what would have been the worst bleaching of the GBR,
if not for the mortality from 2016. Heat stress was limited in the Indian Ocean, with the only pocket of moderate bleaching
reported from southwestern Madagascar in April
CORDIO-EA
).
Reports indicate that bleaching elsewhere in the Indian Ocean has been mild. Figure 2 shows the total extent of heat stress in 2017 and regions with confirmed bleaching reports.
As of September 2017, NOAA's El Niño-Southern Oscillation Alert System has issued a La Niña Watch, with a
55-60% chance of La Niña formation during late 2017. NOAA Coral Reef Watch's
Four-Month Coral Bleaching Heat Stress Outlook
indicates that bleaching is much less
likely in most of the Northern Hemisphere this summer (Figure 3). However, the Outlook through December 2017 does indicate a potential for
significant bleaching and coral mortality in the western Pacific Ocean (from Guam through Micronesia); in the eastern portion of the
Papaha̅naumokua̅kea Marine National Monument; and in the Caribbean Sea.
While more coral bleaching may still occur in 2017, the absence of widespread coral bleaching in the Indian Ocean appears to signal that the three-year-long global event has ended.
Figure 3. Map of areas where 60% or more of the model ensemble members were predicting heat stress at each of NOAA Coral Reef Watch's bleaching
heat stress alert levels through December 2017 (as of September 12, 2017). Data from Coral Reef Watch Four-Month Coral Bleaching Heat Stress Outlook version 4
Liu
et al
. 2017
).
Documenting the 2014-2017 Global Bleaching Event
With the Third Global Coral Bleaching Event apparently coming to a close, NOAA Coral Reef Watch is now working in earnest to collate reports
on the global extent of this event. We are planning a follow-on global summary paper similar to our 2005 Caribbean Bleaching Event paper
Eakin
et al
. 2010
). We truly
appreciate all reports we have received so far, many of which contributed to this brief review of the global event. Please assist us further
by continuing to report coral bleaching and disease observations to your existing regional programs, such as the Global Coral Reef Monitoring Network
nodes, ReefCheck, CORDIO-EA, AGRRA, etc. Also, please send a brief email to
coralreefwatch@noaa.gov
to let us know where you submitted them. If you aren't involved in one of these monitoring programs, please submit your reports directly to
the Coral Reef Watch
Report Bleaching web page
. Coral Reef Watch
needs both bleaching and non-bleaching observations to document the spatial extent and timing of the event and to continue to improve its
satellite and climate model-based products. Contributing your observations ensures that your site's data are considered in global analyses;
gives context to how bleaching patterns at your sites compare with global patterns; and provides access to the latest global coral bleaching
data analyses to communicate climate impacts to decision makers. All contributors will have the opportunity to co-author peer-reviewed
publication(s) on global and/or regional bleaching.
A special issue or portion of an issue of the International Society for Reef Studies journal
Coral Reefs
will focus on this event. This will be an
opportunity for you to publish more detailed studies on coral health, bleaching, disease, and mortality in your country or region associated
with the Third Global Coral Bleaching Event.
Since our last update
Eakin
et al
. 2016
),
filmmakers at Exposure Labs completed a 90-minute documentary on their efforts to capture time-lapse imagery of coral bleaching during the
Third Global Coral Bleaching Event. The film includes many of your contributions to their global call for bleaching reports and part was
shot at the 13th International Coral Reef Symposium in Honolulu, Hawaii. The resulting film,
Chasing Coral
, just premiered on Netflix on
July 14, 2017 (see two more detailed articles about the film in the August 2017 edition of
Reef Encounter
).
Final Thoughts
With the end of the Third Global Coral Bleaching Event, it is more essential than ever that coral reef ecosystem scientists, managers, and other
stakeholders, including the public, work together to increase our collective knowledge as we continue toward a future with a changed climate.
While continuing and expanding efforts to reduce local stressors, we all must work to address the main cause of global warming through reducing atmospheric
carbon dioxide concentrations and emissions.
Acknowledgements
NOAA Coral Reef Watch's work is supported primarily by the NOAA Coral Reef Conservation Program and the NOAA National Environmental Satellite,
Data, and Information Service's Center for Satellite Applications and Research.
References
AFP (Agence France-Presse) (2016) Thailand closes dive sites over coral bleaching crisis. The Guardian, May 26, 2016.
Bahr, KD, Jokiel PL, and Rodgers KS (2015) The 2014 coral bleaching and freshwater flood events in Ka̅ne´ohe Bay, Hawai´i.
PeerJ
3: e1136. doi:10.7717/peerj.1136.
Coffroth MA, Lasker HR, and Oliver JK (1990) Coral Mortality Outside of the Eastern Pacific During 1982-1983: Relationship to El Niño.
In Glynn PW (ed.) Global Ecological Consequences of the 1982-83 El Niño-Southern Oscillation.
Elsevier Oceanography Series
52:141-182.
CORDIO-EA (Coastal Oceans Research and Development - Indian Ocean East Africa) Responding to coral bleaching (database). http://cordioea.net/bleaching_resilience/wio-bleaching-2016/.
DAR (Division of Aquatic Resources). 2014. Coral bleaching 2014: important findings. http://dlnr.hawaii.gov/reefresponse/current-rapid-responses/coral-bleaching-2014/.
DeCarlo TM, Cohen AL, Wong GTF, Davis KA, Lohmann P, Soong K. (2017) Mass coral mortality under local amplification of 2°C ocean warming.
Scientific Reports
7, 44586. doi:10.1038/srep44586.
Eakin CM, Liu G, Gomez AM, De La Cour JL, Heron SF, Skirving WJ, Geiger EF, Tirak KV, Strong AE (2016) Global coral bleaching 2014-2017?
Status and an appeal for observations.
Reef Encounter 43
31(1): 20-26.
FRRP (Florida Reef Resilience Program) (2015a). Florida Reef Resilience Program disturbance response monitoring quick look report: Winter 2015.
FRRP (2015b). Florida Reef Resilience Program disturbance response monitoring quick look report: Summer 2015.
FRRP (2016a). Florida Reef Resilience Program disturbance response monitoring quick look report: Winter 2016.
FRRP (2016b). Florida Reef Resilience Program disturbance response monitoring quick look report: Summer 2016.
Fellenius K (2014) Republic of the Marshall Islands coral bleaching report. University of Hawai'i Sea Grant, Coastal Management Extension. Dec 31, 2014.
GBRMPA (Great Barrier Reef Marine Park Authority) (2016) Reef health, Updated: 29 May 2017. http://www.gbrmpa.gov.au/about-the-reef/reef-health.
Harvey, C (2016) More than 70 percent of Japan's largest coral reef has died. The Washington Post, April 12, 2016.
Harvey, C (2017) Why dead coral reefs could mark the beginning of 'dangerous' climate change. The Washington Post, January 13, 2017.
Heron, S.F., Johnston L., Liu G., Geiger E.F., Maynard J.A., De La Cour J.L., Johnson S., Okano R., Benavente D., Burgess T.F.R., Iguel J.,
Perez D., Skirving W.J., Strong A.E., Tirak K., Eakin C.M. (2016a) Validation of Reef-scale Thermal Stress Satellite Products for Coral
Bleaching Monitoring.
Remote Sens.
8(1): 59, doi:10.3390/rs8010059.
Hughes, TP, JT Kerry, M Álvarez-Noriega, JG Álvarez-Romero, KD Anderson, AH Baird, RC Babcock, M Beger, DR Bellwood, R Berkelmans, TC Bridge,
I Butler, M Byrne, NE Cantin, S Comeau, SR Connolly, GS Cumming, SJ Dalton, G Diaz-Pulido, CM Eakin, WF Figueira, JP Gilmour, HB Harrison,
SF Heron, AS Hoey, J-PA Hobbs, MO Hoogenboom, EV Kennedy, C Kuo, JM Lough, RJ Lowe, G Liu, MT McCulloch, HA Malcolm, MJ McWilliam, JM Pandolfi,
RJ Pears, MS Pratchett, V Schoepf, T Simpson, WJ Skirving, B Sommer, G Torda, DR Wachenfeld, BL Willis, SK Wilson (2017). Global warming and
recurrent mass bleaching of corals.
Nature
543(7645): 373-377, doi:10.1038/nature21707.
Hughes TP, Kerry JT (2017b) Back-to-back bleaching has now hit two-thirds of the Great Barrier Reef, The Conversation,
published online April 12 2017, http://theconversation.com/back-to-back-bleaching-has-now-hit-two-thirds-of-the-great-barrier-reef-76092.
Kramer, KL, Cotton SP, Lamson MR, Walsh WJ. 2016. Bleaching and catastrophic mortality of reef-building corals along west Hawai'i island:
findings and future directions.
Proc 13th Int Coral Reef Symp
: 219-230.
Liu G, Skirving WJ, Geiger EF, De La Cour JL, Marsh BL, Heron SF, Tirak KV, Strong AE, Eakin CM (2017) NOAA Coral Reef Watch's 5km
Satellite Coral Bleaching Heat Stress Monitoring Product Suite Version 3 and Four-Month Outlook Version 4.
Reef Encounter 45
32(1): 39-45 (this issue).
National Oceanic and Atmospheric Administration (NOAA) (2015) NOAA declares third ever global coral bleaching event.
NOAA (2017) Third global coral bleaching event appears to be over. http://www.noaa.gov/media-release/global-coral-bleaching-event-likely-ending.
Rodgers KS, Bahr KD, Jokiel PL, Donà AR (2017) Patterns of bleaching and mortality following widespread warming events in 2014 and 2015 at
the Hanauma Bay Nature Preserve, Hawai'i.
PeerJ
5:e3355. doi:10.7717/peerj.3355.
Rosinski A, Gove J, Birkeland C, Gorospe K, White D, Oliver T, Conklin E, Walsh W, Williams I (2017) Coral bleaching recovery plan. University of
Hawai'i, Social Science Research Institute, March 2017. 47 pp. https://dlnr.hawaii.gov/dar/files/2017/04/Coral_Bleaching_Recovery_Plan_final.pdf.
SIF (2017) Seychelles Islands Foundation newsletter. April 2017. Issue 52.
The Nature Conservancy (TNC) (2015) Summary of findings: 2015 coral bleaching surveys: South Kohala, North Kona.
For more information, please contact
coralreefwatch@noaa.gov
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