Morphological change in the Qinzhou Bay (QZB), southwest China, has been studied, using bathymetric charts and remote sensing data. Historical admiralty charts were digitized and analyzed in a Geographical Information System (GIS) environment to provide quantitative estimates of underwater topography changes for exploring the accretion-erosion characteristics from 1960s to 2010s. Multi-temporal satellite images have been used to analyze the coastline developments. The results showed that the bathymetry and coastline of QZB changed dramatically in recent decades. The subaqueous area decreased by about 8% in the study area during the last 50 years, mainly due to coastal land reclamation. The average growth rate of the coastlines was 2.07 km/yr. between 1978 and 2013 with natural curvy coastlines being replaced by straighter artificial shorelines. During the period from 1960s to 1990s, the evolution of QZB was mainly governed by natural factors with slight deposition or erosion in the deep troughs. From 1990s to 2010s, intensive large-scale human activities, such as port building, channel dredging and artificial island construction became the main causes affecting morphological changes in the QZB. Approximately half of the underwater terrain had undergone significant changes (greater than +/- 0.5 m), and the proportion of deposition area accounting for 32.26% of the subaqueous area, about twice more than erosion area. Large scale reclamation projects have made dramatic negative impact on coastal natural ecosystem. Integrated coastal zone management need to be carried out to maintain the balance between economic development and ecological health.

Instrumental records reveal that intense tropical cyclone (TC) activity varies with tropical sea surface temperature (SST) on annual-decadal scales. Drivers of intense TC activity at the centennial-millennial scale are less clear, due to the sparseness of pre-observational reconstructions. Here, we present a new 2 kyr continuous activity record of intense TCs from offshore eastern China. Our reconstruction indicates that this site witnessed enhanced TC activity during relatively warm periods, with a widespread increase in TC activity during the later part of the Little Ice Age. This latter observation reveals that enhanced TC activity was synchronized with increased Asian dust emissions during the Little Ice Age. TC activity was also lower in the late Roman Warm Period, when SST was higher but Asian dust emissions were lower than in the early phase. Such patterns suggest a centennial-millennial link between TC climatology and a combination of SST changes and Asian dust levels.© 2022. The Author(s).

Understanding the fate of terrestrial organic carbon (Corg) delivered to oceans by rivers is critical for constraining models of biogeochemical cycling and Earth surface evolution. Corg fate is dependent on both intrinsic characteristics (molecular structure, matrix) and the environmental conditions to which fluvial Corg is subjected. Three distinct patterns are evident on continental margins supplied by rivers: (a) high-energy, mobile muds with enhanced oxygen exposure and efficient metabolite exchange have very low preservation of both terrestrial and marine Corg (e.g., Amazon subaqueous delta); (b) low-energy facies with extreme accumulation have high Corg preservation (e.g., Ganges-Brahmaputra); and (c) small, mountainous river systems that sustain average accumulation rates but deliver a large fraction of low-reactivity, fossil Corg in episodic events have the highest preservation efficiencies. The global patterns of terrestrial Corg preservation reflect broadly different roles for passive and active margin systems in the sedimentary Corg cycle.