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Ocean Acidification in the Coral Triangle, Recommendation - Coggle Diagram
Ocean Acidification in the Coral Triangle
Problem :
Carbonate ion (CO₃²⁻) decline
CO₂ + H₂O + CO₃²⁻ → 2HCO₃⁻
Reduced CO₃²⁻ availability for calcification (Orr et al. 2005)
Aragonite saturation state (Ω) declining (NOAA)
Coral calcification decline
Reduced Ω impairs CaCO₃ precipitation (Manahan Ch. 4)
Slower reef growth; increased dissolution (Albright et al. 2018)
Coral Triangle reefs at risk (Hoegh-Guldberg et al. 2017)
pH decline
Projected additional 0.3–0.4 unit drop by 2100 (IPCC 2021)
Surface ocean pH dropped ~0.1 units since pre-industrial times (IPCC 2021)
Coral Triangle particularly vulnerable due to warm waters (CSIRO)
Ecosystem and livelihood threats
Biodiversity loss (CTI-CFF)
Fisheries decline (Munday et al. 2010)
Food security threats (UNEP 2023)
Causes
PRIMARY: Rising atmospheric CO₂
Fossil fuel combustion (IPCC 2021)
Deforestation (IPCC 2019)
Industrial processes (cement, steel) (WMO 2023)
Industrial processes (cement, steel) (WMO 2023)
SECONDARY: Local stressors
Nutrient runoff → organic matter decomposition → CO₂ release (UNEP 2023)
Coastal development → mangrove/seagrass loss → reduced carbon sinks (CTI-CFF)
Overfishing → ecosystem imbalance (Munday et al. 2010)
Sedimentation → reduced light → coral stress (Golbuu et al. 2011)
NATURAL: Upwelling
Brings CO₂-rich water to surface (Doney et al. 2009)
Some Coral Triangle regions naturally low pH (Fabricius et al. 2011)
Compounds anthropogenic acidification (CSIRO)
CLIMATE INTERACTIONS
Warming reduces CO₂ solubility (IPCC 2021)
Deoxygenation (oxygen minimum zones) (IPCC 2019)
"Deadly trio": warming + acidification + deoxygenation (Hoegh-Guldberg et al. 2017)
SOLUTIONS
GLOBAL
CO₂ emission reduction (IPCC 2023)
Paris Agreement commitments
Carbon pricing
Renewable energy transition
Carbon capture and storage (IPCC 2021)
International policy coordination (UNFCCC)
REGIONAL
Coral Triangle Initiative (CTI-CFF)
Regional Plan of Action
Shared monitoring networks
Capacity building
SPREP coordination (SPREP)
Pacific Islands Forum (FFA)
LOCAL
Marine protected areas (MPAs) (CTI-CFF)
Blue carbon restoration (UNEP 2023)
Mangrove restoration
Seagrass protection
Salt marsh conservation
Coral reef restoration (Fabricius et al. 2011)
Coral gardening
Selective breeding for acidification tolerance
Artificial reefs
Pollution control (Golbuu et al. 2011)
Nutrient runoff reduction
Wastewater treatment
Sedimentation control
Community-based adaptation (SPREP)
Alternative livelihoods
Aquaculture diversification
Education and awareness
SCIENTIFIC
Monitoring networks (GOA-ON)
pH sensors
Ω measurements
pCO₂ monitoring
Early warning systems (NOAA)
Research on resistant coral genotypes (CSIRO)
POLICY
Carbon pricing (IPCC 2023)
Paris Agreement commitments (UNFCCC)
CTI action plans (CTI-CFF)
PNG CEPA regulations (PNG CEPA)
SDG 14 targets (UNEP 2023)
EMERGING
Ocean alkalinity enhancement (IPCC 2021)
Olivine dissolution
Lime addition
Electrochemical methods
Blue carbon markets (UNEP 2023)
Nature-based solutions (CTI-CFF)
Chemistry
CO₂ dissolution
CO₂(aq) + H₂O ⇌ H₂CO₃ (carbonic acid)
Henry's Law: [CO₂(aq)] = K_H × pCO₂
CO₂(g) ⇌ CO₂(aq) (Manahan Ch. 2)
Carbonate equilibria
HCO₃⁻ ⇌ H⁺ + CO₃²⁻ (carbonate)
Net: CO₂ + H₂O + CO₃²⁻ → 2HCO₃⁻ (Manahan Ch. 3)
H₂CO₃ ⇌ H⁺ + HCO₃⁻ (bicarbonate)
Buffer capacity: ocean's carbonate system resists pH change
Trace metal speciation
Fe, Zn, Cu speciation changes with pH (Doney et al. 2009)
Affects phytoplankton nutrient availability
Impacts primary productivity (UNEP 2023)
Biogeochemical cycling
Carbon cycle: ocean as sink (IPCC 2021)
Nitrogen cycle: N₂ fixation, nitrification, denitrification (Manahan Ch. 5)
Phosphorus cycle: adsorption/desorption (Bleam 2016)
Coupled cycles: C-N-P interactions (IPCC 2019)
pH and saturation state
pH = -log[H⁺]
Ω_aragonite = [Ca²⁺][CO₃²⁻] / K_sp (Manahan Ch. 4)
Ω < 1 = undersaturated = dissolution
Ω > 1 = supersaturated = calcification possible
Carbonate chemistry parameters
DIC (Dissolved Inorganic Carbon)
TA (Total Alkalinity)
pCO₂ (partial pressure of CO₂)
HCO₃⁻ and CO₃²⁻ concentrations
Relationships: DIC = CO₂ + H₂CO₃ + HCO₃⁻ + CO₃²⁻ (Gattuso & Hansson
IMPACTS :
ECOLOGICAL
Reduced coral calcification (Orr et al. 2005)
Coral bleaching (Hoegh-Guldberg et al. 2017)
Biodiversity loss (CTI-CFF)
Altered food webs (Kroeker et al. 2013)
Fish behaviour changes (Munday et al. 2010)
Shellfish and plankton decline (Doney et al. 2009)
CHEMICAL
Lower pH (IPCC 2021)
Reduced Ω (NOAA)
Shifts in trace metal speciation (Doney et al. 2009)
Changes in nutrient availability (UNEP 2023)
Altered carbonate chemistry (Gattuso & Hansson 2011)
ECONOMIC
Declining fisheries (Munday et al. 2010)
Reduced tourism (CTI-CFF)
Shellfish industry losses (NOAA)
Increased coastal protection costs (UNEP 2023)
SOCIAL
Food security threats (UNEP 2023)
Displacement of coastal communities (IPCC 2019)
Cultural loss (CTI-CFF)
Livelihood loss for fishers (SPREP)
CUMULATIVE
"Deadly trio": warming + acidification + deoxygenation (Hoegh-Guldberg et al. 2017)
Interaction with pollution (Golbuu et al. 2011)
Interaction with overfishing (Munday et al. 2010)
Reduced reef resilience (Fabricius et al. 2011)
RECOMMENDATION
Integrated multi-scale approach
GLOBAL: Emission reduction
Support Paris Agreement
Carbon pricing
Renewable energy
REGIONAL: CTI coordination
Shared monitoring (SPREP, NOAA)
Policy harmonisation
Capacity building
LOCAL: Ecosystem restoration
MPAs
Blue carbon
Coral restoration
Pollution control
SCIENTIFIC: Monitoring
Long-term pH/Ω monitoring
Research on resistant corals
Early warning systems
POLICY: Strengthen regulations
PNG CEPA enforcement
CTI action plans
SDG 14 integration
JUSTIFICATION
Addresses root cause (CO₂ emissions) (IPCC 2023)
Addresses local stressors (pollution, overfishing) (Golbuu et al. 2011)
Builds ecosystem resilience (Fabricius et al. 2011)
Evidence-based (multiple sources)
Feasible at multiple scales (CTI-CFF)
Aligned with international frameworks (UNFCCC, SDG 14)
LIMITATIONS
Emission reduction is slow (IPCC 2023)
Ocean alkalinity enhancement is research-stage (IPCC 2021)
Coral restoration is expensive (Fabricius et al. 2011)
Monitoring requires sustained funding (GOA-ON)
Policy enforcement is challenging (PNG CEPA)
MONITORING & EVALUATION
pH and Ω monitoring (NOAA)
Coral cover surveys (CTI-CFF)
Fish population assessments (Munday et al. 2010)
Policy compliance checks (PNG CEPA)
Community feedback (SPREP)
STAKEHOLDERS
GOVERNMENT
PNG CEPA (PNG CEPA)
PNG National Fisheries Authority
Pacific Islands Forum Fisheries Agency (FFA)
National governments (Indonesia, Philippines, etc.)
REGIONAL BODIES
Coral Triangle Initiative (CTI-CFF)
SPREP (SPREP)
Pacific Community (SPC)
INTERNATIONAL
UNEP (UNEP 2023)
IPCC (IPCC 2021)
NOAA (NOAA)
CSIRO (CSIRO)
WWF (WWF)
LOCAL COMMUNITIES
Coastal fishers
Foe people (Lake Kutubu — if applicable)
Village councils
Women's groups
SCIENTIFIC
Universities (UPNG, PAU)
Research institutes (CSIRO, NOAA)
GOA-ON (GOA-ON)
PRIVATE SECTOR
Fisheries industry
Tourism operators
Oil and gas companies
NGOs
WWF Coral Triangle Programme (WWF)
The Nature Conservancy (TNC)
Local NGOs
PNG RELEVANCE
GEOGRAPHY
PNG sits within the Coral Triangle (CTI-CFF)
One of six Coral Triangle countries
Extensive coral reefs and coastal ecosystems
High marine biodiversity
VULNERABILITY
Warm tropical waters (CSIRO)
Coastal communities depend on reefs (SPREP)
Limited monitoring capacity (GOA-ON)
Local stressors (sedimentation, overfishing) (Golbuu et al. 2011)
POLICY
PNG CEPA regulations (PNG CEPA)
CTI commitments (CTI-CFF)
National Communications to UNFCCC
SDG 14 integration (UNEP 2023)
RESEARCH
UPNG Marine Science Programme
PAU research (if applicable)
CSIRO partnerships (CSIRO)
SPREP monitoring (SPREP)
STAKEHOLDERS
PNG CEPA
National Fisheries Authority
Provincial governments
Coastal communities
NGOs (WWF, TNC)
Recommendation