Visualization of the spatial transport of nutrients and organic matter contents in sediments under hydrodynamic perturbation conditions

Hydrodynamics can force nutrients and organic matter in sediments to migrate through perturbation, causing changes in their spatial patterns. The effectiveness of hydrodynamics is often validated through microcosm experiments, but the reliability of the experimental results is questionable because of the small experimental scale, which makes it difficult to capture small changes in pollutant content in sediments. This study focuses on data processing methods under small-scale conditions, and through an in-depth study of the characteristics and applicability of different interpolation methods, we provide a better visualization of nutrient salt and organic matter contents in sediment spatial patterns under hydrodynamic perturbations. Under hydrodynamic perturbation conditions, a more reliable and accurate method is provided to support the visualization of nutrient and organic matter contents in sediments under hydrodynamic perturbation. The results show that among the four kriging interpolation methods, Ordinary Kriging (OK) performs best. Taking total nitrogen in sediments as an example, the accuracy of the semivariogram function was discussed, and the composite function performed well, but it was not as good as the linear function, which may be due to the relatively simple spatial distribution of pollutants in sediments. Compared with the OK method and Inverse Distance Weighted (IDW) interpolation method, the IDW method can better capture local changes and yield better accuracy. However, the OK method results in a more delicate gradient change on the spatial distribution map.