Effect of land use on the biogeochemistry of dissolved nutrients and suspended and sedimentary organic matter in the tropical Kallada River and Ashtamudi estuary, Kerala, India

Jennerjahn, Tim C; Soman, K.; Ittekkot, V.; Nordhaus, Inga; S, Sooraj; Priya, R. Sathya; Lahajnar, Niko

doi:10.1007/s10533-008-9228-1

Cited by 61 publications

(30 citation statements)

References 46 publications

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“…The Nanliu River is characterized by intermediate concentrations of suspended particulate matter compared to other rivers (Bouillon et al, 2007a;Burns et al, 2008;Davies, 2004;Gao et al, 2007;Jennerjahn et al, 2008Jennerjahn et al, , 2004Unger et al, 2013), including some major Chinese streams (Ni et al, 2008;Zhang et al, 1998), but concentrations are lower than in the Changjiang (Ittekkot and Zhang, 1989;Mao et al, 2010;Wang et al, 2012) and Huanghe (Ittekkot and Zhang, 1989;Mayer et al, 1998;Wang et al, 2012). The Red River, also debouching into the Beibu Gulf, carries considerably higher SPM concentrations of 4200 mg L À 1 (Dang et al, 2010).…”

Section: Concentrations and Fluxes Of Suspended Particulate Mattermentioning

confidence: 99%

“…3) and indicating an increasing contribution of marine OM in offshore direction (e.g. Jennerjahn et al, 2008). δ 13 C in sediments is generally higher than in the deposited OM source because of increasing contribution of bacteria in sediment OM compared to source OM (Ehleringer et al, 2000).…”

Section: Composition Of Sediments Along the Estuarymentioning

confidence: 99%

“…Kao and Liu, 1997;Lyons et al, 2002;Milliman and Syvitski, 1992). Small rivers are also better suited for investigating processes and dynamics because they respond rapidly to seasonal and subseasonal natural or anthropogenic influences, while in major rivers short term regional changes may be masked by integration over the large catchments (Jennerjahn et al, 2008;Unger et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…In other estuaries, δ 15 N enrichment has been attributed to preferential loss of 14 N during OM degradation (see e.g. Jennerjahn et al, 2008). In the Nanliu Estuary this can be excluded because amino acid derived indicators reflect low degradation and increasing OM freshness off the river mouth.…”

mentioning

confidence: 99%

“…Short residence time in Nanliu Estuary and Lianzhou Bay (Sun et al, 2014) probably limits δ 15 N increase by shortening N processing and utilization times. In aquaculture SPM, low δ 15 N is due to the rapid direct uptake of applied synthetic fertilizer with low δ 15 N (À 3 to þ3‰; Jennerjahn et al, 2008;Maksymowska et al, 2000;Panno et al, 2006), as particulate δ 15 N is low in areas of direct excessive fertilizer application (see Kuramoto and Minagawa, 2001). This further shows that aquaculture production is sustained mainly by fertilizer enhanced phytoplankton biomass.…”

mentioning

confidence: 99%

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Particulate organic matter dynamics in coastal systems of the northern Beibu Gulf

Kaiser

Unger

Qiu

2014

Continental Shelf Research

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Section: Concentrations and Fluxes Of Suspended Particulate Mattermentioning

confidence: 99%

Section: Composition Of Sediments Along the Estuarymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Particulate organic matter dynamics in coastal systems of the northern Beibu Gulf

Kaiser

Unger

Qiu

2014

Continental Shelf Research

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Particulate carbon and nitrogen dynamics in a headwater catchment in Northern Thailand: hysteresis, high yields, and hot spots

Ziegler

Benner

Kunkel

et al. 2016

Hydrological Processes

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Abstract:Rivers of South and Southeast Asia disgorge large suspended sediment loads, reflecting exceptionally high rates of erosion promoted by natural processes (tectonic and climatic) and anthropogenic (land-use change) activities that are characteristic of the region. While particulate carbon and nitrogen fluxes have been characterized in some large Asian rivers, less is known about the headwater systems where much sediment and organic material are initially mobilized. This study, conducted in the 74-km 2 Mae Sa Experimental Catchment in northern Thailand, shows that the Sa River is an important source for particulate organic carbon (POC) and particulate organic nitrogen (PON) transported to larger river systems and downstream reservoirs. However, the yields during three years of investigation varied greatly: 5.0-22.3 Mg POC km À2 y À1 and 0.48-2.02 Mg PON km À2 y À1. The 22.3 Mg POC km À2 y À1 yield is the highest reported for any river on the Asian continent. Stream samples collected during 12 storms showed that almost 3% of the total suspended solid load is POC 0.7 μm to 2.0 mm in size. This percentage is higher than other values for most large rivers on the continent. Further, we documented a strong pulse hysteretic behaviour in the stream, whereby peak fluxes of POC and PON are often delayed (anticlockwise hysteresis) or accelerated (clockwise hysteresis) relative to stream flow peaks (or are complex), complicating the prediction of storm-based or annual particulate carbon and nitrogen fluxes. Stream turbidity and total suspended sediment are reasonable proxies for POC and PON concentrations, while stream discharge is not a good predictor variable. Observed C:N ratios for measured particulate samples range from 3 to 83, with the high-end values likely associated with fresh (non-decomposed) vegetative material greater than 2 mm in diameter. The C:N ratio (weighted based on three sediment sizes) for 12 events ranges from 7.5 to 15.3. These modest values reflect the relatively low C:N ratios for small size fractions (0.7-0.63 μm) that comprise 50-90% of the TSS load in the events. Overall, organic material <0.63 μm contribute about 75% of the total POC load and 80% of the PON load. The annual C:N ratio for the river is approximately 10-11. Collectively, our findings indicate the occasionally high yields make the Sa River-and potentially other similar headwater rivers-a hot spot for POC and PON transported to downstream water bodies. Complex hysteresis patterns and high year-to-year variability hinders our ability to calculate and predict these yields without continuous, automated monitoring of discharge and turbidity.

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Dynamics and fluxes of organic carbon and nitrogen in two Guiana Shield river basins impacted by deforestation and mining activities

Gallay¹,

Mora

Martinez

et al. 2017

Hydrological Processes

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Deforestation and mining activities have proven to be very damaging to rivers because these activities disturb the environmental characteristics of rivers. Thus, the concentrations of dissolved organic carbon (DOC), particulate organic carbon (POC), particulate nitrogen (PN), and Chlorophyll-a (Chl-a) were measured monthly during 2 hydrological years in the Maroni and Oyapock Rivers to assess the dynamics and fluxes of organic carbon and nitrogen in these 2 Guiana Shield basins, which have been strongly (Maroni) and weakly (Oyapock) impacted by deforestation and mining activities. The 2-year time series show that DOC, POC, PN, and Chl-a concentrations vary seasonally with discharge in both rivers, indicating a hydrologically dominated control. Temporal patterns of DOC, POC, and PN indicate that these variables show maximum concentrations in rising waters due to the yield of organic matter and nitrogen accumulated in soils, which are incorporated into the rivers during rainfall. However, the Chl-a concentrations were at a maximum during low-water stages. The C/N and C/Chl-a ratios also showed a seasonal trend, with lower values during the low water periods due to an increase in algal biomass. During high water, the POC in both rivers is the result of terrestrial organic matter, whereas during low-water autochthonous organic matter can reach up to 34% of the POC. The mean annual fluxes of TOC and PN were higher (4.56 × 10 5 tonC year −1 and 1.77 × 10 4 tonN year −1 , respectively) in the Maroni River than those (1.84 × 10 5 tonC year −1 and 0.54 × 10 4 tonN year −1 , respectively) in the Oyapock River. However, the specific fluxes of DOC, POC, and PN from both basins were nearly the same. Although gold mining activities are performed in both basins, there is no conclusive evidence regarding the impact of these activities on the dynamics of organic matter and particulate nitrogen in the Maroni and Oyapock Rivers.

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Effect of land use on the biogeochemistry of dissolved nutrients and suspended and sedimentary organic matter in the tropical Kallada River and Ashtamudi estuary, Kerala, India

Cited by 61 publications

References 46 publications

Particulate organic matter dynamics in coastal systems of the northern Beibu Gulf

Particulate organic matter dynamics in coastal systems of the northern Beibu Gulf

Particulate carbon and nitrogen dynamics in a headwater catchment in Northern Thailand: hysteresis, high yields, and hot spots

Dynamics and fluxes of organic carbon and nitrogen in two Guiana Shield river basins impacted by deforestation and mining activities

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