Oceanic Blue Carbon

Oceanic Blue CarbonGOC High Seas Symposium, 12 - 13 November 2015, Somerville College, Oxford

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Chris Pincetich-Marine Photobank Øystein Paulsen - MAR-ECO

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Oceanic Blue Carbon explores a potential connection between marine conservation and climate change, with broad global relevance: the conservation and restoration of the marine environment – including populations of sea turtles, whales, krill and tuna – as part of the solution to the global climate challenge.

The concept was supported by three publications from late 2014.

The GOC report estimated amount and value of the biological carbon-sequestering activity provided by the high seas to be:• Almost half a billion tonnes of carbon per year• Valued between USD $74 billion to $222 billion per year

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So what we are exploring now is understanding the concept and refining that value.

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For example, eight natural carbon pathways, pumps and trophic cascades associated with marine vertebrates have been identified.

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The primary apparatus used in carbon flux research the sediment trap, which sits on the sea bed & collects particles that drift to the ocean floor.

One possible reason that marine organisms beside plankton have largely been excluded from carbon cycling models.

Does not capture the movement of carbon associated with marine organisms, including deposition via faecal events and sinking carcasses.

Heithaus et al. 2014

1. Trophic Cascade Carbon

E.g. natural predation by sharks controls sea turtle populations, whose grazing behaviour maintains optimal carbon function of seagrass meadows.

Food web dynamics help to maintain carbon storage & sequestration by coastal ecosystems.

Disruption of marine vertebrate populations impacts natural cycles; where this includes the role of marine ecosystems it can reduce the oceans capacity to capture & store carbon.

2. Biomixing carbon

Keith Ellenbogen, Oceana

Turbulence & drag associated with movement of marine animals mixes nutrient rich water from deep to surface waters, enhancing primary production by phytoplankton & thus uptake of atmospheric CO2.

This mechanism has been reported for all sizes of marine including krill and whales.

3. Bony fish carbonate

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As a by-product of their metabolism, bony fish secrete calcium carbonate, which is alkaline. Restoration of bony fish populations can potentially help to buffer against increased acidity of the ocean and protect some of the organisms that are susceptible to ocean acidification.

Tony Wu4. Whale Pump

Some whales excrete nutrient rich, flocculent faecal plumes. These can fertilize surface waters & nutrient-limited oceans to stimulate primary production by phytoplankton, thus uptake of atmospheric carbon dioxide into oceans.

5. Twilight Zone Carbon

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Deep water (twilight zone) fish feed on organisms in the upper ocean & transport consumed organic carbon to deeper waters, where it is stored in biomass or released as fish poop.

Amount and value of carbon sequestration by twilight zone fish off the UK-Irish continental slope, from Trueman et al.:• Over 1 million tonnes of carbon per year• Between USD $12.4 and $21.8 million per year

Trueman et al. 2014 NOAA

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6. Biomass Carbon and 7. Deadfall Carbon

Denis Hawkins © 2007 MBARI

Marine vertebrates store carbon as biomass with larger individuals storing proportionally greater amounts over prolonged lifespans.

The carcasses of marine vertebrates sink, exporting carbon to the ocean floor, entering benthic food webs and sometimes sediments.

8. Marine Vertebrate Mediated CarbonCatlin Seaview Survey

Marine vertebrates transfer organic carbon through marine food webs and transport it to deep waters via rapidly sinking faecal material

Carbon particles associated with fish, e.g. tuna, are orders of magnitude larger than those associated with plankton, & can rapidly sink to depth, providing an efficient mechanism to export carbon from surface waters.

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What is the biological-carbon sequestration value of a living ocean versus a depleted one?

Gap analysis and targeted research needed to advance scientific, policy and economic understanding

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What is thetotal significance & do we have the ability to value it?

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We also think it is important to keep a connection to the other ocean ecosystem values vital for coastal communities:

• Sustainable development• Food security• Connections to EEZs

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Fish Carbon report: www.grida.no/publications/fish-carbonFollow on twitter: #FishCarbonSteven LutzGRID-Arendalsteven.lutz@grida.no

Angela MartinBlue Climate Solutionsangela.martin@bluecsolutions.org

Thank you!

Questions?

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