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Why is coral bleaching a wicked problem? - Coggle Diagram
Why is coral bleaching a wicked problem?
How has coral bleaching affected the reefs around Australia?
Effects on Great Barrier Reef?
Nearly 1/3 of coral cover effected in the 2016 coral bleaching event (Edmondson et al., 2019).
Cape York peninsula hit worst with 80% + of its corals bleached (Leggat et al., 2016).
Means 50% or more mortality (Leggat et al., 2016).
In 2016, 29% of corals died, mainly in the Northern section where waters are warmest (AMCS, 2021).
From 2016-2017 approximately 1/2 of shallow water corals were reported dead (AMCS, 2021).
In 2017 it was estimated that a further 20% of corals died from the 2017 bleaching event
This reached further south, from Port Douglas to Townsville (AMCS, 2021).
Effect on Scott's Reef?
Is located 400km from Broome, WA (Gilmour, 2016).
Coral in dire condition (Gilmour, 2016).
Gilmour (2016) recorded 60-90% of the corals in this reef bleached.
What is coral bleaching?
Coral is a type of animal, plant and mineral. It needs algae to survive, specifically microscopic singe celled algae of the genus symbiodinium (Leggat et al., 2016).
This algae is what gives the coral its colour (Leggat et al., 2016).
Coral takes algae from the water to live symbiotically inside its own cells (Leggat et al., 2016).
This marine algae found in their tissues is called Zooxanthellae (AMCS, 2021).
This is a species of the genus Symbiodinium (Leggat et al., 2016).
Algae receives: shelter and carbon dioxide from its host (Leggat et al., 2016).
As well as other essential nutrients e.g. nitrogen and inorganic carbon (van Oppen & Lough, 2018).
Coral receives nutrition from sugars that the algae make through photosynthesis (Leggat et al., 2016).
This food and energy allows the coral to grow and/or reproduce (AMCS, 2021).
The zooxanthellae also plays a role in light enhance calcification of scleractinian corals, which is necessary to form reef structures (van Oppen & Lough, 2018).
However sometimes, some corals can feed themselves without it (AMCS, 2021).
Breakdown of symbiosis results in the expulsion of symbiodinium from coral tissues (van Oppen & Lough, 2018).
This results in a phenomenon called coral bleaching (van Oppen & Lough, 2018).
This algae is expelled when coral is stressed generally by heat or pollution, amongst other factors (AMCS, 2021).
When this occurs, this results in a ghostly transparent skelleton, as the coral is ultimately starved (AMCS, 2021).
The white calcium carbonate skeleton becomes visible through the now translucent tissue layer (van Oppen & Lough, 2018),
What causes and contributes to coral bleaching?
Climate Change (AMCS, 2021; Great Barrier Reef Marine Park Authority [GBRMPA], 2016; Leggat et al., 2016; van Oppen & Lough, 2018).
The mining and burning of coal releases carbon pollution into the air, heating our planet and warming our oceans causing bleaching (AMCS, 2021).
Struggling with global warming, change in just a few degrees (Leggat et al., 2016).
High water temperatures (Edmondson et al., 2019).
Coral is heat stressed (Leggat et al., 2016).
These carbon emissions pollute the atmosphere and cause global warming. This increased carbon pollution in our atmosphere traps heat which causes the temperature to rise on Earth (AMCS, 2018).
This increases ocean temperatures, as driven by carbon pollution (AMCS, 2021).
This threatens reefs on a global level and is its biggest threat (AMCS, 2021)
Evident since the 1980's, bleaching is clearly related to human induced global warming that is effecting large scale mass coral bleaching events (van Oppen & Lough, 2018).
Other more minor impacts of climate change on coral bleaching
More intense tropical cyclones = destruction of reefs (van Oppen & Lough, 2018).
More extreme rainfall = effects the periodic extent of freshwater onto reefs (van Oppen & Lough, 2018).
Gradual rise in sea level = affects light penetration and availability of suitable areas or corals to live (van Oppen & Lough, 2018).
Changes in large scale atmpospheric and ocan circulation patterns = affects connectivity between reefs (van Oppen & Lough, 2018).
Changes in ocean acidification as 1/3 of excess atmposhperic CO2 is absorbed by oceans = detremental impacts on corals and reef associated organisms (van Oppen & Lough, 2018).
Local and regional human pressures on coral reef environments (van Oppen & Lough, 2018).
Overfishing (AMCS, 2021; GBRMPA, 2016; van Oppen & Lough, 2018).
Destructive fishing (van Oppen & Lough, 2018),
Decline in water quality due to land use changes (GBRMPA, 2016; van Oppen & Lough, 2018).
Nutrient and Chemical pollution (van Oppen & Lough, 2018).
Coastal development/ development on coasts (AMCS, 2021; GBRMPA, 2016; van Oppen & Lough, 2018).
Mining of coral (van Oppen & Lough, 2018).
Water pollution (AMCS, 2021; GBRMPA, 2016).
Why is it important to overcome coral bleaching?
Coral reefs are home to millions of fish (AMCS, 2021).
Thousands of species effected (AMCS, 2021).
There are consequences right up the food chain, impacting larger creatures like sharks and dolphins that rely on reef fish for their diet (AMCS, 2021).
At least 1/4 of the worlds marine life needs coral reefs for some part of their life cycle (AMCS, 2021).
Livelihood and food security of over 1/2 a billion people worldwide (AMCS, 2021).
Tens of millions of people in over 100 countries with coral reefs along their coastline depend on the economic and social goods and services provided by these rich ecosystems (van Oppen & Lough, 2018).
Tourism (Ainsworth et al., 2021; Edmondson et al., 2019; GBRMPA, 2013; Leggat et al., 2016).
In Australia rewards 6 Billion $ per year through the tourist industry (Edmondson et al., 2019; Leggat et al., 2016).
In Australia, it provides 70, 000 jobs (Leggat et al., 2016).
Food sources (Subsistence, recreational and commercial fishing) (Ainsworth et al., 2021).
Water sports (surfing, kite surfing, boating) (Ainsworth et al., 2021).
Ecosystem repair and restoration (Ainsworth, 2021).
Culturally Specific Activities (festivals, ceremonies, culturally important sites or objects) (Ainsworth et al., 2021).
If we don't?
If we continue to produce carbon emissions at our high rate, coral reefs around the world will face a catastrophic future in coming decades and within our lifetime (AMCS, 2021).
Prolonged warmer temperature and other stressors = weakened coral state (AMCS, 2021).
Vulnerable to coral disease and mortality (AMCS, 2021).
Struggle to regrow and reproduce (AMCS, 2021).
Is susceptible to bacteria and other microbes which can cause deadly infections (Leggat et al., 2016).
severe bleaching events likely to occur annually, by the middle of the century (AMCS, 2021).
Events are becoming more frequent, which means recovery time is becoming shorter and shorter (Leggat et al., 2016).
No chance to recover (AMCS, 2021).
With warming of the oceans these events may not only be bigger but occur more frequently (Edmondson et al., 2019).
This century could be their last (Leggat et al., 2016).
Importance is mirrored in the 'Paris Agreement to the United Nations Framework Convention on Climate Change'
This has been today signed and joined by 190 countries plus the European Union (Australia included).
Aims to hold "the increase in the global average temperature to well below 2 degrees above pre-industrial levels."
Aims to foster "Low greenhouse gas emissions development."
Illustrates a "pathway towards low greenhouse gas emissions and climate resilient development.
Aims to "promote sustainable development and environmental integrity."
Can coral recover from coral bleaching?
If conditions return to normal and stay that way, corals can regain their algae and survive (AMCS, 2021).
They can grow back but it takes time (Edmondson et al., 2019).
During this time the coral must take up symbiods again, repair tissues and fight off infections (Leggat et al., 2016).
If the algae are not replaced that the coral slowly starves (Leggat et al., 2016).
However it can take decades to fully recover from a bleaching event (AMCS, 2021).
This is also supported by research conducted by Terry Hughes (Leggat et al., 2016).
How can we act further on an individual, local, national and global level to overcome coral bleaching and save these ecosystems?
What can I do?
Insulate your home (means you will use less energy for heating and cooling) (FutureLearn, 2021).
Switch to Renewables (Use companies that provide electricity from solar, wind or hydroelectric energy) (Could install solar panels) (FutureLearn, 2021).
Buy energy efficient (choose appliances with a high energy star rating) (FutureLearn, 2021).
Use less water (FutureLearn, 2021).
Change your diet (meat and dairy products require a lot of land, water and energy to produce and create a lot of methane. Therefore you should try to eat fewer of these products and ensure you shop for locally sourced food (FutureLearn, 2021).
Turn off Lights and Appliances when they are not in use (FutureLearn, 2021).
Reduce your travel (FutureLearn, 2021).
Go digital for work or study - collaborate with others online (FutureLearn, 2021).
Cycle or walk to work or other places or if needed use public transport (FutureLearn, 2021).
Shop locally (FutureLearn, 2021).
Fly direct (FutureLearn, 2021).
Reduce, reuse and recycle (Reduce the amount of waste you generate e.g. paper, packaging; reuse IT equipment; and recycle waste) (FutureLearn, 2021).
Eliminate single use plastics (stop using disposable coffee cups and cutlery etc...) (FutureLearn, 2021)
Use reusable waterbottles and containers (FutureLearn, 2021).
Compost (FutureLearn, 2021).
What can we do on a national level?
Australia produces the most emissions of CO2 in comparison of any country in the world as based off data collected in 2017 (FutureLearn, 2021).
This data shows that Australia produces 16.96 tonnes of CO2 emissions per capita (FutureLearn, 2021).
This amounts to 417.04 million tonnes of CO2 in total annual emissions (FutureLearn, 2021).
We are a part of an international agreement to limit global warming to below 2 degrees (Leggat et al., 2016).
What can we do on a global level?
Global data from 2016 shows the main culprits that cause our carbon footprint and therefore moving into the future, governments internationally must limit these (FutureLearn, 2021).
Energy (the burning of fossil fuels) produced 36013.52 million tonnes of CO2e (FutureLearn, 2021).
Agriculture produced 5795.51 million tonnes of CO2e (FutureLearn, 2021).
Land-use change and forestry (altering or converting land) produced 3217.07 million tonnes of CO2e (FutureLearn, 2021).
Industrial processes produced 2771.08 million tonnes of CO2e (FutureLearn, 2021).
Waste produced 1560.85 million tonnes of CO2e (FutureLearn, 2021).
Is vital that we act together as supported by real climate leadership (AMCS, 2021).
Implement adaption initiatives (Ainsworth et al., 2021).
Assisted evolution (Ainsworth et al., 2021).
Ecosystem engineering (Ainsworth et al., 2021).
Climate engineering (Ainsworth et al., 2021).
What can we do on a local level?
Development of habitat specific bleaching alert tools (Ainsworth et al., 2021).
Temperature sensors placed in key end user areas of our reefs (Ainsworth et al., 2021).
These can be linked to online dashboards (Ainsworth et al., 2021).
Satellite based heat stress accumulation can act as a bleaching alert (Ainsworth et al., 2021).
From these we can then implement intervention strategies (Ainsworth et al., 2016).
Local scale mitigation (Ainsworth et al., 2021).
Restoration (Ainsworth et al., 2021).
E.g. Coral reef restoration through mineral accretion technology (Ainsworth et al., 2021)
Rehabilitation (Ainsworth et al., 2021).
Conservation (Ainsworth et al., 2021).
Coral reef management (Edmondson et al., 2019).
Ensure good emission policies (Edmondson et al., 2019).
Not let giant mining cooperation's like Adani and Clive Palmers Central QLD Coal, dig for new coal (AMCS, 2021).