Transcript Coral Bleaching 101 - NSTA Learning Center

LIVE INTERACTIVE LEARNING @ YOUR DESKTOP
NOAA: The Heat is ON! Climate Change and
Coral Reef Ecosystems
Coral Bleaching
Dr. Mark Eakin
Thursday, April 30, 2009
Coral Bleaching 101
Presented by Mark Eakin
Coordinator, NOAA Coral Reef Watch
Outline
1.
2.
3.
4.
5.
6.
Climate change
Introduction to coral reefs
Coral bleaching basics
Bleaching surprises
What does the future hold?
Classroom resources
Outline
1.
2.
3.
4.
5.
6.
Climate change
Introduction to coral reefs
Coral bleaching basics
Bleaching surprises
What does the future hold?
Classroom resources
Is Climate Changing?
“Warming of the climate system is unequivocal” IPPC 4th Assessment Report, WG 1
Top-ten warmest years
since 1880
2005
1998
2002
2003
2006
2007
2004
2001
2008
1997
http://www.ipcc.ch/ipccreports/assessments-reports.htm
http://www.ncdc.noaa.gov/oa/climate/research/2008/ann/global.html
Carbon Dioxide and Temperature
386 ppm
Current CO2
highest in
650,000
years of ice
core data
and 24
million years
from soil
data
Carbon Dioxide and Temperature
386 ppm
Current CO2
highest in
650,000
years of ice
core data
and 24
million years
from soil
data
The Rates are Important
The Rates are Important
From IPCC 2007 4AR WG-1
Reality is Following the Worst
Projections
http://www.ipcc.ch/ipccreports/ar4-wg1.htm
Questions?
Outline
1.
2.
3.
4.
5.
6.
Climate change
Introduction to coral reefs
Coral bleaching basics
Bleaching surprises
What does the future hold?
Classroom resources
What is a coral reef?
Animal
Vegetable Mineral
What is a coral reef?
All of the above!
Animal / Vegetable/ Mineral
Slide after of Joan Kleypas, NCAR
http://www.coris.noaa.gov/about/what_are/#Anchor-From-63388
Plant / Animal / Mineral
Reef Community
Slide after of Joan Kleypas, NCAR
http://www.coris.noaa.gov/about/what_are/#Anchor-From-63388
What do corals eat?
-Like a sea anemone,
the polyp captures
small prey with its
tentacles
-Also get nutrition from
a symbiotic relationship
with zooxanthellae….
http://www.coris.noaa.gov/about/biology/#feeding
What are zooxanthellae?
Algae
Fish
Shrimp
What are zooxanthellae?
• Algae that live in the coral
polyp’s surface layer
• Algae get nutrients and a
safe place to grow
• Corals get many benefits:
Photo: Michael ten Lohuis
– most of their food
– oxygen
– help with waste removal
– help in building their
skeletons
Questions?
Outline
1.
2.
3.
4.
5.
6.
Climate change
Introduction to coral reefs
Coral bleaching basics
Bleaching surprises
What does the future hold?
Classroom resources
What is coral bleaching?
Healthy
coral
Bleached
coral
Coral bleaching is caused by stress
What turns the coral white?
Healthy
coral
with
algae
Bleached
coral with
no algae
- As a stress response, corals expel the
symbiotic zooxanthellae from their tissues
- The coral tissue is clear, so you see the
white limestone skeleton underneath
http://coralreefwatch.noaa.gov/satellite/education/tutorial/crw04_morebleaching.html
What will stress a coral and
cause bleaching?
A. Nutrient enrichment (eutrophication).
B. Fish bites.
C. Lack of vitamin D.
D. High water temperature.
E. Too much homework.
What will stress a coral and cause
bleaching?
-High light or UV levels
-Cold temperatures
-Low salinity from coastal
runoff or heavy rain
-Exposure to air during very
low tides
Most important:
high water temperature
Photos: AIMS and GBRMPA
http://www.coris.noaa.gov/about/hazards/
Thermal stress
-Corals live close to their
thermal maximum limit
-If water gets 1 or 2°C
higher than the summer
average, corals get
stressed and bleach
-NOAA satellites measure
global ocean temperature
and thermal stress
http://coralreefwatch.noaa.gov/satellite
How warm is too warm?
How hot do you think the ocean has to get
before corals start to bleach?
How warm is too warm?
Bleaching threshold temperatures vary from
~27 – 33°C (81 – 91°F).
Corals from naturally warmer areas are
adapted to high temperatures, and have a
higher bleaching threshold.
http://coralreefwatch.noaa.gov/satellite/education/tutorial/crw22_bleachingthreshold.html
Can corals recover?
-Yes, if the stress doesn’t
last too long
-Some corals can eat more
zooplankton to help survive
the lack of zooxanthellae
-Some species are more
resistant to bleaching, and
more able to recover
Photos: AIMS
and GBRMPA
http://www.reefresilience.org/Toolkit_Coral/C2d_Recovery.html
Can corals recover?
-Corals may eventually
regain color by repopulating
their zooxanthellae
-Algae may come from the
water column
-Or they may come from
reproduction of the few cells
that remain in the coral
Jeff Miller, National Park Service
Can corals recover?
-Corals can begin to
recover after a few weeks
Jeff Miller, National Park Service
Does bleaching kill corals?
-Yes, if the stress is severe
-Some of the polyps in a
colony might die
-If the bleaching is really
severe, whole colonies
might die
-Bleaching in Puerto Rico
killed an 800-year-old star
coral colony in 2005
2005 Bleaching in the Virgin
Islands National Park
Mennebeck Bay
Over 90%
bleached
Yawzi Point
Over 60%
died
Newfound Reef
J. Miller (unpublished)
South Florida/Caribbean Network I&M Program
Questions?
Outline
1.
2.
3.
4.
5.
6.
Climate change
Introduction to coral reefs
Coral bleaching basics
Bleaching surprises
What does the future hold?
Classroom resources
What else can thermal stress
do to corals?
Photo:
Caroline Rogers, USGS
Question: what is something that happens to
people when they are highly stressed?
Gain weight
Get sick
Turn orange
What else can thermal stress
do to corals?
Photo:
Caroline Rogers, USGS
Question: what is something that happens to
people when they are highly stressed?
Answer: more likely to get sick
Bleaching and coral disease
-Coral diseases are
found around the world
-High temperatures
and bleaching can
leave corals more
vulnerable to disease
-Can quickly kill part or
all of the coral colony
Marilyn E. Brandt, University of Miami
Hurricanes: a mixed blessing
-Hurricanes can cause
direct physical damage
to coral reefs
-However, the storms
also cool the water
22 Aug 2005
-Hurricane Katrina led
to less bleaching in the
Florida Keys, 2005
2 Sept 2005
Hurricanes: a mixed blessing
2005:
Most named storms
Most hurricanes
Most damage in US
The same warm water that causes corals to
bleach can also lead to strong hurricanes.
Hurricanes: a mixed blessing
Sombrero Reef , FL
SST (degC)
DHW (degC week)
Dennis
9 July Katrina
26 Aug
Rita
21 Sept
Wilma
24 Oct
Each passing hurricane in 2005 cooled the
water in the Florida Keys.
-Ocean acidification may
make global warming
effects worse
~1150 ppm
0.4
0.2
~600 ppm
-Lower pH → more
bleaching for a given
temperature
0.6
380 ppm
-Recent study: synergy
between pH and warming
Fraction Bleached at 29°C
Bleaching and Acidification
0.0
pH
8.0
8.4
7.85
7.95
7.60
7.70
Anthony, K.R.N. et al., 2008. Ocean acidification causes bleaching and productivity
loss in coral reef builders. Proc. Natl. Acad. Sciences 105:45, p. 17442 – 17446.
Questions?
Outline
1.
2.
3.
4.
5.
6.
Climate change
Introduction to coral reefs
Coral bleaching basics
Bleaching surprises
What does the future hold?
Classroom resources
A Worldwide Crisis
Bleaching has already happened around the
world. (map shows all bleaching reports since 1963)
Adds to other stress (fishing, pollution, etc.)
19% of reefs have been lost
15% more are under imminent threat
http://www.reefbase.org/gis_maps/default.aspx
Future Warming
Coral
bleaching
threshold
Hoegh-Guldberg, 1999. Climate change, coral bleaching, and the future
of the world’s reefs. Marine and Freshwater Research 50(8), 839-866.
Two-part Solution:
1: lower global CO2 emissions
Sea Level Rise from
“Even if the
concentrations of all
greenhouse gases and
aerosols had been kept
constant at year 2000
levels, a further
warming of about
0.1°C per decade
would be expected.”
- IPCC 4th Assessment
Report, WG1
Two-part Solution:
2: increase reef resilience
–
–
–
–
–
Shade reefs
Cool reefs
Improve water quality
Reduce other stress (pollution, disease)
Reduce overfishing
http://www.reefresilience.org/Toolkit_Coral/C1_Intro.html
Coral Reefs Are
Too Valuable to Lose
-Not just a nice place to visit on vacation!
-Over $375 billion in fish, seafood, tourism,
and coastal protection worldwide
-0.5 to 1 Billion people directly depend on
healthy reefs for their food and livelihood
-Highest marine biodiversity in the world
http://coralreef.noaa.gov/outreach/protect/welcome.html
The Future of Reefs
Is Up To Us
A
B
C
Hoegh-Guldberg et al., 2007. Coral reefs under rapid climate change and ocean
acidification. Science 318, 1737 - 1742.
What Can YOU Do?
1. Don’t buy jewelry/souvenirs made from
coral or other reef animals.
2. Reduce fertilizer use.
3. Be a responsible tourist.
4. Learn more about coral reefs.
5. Spread the word.
http://coralreef.noaa.gov/outreach/thingsyoucando.html
http://www.projectaware.org/english/templates/info.aspx?id=407
Questions?
Outline
1.
2.
3.
4.
5.
6.
Climate change
Introduction to coral reefs
Coral bleaching basics
Bleaching surprises
What does the future hold?
Classroom resources
Satellite Data and Animations
(website demonstration)
• NOAA Coral Reef Watch website
• provides current conditions, data,
Google Earth, etc.
• Anomaly animation shows ENSO
status, etc.
http://coralreefwatch.noaa.gov/satellite/index.html
http://www.osdpd.noaa.gov/PSB/EPS/SST/anom_anim.html
Google Earth
• Fun, interactive tool
• Also teaches
tropical geography!
• See where
conditions are right
for coral bleaching
right now.
• Live links to data on
the web.
http://coralreefwatch.noaa.gov/satellite/ge/index.html
Google Earth
• Fun, interactive tool
• Also teaches
tropical geography!
• See where
conditions are right
for coral bleaching
right now.
• Live links to data on
the web.
http://coralreefwatch.noaa.gov/satellite/ge/index.html
Classroom Resources
• Satellite data/coral bleaching
– Lesson plans, data activity, tutorial
– http://coralreefwatch.noaa.gov/satellite/education/index.html
• Ocean education
– Tutorial and online resources for corals
– http://oceanservice.noaa.gov/education/welcome.html
• Coral Reef Conservation Program
– Central listing for coral education resources
– http://coralreef.noaa.gov/outreach/welcome.html
Bleaching 101: summary
- Corals are animal, vegetable, AND mineral
- Hot water bleaches corals
- Corals may die after bleaching
- Diseases follow many warming/bleaching
stress events
-We need to act now to save coral reefs
Special Thanks to
for
Sponsoring Tonight’s Web
Seminar
http://www.elluminate.com
http://learningcenter.nsta.org
National Science Teachers Association
Dr. Francis Q. Eberle, Executive Director
Zipporah Miller, Associate Executive Director
Conferences and Programs
Al Byers, Assistant Executive Director e-Learning
NSTA Web Seminars
Paul Tingler, Director
Jeff Layman, Technical Coordinator
LIVE INTERACTIVE LEARNING @ YOUR DESKTOP