Global trends in the nature of organic matter in river suspensions

Ittekkot, V.

doi:10.1038/332436a0

Cited by 317 publications

(177 citation statements)

References 16 publications

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“…This seems to be realistic because long-distance transport of material from the source (here the Laptev Sea shelf) has been found, suggesting that only the more stable terrigenous fraction reaches the Lomonosov Ridge (for discussion of degradation of terrigenous organic matter, see Ittekkot, 1988). This calculation gives a lateral transport of terrigenous organic carbon of 0.34 g m À2 y À1 at 1550 m, which is 42% of the terrigenous POC flux (0.81 g m À2 y À1 ) ( Table 7).…”

Section: Source and Transport Of The Lithogenic Mattermentioning

confidence: 99%

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Fahl

Nöthig

2007

Deep Sea Research Part I: Oceanographic Research Papers

108

107

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Investigations of lithogenic and biogenic particle fluxes using long-term sediment traps are still very rare in the northern high latitudes and are restricted to the arctic marginal seas and sub-arctic regions. Here data on the variability of fluxes of lithogenic matter, CaCO 3 , opal, and organic carbon and biomarker composition from the central Arctic Ocean are presented for a 1-year period. The study was carried out on material obtained from a long-term mooring system equipped with two multi-sampling traps, at 150 and 1550 m depth, and deployed on the southern Lomonosov Ridge close to the Laptev Sea continental margin from September 1995 to August 1996. In addition, data from surface sediments were included in the study. Annual fluxes of lithogenic matter, CaCO 3 , opal, and particulate organic carbon were 3.9, 0.8, 2.6, and 1.5 g m À2 y À1 , respectively, in the shallow trap and 11.3, 0.5, 2.9, and 1.05 g m À2 y À1 , respectively, in the deep trap.Both the shallow and the deep trap showed significant variations in vertical flux over the year. Higher values were found from mid-July to the end of October (total mass flux of 75-130 mg m À2 d À1 in the shallow trap and 40-225 mg m À2 d À1 in the deep trap). During all other months, fluxes were fairly low in both traps (most total mass flux values o10 mg m À2 d À1 ). The interval of increased fluxes can be separated into (1) a mid-July/August maximum caused by increased primary production as documented in high abundances of marine biomarkers and diatoms and (2) a September/October maximum caused by increased influence of Lena River discharge indicated by maximum lithogenic flux and large amounts of terrigenous/fluvial biomarkers in both traps. During September/October, total mass fluxes in the deep trap were significantly higher than in the shallow trap, suggesting a lateral sediment flux at greater depth. The lithogenic flux data also support the importance of sediment input from the Laptev Sea for the sediment accumulation on the Lomonosov Ridge on geological time scales, as indicated in sedimentary records from this region. r

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Section: Source and Transport Of The Lithogenic Mattermentioning

confidence: 99%

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Fahl

Nöthig

2007

Deep Sea Research Part I: Oceanographic Research Papers

108

107

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“…In near-shore areas an important fraction of the organic carbon registered in our sampies may originate from riverine supply of organic matter (Ittekkot, 1988) and thus bias our paleoproductivity data. However, both first isotopic data of the organic carbon fraction and CIN data (summarized in Sarnthein et al, 1988; L. Westerhausen, letter to M. Sarnthein, November, 1988) imply that the bulk of organic matter originates from the marine plankton production, except for a few of the shallower sites such as off the mouth of the Senegal river and in the northern Bay of Bengal (not included in the data set, Tablei).…”

Section: Temporal and Spatial Variability Of P Newmentioning

confidence: 99%

Reconstruction of Low and Middle Latitude Export Productivity, 30,000 Years BP to Present: Implications for Global Carbon Reservoirs

Sarnthein¹,

Winn²

1990

Climate-Ocean Interaction

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ABSTRACf. BasOO on organic carbon accumulation rates, nine time slices of oceanic export paleoproductivity (Pnew) are presentOO which depict the variability of P new on aglobal scale through the last 30,000 years and document that the basic distribution patterns did not change through glacial and interglacial times.However, the glacial ocean shows an increased contrast of high-versus low-productivity zones. Ö 13 C values of near-surface-dwelling planktonic foraminifera Globigerinoides ruber suggest that the same contrast applies to the glacial nutrient inventories of the ambient surface waters, with a significant glacial transfer of P0 4 from low-to high-productivity zones. In this way, glacial P new increasOO by a global average of about 2-4 Gt Cyc 1 and 100, via an enhancOO caCo 3 dissolution and alkalinity in the deep ocean, to a significant extraction of CO 2 from the surface water and the atrnosphere.

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“…The consumption of CO 2 by the silicate weathering in the Ganga and Yamuna watersheds in the Himalayan region is balanced by the release of CO 2 through weathering of organic-rich materials like black shale from the basin further suggests the presence of organic-rich materials in the high Himalaya region (Dalai et al 2002). Furthermore, it has been documented that erosion from the Himalayan basin delivers high amount of organic carbon to the Bay of Bengal (Ittekkot 1988;Subramanian and Ittekkot 1991;France-Lanord and Derry 1997).…”

Section: Hypothesis 1: Elevation Trends Of Measured Chemical Parametersmentioning

confidence: 99%

Chemistry of Supraglacial Ponds in the Debris-Covered Area of Lirung Glacier in Central Nepal Himalayas

2015

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Glacial meltwater samples were collected from 15 supraglacial ponds at elevations ranging between 3989 and 4292 m above sea level in the debris-covered area of Lirung glacier in central Nepal Himalayas, from November 2010 to October 2011 on a bimonthly basis. We examined elevation trends, and their control by seasonality, dominant geochemical processes, and seasonal dynamics in these supraglacial ponds. Concentration of some parameters showed a decreasing trend with elevation but with high variability and modulation by seasons, being more prevalent in the post-monsoon. Sulfate is the only parameter showing significant elevation trends regardless of the season, although the trend is also affected by the monsoon. The concentrations of major chemical solutes were highest during post-monsoon season and lower in the pre-monsoon and monsoon seasons, indicating influence of seasonality on dissolution, dilution, and hydrological processes. Contribution to chemical loads from marine aerosols to these pond water appeared to be minor except for sodium and magnesium. Chemical weathering of carbonate and silicate minerals fueled by dissolution of pyrite appeared as the dominant geochemical processes.

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Global trends in the nature of organic matter in river suspensions

Cited by 317 publications

References 16 publications

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Reconstruction of Low and Middle Latitude Export Productivity, 30,000 Years BP to Present: Implications for Global Carbon Reservoirs

Chemistry of Supraglacial Ponds in the Debris-Covered Area of Lirung Glacier in Central Nepal Himalayas

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