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Carbon Fluxes and Sinks: the Consumption of Atmospheric and Soil CO 2 by Carbonate Rock Dissolution
Author(s) -
Jianhua CAO,
Daoxian YUAN,
GROVES Chris,
Fen HUANG,
Hui YANG,
Qian LU
Publication year - 2012
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2012.00720.x
Subject(s) - carbon sink , carbonate , sink (geography) , dissolution , carbon cycle , environmental science , carbon sequestration , total inorganic carbon , carbon dioxide , dissolved organic carbon , environmental chemistry , geochemical cycle , carbonate minerals , soil science , geology , ecosystem , chemistry , oceanography , climate change , ecology , cartography , organic chemistry , geography , biology
Carbonate rock outcrops cover 9%–16% of the continental area and are the principal source of the dissolved inorganic carbon (DIC) transferred by rivers to the oceans, a consequence their dissolution. Current estimations suggest that the flux falls between 0.1–0.6 PgC/a. Taking the intermediate value (0.3 PgC/a), it is equal to 18% of current estimates of the terrestrial vegetation net carbon sink and 38% of the soil carbon sink. In China, the carbon flux from carbonate rock dissolution is estimated to be 0.016 PgC/a, which accounts for 21%, 87.5%–150% and 2.3 times of the forest, shrub and grassland net carbon sinks respectively, as well as 23%–40% of the soil carbon sink flux. Carbonate dissolution is sensitive to environmental and climatic changes, the rate being closely correlated with precipitation, temperature, also with soil and vegetation cover. HCO – 3 in the water is affected by hydrophyte photosynthesis, resulting in part of the HCO – 3 being converted into DOC and POC, which may enhance the potential of carbon sequestration by carbonate rock dissolution. The possible turnover time of this carbon is roughly equal to that of the sea water cycle (2000a). The uptake of atmospheric/soil CO 2 by carbonate rock dissolution thus plays an important role in the global carbon cycle, being one of the most important sinks. A major research need is to better evaluate the net effect of this sink in comparison to an oceanic source from carbonate mineral precipitation.