Fluvial organic carbon losses from a Bornean blackwater river

Abstract

Abstract.Concentrations of dissolved organic carbon (DOC) and particulate organic carbon (POC) were analysed from the source to the mouth of the River Sebangau in Central Kalimantan, Indonesia during the dry and wet seasons in 2008/2009 and an annual total organic carbon (TOC) flux estimated. DOC concentrations were higher and POC concentrations lower in the wet season compared to the dry season. As seen in other tropical blackwater rivers, DOC concentration is consistently around 10 times greater than POC concentration. We estimate the annual TOC flux discharged to the Java Sea to be 0.46 Tg year −1 comprising of 93% (0.43 Tg) DOC and 7% (0.03 Tg) POC. This equates to a fluvial TOC loss flux per unit area over the entire Sebangau catchment of 88 g C m −2 yr −1 . When extrapolating the River Sebangau DOC loss flux (83 g C m −2 yr −1 ) to the peat covered area of Indonesia (206 950 km 2 ), we estimate a DOC loss of 17.2 Tg C yr −1 or ∼10% of current estimates of the global annual riverine DOC discharge into the ocean.

Impact of deforestation on solid and dissolved organic matter characteristics of tropical peat forests: implications for carbon release

“…) and higher than the concentrations measured by (Baum et al 2007) in the Siak river in Sumatra, but in the low range of the concentration measured by (Moore et al 2011) in the river Sebangau in South Kalimantan.…”

“…In tropical peatlands, investigations of land use change impact mainly focused on solid peat (Calvert et al 1991;Anshari et al 2010). DOC dynamic has been studied after its exportation to rivers in Indonesia (Baum et al 2007, Rixen et al 2008Moore et al 2011) and little information is available on DOM dynamic in pore water of pristine peatlands and land use change affects them.…”

“…Elemental composition and elemental ratios have been used for this purpose, especially C/N, in both temperate (Comont et al 2006) and tropical (Anshari et al 2010) peatlands, as well as molecular analysis of sugars (Comont et al 2006) and FT-IR (Fourier transform infrared spectroscopy) analysis (Artz et al 2008) in temperate peats. Dissolved organic carbon (DOC) is a key component of the carbon cycle in peatlands, which might contribute significantly to carbon budget assessment of these ecosystems (Hirano et al 2009;Moore et al 2011) both as a product and a substrate of microbial reactions (Porcal et al 2009). Its composition reflects its origin (vegetation and soil leaching, microbial production) and reveals carbon cycling processes occurring in the peatland (Glatzel et al 2003;Fellman et al 2008).…”

Spatiotemporal characterization of dissolved carbon for inland waters in semi-humid/semi-arid region, China

“…The spatiotemporal dynamics of dissolved carbon and its association with terrestrial inputs for inland aquatic ecosystems in semi-arid environments have only been investigated in a few regions (Brooks and Lemon, 2007;Mattsson et al, 2009;Moore et al, 2011). Further study is needed for characterizing dissolved carbon in inland saline waters Tranvik et al, 2009), and quantifying the role of inland saline waters for carbon cycling Duarte et al, 2008).…”

Carbon dioxide emissions from an <i>Acacia</i> plantation on peatland in Sumatra, Indonesia

“…The carbon dynamics of tropical peatland involve CO 2 uptake via photosynthesis and losses through autotrophic respiration of vegetation, CO 2 and CH 4 emissions from soil organic matter decomposition (heterotrophic respiration), and fluvial exports of dissolved and particulate organic carbon (DOC and POC) (e.g. Jauhiainen et al, 2005Jauhiainen et al, , 2008Rieley et al, 2008;Moore et al, 2011). The quantity of methane (CH 4 ) emitted from anaerobic peat decomposition is small and its effect on atmospheric processes is much less than concurrent CO 2 emissions (Hadi et al, 2005;Jauhiainen et al, 2005Jauhiainen et al, , 2008Jauhiainen et al, , 2012.…”