Effect of water table drawdown on peatland dissolved organic carbon export and dynamics

Abstract. Permafrost thawing in peatland has the potential to alter the catchment export of dissolved organic carbon (DOC), thus influencing carbon cycling in linked aquatic and ocean ecosystems. However, peatland along the southern margins of Eurasian permafrost are seldom examined in spite of the presence of considerable risks associated with degradation due to climate warming. This study examines dynamics of DOC export from a permafrost peatland catchment located in northeastern China during the growing seasons of 2012 to 2014. Our findings show that runoff processes affect observed DOC concentrations, magnitudes, sources, and chemical characteristics of stream discharge. The entire catchment exhibits strong potential for annual DOC exporting (4.87 g C m−2), and DOC from the peatland landscape alone is estimated to amount to 12.89 g C m−2. Annual DOC export processes are closely related to total discharge levels, and floods contribute to approximately 85 % of DOC export levels. Flood volumes derived mainly from peat pore water stored in the upper organic layer of the soil profile prior to rainfall events, creating a strong linkage between discharge and DOC concentrations. DOC source and chemical characteristics, as indicated by three fluorescence indexes, have changed regularly according to source shifts occurring as a result of flood and baseflow processes. A deepening of the active layer due to climate warming should elevate proportions of microbial-originated DOC in the baseflow. Given expected future increases in precipitation, our results show that the magnitude of DOC exports from the study region will increase.

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Study of Dissolved Organic Carbon Concentration in KHDTK Forest Peatland Area, Central Kalimantan, Indonesia

Journal of Tropical Peatlands ◽

10.52850/jtpupr.v10i2.3034 ◽

2021 ◽

Vol 10 (2) ◽

pp. 29-35

Author(s):

Galih Widhi Pratama ◽

Fengky F. Adji ◽

Panji Surawijaya ◽

Nina Yulianti ◽

Zafrullah Damanik

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Water Table ◽

Sustainable Management ◽

Forest Site ◽

Average Amount ◽

Rapid Decomposition ◽

Organic Carbon Concentration ◽

Different Types ◽

Water Ph

The study was conducted to determine whether are differences in dissolved organic carbon (DOC) in three different types of peatland conditions. The study was conducted from March 1st to April 30, 2020. The research was carried out in the Tumbang Nusa Special Purpose Forest Area (KHDTK). Furthermore, the analysis of DOC samples was carried out at the BALITRA Laboratory, Banjar Baru, South Kalimantan. The analysis of water pH samples was conduct at the UPT. LLG – CIMTROP, UPR Laboratory. The results showed that DOC in degraded peatlands site ranged from 36.18 mg L-1 to 76.86 mg L-1 with an average of 53.1 mg L-1, water pH between 3.6 to 4 with an average of 3.88, and the water table of 26.51 cm. Then in the forest site ranged from 37.12 mg L-1 to 49.81 mg L-1 with an average of 40.95 mg L-1, water pH ranged of 4 to 4.4 with an average of 4.32, and water table -5.13 cm. Furthermore, the re-vegetation site ranged from 29.27 mg L-1 to 34.90 mg L-1 with an average of 30.73 mg L-1, water pH between 4 to 4.3 with an average of 4.18, and water table 36.28 cm. Based on the results of the study it can be concluded that there is a difference in DOC in three sites, in the degradation site contributes higher dissolved organic carbon than other sites with an average amount of 53.1 mg L-1, compared to forest site with an average amount of 40.95 mg L-1, and re-vegetation site with an average amount of 30.73 mg L-1. Therefore, sustainable management of peat is expected to minimize the rapid decomposition of organic material in peat.

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