scholarly journals Methane emissions partially offset “blue carbon” burial in mangroves

2018 ◽  
Vol 4 (6) ◽  
pp. eaao4985 ◽  
Author(s):  
Judith A. Rosentreter ◽  
Damien T. Maher ◽  
Dirk V. Erler ◽  
Rachel H. Murray ◽  
Bradley D. Eyre
Keyword(s):  
Methane Emissions ◽  
Blue Carbon ◽  
Carbon Burial

scholarly journals Relevance of carbon burial and storage in two contrasting blue carbon ecosystems of a north-east Pacific coastal lagoon

2019 ◽  
Vol 675 ◽  
pp. 581-593 ◽  
Author(s):  
Tomasa Cuellar-Martinez ◽  
Ana Carolina Ruiz-Fernández ◽  
Joan-Albert Sanchez-Cabeza ◽  
Libia-Hascibe Pérez-Bernal ◽  
Jose Sandoval-Gil
Keyword(s):  
Coastal Lagoon ◽  
Blue Carbon ◽  
North East ◽  
East Pacific ◽  
Carbon Burial ◽  
And Storage

scholarly journals Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Kevin D. Kroeger ◽  
Stephen Crooks ◽  
Serena Moseman-Valtierra ◽  
Jianwu Tang
Keyword(s):  
Climate Change ◽  
Methane Emissions ◽  
Blue Carbon

scholarly journals Sequestration of macroalgal carbon: the elephant in the Blue Carbon room

2018 ◽  
Vol 14 (6) ◽  
pp. 20180236 ◽  
Author(s):  
Dorte Krause-Jensen ◽  
Paul Lavery ◽  
Oscar Serrano ◽  
Núria Marbà ◽  
Pere Masque ◽  
...  
Keyword(s):  
Paradigm Shift ◽  
Carbon Sink ◽  
Blue Carbon ◽  
Coastal Habitats ◽  
Management Actions ◽  
Carbon Burial

Macroalgae form the most extensive and productive benthic marine vegetated habitats globally but their inclusion in Blue Carbon (BC) strategies remains controversial. We review the arguments offered to reject or include macroalgae in the BC framework, and identify the challenges that have precluded macroalgae from being incorporated so far. Evidence that macroalgae support significant carbon burial is compelling. The carbon they supply to sediment stocks in angiosperm BC habitats is already included in current assessments, so that macroalgae are de facto recognized as important donors of BC. The key challenges are (i) documenting macroalgal carbon sequestered beyond BC habitat, (ii) tracing it back to source habitats, and (iii) showing that management actions at the habitat lead to increased sequestration at the sink site. These challenges apply equally to carbon exported from BC coastal habitats. Because of the large carbon sink they support, incorporation of macroalgae into BC accounting and actions is an imperative. This requires a paradigm shift in accounting procedures as well as developing methods to enable the capacity to trace carbon from donor to sink habitats in the ocean.

scholarly journals Blue Carbon Soil Stock Development and Estimates Within Northern Florida Wetlands

2021 ◽  
Vol 9 ◽  
Author(s):  
Derrick R. Vaughn ◽  
Thomas S. Bianchi ◽  
Michael R. Shields ◽  
William F. Kenney ◽  
Todd Z. Osborne
Keyword(s):  
Salt Marshes ◽  
Carbon Stock ◽  
Gulf Coast ◽  
Carbon Stocks ◽  
Blue Carbon ◽  
Total Carbon ◽  
Carbon Burial ◽  
Stable Isotopic ◽  
Ipcc Guidelines ◽  
Different Depths

Blue carbon habitats, such as mangroves and salt marshes, have been recognized as carbon burial hotspots; however, methods on measuring blue carbon stocks have varied and thus leave uncertainty in global blue carbon stock estimates. This study analyzes blue carbon stocks in northern Florida wetlands along the Atlantic and Gulf coasts. Carbon measurements within 1–3m length vibracores yield total core stocks of 9.9–21.5 kgC·m−2 and 7.7–10.9 kgC·m−2 for the Atlantic and Gulf coast cores, respectively. Following recent IPCC guidelines, blue carbon stock estimates in the top meter are 7.0 kgC·m−2–8.0 kgC·m−2 and 6.1 kgC·m−2–8.6 kgC·m−2 for the Atlantic and Gulf cores, respectively. Changes in stable isotopic (δ13C, C/N) and lignin biomarker (C/V) indices suggest both coastlines experienced salt marsh and mangrove transgressions into non-blue carbon habitats during the mid- to late-Holocene following relative sea-level rise. These transgressions impact carbon storage within the cores as the presence of carbon-poor soils, characteristic of non-blue carbon habitats, result in lower 1m carbon stocks in north Florida Gulf wetlands, and a deeper extent of carbon-rich soils, characteristic of blue carbon habitats, drive higher 1m and total carbon stocks in north Florida Atlantic wetlands. Future blue carbon research should assess carbon stocks down to bedrock when possible, as land-cover and/or climate change can impact different depths across localities. Ignoring carbon-rich soil below the top meter of soil may underestimate potential carbon emissions based on these changes.

scholarly journals Carbon isotope evidence for large methane emissions to the Proterozoic atmosphere

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pierre Cadeau ◽  
Didier Jézéquel ◽  
Christophe Leboulanger ◽  
Eric Fouilland ◽  
Emilie Le Floc’h ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Cycle ◽  
Carbon Isotope ◽  
Methane Emissions ◽  
Unique Combination ◽  
Isotopic Signatures ◽  
The Earth ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Isotope Evidence

Abstract The Proterozoic Era records two periods of abundant positive carbon isotope excursions (CIEs), conventionally interpreted as resulting from increased organic carbon burial and leading to Earth’s surface oxygenation. As strong spatial variations in the amplitude and duration of these excursions are uncovered, this interpretation is challenged. Here, by studying the carbon cycle in the Dziani Dzaha Lake, we propose that they could be due to regionally variable methane emissions to the atmosphere. This lake presents carbon isotope signatures deviated by ~  + 12‰ compared to the modern ocean and shares a unique combination of analogies with putative Proterozoic lakes, interior seas or restricted epireic seas. A simple box model of its Carbon cycle demonstrates that its current isotopic signatures are due to high primary productivity, efficiently mineralized by methanogenesis, and to subsequent methane emissions to the atmosphere. By analogy, these results might allow the reinterpretation of some positive CIEs as at least partly due to regionally large methane emissions. This supports the view that methane may have been a major greenhouse gas during the Proterozoic Era, keeping the Earth from major glaciations, especially during periods of positive CIEs, when increased organic carbon burial would have drowned down atmospheric CO2.

scholarly journals Calcification-driven CO2 emissions exceed “Blue Carbon” sequestration in a carbonate seagrass meadow

2021 ◽  
Author(s):  
Bryce Van Dam ◽  
Mary Zeller ◽  
Christian Lopes ◽  
Ashley Smyth ◽  
Michael Böttcher ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Sequestration ◽  
Organic Carbon ◽  
Seagrass Meadow ◽  
Blue Carbon ◽  
Carbonate Sediments ◽  
Seagrass Meadows ◽  
Carbon Burial ◽  
Organic Carbon Burial

Abstract Long-term “blue carbon” burial in seagrass meadows is complicated by other carbon and alkalinity exchanges that shape net carbon sequestration. We measured a suite of such processes, including denitrification, sulfur, and inorganic carbon cycling, and assessed their impact on air-water carbon dioxide exchange in a typical seagrass meadow underlain by carbonate sediments. Contrary to the prevailing concept of seagrass meadows acting as carbon sinks, eddy covariance measurements reveal this ecosystem as a consistent source of carbon dioxide to the atmosphere, at an average rate of 610 ± 990 µmol m-2 hr-1 during our study and 700 ± 660 µmol m-2 hr-1 over an annual cycle. A robust mass-balance shows that net alkalinity consumption by ecosystem calcification explains >95% of the observed carbon dioxide emissions, far exceeding alkalinity generated by net reduced sulfur, iron and organic carbon burial. Isotope geochemistry of porewaters suggests substantial dissolution and re-crystallization of more stable carbonates mediated by sulfide oxidation-induced acidification, enhancing long-term carbonate burial and ultimate carbon dioxide production. We show that the “blue carbon” sequestration potential of calcifying seagrass meadows has been over-estimated, and that in-situ organic carbon burial only offsets a small fraction (<5%) of calcification-induced CO2 emissions. Ocean-based climate change mitigation activities in such calcifying regions should be approached with caution and an understanding that net carbon sequestration may not be possible.

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