Seagrass meadows as a globally significant carbonate reservoir

Mazarrasa, I., Marba, N., Lovelock, C. E., Serrano, O., Lavery, P. S., Fourqurean, J. W., Kennedy, H., Mateo, M. A., Krause-Jensen, D., Steven, A. D. L. and Duarte, C. M. (2015) Seagrass meadows as a globally significant carbonate reservoir. Biogeosciences, 12 16: 4993-5003. doi:10.5194/bg-12-4993-2015

Author Mazarrasa, I.
Marba, N.
Lovelock, C. E.
Serrano, O.
Lavery, P. S.
Fourqurean, J. W.
Kennedy, H.
Mateo, M. A.
Krause-Jensen, D.
Steven, A. D. L.
Duarte, C. M.
Title Seagrass meadows as a globally significant carbonate reservoir
Journal name Biogeosciences   Check publisher's open access policy
ISSN 1726-4189
Publication date 2015-08-24
Year available 2015
Sub-type Article (original research)
DOI 10.5194/bg-12-4993-2015
Open Access Status DOI
Volume 12
Issue 16
Start page 4993
End page 5003
Total pages 298
Place of publication Goettingen, Germany
Publisher Copernicus
Language eng
Formatted abstract
There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha−1, with an average of 654 ± 24 Mg PIC ha−1, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of −8 ± 2 Mg PIC ha−1 per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m−2 yr−1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr−1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrated by the comparison of carbon (PIC and POC) stocks between vegetated and adjacent un-vegetated sediments.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Biological Sciences Publications
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