Fluvial carbon fluxes in tropical rivers

Huang, Ting-Hsuan; Fu, Yaw-Syan; Pan, Pei-Yi; Chen, Chen‐Tung Arthur

doi:10.1016/j.cosust.2012.02.004

Cited by 147 publications

(130 citation statements)

References 59 publications

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“…The export of carbon by rivers comprises 40 % organic carbon (0.22 Pg C yr −1 of dissolved organic carbon (DOC) and 0.18 Pg C yr −1 of particulate organic carbon (POC)) and 60 % inorganic carbon (0.43 Pg C yr −1 of dissolved inorganic carbon (DIC) and 0.17 Pg C yr −1 of particulate inorganic carbon (PIC)) (Meybeck, 1982;Richey, 2004;IPCC, 2007;Schlunz and Schneider, 2000;Dai et al, 2012;Huang et al, 2012). However, estuarine filtering prevents some of the carbon that reaches the estuaries from also entering the oceans Kemp et al, 1997;Middelburg and Herman, 2007;Chen et al, 2012;Dai et al, 2012).…”

Section: C-t a Chen Et Al: Air-sea Exchanges Of Co 2 In The Worldmentioning

confidence: 99%

Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas

et al. 2013

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Abstract. The air-sea exchanges of CO 2 in the world's 165 estuaries and 87 continental shelves are evaluated. Generally and in all seasons, upper estuaries with salinities of less than two are strong sources of CO 2 (39 ± 56 mol C m −2 yr −1 , positive flux indicates that the water is losing CO 2 to the atmosphere); mid-estuaries with salinities of between 2 and 25 are moderate sources (17.5 ± 34 mol C m −2 yr −1 ) and lower estuaries with salinities of more than 25 are weak sources . Mixing with low-pCO 2 shelf waters, water temperature, residence time and the complexity of the biogeochemistry are major factors that govern the pCO 2 in estuaries, but wind speed, seldom discussed, is critical to controlling the air-water exchanges of CO 2 . The total annual release of CO 2 from the world's estuaries is now estimated to be 0.10 Pg C yr −1 , which is much lower than published values mainly because of the contribution of a considerable amount of heretofore unpublished or new data from Asia and the Arctic. The Asian data, although indicating high pCO 2 , are low in sea-to-air fluxes because of low wind speeds. Previously determined flux values rely heavily on data from Europe and North America, where pCO 2 is lower but wind speeds are much higher, such that the CO 2 fluxes are higher than in Asia. Newly emerged CO 2 flux data in the Arctic reveal that estuaries there mostly absorb rather than release CO 2 .Most continental shelves, and especially those at high latitude, are undersaturated in terms of CO 2 and absorb CO 2 from the atmosphere in all seasons. Shelves between 0 and 23.5 • S are on average a weak source and have a small flux per unit area of CO 2 to the atmosphere. Water temperature, the spreading of river plumes, upwelling, and biological production seem to be the main factors in determining pCO 2 in the shelves. Wind speed, again, is critical because at high latitudes, the winds tend to be strong. Since the surface water pCO 2 values are low, the air-to-sea fluxes are high in regions above 50 • N and below 50 • S. At low latitudes, the winds tend to be weak, so the sea-to-air CO 2 flux is small. Overall, the world's continental shelves absorb 0.4 Pg C yr −1 from the atmosphere.

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Section: C-t a Chen Et Al: Air-sea Exchanges Of Co 2 In The Worldmentioning

confidence: 99%

Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas

et al. 2013

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“…128 × 10 12 g C yr −1 ) organic matter to the oceans, by delivering more than 50 % of global organic carbon inputs (about 335 × 10 12 g C yr −1 excluding Australia). More recently, Huang et al (2012) estimated that the tropical rivers of Asia have the highest specific total, inorganic and organic, dissolved and particulate carbon yield in which ca. 25 % of the delivery occurs as particulate organic matter (POM).…”

Section: Introductionmentioning

confidence: 99%

Sources and export of particle-borne organic matter during a monsoon flood in a catchment of northern Laos

et al. 2015

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Abstract. The yields of the tropical rivers of Southeast Asia supply large quantities of carbon to the ocean. The origin and dynamics of particulate organic matter were studied in the Houay Xon River catchment located in northern Laos during the first erosive flood of the rainy season in May 2012. This cultivated catchment is equipped with three successive gauging stations draining areas ranging between 0.2 and 11.6 km 2 on the main stem of the permanent stream, and two additional stations draining 0.6 ha hillslopes. In addition, the sequential monitoring of rainwater, overland flow and suspended organic matter compositions was conducted at the 1 m 2 plot scale during a storm. The composition of particulate organic matter (total organic carbon and total nitrogen concentrations, δ 13 C and δ 15 N) was determined for suspended sediment, soil surface (top 2 cm) and soil subsurface (gullies and riverbanks) samples collected in the catchment (n = 57, 65 and 11, respectively). Hydrograph separation of event water was achieved using water electric conductivity and δ 18 O measurements for rainfall, overland flow and river water base flow (n = 9, 30 and 57, respectively). The composition of particulate organic matter indicates that upstream suspended sediments mainly originated from cultivated soils labelled by their C 3 vegetation cover (upland rice, fallow vegetation and teak plantations). In contrast, channel banks characterized by C 4 vegetation (Napier grass) supplied significant quantities of sediment to the river during the flood rising stage at the upstream station as well as in downstream river sections. The highest runoff coefficient (11.7 %), sediment specific yield (433 kg ha −1 ), total organic carbon specific yield (8.3 kg C ha −1 ) and overland flow contribution (78-100 %) were found downstream of reforested areas planted with teaks. Swamps located along the main stream acted as sediment filters and controlled the composition of suspended organic matter. Total organic carbon specific yields were particularly high because they occurred during the first erosive storm of the rainy season, just after the period of slash-andburn operations in the catchment.

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“…Dissolved organic matter (DOM) found ubiquitously in aquatic environments comprises a massive reservoir of reduced carbon (Hedges 1992) and DOM fluxes from rivers to oceans result in a globally significant transport of carbon and energy (Hedges et al 1997;Huang et al 2012). Nutrients (P, N, and trace metals) often occur in organic form and thus dissolved organic matter plays an important role in carbon and nutrient cycles from local to global scales (Mopper et al 1991;Hedges 1992;Jiao et al 2010).…”

mentioning

confidence: 99%

Rapid solid phase extraction of dissolved organic matter

Swenson

Oyler

Minor

2014

Limnology & Ocean Methods

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Dissolved organic matter (DOM) is a complex mixture of molecules found ubiquitously in freshwater and saltwater environments. Its structures contain valuable information content on the sources of molecules as well as the mechanisms at work within an aquatic ecosystem. Recent advancements in high resolution mass spectrometry and liquid chromatography have made inroads into determinations of the molecular structures within DOM. Such analyses, however, generally require a prior step to concentrate/isolate DOM, and this step often limits the number of samples that can be analyzed. This study has developed a fast method to concentrate DOM on commercially available online solid phase extraction (SPE) cartridges, which can be directly eluted onto an HPLC‐MS system. This rapid solid phase extraction (RSPE) method requires less sample (10‐100 mL) than previous SPE methods for DOM isolation. Additionally, this study tested a suite of SPE phases to find a combination that improves DOM recovery as compared with commonly used approaches. When a polystyrene divinylbenzene phase (RP‐1) was coupled with an activated carbon (CAR) phase, recoveries were found to be significantly higher than in previous SPE studies relying upon single phases. RSPE was tested for a diverse set of salty and freshwater samples with recoveries ranging from 46% to 78% of the total DOC. It was also tested on a suite of model compounds (including caffeine) and should be applicable to anthropogenic compounds in aquatic environments, although, in such cases, optimization may be needed to minimize the natural organic matter signal that was maximized in this study.

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Fluvial carbon fluxes in tropical rivers

Cited by 147 publications

References 59 publications

Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas

Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas

Sources and export of particle-borne organic matter during a monsoon flood in a catchment of northern Laos

Rapid solid phase extraction of dissolved organic matter

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Fluvial carbon fluxes in tropical rivers

Cited by 147 publications

References 59 publications

Air–sea exchanges of CO&lt;sub&gt;2&lt;/sub&gt; in the world's coastal seas

Air–sea exchanges of CO&lt;sub&gt;2&lt;/sub&gt; in the world's coastal seas

Sources and export of particle-borne organic matter during a monsoon flood in a catchment of northern Laos

Rapid solid phase extraction of dissolved organic matter

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Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas

Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas