Coral Reefs and Climate Change Management Solutions and Challenges for a Changing System By: William Adams ATOC 4800 17 April, 2017

Table of Contents I-Coral Reefs II-Environmental Threats A. Climate Change B. Ocean Acidification III-Coral Bleaching IV-Managing Impacts V-Reef Resilience: Management Opportunities/Limitations A. Local Solutions B. Limits VI-Adaptation VII-Discussion

I. Coral Reefs Make up 1% of ocean floor, but are home to over 25% of species in the ocean Result of symbiotic relationship between coral and unicellular algae known as zooxanthellae Relationship possible only under small range of environmental conditions Not only essential for biodiversity, but monetary value to humans

II. Reefs Under Threat 3 Most important factors to reef growth and health: 1. Seawater Temperature 2. Carbon Chemical Conditions 3. Light The biggest threats to coral reefs: A. Climate Change B. Ocean Acidification

A. Climate Change Physical consequence of carbon in the atmosphere Drives ocean warming which disrupts biological and ecological reef processes, that drives coral bleaching NOAA: 2014/2015 ocean temperatures are approximately .74 degrees C warmer than the global average for the 20th century Since the start of the industrial era, the ocean has absorbed 1/3 of CO2 emitted from human activity Source: Ken Anthony—Australian IMS

B. Ocean Acidification Chemical consequence of increased CO2 in the atmosphere Process 1. CO2 in the ocean produces carbonic acid 2. Lowers the pH and reduces concentrations of carbonate ions 3. Chemical building blocks of marine carbonic structures are destroyed and reef growth and function is impaired Unlike climate variability, ocean acidification is a creeping stressor that results in marine calcification

III. Bleaching The result of warming, as well as, acidification Breakdown in relationship between coral and algae Host expel dysfunctional algae, causing coral to turn white Algae loss starves coral of energy from photosynthesis, causing extensive reef systems to die out 2016: Great Barrier Reef undergoes the worst bleaching event in history enhanced by an El Nino event, bleaching 90% of the corals in the reef system Great Barrier Reef 2016 Source: GBRMPA

IV. Managing Impacts Managing impacts requires 3 things: Drivers/activities that result in stress on reef systems The scales they operate on What way these influences interact These indicators help identify stress pathways and management possibilities through these “effective management levers” Maps pathways from sources to impacts on the ecosystem goods and services and a possible analysis for mitigation by closing the loop back to stressors through management policies

Source: Ken Anthony—Australian IMS

V. Reef Resilience: Management Opportunities and Limitations Ecological Resilience capacity of a system to absorb stress, reorganize and recover from disturbances and over time, retain same function, structure and identity Managing for Resilience: builds on the premise that smart actions on the ground can provide some level of protection against decline caused by climate change Example: protected marine parks and no-take fishing reserves

A. Local Solutions Examples Challenges Example Spatial planning Improved land-use practices to enhance water quality in costal zones Protection of herbivorous fish to promote top- down control of macroalgae Intensified control of coral eating organisms Challenges Limits to resilience (maximum resilience potential) Local-scale actions have limited geographical reach Example Crown-of-Thorns Starfish Outbreaks and the Great Barrier Reef Source: GBRMPA

B. Limitations Resilience lost to one pressure might not be replaceable by mitigation of another pressure and impairment of resilience caused by acidification and warming cannot directly be restored by protecting more fish or reef systems Reduced coral calcification will be a resilience handicap that can only be addressed by the reversal of changes in ocean carbon chemistry Management--Understanding the spatial and temporal scope of actions is critical to set realistic expectations for what can be achieved through management actions in the face of global climate change 1. Zone of impact of different stressors 2. Zone of influence from management and policy

VI. Adaptation Human-Assisted Evolution being considered Artificial selection In theory, this approach could help reef managers break through the resilience ceiling imposed by climate change and ocean acidification Genetically engineered or modified organisms are not feasible, but assisted evolution (artificial selection) are an area of research with a mgmt. application in the future

VII. Discussion 3-5 minutes Discuss in a group what the benefits/risks are of the adaptation management strategy are Discuss the question: is spread and dominance of selected keystone species better then total decline?