Riverine transport of terrestrial organic matter to the North Catalan margin, NW Mediterranean Sea

Sánchez-Vidal, Anna; Higueras, M.; Martı́, Eugènia; Liquete, Camino; Calafat, Antoni; Kerhervé, Philippe; Canals, Miquel

doi:10.1016/j.pocean.2013.07.020

Cited by 37 publications

(34 citation statements)

References 34 publications

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“…In our study, total OC and N were lower in all sediment deposits compared to soils, with the exception of suspended load. Increase of N in sediments rich in clay (as suspended load) has been attributed to the presence of ammonium or to the contribution of freshwater algae (Sanchez-Vidal et al, 2013).…”

Section: Mechanisms Of Oc Loss or Gain In Sedimentsmentioning

confidence: 99%

“…Differences in OC pools between sediment deposits can also be the result of transport conditions due to higher or lower rainfall intensity (Martínez-Mena et al, 2012;Zhang et al, 2013) or to the discharge. Smith et al (2013) related high discharge rates with transport of modern C, associated with erosion and the release of organic matter (Sanchez-Vidal et al, 2013), and C from vascular sources (Goñi et al, 2013). Low flows were associated with export of fossil OC (Smith et al, 2013) from biogenic sources dominated by non-vascular plants (Goñi et al, 2013) or from freshwater primary producers (Sanchez-Vidal et al, 2013).…”

Section: Size Selectivity and Sources Of Sedimentmentioning

confidence: 99%

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Sediment flow paths and associated organic carbon dynamics across a Mediterranean catchment

Boix‐Fayos

Nadeu

Quiñonero

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. Terrestrial sedimentation buries large amounts of organic carbon (OC) annually, contributing to the terrestrial carbon sink. The temporal significance of this sink will strongly depend on the attributes of the depositional environment, but also on the characteristics of the OC reaching these sites and its stability upon deposition. The goal of this study was to characterise the OC during transport and stored in the depositional settings of a mediumsized catchment (111 km 2 ) in SE Spain, to better understand how soil erosion and sediment transport processes determine catchment-scale OC redistribution. Total organic carbon (TOC), mineral-associated organic carbon (MOC), particulate organic carbon (POC), total nitrogen (N) and particle size distributions were determined for soils (i), suspended sediments (ii) and sediments stored in a variety of sinks such as sediment wedges behind check dams (iii), channel bars (iv), a small delta in the conjunction of the channel and a reservoir downstream (v), and the reservoir at the outlet of the catchment (vi). The data show that the OC content of sediments was approximately half of that in soils (9.42 ± 9.01 g kg −1 versus 20.45 ± 7.71 g kg −1 , respectively) with important variation between sediment deposits. Selectivity of mineral and organic material during transport and deposition increased in a downstream direction. The mineralisation, burial or in situ incorporation of OC in deposited sediments depended on their transport processes and on their post-sedimentary conditions. Upstream sediments (alluvial wedges) showed low OC contents because they were partially mobilised by non-selective erosion processes affecting deeper soil layers and with low selectivity of grain sizes (e.g. gully and bank erosion). We hypothesise that the relatively short transport distances, the effective preservation of OC in microaggregates and the burial of sediments in the alluvial wedges gave rise to low OC mineralisation, as is arguably indicated by C : N ratios similar to those in soils. Deposits in middle stream areas (fluvial bars) were enriched in sand, selected upon deposition and had low OC concentrations. Downstream, sediment transported over longer distances was more selected, poorly microaggregated, and with a prevalence of silt and clay fractions and MOC pool. Overall, the study shows that OC redistribution in the studied catchment is highly complex, and that the results obtained at finer scales cannot be extrapolated at catchment scale. Selectivity of particles during detachment and transport, and protection of OC during transport and deposition are key for the concentration and quality of OC found at different depositional settings. Hence, eco-geomorphological processes during the different phases of the erosion cycle have important consequences for the temporal stability and preservation of the buried OC and in turn for the OC budget.

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Section: Mechanisms Of Oc Loss or Gain In Sedimentsmentioning

confidence: 99%

Section: Size Selectivity and Sources Of Sedimentmentioning

confidence: 99%

Sediment flow paths and associated organic carbon dynamics across a Mediterranean catchment

Boix‐Fayos

Nadeu

Quiñonero

et al. 2015

Hydrol. Earth Syst. Sci.

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“…It is well known that rapid increases of Q associated with heavy rainstorms cause erosion of riverbanks and the resuspension of riverbed sediments, removing the sediments accumulated during low water flow periods (Sanchez-Vidal et al, 2013). In order to elucidate the relationship between water discharges and TSM, a sediment rating curve was established.…”

Section: Meteorological and Hydrological Drivers Of Continental Organmentioning

confidence: 99%

“…6 and 7). Therefore, trapping of sediments by dams may also cause a decrease of POC and PN transport from the terrestrial to the marine environments (Sanchez-Vidal et al, 2013).…”

Section: Biogeosciencesmentioning

confidence: 99%

“…Indeed, carbon and nitrogen isotopic ratios (δ 13 C and δ 15 N) are widely used as natural tracers of carbon sources in riverine, estuarine and marine coastal ecosystems (Riera and Richard, 1997;Rolff and Elmgren, 2000;Darnaude et al, 2004;Wissel and Fry, 2005). In the NW Mediterranean, several studies on the Rhône River (Aucour et al, 2003;Darnaude et al, 2004;Harmelin-Vivien et al, 2010) determined the isotopic signatures of total suspended matter (TSM) within the range −27.4 to −26.1 ‰ for δ 13 C and 4.8 to 5.7 ‰ for δ 15 N. Recently, the suspended matter in coastal rivers Fluvià, Ter and Tordera has been isotopically characterized by a δ 13 C mean of 28 ‰ and a δ 15 N mean of 9.3 ‰ (Sanchez-Vidal et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Biogeochemical characterization of the riverine particulate organic matter transferred to the NW Mediterranean Sea

et al. 2014

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Abstract.A large amount of terrestrial organic matter is annually delivered by rivers to the continental shelf, where this material is either degraded, buried or transferred to the deep sea by hydrodynamic processes such as storms. The relative amount of terrestrial organic matter in the marine sediments is often determined by analysing the stable isotopes (δ 13 C and δ 15 N) and the C / N ratio of organic matter because the various particulate organic matter (POM) sources have distinct isotopic compositions. With the objective to refine and better interpret POM sources in the marine environment, we have characterized monthly terrestrial POM delivered by eight rivers discharging to the NW Mediterranean Sea: the Rhône, Hérault, Orb, Aude, Têt, Fluvià, Ter and Tordera rivers. These rivers were simultaneously sampled from November 2008 to December 2009 and the concentrations of total suspended matter (TSM), particulate organic carbon (POC) and nitrogen (PN), as well as their stable isotopic ratios (δ 13 C and δ 15 N) were determined.During the survey, three rainstorm events with winds coming from the E-NE and the S-SE impacted the NW Mediterranean. Depending on the direction of incoming winds, the fluvial response (amount of water discharge and TSM) was different. Rivers draining the Alps (Rhône River) and Central Massif (Hérault, Orb, and Aude rivers) were mostly impacted by rainstorms associated with winds coming from the S-SE, while rivers draining the Pyrenees (Têt, Fluvià, and Ter rivers) and the Montseny Massif (Tordera River) were impacted by rainstorms associated with winds coming from the E-NE. In addition, the spatial evolution of water discharges shows a different hydrological regime of the Rhône River, with relatively constant and high water stages and TSM concentrations when compared to coastal rivers, characterized by long periods of low water stages. TSM concentrations are positively correlated to water discharges (high water flows resuspended riverbed sediments) but show an inverse relationship with POC and PN relative contents (mostly due to dilution and by low availability of light in river waters during flood events). TSM in most of the coastal rivers have on average 2.5-3 times higher POC and PN mean contents than the Rhône River (8.5 and 1.5 %, respectively, for coastal rivers compared to 3.6 and 0.5 %, respectively, for the Rhône River). This discrepancy may be caused by the long drought periods in small coastal Mediterranean watersheds that enhance the eutrophication in studied coastal rivers. The δ 13 C ratios of organic matter also reflect this discrepancy between high and low water stages with values ranging from −33.2 to −24.5 ‰. The enriched 13 C values (−26.3 ± 0.4 ‰ for the Rhône River and −26.9 ± 1.2 ‰ for coastal rivers), measured during high water stages, express mostly a mixture of terrestrial source (plant remains and soils) whereas

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Fluxes of dissolved organic carbon and nitrogen to the northern Indian Ocean from the Indian monsoonal rivers

et al. 2015

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Dissolved organic carbon (DOC) and nitrogen (DON) were measured in 27 major and medium monsoonal estuaries along the Indian coast during southwest monsoon in order to understand the spatial variability in their concentrations and fluxes to the northern Indian Ocean. A strong spatial variability (~20‐fold) in DOC and DON was observed in the Indian monsoonal estuaries due to variable characteristics of the catchment area and volume of discharge. It is estimated that the Indian monsoonal estuaries transport ~2.37 ± 0.47 Tg (1 Tg = 1012 g) of DOC and ~0.41 ± 0.08 Tg of DON during wet period to the northern Indian Ocean. The Bay of Bengal receives 3 times higher DOC and DON (1.82 and 0.30 Tg, respectively) than the Arabian Sea (0.55 and 0.11 Tg). Catchment area normalized fluxes of DOC and DON were found to be higher in the estuaries located in the southwestern than the estuaries from other regions of India. It was attributed to relatively higher soil organic carbon, biomass carbon, and heavy rainfall in catchment areas of the rivers from the former region. It has been noticed that neither catchment area nor discharge volume of the river controls the fluxes of DOC and DON to the northern Indian Ocean. Since the total load of DOC and DON is strongly linked to the volume of discharge, alterations in the freshwater discharge due to natural or anthropogenic activities may have significant influence on organic matter fluxes to the Indian coastal waters and its impact on microbial food web dynamics needs further evaluation.

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Riverine transport of terrestrial organic matter to the North Catalan margin, NW Mediterranean Sea

Cited by 37 publications

References 34 publications

Sediment flow paths and associated organic carbon dynamics across a Mediterranean catchment

Sediment flow paths and associated organic carbon dynamics across a Mediterranean catchment

Biogeochemical characterization of the riverine particulate organic matter transferred to the NW Mediterranean Sea

Fluxes of dissolved organic carbon and nitrogen to the northern Indian Ocean from the Indian monsoonal rivers

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