Comment on: Mid-Holocene water-level changes in the lower Rhine-Meuse delta (western Netherlands): implications for the reconstruction of relative mean sea-level rise, palaeoriver-gradients and coastal evolution by Van de Plassche et al. (2010)

In May 2009, Orson van de Plassche sadly passed away. In a paper that was partially written after his death, new data and a revision of an existing sea level curve are published for the Rotterdam area (Van de Plassche et al., 2010). Our comment concerns two topics they address in their discussion section: 1) connection of their revised Rotterdam relative sea-level curve for the period 7900-5300 cal yr BP (Jelgersma, 1961; Van de Plassche, 1982; 1995; Berendsen et al., 2007; Van de Plassche et al., 2010) to the sea-level curve for the same area for the period 9000-7500 cal yr BP (Hijma and Cohen, 2010); 2) The role of the river gradient on our calculation of a sea-level jump that occurred between 8450-8250 cal yr BP (Hijma and Cohen, 2010)