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 Symbiotic Algae Zooxanthellae Corals  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 zooxanthellaeReef 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?

Status of Coral Reef Ecosystems of the World Report 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 CO 2 from atmosphere - important for the mitigation of global warming 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 CO 2 from atmosphere - important for the mitigation of global warming 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  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 Maps

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

pH Time Series What’s happening over time?

CO 2 + H 2 O HCO 3 - Bicarbonate ion H 2 CO 3 Carbonic acid CO 3 2- Carbonate ion H + Hydrogen ion + Ca 2+ pH CO 2 + = CaCO 3 Calcium Carbonate X X 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 CaCO 3 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 After 45 days, the shell is dissolved.