Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such cross-dune braided rivers. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. The Ulan Buh desert is the main coarse sediment source for this desert braided channel, and the mean percentage of the coarser ( > 0.08 mm) grains on the aeolian dunes surface is 95.34 %. The lateral selective deposition process is developed by the interaction between the flows and the aeolian-fluvial sediment supplies, causing the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel centre and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces, forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of an "aboveground" river in the braided reach of the upper Yellow River in response to aeolian and fluvial sediment supplies.

Key-words:degree of phosphorus saturation, phosphorus sorption behavior, land use, sediment, soil To test the relationship between phosphorus buffering capacity in sediments of littoral zone and land use, seasonal samples were taken from the soils representing different patterns of land use, together with the littoral zone sediments, along shoreline in Lake Chaohu. There existed significantly positive relationships between equilibrium phosphorus concentration (EPC 0 ) and degree of phosphorus saturation (DPS) defined as ratios of Olsen-P, algae available phosphorus (AAP) and inorganic phosphorus (IP) to maximum sorption capacity (Q max ). So, some easily accessible P parameters especially DPS were indicative of EPC 0 in the sediments. Furthermore, the contents of IP, total phosphorus (TP) and organic matter (OM) in the sediments were significantly related to those in the soils. Therefore, the soils could provide the littoral zone with IP either directly or indirectly through TP input; it also provided the Olsen-P through the OM input, as evidenced by the relationship between Olsen-P and OM. It meant that the enhanced OM would enlarge the DPS. On the other hand, the increase in OM paralleled with the increases in Q max , which lower the DPS simultaneously. Thus, the OM modified sediment phosphorus sorption behaviors in complicated manners. Finally, the soil covered by Fleabane was coupled with the sediment whose EPC 0 values were lower and further decreased with strong diffusion from the soils after heavy rains. Hence, shoreline soil may input TP including IP and OM into the lake and alter the DPS together with EPC 0 thereby regulating the sediment functions to act as sink or source of phosphorus. RÉSUMÉLien entre les modes d'utilisation des terres et le comportement de sorption du phosphore des sédiments le long du littoral d'un lac peu profond en Chine (lac Chaohu) Mots-clés :degré de saturation en phosphore, comportement de sorption du phosphore, utilisation des terres, sédiments, sols Afin de tester la relation entre la capacité tampon phosphore des sédiments de la zone littorale et l'utilisation des terres, des échantillons de sols représentant différents modes d'utilisation des terres ont été prélevés saisonnièrement en même temps que des sédiments en zone littorale, le long des rives du lac Chaohu. Il existe des relations significativement positives entre la concentration de phosphore à l'équilibre (EPC) et le degré de saturation en phosphore (DPS) défini comme les ratios du Olsen-P, du phosphore disponible aux algues (PAA) et du phosphore inorganique (IP) à un maximum de capacité de sorption (Q max ). Ainsi, certains paramètres facilement accessibles du P, en particulier DPS sont indicatifs d'EPC 0 dans les sédiments. Par ailleurs, le contenu en phosphore inorganique (IP), le phosphore total (TP) et la matière organique (OM) dans les sédiments sont Article published by EDP Sciences C. Zhou et al.: Knowl. Managt. Aquatic Ecosyst. (2011) 403, 06 significativement corrélés à ceux des sols. ...