climate change and corals. are they plants? are they animals? are they rocks? what are corals?

Climate Change

and Corals

Are they plants?

Are they animals?

Are they rocks?

What are Corals?

Invertebrates Phylum Cnidaria Class Anthozoa

(relatives of jellyfish and anemones)

Predators

Corals are Animals

Individual coral polyps sit inside a hard, calcium carbonate cup called the calyx

But kind of like a Rock…

The polyp is the soft part of the coral’s body resting inside of the calyx cup (a jellyfish with its head stuck)

Tentacles and mouth face upwards

Mostly come out at night to feed on plankton

What is a polyp?

 Photo: NOAA Office of National Marine Sanctuaries

Symbiotic Relationship

ShelterProvides CO2

Fertilizer from waste

Provides O2

Sugar (up to 90% to coral)

Coloration Symbiotic Algae

ZooxanthellaeCorals

Not a plant – more like a farmer Symbiotic relationship with photosynthetic

Zooxanthellae (pronounced zoo-zan-tell-e)

Shallow Water Corals

Deep Water

Sometimes called cold-water corals, live

in deep waters on continental shelves,

slopes, canyons

Lack zooxanthellae, consume detritus and

plankton

Only a few species build reefs, mostly

these corals mound or create patches

Provide habitat for important fisheries

species like sea bass and snapper

Destroyed by bottom fishing and oil/gas

exploration

Shallow Water

Require warm, clear water, restricted to

tropics

Have zooxanthellae

Reef builders

Provide habitat for numerous species like sponges, fish,

lobsters, clams, etc.

Threatened by pollution, climate change, damaging fishing practices

Deep Water Corals

Two Types of Corals: Differences and Similarities

Polyp Close-up

Photo credit: Maricopa Community College.

Algae

In some corals, the males and females are separate

Some species are hermaphroditic Male and female colonies can be

far apart so they release sperm and egg cells simultaneously

Can be initiated by change in temperature, lunar cycle, day length

Broadcast spawning species only release gametes on a few nights a year, different species may spawn at different times

Some corals reproduce asexually by budding

Something to Think About…

Symmetrical brain coral releasing eggs during a spawning event in the Flower Garden Banks National Marine Sanctuary.

Photo credit: Emma Hickerson, Flower Garden Banks National Marine Sanctuary;

Corals are stuck in one place, so how do they reproduce? Are they male, female, or

both?

Marine Fisheries = 1 million marine species

depend on corals 25% of all species in the

ocean (rainforests of the ocean)

60 nations and ½ billion people depend on reefs for food, income, and protection

Net benefit thought to be $29.8 billion/year

Why are Corals Important?

Tour

ism

Coast

al P

rote

ctio

n

Fishe

ries

Biodi

vers

ity0

4

8 9.6 95.7 5.5

Economic Value Per Year of the World's

Coral Reefs

Billions o

f D

ollars

http://www.coastalvalues.org/work/coralvalues.pdf

Status of Coral Reef Ecosystems of the World - 2008 Report

http://coralreef.noaa.gov/conservation/status/

19%15%

20%

46%

2008 Status of Coral Reef Ecosystems of the World

Report 19% original worldwide area lost 15% seriously threatened in 10-20 yrs

20% threat of loss in 20-40 yrs 46% not under threat

business as usual estimates

Where are the U.S. Protected Reefs?

3 Major Threats: Climate Change Pollution Unsustainable

Fishing EDUCATION IS THE KEY TO REEF SURVIVAL!

Why Teach About Corals?

Tourism: SCUBA diving, snorkeling, glass-bottom-boat viewing

Fisheries: Coral reefs and their surrounding ecosystems (mangroves and seagrass beds) provide fish habitat, spawning grounds

Coastal protection: Coral reefs = natural barriers to storm surges

Biodiversity: UN’s Atlas of the Oceans describes coral reefs as among the most biologically rich ecosystems on earth, with about 4,000 species of fish and 800 species of reef-building corals

Carbon sequestration: Coral reefs remove CO2 from atmosphere - important for the mitigation of global warming

http://www.coastalvalues.org/work/coralvalues.pdf

What’s the Big Deal?

Organisms found in coral ecosystems sources of medicine:

cancer, arthritis, asthma, ulcers, human bacterial infections, heart disease, viruses, etc.

Anti-viral drugs like AZT and the anti-cancer agent Ara-C developed from extracts of sponges found on a Caribbean reef

Limestone skeleton of corals tested in bone grafts

There’s a Medical Element too…

Climate Change is a GLOBAL problem!

The majority of ocean pollution comes from activities on LAND (fertilizers, sediment, toxins, trash, etc…)

Do you know where the fish that you eat comes from?

But I don’t live near an ocean…

Coral Bleaching

Photo credit: Erinn Muller, Florida Institute of Technology

Bleached Elkhorn Coral U.S. Virgin Islands, 2005

Photo credit: NOAA

Elkhorn Coral normal coloration - prior to 2005, no reported cases of Elkhorn Coral bleaching in region.

When corals are stressed by changes in light, temperature, and/or nutrients, they

expel their symbiotic algae and turn white.

Tropical weather systems can cool high temperatures that might cause bleaching 2005 - the worst bleaching on

record in the Caribbean 80% of corals bleached 40% + died at many sites

across Caribbean No tropical storms passed close

enough to cool the Virgin Islands 90% of area corals bleached 60% died

Most intense thermal stress recorded in Caribbean during 25-year NOAA satellite record

Weather Matters!

Bleached fire coral and Christmas tree worm on top - Flower Gardens Bank bleaching 2010, Credit:

NOAA, FGBNMS

Bleached corals can regain their zooxanthellae, but it depends on the intensity and duration of stress.

Once corals are bleached, they begin to starve.

NOAA Coral Reef Watch Maps2010

2012

NOAA Environmental Visualization Laboratory

Satellite-based data from NOAA Coral Reef Watch uses sea surface temperature measurements to determine # of weeks of the year

the coral were exposed to water temperatures that exceed traditional conditions

NOAA Environmental Visualization Laboratory

http://www.nnvl.noaa.gov/MediaDetail2.php?MediaID=545&MediaTypeID=1

pH Time Series

What’s happening over time?

CO2+ H2O

HCO3-

Bicarbonate ion

H2CO3 Carbonic

acid

CO32-

Carbonate ion

H+ Hydrogen

ion

+

Ca2+

pH

CO2

+ = CaCO3

Calcium Carbonate

X X

pHOcean pH

Ocean pH

Ocean pH

(pH not to scale)

?

Ocean water will never be acidic, acidification simply means “lowering pH”

Reefs naturally grow and shrink (accretion and dissolution)

Ocean acidification won’t dissolve the reefs, but it will slow accretion – less available carbonate to bind to Ca

pH is lowered and then raises a bit when bicarbonate is formed, but the net pH is still lower than the original

Corals aren’t the only organisms that need CaCO3

Key Points on Ocean Acidification

Pteropods, a pea-sized food source for organisms ranging from whales to salmon. This specimen was placed in seawater with a pH and carbonate level that is projected for the year 2100. After 45 days, the shell is dissolved.