 So Queen Zhuanzu is at the University of Virginia and will be talking, going back more to the marine domain on like seasonal seagrass effects on flow and sediment dynamics, specifically for a back barrier base. Hi, can anyone hear me? We can hear you all right. Yep, thanks Irina and to the CSDNS community for organizing this summer science series. My name is Qin Guangzhu, I am PhD candidate at the University of Virginia. Today I will be talking about quantifying seasonal seagrass effect on flow and sediment dynamics in a back barrier base using modeling approach. These are part of the results that we recently submitted to JGR Oceans. The causes of this study are Pat Weiberg and Matt Reinerbach. This study is founded by the NSF Long-Tone Ecological Research. Previous studies have shown that seasonal seagrass growth and senescence exert a strong influence on coastal waves. During summer when seagrass density is high, the dense seagrass canopy can result in strong attenuation of flow and waves. Therefore, the sedimentary suspension from the seabed is reduced. In contrast, during winter when seagrass density is low, the flow and weight attenuation caused by seagrass is weak. During this period, the sedimentary suspension from the seabed increased. However, mobility investigations and small-scale field measurement cannot fully resolve the spatial variations of dynamic factors in natural environment. The synergistic effect of flow, weight, vegetation, sediment interaction and metal scale need to be better understood. In this study, we apply a hydrodynamic and sediment transform model and couple seagrass effect on flow, weight, sedimentary suspension in South Bay. On Virginia's Autolantic coast, this is a barrier-based system with a shallow water depth of around one meter and the aerial image shows the distribution of a restored seagrass meadow in South Bay. We validated the model using seasonal field hydrodynamic measurement within the seagrass meadow and at the reference bear side for comparison. Then after validation, we used the model to quantify the seasonal seagrass effect. Today, I will focus on interpreting our model result. We used the depth 3D model to simulate the flow, weight and sedimentary suspension in our study area. We divided our overall model into two model domains, the large domain with a resolution with 200 meters and a small domain with a resolution of 70 meters. We ran the model in two-dimensional depth average mode with a time step of 15 seconds and the model was run for two simulation periods in January and June 2011. In order to incorporate vegetation effect in depth 3D, we implemented a depth-based vegetation model and the inflow simulation and the Suzuki vegetation weight energy dissipation model in weight simulation. This approach considered vegetation as cylindrical structures that could be characterized by vegetation height, stand diameter, shield density and vegetation jack coefficient. We used typical seasonal seagrass characteristics based on previous observations in South Bay for our model input. The first thing we are looking at is the seasonal seagrass effect. We output the model current speed on the left, the weight high in the middle and the suspended sediment concentration on the right at Bayer side and seagrass side for comparison. The results show that during winter when seagrass density is low, the seagrass method has a little effect on flow reduction, weight, significant weight high and SSC. In contrast, during summer when seagrass density is high, the dense seagrass canopy could result in 16% of flow reduction and 20% of weight reduction as well as 85% of SSC reduction in seagrass meadows. With different model scenarios, our couple model is able to separate flow and weight attenuation on sedimentary suspension. We calculated the probability density distribution of bashes just within seagrass meadows with and without seagrass effect. You can see here the y-axis is the density and the x-axis is the shear stress in log scale. When seagrass effect was not included in the model, the bashes just in the seagrass meadow is high with a mean value of 0.5 Pascal. Flow attenuation effect alone could significantly reduce the bashes just from 0.5 to 0.08 Pascal. Including flow and weight attenuation could further reduce the shear stress from 0.8 to 0.5, 0.05 Pascal. Therefore, significant reductions in bashes just during summer seagrass were mainly caused by flow attenuation rather than weight attenuation. Although low density seagrass in winter has a limited effect on flow and weight attenuation, small change in winter seagrass density could result in strong variations in sediment flux into the seagrass meadows. We plot the sediment flux in the y-axis as a function of the seagrass density in the x-axis. When the winter seagrass has a density of around 50, we can see that the sediment flux that the seagrass meadow during this period could maintain a nearly balanced sediment budget. Higher seagrass density could gradually increase the sediment input into the seagrass meadow. However, if the density is lower than 50, the seagrass area will become erosional, leading to dramatic sediment export from the system. These strong variations of the sediment flux that are associated with winter seagrass density could have a significant impact on light availability for seagrass growth and may alter the long-term sediment budget of the seagrass ecosystems. In conclusion, we use a flow-weight vegetation sediment interaction depth 3D model to investigate spatial and seasonal seagrass impact in South Bay, Virginia coast reserve. We found that large reductions in sedimentary suspension in dense meadows were mainly caused by flow rather than weight attenuation. We also found that small change in winter seagrass density could result in strong changes in sediment flux into and out of the meadow. That's it. I will end up here. Thanks.