Marine snow is a composite of mostly organic material made from dead plant and animal debris that drifts down into the deeper ocean. The flux of the particulates is important in understanding the biological pump in the carbon cycle.
Atmospheric and ocean surface interactions lead to the upper layer of the oceans absorbing CO2 gas. Phytoplankton absorbs CO2 in a biological process. A complex biological interaction throughout the ocean column ultimately leads to carbon diffusing through the water column to greater depths. The combination of biological processes creates a carbon sink out of the oceans. Providing quantitative data of the ocean snow leads to a better understanding of ecological processes, chemical interactions and air-sea interactions. Data gathered from the Snow-Cam can potentially be used to explain how much carbon the oceans absorb from the atmosphere. Carbon absorption rates of oceans are significant contributors to climate change, leading to a better understanding of global warming.
The objective of the proposed project is to design a device that analyzes the natural flux of marine snow. The device consists of an array of five vertically aligned cameras in a submersible tube sinking at a constant rate. Upon descent, each camera simultaneously takes pictures of snow particles within an area of interest. These images are collected and stored digitally, providing data for analysis.
The device is comprised of two vertical cylinders mechanically coupled together. One cylinder contains cameras and sensors. The other cylinder consists of a power and lighting system. The scale of the device was relatively small and portable, approximately one meter in length. Due to Snow-Cam being made from off the shelf components and materials, it is relatively inexpensive to produce.
The small prototype was able to withstand pressures at depths of up to 200 meters. The pictures taken were of good quality and were in focus. Images taken for the final model used narrow lenses. Although not as clear of a picture as the wide angle, the narrow lenses removed the fish-eye effect caused by the stock lenses.
At a distance of 1 m, the cameras with the new lenses were able to clearly focus at test particles of 0.8128 mm in diameter. The fields of view of the cameras are 17.33º horizontal, 13.04º vertical. These angles matched and were in range of the illumination area produced by the LEDs, which were found to be 20.16º.
Micro-controller, lights, cameras, and sensors were all powered by the battery system and mounted in their respective cylinders. With the bracket system installed, Snow-Cam was able to successfully take pictures as an autonomous profiler.