The Jiulong River plume as cross-strait exporter and along-strait barrier for suspended sediment: Evidence from the endmember analysis of in-situ particle size

• Effects of small river plume on large river derived sediment reaching inner-shelf were examined.
• Small river plume alters and enhances inner-shelf suspended particles transport either along-strait or cross-strait.
• Endmembers of in-situ particle size distribution data track the fate of suspended particle groups.
• LISST is a useful water column profiler to understand 3D pattern of suspended particle transport.

The influences of the Jiulong River on Taiwan Strait sediment resuspension and transport systems was conducted to reveal the extent to which longshore gradients in fine sediments could be related to the existence of a fresh water plume from the Jiulong River. An endmember model was used in the analysis of in-situ suspended particle size data obtained by a LISST Particle Analyzer Device, in order to understand the effect of Jiulong River plume on Taiwan Strait waters during the summer period of 2010. Three in-situ suspended particle endmembers, associated with particular sediment dynamic processes, are identified: Endmember 1, associated with estuarine waters; Endmember 2, associated with a fine sediment zone over longshore clinothem; and Endmember 3, associated with a coarse sediment zone over outer shelf and main channel of the strait. The spatial distribution of the Endmember 1 shows the adjustment of estuarine-related suspended particles from the upper water layer to the halocline layer when they were transported along the plume. The spatial distribution of Endmember 1 can also indicate how the Jiulong River estuarine-related suspended particles transport across the Taiwan Strait, although such a relatively small amount of river-derived suspended particle transport provides limited fine sediment source to the inner-shelf of the west Taiwan Strait. The distribution of the reworking fine sediment dominating Endmember 2 illustrates that the Jiulong River plume acts as a barrier to alter the along-strait transport of fine particles and the strengthened cross-strait transport traps them into the distal depocenter in west part of Taiwan Strait.