A reassessment of the sources and importance of land-derived organic matter in surface sediments from the Gulf of Mexico

Goñi, Miguel A.; Ruttenberg, Kathleen C.; Eglinton, T. I.

doi:10.1016/s0016-7037(98)00217-8

Cited by 390 publications

(256 citation statements)

References 105 publications

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“…When considered together, S:V and C:V ratios indicate plant tissue origin (Hedges and Mann 1979;Goñi et al 1998), while the state of oxidative degradation is indicated by the ratio of acid to aldehyde phenols in both the vanillyl [(Ad/Al) V ] and syringyl [(Ad/Al) S ] groups (Jex et al 2014).…”

Section: Laboratory Analysesmentioning

confidence: 99%

Photodegraded dissolved organic matter from peak freshet river discharge as a substrate for bacterial production in a lake-rich great Arctic delta

Gareis

Lesack

2018

Arctic Science

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Lake-rich Arctic river deltas are recharged with terrigenous dissolved organic matter (DOM) during the yearly peak water period corresponding with the solstice (24 h day −1 solar irradiance). Bacteria-free DOM collected during peak Mackenzie River discharge was exposed to sunlight for up to 14 days in June 2010. As solar exposure increased, carbon and lignin concentrations declined (10% and 42%, respectively, after 14 days), as did DOM absorptivity (62% after 14 days), aromaticity, and molecular weight. Photochemical changes were on par with those normally observed in Mackenzie Delta lakes over the entire open-water season. When irradiated freshet DOM was provided as a substrate, no significant differences were observed in community-level metabolism among five bacterial communities from representative delta habitats. However, bacterial abundance was significantly greater when nonirradiated (0 day) rather than irradiated DOM (7 or 14 days) was provided, while cell-specific metabolic measures revealed that per-cell bacterial production and growth efficiency were significantly greater when communities were provided irradiated substrate. This complex response to rapid DOM photodegradation may result from the production of inhibitory reactive oxygen species (ROS), along with shifts in bacterial community composition to species that are better able to tolerate ROS, or metabolize the labile photodegraded DOM.Key words: circumpolar river delta, photodegradation, dissolved organic matter, bacterial metabolism, Mackenzie River.Résumé : Les deltas arctiques riches en lacs sont rechargés en matière organique dissoute (MOD) terrigène pendant la période annuelle de crue maximale correspondant au solstice (irradiance solaire 24 h jour −1 ). De la MOD sans bactéries collectée durant la pointe de crue du fleuve Mackenzie a été exposée à la lumière du soleil pendant 14 jours en juin 2010. À mesure que l'exposition solaire se prolongeait, les concentrations de carbone et lignine diminuaient (10 % et 42 % respectivement, après 14 jours), tout comme le pouvoir d'absorption de la MOD (62 % après 14 jours), son aromaticité et son poids moléculaire. Les changements photochimiques correspondaient à ceux normalement observés dans les lacs du delta du Mackenzie sur l'ensemble de la saison des eaux libres. Lorsque de la MOD de crue irradiée fut utilisée comme substrat, aucune différence significative n'a été observée quant au métabolisme au niveau de la communauté en comparant cinq communautés bactériennes issues d'habitats représentatifs du delta. Néanmoins, l'abondance de bactéries était considérablement plus grande lorsque de la For personal use only.MOD non irradiée (0 jour) a été fournie au lieu de la MOD irradiée (7 ou 14 jours), tandis que les mesures de l'activité métabolique spécifique aux cellules ont révélé que la production bactérienne par cellule et le rendement de croissance étaient considér-ablement plus élevés lorsque les communautés avaient accès au substrat irradié. Cette réaction complexe à la photodégradation...

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Section: Laboratory Analysesmentioning

confidence: 99%

Photodegraded dissolved organic matter from peak freshet river discharge as a substrate for bacterial production in a lake-rich great Arctic delta

Gareis

Lesack

2018

Arctic Science

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“…However, if plant wax δ 13 C became less depleted and dolomite accumulation rates increased, the cause would likely be increased Mesopotamian aridity. Such an approach would ideally be complimented by the utilization of a biomarker for fluvial input, such as lignin (Goñi et al, 1998), in order to constrain changes in riverine input through time.…”

Section: Controls On the Deposition Of Plant Waxes In The Arabian Seamentioning

confidence: 99%

Terrigenous plant wax inputs to the Arabian Sea: Implications for the reconstruction of winds associated with the Indian Monsoon

Dahl

Oppo

Eglinton

et al. 2005

Geochimica et Cosmochimica Acta

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We have determined the accumulation rates and carbon isotopic compositions (δ 13 C) of longchain (C 24 -C 32 ) terrigenous plant wax fatty acids in 19 surface sediment samples geographically distributed throughout the Arabian Sea in order to assess the relationship between plant wax inputs and the surrounding monsoon wind systems. Both the accumulation rate data and the δ 13 C data show that there are three primary eolian sources of plant waxes to the Arabian Sea: Africa, Asia, and the Arabian Peninsula. These sources correspond to the three major wind systems in this region: the summer (Southwest) monsoon, the winter (Northeast)

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“…While Goni et al (1998) considered the possibility of marsh-derived organic matter as a source of the terrigenous organic matter they observed in Gulf of Mexico sediments, they dismissed this possibility for a number of reasons. They argued that the subsidence of the deltaic plain and surrounding lands should make them a sink and not a source of sediments, and they expected that marsh sediments should be younger in 14 C-age than the old sediments they observed on the shelf and slope.…”

mentioning

confidence: 99%

Carbon isotopes and iodine concentrations in a Mississippi River delta core recording land use, sediment transport, and dam building in the river’s drainage basin

Santschi

Oktay

Cifuentes

2007

Marine Environmental Research

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A reassessment of the sources and importance of land-derived organic matter in surface sediments from the Gulf of Mexico

Cited by 390 publications

References 105 publications

Photodegraded dissolved organic matter from peak freshet river discharge as a substrate for bacterial production in a lake-rich great Arctic delta

Photodegraded dissolved organic matter from peak freshet river discharge as a substrate for bacterial production in a lake-rich great Arctic delta

Terrigenous plant wax inputs to the Arabian Sea: Implications for the reconstruction of winds associated with the Indian Monsoon

Carbon isotopes and iodine concentrations in a Mississippi River delta core recording land use, sediment transport, and dam building in the river’s drainage basin

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