The Chilia III lobe begun developing at the open coast sometimes around 1700 AD (Mikhailova and Levashova, 2001). Although still primitive, the earliest realistically detailed map of the Danube delta region dating from 1771 (Fig. 2a; Panin and Overmars, 2012) provides important information about the earliest growth phase of the lobe. Its wave-dominated

deflected morphology (sensu Bhattacharya and Giosan, 2003) is evident. Two thalwegs at the mouth separated by a submerged middle-ground bar are oriented southward in the direction of the dominant longshore drift. Updrift of the mouth, the offshore-recurving shape of the contemporary Jebrieni beach Gefitinib chemical structure plain ridges clearly indicates that the submarine deltaic deposition was already significant. Only a few islets were emergent on the

updrift side of the submarine channel, but a shallow submerged depositional platform appears to have developed on its downdrift side ( Fig. 2a). Subsequently, as recorded in numerous maps and charts since 1830 ( Fig. 4a), the Chilia III lobe evolved as a typical river-dominated delta in a frictional regime, which has led to repeated bifurcations LY294002 via formation of middle-ground bars ( Giosan et al., 2005). The influence of the longshore drift, expressed as a southward deflection of main distributary of Old Stambul, remained noticeable until the end of the 19th century as documented by a survey in 1871 (Fig. 4a). The isometric shape of the lobe acquired after that time resulted from the infilling of the shallow bay left between the deflected part delta plain and the mainland (Fig. 4a). Throughout the history of Chilia III growth, deltaic progradation was favored at northern Oceacov mouth, which advanced into the dominant direction of the waves, and the southern Old Stambul distributary mouth, which grew in the direction longshore drift. Slower progradation

is evident along the central coast (Fig. 4a) fed by eastward directed distributaries that had to contend with the strong longshore drift removing sediments GPX6 southward (Giosan et al., 2005). The decrease in new fluvial sediment delivered per unit shoreline as the lobe grew larger and advanced into deeper water resulted in progressively slower growth of the entire lobe in the 20th century (Fig. 4a). By 1940, clear signs of erosion were apparent, and a general erosional trend continues until today leading to a wave-dominated morphology characterized by barrier islands and spit development (Fig. 4b and c). Our reconstruction of the Chilia lobe evolution supports the idea that the rapid Danube delta growth in the late Holocene (Giosan et al., 2012) led to its radical reorganization via flow redistribution across the delta. Initially the southernmost St. George branch was reactivated around 2000 years BP and constructed the bulk of its wave-dominated open coast lobe (Fig. 1) in the last 1000–1500 years (Giosan et al., 2006 and Giosan et al.