From soil to sea: sources and transport of organic carbon traced by tetraether lipids in the monsoonal Godavari River, India
Notice bibliographique
Résumé
Abstract. Monsoonal rivers play an important role in the land-to-sea transport of soil-derived organic carbon (OC). However, spatial and temporal variation in the concentration, composition, and fate of this OC in these rivers remains poorly understood. We investigate soil-to-sea transport of soil OC by the Godavari River in India using glycerol dialkyl glycerol tetraether (GDGT) lipids in soils, river suspended particulate matter (SPM), and riverbed sediments, as well as in a marine sediment core from the Bay of Bengal. The abundance and composition of GDGTs in SPM and sediments in the Godavari River differs between the dry and wet season. In the dry season, SPM and riverbed sediments from the whole basin contain more 6-methyl branched GDGTs (brGDGTs) than the soils. In the upper basin, where mobilisation and transport of soils is limited due to deficient rainfall and damming, contributions of 6-methyl brGDGTs in SPM and riverbed sediments are relatively high year-round, suggesting that they have an aquatic source. Aquatic brGDGT production coincides with elevated values of the isoprenoid GDGT-0 / crenarchaeol ratio in SPM and riverbed sediments from the upper basin, indicating low-oxygen conditions. In the wet season, brGDGT distributions in SPM from the lower basin closely resemble those in soils, mostly from the north and east tributaries, corresponding to precipitation patterns. The brGDGT composition in SPM and sediments from the delta suggests that soil OC is only effectively transported to the Bay of Bengal in the wet season, when the river plume extends beyond the river mouth. The sediment geochemistry indicates that also the mineral particles exported by the Godavari River primarily originate from the lower basin, similar to the brGDGTs, suggesting that they are transported together. However, river depth profiles in the downstream Godavari reveal no hydrodynamic sorting effect on brGDGTs in either season, indicating that brGDGTs are not closely associated with mineral particles. The similarity of brGDGT distributions in bulk and fine-grained sediments (≤ 63 µm) further confirms the absence of selective transport mechanisms. Nevertheless, the composition of brGDGTs in a Holocene, marine sediment core near the river mouth appears substantially different from that in the modern Godavari basin, suggesting that terrestrial-derived brGDGTs are rapidly lost upon discharge into the Bay of Bengal and/or overprinted by marine in situ production. The large change in brGDGT distributions at the river–sea transition implies that this zone is key in the transfer of soil OC, as well as that of the environmental signal carried by brGDGTs from the river basin.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».