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Long term effect of land reclamation from lake on chemical composition of soil organic matter and its mineralization.

He D, Ruan H - PLoS ONE (2014)

Bottom Line: It has greatly diminished the lake area, and altered natural ecological succession.However, little is known about its impact on the carbon (C) cycle.The active C pool in EBF at 10-25 cm had longer (62 days) mean residence time (MRT).

View Article: PubMed Central - PubMed

Affiliation: Faculty of Forest Resources and Environmental Science, and Key Laboratory of Forestry and Ecological Engineering of Jiangsu Province, Nanjing Forestry University, Nanjing, Jiangsu, China.

ABSTRACT
Since the late 1950s, land reclamation from lakes has been a common human disturbance to ecosystems in China. It has greatly diminished the lake area, and altered natural ecological succession. However, little is known about its impact on the carbon (C) cycle. We conducted an experiment to examine the variations of chemical properties of dissolved organic matter (DOM) and C mineralization under four land uses, i.e. coniferous forest (CF), evergreen broadleaf forest (EBF), bamboo forest (BF) and cropland (CL) in a reclaimed land area from Taihu Lake. Soils and lake sediments (LS) were incubated for 360 days in the laboratory and the CO2 evolution from each soil during the incubation was fit to a double exponential model. The DOM was analyzed at the beginning and end of the incubation using UV and fluorescence spectroscopy to understand the relationships between DOM chemistry and C mineralization. The C mineralization in our study was influenced by the land use with different vegetation and management. The greatest cumulative CO2-C emission was observed in BF soil at 0-10 cm depth. The active C pool in EBF at 10-25 cm had longer (62 days) mean residence time (MRT). LS showed the highest cumulative CO2-C and shortest MRT comparing with the terrestrial soils. The carbohydrates in DOM were positively correlated with CO2-C evolution and negatively correlated to phenols in the forest soils. Cropland was consistently an outlier in relationships between DOM chemistry and CO2-evolution, highlighting the unique effects that this land use on soil C cycling, which may be attributed the tillage practices. Our results suggest that C mineralization is closely related to the chemical composition of DOM and sensitive to its variation. Conversion of an aquatic ecosystem into a terrestrial ecosystem may alter the chemical structure of DOM, and then influences soil C mineralization.

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Carbon mineralized at the end of the 360 days incubation period for different land uses and lake sediments.Bars represent standard errors (n = 4). Different letters above bars indicate significant differences (p<0.05) of mean values of different sites. * indicates the significant difference (p<0.05) between the soil depth.
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pone-0099251-g002: Carbon mineralized at the end of the 360 days incubation period for different land uses and lake sediments.Bars represent standard errors (n = 4). Different letters above bars indicate significant differences (p<0.05) of mean values of different sites. * indicates the significant difference (p<0.05) between the soil depth.

Mentions: The cumulative CO2 production under different land uses and sediments ranged from 0.88 to 7.72 g CO2-C kg−1 soil and there were significant difference between soil depths (Fig. 2a). At 0–10 cm soil depth, cumulative C mineralization in BF soils (2.87 g CO2-C kg−1 soil) was significantly greater than other land uses and CL had the lowest amounts of cumulative CO2-C (1.62 g CO2-C kg−1 soil). The cumulative CO2-C for the three forest sites decreased with the increasing soil depth. At 10–25 cm soil depth, C mineralization was found to be significantly different in the following order of CL>BF>CF>EBF (Table 3). Representing the precursor of the four terrestrial soils, LS had different C mineralization patterns than the four terrestrial soils, and its evolution of cumulative CO2-C (4.59 and 7.72 g CO2-C kg−1 soil, respectively) was significantly larger than other soils, at 0–10 cm and 10–25 cm soil depth. After 360 days of incubation, the percentage of cumulative mineralized C (as % of TC) ranged from 5.11% to 47.19% with the highest C mineralization in LS at 10–25 cm depth (Fig. 2b). At 0–10 cm soil depth, the percentage of mineralized C was significantly different between each other site with largest value in EBF (15.23%) and lowest value in BF (8.11%). At 10–25 cm soil depth, CL had the highest percentage of cumulative mineralized CO2-C (21.07%) among the four land uses, approximately four times larger than BF, which had the lowest percentage of mineralized C (5.11%).


Long term effect of land reclamation from lake on chemical composition of soil organic matter and its mineralization.

He D, Ruan H - PLoS ONE (2014)

Carbon mineralized at the end of the 360 days incubation period for different land uses and lake sediments.Bars represent standard errors (n = 4). Different letters above bars indicate significant differences (p<0.05) of mean values of different sites. * indicates the significant difference (p<0.05) between the soil depth.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048317&req=5

pone-0099251-g002: Carbon mineralized at the end of the 360 days incubation period for different land uses and lake sediments.Bars represent standard errors (n = 4). Different letters above bars indicate significant differences (p<0.05) of mean values of different sites. * indicates the significant difference (p<0.05) between the soil depth.
Mentions: The cumulative CO2 production under different land uses and sediments ranged from 0.88 to 7.72 g CO2-C kg−1 soil and there were significant difference between soil depths (Fig. 2a). At 0–10 cm soil depth, cumulative C mineralization in BF soils (2.87 g CO2-C kg−1 soil) was significantly greater than other land uses and CL had the lowest amounts of cumulative CO2-C (1.62 g CO2-C kg−1 soil). The cumulative CO2-C for the three forest sites decreased with the increasing soil depth. At 10–25 cm soil depth, C mineralization was found to be significantly different in the following order of CL>BF>CF>EBF (Table 3). Representing the precursor of the four terrestrial soils, LS had different C mineralization patterns than the four terrestrial soils, and its evolution of cumulative CO2-C (4.59 and 7.72 g CO2-C kg−1 soil, respectively) was significantly larger than other soils, at 0–10 cm and 10–25 cm soil depth. After 360 days of incubation, the percentage of cumulative mineralized C (as % of TC) ranged from 5.11% to 47.19% with the highest C mineralization in LS at 10–25 cm depth (Fig. 2b). At 0–10 cm soil depth, the percentage of mineralized C was significantly different between each other site with largest value in EBF (15.23%) and lowest value in BF (8.11%). At 10–25 cm soil depth, CL had the highest percentage of cumulative mineralized CO2-C (21.07%) among the four land uses, approximately four times larger than BF, which had the lowest percentage of mineralized C (5.11%).

Bottom Line: It has greatly diminished the lake area, and altered natural ecological succession.However, little is known about its impact on the carbon (C) cycle.The active C pool in EBF at 10-25 cm had longer (62 days) mean residence time (MRT).

View Article: PubMed Central - PubMed

Affiliation: Faculty of Forest Resources and Environmental Science, and Key Laboratory of Forestry and Ecological Engineering of Jiangsu Province, Nanjing Forestry University, Nanjing, Jiangsu, China.

ABSTRACT
Since the late 1950s, land reclamation from lakes has been a common human disturbance to ecosystems in China. It has greatly diminished the lake area, and altered natural ecological succession. However, little is known about its impact on the carbon (C) cycle. We conducted an experiment to examine the variations of chemical properties of dissolved organic matter (DOM) and C mineralization under four land uses, i.e. coniferous forest (CF), evergreen broadleaf forest (EBF), bamboo forest (BF) and cropland (CL) in a reclaimed land area from Taihu Lake. Soils and lake sediments (LS) were incubated for 360 days in the laboratory and the CO2 evolution from each soil during the incubation was fit to a double exponential model. The DOM was analyzed at the beginning and end of the incubation using UV and fluorescence spectroscopy to understand the relationships between DOM chemistry and C mineralization. The C mineralization in our study was influenced by the land use with different vegetation and management. The greatest cumulative CO2-C emission was observed in BF soil at 0-10 cm depth. The active C pool in EBF at 10-25 cm had longer (62 days) mean residence time (MRT). LS showed the highest cumulative CO2-C and shortest MRT comparing with the terrestrial soils. The carbohydrates in DOM were positively correlated with CO2-C evolution and negatively correlated to phenols in the forest soils. Cropland was consistently an outlier in relationships between DOM chemistry and CO2-evolution, highlighting the unique effects that this land use on soil C cycling, which may be attributed the tillage practices. Our results suggest that C mineralization is closely related to the chemical composition of DOM and sensitive to its variation. Conversion of an aquatic ecosystem into a terrestrial ecosystem may alter the chemical structure of DOM, and then influences soil C mineralization.

Show MeSH
Related in: MedlinePlus