High resolution sediment records in the Yangtze Delta front were constructed to reveal recent environmental
changes in response to river basin human activities. Increases in nutrient and organic C influxes
that began in the 1950s, together with elevated primary productivity and increased chemical
fertilizer application, suggested a shift toward anthropogenic-predominated environmental changes
during this period. The depletion of total organic C (TOC), total N (TN), and biogenic Si (BSi), along with
the decline in sedimentation rate and coarsening of sediment coincided with the development of hydrological
engineering in the river basin from the 1980s. Reservoir Si retention substantially altered river
mouth primary productivity community composition from diatoms to non-diatoms, thereby changing
the BSi/TOC molar ratio in the sediment profile. Estimation of biogenic component burial fluxes was
conducted to assess the variation and potential impacts. A recent dramatic decline in biogenic component
burial in the delta area suggested a low nutrient removal efficiency in this region, due to the
decrease in sediment discharge. Consequently, more nutrients have been further transported to the inner
shelf and open waters instead of being buried in the delta sediment, thereby increasing the environmental
pressure in the Yangtze Delta and adjoining coastal area.