With the ocean covering more than 70% of the Earth's surface, the National Oceanic and Atmospheric Administration (NOAA) said scientists and researchers had depended on sonar (声呐) technologies to understand and map the sea floor which had charted only about 10% of the world's ocean. For the ocean and coastal waters in the US, the number is just around 35%.
We know less about our planet's ocean than what we know about the far side of the moon or the surface of Mars. Part of the reason for the lack of observation is the challenge of powering an underwater camera. Researchers have used ships to recharge cameras or observed with a camera tied to a ship to solve the issue, which is expensive and unsuitable for long-term observations.
Recently, researchers at the Massachusetts Institute of Technology (MIT) have taken a major step to iron out this problem by developing a battery-free, wireless underwater camera that could harvest energy underwater on its own for long periods.
To keep power consumption as low as possible, the researchers used off-the-shelf, ultra-low-power imaging sensors. The device takes color photos, even in dark underwater environments, and sends image data wirelessly through the water.
The camera is powered by sound. It changes mechanical energy from sound waves traveling through water into electrical energy that powers its imaging and communications equipment. After getting and encoding image data, the camera also uses sound waves to send the data to a receiver that reconstructs the image. Those sound waves could come from any source, like a passing ship or marine life. As it doesn't need a power source, the camera could run for weeks on end before getting it back, enabling scientists to search remote parts of the ocean for new species.
Now that researchers have demonstrated a working prototype (原型), they plan to enhance the device so it is practical in real-world settings. For future application, these cameras may be used to take images of ocean pollution and create more accurate models to monitor climate change to better understand how climate change impacts the underwater world, and advance various undersea scientific fields.
