# Study of Marine Particles Using Submersible Digital Holographic Camera during the Arctic Expedition
## 3 Results and Discussion  
The classification features of the algorithm were sufficient to explicitly identify the terrigenous suspension, mesoplankton, zooplankton, marine snow, and floating methane bubbles released from the bottom sediments of the Eastern Arctic Seas. We compared the corresponding DHC results with independent data obtained under the same conditions  
Figure 9: Echograms of drift were obtained at stations (**a**) No. 6947 and (**b**) No. 6962. An arrow marks the start time of the hologram recording. An oval indicates a section of the water column with a significant number of bubbles. A green line shows the estimated trajectory of the camera as it drifts. by other research teams during the AMK-82 expedition to assess the correctness of the processing algorithm (and therefore the choice of the pre-set values of the \(H\) and \(M\) criteria). The objects of interest shown in Table 3 were described depending on the geographical location of the stations. Furthermore, the data are given in accordance with these descriptions. A map of the stations considered in this work is shown in Figure 10.  
The operating characteristics of the DHC probe at the stations are given in Table 4.  
If the performance characteristics of the DHC are evaluated by the station No. 6961 with the largest number of holograms, then the performance characteristics per 1 m of profile are as follows:  
* Time for recording and reading the holographic sample data-3.5 min/m;
* Required memory, taking into account the post-processing data-400 MB/m;
* Data processing time-1.2 h/m. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Station No.** & **Coordinates** &
\begin{tabular}{c} **Geographical** \\ **Description** \\ \end{tabular} & **Depth, m** & **Range of Interest** \\ \hline
6932 &
\begin{tabular}{c} 72°57°34.8′′ N \\ 73°10’13.2′′ E \\ \end{tabular} & Kara Sea & 29 & Comparison of turbidimetric data \\ \hline
6941 &
\begin{tabular}{c} 77°06°07.2′′ N \\ 125°05°43.2′′ E \\ \end{tabular} & Laptev Sea & 364 & Comparison of turbidimetric data \\ \hline
6947 &
\begin{tabular}{c} 76°46°33.0′′ N \\ 125°49°40.8′′ E \\ \end{tabular} & Laptev Sea & 72 & In situ study of bubbles by depth \\ \hline
6961 & \
\begin{tabular}{c} 74°59°31.8′′ N \\ 160°58°47.4′′ E \\ \end{tabular} & East Siberian Sea & 45.5 &
\begin{tabular}{c} Validation of classification, comparison of turbidimetric data \\ \end{tabular} \\ \hline
6962 &
\begin{tabular}{c} 74°59°25.2′′ N \\ 160°59°10.8′′ E \\ \end{tabular} & East Siberian Sea & 45.5 & In situ study of bubbles by depth \\ \hline
6975 & \
\begin{tabular}{c} 72°28°57.6′′ N \\ 130°32°16.8′′ E \\ \end{tabular} & Laptev Sea & 14.5 &
\begin{tabular}{c} In situ study of bubbles in the surface layer of the area of massive methane release \\ \end{tabular} \\ \hline
6995 &
\begin{tabular}{c} 77°54’00.0′′ N \\ 105°03’05.4′′ E \\ \end{tabular} & Vilkitsky Strait & 223 & Validation of classification \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Description of the AMK-82 stations. Figure 10: Map of the studied AMK-82 stations. Figure 11 shows the results of the DHC's performance on the registration of changes in the depth of concentrations of _Mesoplankton_, _Marine snow_, and _Suspension_ taxa at two stations. The comparison of the graphs shows that:  
* The measurements in the Kara Sea were taken near the Ob River estuary, which showed a very high content of the river-borne terrigenous suspension [65]. These factors determine the high turbidity of the water area and the reduced content of plankton;
* The water was more transparent, and there was more plankton in the Laptev Sea outside the area of the river flow. Tables 5 and 6 compare the results of plankton number measurements by sampling and analysis with the DHC measurements of plankton. The analysis of these tables shows that, along with some differences, the classification performed by different methods matches in most cases. Below are the most probable sources of mismatch related to the peculiarities of selection:  
1.