A prototype for detection of particles in sea water by using polarize-light scattering

Marine particles, including phytoplankton, silt and microplastics, play vital roles in the global issues such as carbon loop, ecological hazard, marine deposit, etc. In situ detection of the suspended particles is very important to the marine environmental monitoring and ecological research. In this paper, we present a prototype using polarized-light scattering method to detect the suspended particles. The optical schematic diagram is shown at first to describe how the polarized light is launched and the scattered polarizations are measured. The concept profile and physical image of the prototype and its battery are shown. The prototype was deployed in the Daya Bay (at the edge of South China Sea) in December, 2017. The data showed that the polarization parameters of particles in two deployment sites were quite different. And moreover, the polarization parameters normalized by the intensity, can characterize the difference between the particles in two sites. The prototype can detect the concentration of the particles in water. Advices for the next generation are given in the end.