UTSpeaks: Keeping Seas Green

UTSpeaks: Keeping seas green17 November, 2011 CAN PRESERVING HUMBLE SEAGRASS HELP PROTECT US FROM THE EXTREMES OF HUMAN-INDUCED CLIMATE CHANGE?

What are we talking about?● Bill Gladstone – Values and services – Loss and recovery● Peter Macreadie – Seagrass as a carbon sink – Carbon capture and storage● Peter Ralph – Protecting seagrass carbon

Seagrasses● Marine flowering plants● Australia: a global hotspot – Greatest number of seagrass species (50%) – Largest area (95,000 km2) Mcleod et al 2011

Where is it, how much is there, how is it changing? ● Global seagrass area 177,000 - 600,000 km2 ● Mapping seagrass: – diver surveys – side scan sonar – aerial imagery – satellite remote sensing ● Uncertainties in estimates of seagrass area and rate of change: – technological constraints – lack of historical data – environmental constraints NSW DPI 2008 – human capacity constraints

Values and Services: Biodiversity● Structural complexity of seagrass – epiphytes – periphytes – encrusting invertebrates – infauna – mobile fauna – fishes, rays, invertebrates – birds● Charismatic fauna – dugong, turtles, seahorses reeframblings.co.uk● ~ 60 threatened and endangered species rely on seagrass

Values and Services: Fish Nurseries● 50% of the worlds fisheries rely on seagrass● Seagrass-associated prawn fisheries in North Qld: $1500 ha-1 yr-1● Seagrass-supported fisheries in South Australia: $100 million yr-1 Unsworth et al. 2010● Economic and social value of artisanal seagrass-based fisheries

Values and Services Blue Carbon Marine Biodiversity Fish Nurseries Coastline and Coastal Water Quality Beach Stabilisation Source: Forest Trend • Climate Change Adaptation• Sustaining Community Resilience and Coastal Livelihoods

Value, Appreciation, Understanding Orth et al. 2006

Scientists’ Concerns for Seagrass

Loss of SeagrassLocation % Seagrass ● Global losses area lost – 29% of known areaClarence River 60% – 7% per yearLake Macquarie 44%Tuggerah Lakes 50%Port Hacking 60%Botany Bay 58%NSW 50% CSIRO

Human Activities Damaging Seagrasses● More than 1 billion people live within 50 km of seagrass● In situ impacts – dredging, scouring – changes in water flow Seagrasswatch – trawling – smothering, shading – contamination● Indirect impacts – eutrophication – sedimentation – increasing water temperature – introduced species

Consequences of Seagrass Loss● 70% decline in seagrass cover 40% decline in commercial fish catches – Western Port Bay (Vic)● 22% decline in seagrass Pittwater.nsw.gov.au cover 30% decline in commercial and recreational fish catches – Adelaide

Recovery of Seagrass● Vegetative growth Cosmos● Germination from seed bank● Seed dispersal● Rafting● Halophila: months● Zostera: years● Posidonia: decades● Success of seagrass restoration, transplants: 30% – Cost $8,000 to $1 m per hectare

Recovering Seagrass: Manly CoveNSW DPI

Recovering Seagrass: Manly Cove Bring Back the Fish

Recovering Seagrass: Shoal BayR Carraro

Recovering Seagrass: Shoal Bay 18 months Recovery begins with colonisation by Halophila

Recovering Seagrass: Manly Cove Eco Divers 18 monthsLocal environmental factors and condition of seagrass meadow might compromise recovery potential

Values, Impacts, Conservation● Seagrasses provide human society with valuable goods and services● Despite the impacts of their loss, seagrasses continue to decline and natural recovery processes are slow● The potential for carbon biosequestration by seagrasses (Blue Carbon) provides further support for their conservation

Climate change lingo ● Carbon dioxide (CO2) is most significant human-produced greenhouse gas ● Greenhouse effect = global warming ≈ climate change Kosland Science Museum

Climate Change: How are we doing?US Dept of Energy report (Nov 2011):● “Biggest jump ever in global warming gases”● CO2 output in 2010 was 6% higher (512 million tonnes) than in 2009● Greenhouse gas emissions were higher than the worst-case scenario outlined by climate experts (the IPCC)

Fighting climate change using nature● Reducing greenhouse gas emissions is necessary, but how do we get rid of all the emissions already floating around the atmosphere?● Biosequestration: nature‟s way of capturing and storing carbon in sediments● It‟s the same process that created fossil fuels in the first istockphoto place!

Carbon Farming1. Reducing greenhouse gasemissions1. Capturing and storing carbon invegetation and soils (creating„carbon sinks‟) RDAMRTerrestrial only. Not aquatic.

Could seagrasses be the mostpowerful carbon sinks on the planet?

Global area: Tropical Rainforests vs. Seagrasses Tropical rainforests 2.5 times the area of Australia Destination 360 Seagrasses The area of VIC or NSW OR (?) IndexO

Carbon burial: Tropical Rainforests vs. Seagrasses C m-2 y-1 Tg C yr-1

Seagrasses are long-term sinks● Terrestrial forests typically store carbon for decades, whereas seagrasses store carbon for millennia!● Carbon rich deposits can be >10-m thick● Unlike terrestrial soils, the sediment in seagrass meadows do not become saturated with carbon● Why? Because the sediments accrete vertically in response to rising sea levels.

Carbon farming: too good to be true?‘Leakage’ is a big concern● Increasing forest productivity can trigger CO2 release from soils● Increasing CO2 levels in terrestrial soils can stimulate production of other greenhouse gases iStockPhoto

Do seagrass meadows leak carbon?Could 1000s of years ofancient carbon leak outinto the atmosphere ifseagrass meadows aredisturbed?Likely mechanism: lossof seagrass meadows(i.e. the „top layer‟)exposes buried carbonto the forces of nature

When sinks become sources…Unhealthy meadows canturn from being carbonsinks, to carbon sources Source Sink OpenLig ht

Positive O2 flux Negative O2 flux Carbon sink Carbon source

Measuring FLUX of carbon and oxygen Ponlachart ChotikarnO2 flux Light level Night Day Night Andrew

How do we study carbon capture and storage?

What impact have humans had on coastal carbon sinks?Industrial developments:• Tanneries• Sewerage farms• Breweries• Quarries Algernon Talmadge R.A.• Oil refineries• Sand mining• Port constructionConsequences:• Loss of seagrass, mangroves,and saltmarsh• Increases in algae Proni

Paleoreconstruction: going back in time

Industrialization weakens coastal carbon sinkFingerprinting ofstored carbon(„carbon stock‟) CoreMedia

Take home messages so far● Highly efficient carbon biosequestration● Large carbon storage in seagrass sediment● Carbon stays in the sediment for a long time● Degradation results in substantial carbon emissions and loss of biosequestration

How to protect seagrass carbon?● What is Blue Carbon?● What dont we know? – Can a degraded meadow release it stored carbon?● How do currently protect plant-based carbon? – How can we protect seagrass carbon?● What is happening internationally?● What can you do locally?

Is there carbon leakage ???? Assume it “comes out quicker than it goes in” Assume the loss of seagrass leads to substantial CO2 emissions and loss of highly efficient biosequestration

Drained marshes emit CO2● Sacramento Delta – 1,800 km2 of wetlands (not seagrass) wikipedia● has released 1 GtCO2 (1,000,000,000 tons of CO2) • 50% of tree biomass in Californian forests • 1.5% of California total GHG emissions● C sequestered over 5,000 years, released in 100 years

Do degraded seagrasses emit CO2?● Yes● Does it contribute to the atmospheric CO2? – we don‟t know, – If they do, then seagrasses matter, because their loss will further enhance climate change.

How to protect seagrass carbon?● create incentives for coastal conservation and restoration activities● create disincentives to damage coastal ecosystems

Better to conserve than restore● Conserve = Dual benefit● More efficient to sustainably manage than to allow loss and then attempt to re-colonise● Restoration may be necessary wikipedia wikipedia

Past methods of protecting carbon● Kyoto Protocol (1997) – Countries agreed to limit GHG emissions • “flexible mechanisms” to meet these limits • Annual inventory • Doesn‟t include coastal wetlands● Copenhagen Accord (2009) – Ratify REDD● Cancun Agreement (2010) – Ratify REDD+ which includes mangroves (not seagrass) – Blue Carbon recognised

International carbon credits● finance to encourage sustainable management – Norway-Indonesia● Australia-Indonesia Carbon Partnership● Australia could buy Indonesian “ecosystem restoration concessions” – Australian Clean Energy Scheme wikipedia● How can seagrass be included in a carbon accounting scheme?

Seagrass carbon accounting● Does seagrass loss actually leads to increased atmospheric CO2?● IPCC needs to recognise sediment-based C storage – above-ground biomass is easy to count and satellites can monitor● Develop a seagrass carbon budget protocol: – quantification – verification of stock over time – how long does the carbon remain within the financial unit – estimate of risk of loosing stock (insurance)● Engage with a carbon trading market – voluntary market already operational for mangrove (Blue Carbon)

How is IUCN helping this happen?● creating political awareness● helping NGO generate public awareness● drafting policy for IPCC, such as REDD+● establishing a international research and policy agenda

What can you do?● Ask questions about removal of local seagrasses● Ask questions if you see seagrass dying● Engage with community monitoring of seagrasses● Support seagrass restoration programs● Increase public/political awareness of Blue Carbon

Co-benefits of protecting seagrass Blue Carbon Marine Biodiversity Fish Nurseries Coastline and Coastal Water Quality Beach Stabilization Source: Forest Trend • Adapt to climate change • Sustain community resilience and coastal livelihoods

Acknowledgements Bring Back the Fish

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UTSpeaks: Keeping Seas Green

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