Challenges facing coral reefs: Monitoring for solutions first reefs end Ordovician Late Devonian end Permian first Scleractinia end Triassic K/T Siluri Ordovician an Devonian Carboniferous Permian Triassic Jurassic Cretaceous Palaeozoic Mesozoic Cenozoic 490 434 410 354 298 251 205 141 65 Millions of years ago Photo: Thomas Heeger Photo: James Oliver Over half a billion people rely on coral reefs for food. Photos: James Oliver Photo: Shamala Palaniappan BENEFITS OF HAVING REEFS Keep biodiversity Protect shoreline Support for coastal communities Revenue Food & Tourism Economic evaluation Belize reefs: WRI 2008 ESTIMATED CORAL REEF AND MANGROVE CONTRIBUTIONS TO THE ECONOMY (USD)* Activity Coral Reefs Mangroves Combined Contribution Tourism $135 176 m $60 78 m $150 196 m Fisheries $13 14 m $3 4 m $14 16 m Shoreline Protection $120 180 m $111 167 m $231 347 m 1
Entire Caribbean 80% decline in 25 yrs 6% decrease per yr % coral cover 1977 2003 Coral cover 54% 13% Macroalgae 3% 20% Turf algae 8% 32% Stingray Motel has more angels, leatherjackets, and pelagics Happy Hour has higher butterflyfish diversity & abundance Gardner et al. (2003) Science 301:958-960 Comparison % cover 60 50 40 30 20 10 0 Sand Rubble Bare Cyanobacteria June 2009 Turf CCA Encrusting algae All macroalgae Fire Coral Live Stony Coral Happy Hour Diseased/bleached stony coral Aggro Invert Sting Ray Motel Sponge Gorgo HF Caribbean 80 70 60 50 40 30 Site 12 percent cover Site 11 Percent cover Clipperton 20 10 0 Rub Cyan CCA TA LSC 2
Are herbivorous fishes a single functional group? Sub-groups within the herbivore guild play different roles in coral recovery (Bellwood et al. 2004 Nature) Large-bodied scarids alone can reduce macroalgal cover (Mumby et al. 2006 Science) Grazing intensity enhanced in MPA s Grazing intensity Macroalgal cover Status of Coral Reefs of the World 20% destroyed beyond recovery 24% under imminent risk of collapse 1998: unprecedented global bleaching event 16% of world s coral reefs Seriously damaged 26% at longer-term threat of collapse Photo: Yusri Yusuf; Palau Payar 1998 Mumby et al. 2006 Science 311:98-101 60% have not recovered http://www.aims.gov.au/pages/research/coral-bleaching/scr2004/index.htm Multiple Stressors & Impacts on Coral Reefs Climate change: Increased SST -> Coral bleaching Inc. levels of CO2 -> decreased accretion - acidification Increase storm frequency -> decreased resilience Indirect/unknown Diseases -> plagues Invasions -> community shifts Direct Human Pressures Coastal development -> direct loss, mangrove removal Deforestation/dredging/poor land use -> Sedimentation Agriculture/sewage -> Nutrient/chemical pollution Destructive fishing -> habitat destruction Poverty/Poor mgmt -> unsustainable exploitation Over-fishing -> decreased stocks, etc. Photo: Thomas Heeger 3
Reefs in Peril? Components of resilience They are geological structures made by living organisms Ecosystem Structure Biodiversity Community structure Water Quality Habitat heterogeneity Extent of Habitat spatial connectivity Ecosystem Function Recruitment Coral Health Reef Accretion Herbivory Corals are closely attuned to their environment Coral Disease Light Temperature: 31ºC Carbonate chemistry of the ocean 4
Corals live in symbiosis with zooxanthellae Temperature stress 5
K/T Pleistocene Palaeocene 65 Ordovician Eocene 55 Oligocene 38 Siluri an Devonian Carboniferous Miocene 24 Permian Triassic Jurassic Palaeozoic 490 434 410 Pliocene 5.3 Cretaceous Mesozoic 354 298 251 205 2.6 141 Cenozoic 65 Millions of years ago 6
Closest analog to the present acidification was likely the PETM. -0 gigatons of C: volcanoes, seafloor methane hydrates. Today 387 K/T Today s rate of release is 10X faster. What took 1000 s years is taking 100 s today Late Palaeocene Thermal Maximum 0 360 320 Mid Eocene Extinctions 0 Last interglacial 280 Origin of the GBR? 1000 240 Not much information Pleistocene 200 Palaeocene Eocene Oligocene Miocene Pliocene 0 65 55 38 24 5.3 2.6 Millions of years ago 200 100 0 Thousands of years ago It takes about 1000 yrs. to flush surface into deep sea sediments, where acid is neutralized. The PETM release was slow enough to avoid a biological catastrophe in the surface ocean waters. 320 No harm to reefs in the long term? Today s rate of acidification is leading to a build up of acidic water in the ocean s surface. The ocean s natural buffering system takes longer than we are giving it. 1750 1 320 350 Periodic mass bleaching on the GBR 387 (Today) Compounding long-term degradation for GBR 1750 1 350 1750 1 387 7
Will be reached by ~2015 Will cause major weather events Will cause severe bleaching, mainly during El Niño cycles 450 Will be reached by 2030-2040? Will cause severe bleaching most years 1750 1 1750 1 450 Will result in a global increase of >3 C Will cause severe bleaching every year. 550 Will result in 2.8 5.8 C warming C +5 Present -5 Pleistocene 550 Palaeocene Eocene Oligocene Miocene Pliocene 1750 1 65 55 38 24 5.3 2.6 Millions of years ago 1750 1 Some key points about ocean acidification: The chemistry of the oceans and ocean acidification are well known It is the rate that is important. The oceans can buffer acidification in about a 1000 year cycle (into deep sea sediments)/ The acidity of the oceans has increased since pre-industrial times and will continue to increase in coming decades, due to human-generated carbon dioxide (CO2) emissions. The ph of the surface oceans could decline by up to 0.5 units by if CO2 emissions continue to increase on present trends. Increasing oceanic acidity will adversely affect the health of corals and other marine calcifiers (e.g., marine snails). 8
? But we didn t realize......the size of the problem...the domino effect...ecosystem failures are mass extinctions...that 450 ppm will bring on the demise of the GBR and other reef systems Oceanography is linked to global patterns Marine systems help us understand global systems But there is so much we don t know! MANAGEMENT What we manage are human interactions with the reef Coastal Zone Management Negotiates acceptable levels of use amongst often conflicting demands Facilitates changes from resource use maximization to resource use optimization and balancing 9
MANAGEMENT TO ENSURE IT: Coordination between stakeholders and involve local communities Educate Ensure implementation & enforcement Adapt OBJECTIVE: To decrease pressure on the resource and attain sustainability, via protection of resources Zoning programs Involve research, education, alternative livelihoods But we cannot lose hope. Knowledge is power. It arms us with the tools for action. Earth is and will change. But we can influence the rate of change, which can allow Earth s systems to respond and buffer the effects of change. Do NOT underestimate the effects of your actions. individual understanding and action are the key to the future of our blue planet. Hope will ensure we seek that understanding, and translate it into action. 10