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New palynological and ostracod data are presented from the Holocene Volga delta, obtained from short cores and surface samples collected in the Damchik region, near Astrakhan, Russian Federation in the northern Caspian Sea. Four phases of delta deposition are recognized and constrained by accelerated mass spectrometry (AMS) radiocarbon ages. Palynological records show that erosive channels, dunes (Baer hills) and inter-dune lakes were present during the period 11,500-8900 cal. BP at the time of the Mangyshlak Caspian lowstand. The period 8900-3770 cal. BP was characterized regionally by extensive steppe vegetation, with forest present at times with warmer, more humid climates, and with halophytic and xerophytic vegetation present at times of drought. The period 3770-2080 cal. BP was a time of active delta deposition, with forest or woodland close to the delta, indicating relatively warm and humid climates and variable Caspian Sea levels. From 2080 cal. BP to the present-day, aquatic pollen is frequent in highstand intervals and herbaceous pollen and fungal hyphae frequent in lowstand intervals. Soils and incised valley sediments are associated with the regional Derbent regression and may be time-equivalent with the 'Medieval Warm Period'. Fungal spores are an indicator of erosional or aeolian processes, whereas fungal hyphae are associated with soil formation. Freshwater algae, ostracods and dinocysts indicate mainly freshwater conditions during the Holocene with minor brackish influences. Dinocysts present include Spiniferites cruciformis, Caspidinium rugosum, Impagidinium caspienense and Pterocysta cruciformis, the latter a new record for the Caspian Sea. The Holocene Volga delta is a partial analogue for the much larger oil and gas bearing Mio-Pliocene palaeo-Volga delta.

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Sedimentary coasts and shallow-sea beds may be dynamic. The large-scaled spatial variation in these dynamics and the smaller-scaled behaviour of individual marine bedforms are largely unknown. Sea-bed dynamics are relevant for the safety of shipping, and therefore for monitoring strategies, and for offshore engineering projects and archaeological investigations. To date, sea-bed dynamic studies in the North Sea that are based on high-resolution echo soundings are mostly local. Recently, sufficient time series of modern, digital echo sounder surveys have become available to allow for a Netherlands Continental Shelf-wide quantification of vertical dynamic trends as well as for the detailed analysis of the morphodynamics of marine bedforms. Results show that (i) tidal channels, estuaries and longshore bars are particularly dynamic, (ii) the shelf offshore is less dynamic in general, and (iii) the most dynamic zones offshore are the zones where marine bedforms occur. The occurrence of superimposed sand banks, long bed waves, sand waves and megaripples is limited to the sandy shelf and sand wave migration rates vary spatially between 0 to 20 m/year. This spatial knowledge of morphodynamics is used in combination with environmental conditions and sea traffic to validate and to optimise re-survey policies.

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