Abstract
Rising atmospheric CO2 is intensifying climate change but it is also driving global and particularly polar greening. However, most blue carbon sinks (that held by marine organisms) are shrinking, which is important as these are hotspots of genuine carbon sequestration. Polar blue carbon increases with losses of marine ice over high latitude continental shelf areas. Marine ice (sea ice, ice shelf and glacier retreat) losses generate a valuable negative feedback on climate change. Blue carbon change with sea ice and ice shelf losses has been estimated, but not how blue carbon responds to glacier retreat along fjords. We derive a testable estimate of glacier retreat driven blue carbon gains by investigating three fjords in the West Antarctic Peninsula (WAP). We started by multiplying ~40 year mean glacier retreat rates by the number of retreating WAP fjords and their time of exposure. We multiplied this area by regional zoobenthic carbon means from existing datasets to suggest that WAP fjords generate 3,130 tonnes of new zoobenthic carbon per year (t zC/year) and sequester >780 t zC/year. We tested this by capture and analysis of 204 high resolution seabed images along emerging WAP fjords. Biota within these images were identified to density per 13 functional groups. Mean stored carbon per individual was assigned from literature values to give a stored zoobenthic Carbon per area, which was multiplied up by area of fjord exposed over time, which increased the estimate to 4,536 t zC/year. The purpose of this study was to establish a testable estimate of blue carbon change caused by glacier retreat along Antarctic fjords and thus to establish its relative importance compared to polar and other carbon sinks.
Highlights
Declarations of ‘climate emergency’ and more urgent aim at developing carbon neutral economies has drastically increased interest in carbon capture, storage and sequestration. Saban, Chapman, & Taylor (2018) have shown that global greening, and potential carbon capture, has increased with rising atmospheric CO2 levels but what of storage and sequestration? Blue carbon is prolific in capture and efficient in sequestration rate to the extent that Duarte, Middelburg & Caraco, (2005) estimate blue carbon to be responsible for 50% of all oceanic carbon burial
We found that newly emerged study– fjord seabeds may gain about 12–31 t zC yr–1
Compared with lower latitude sinks, glacier retreat and even sea ice and ice shelf losses are clearly small In carbon store and efficiency, but unlike elsewhere polar blue carbon is increasing with climate change, and the productivity within emerging fjords is likely to further increase with age, seasonal sea ice loss (Barnes 2017) and limited sea temperature increases (Ashton et al 2017)
Summary
Dyfyniad o'r fersiwn a gyhoeddwyd / Citation for published version (APA): Barnes, D., Sands, C., Cook, A., Howard, F., Román González, A., Muñoz-Ramirez, C., Retallick, K., Scourse, J., Van Landeghem, K., & Zwerschke, N. (2020). Blue carbon gains from glacial retreat along Antarctic fjords: what should we expect? Hawliau Cyffredinol / General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal ?. Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim
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