Development of a coral monitoring system for the use of underwater vehicle

Abstract

The purpose of this research is to develop a coral monitoring system for the use of underwater vehicles. Reef coral is very sensitive about changes of ocean environment, such as unusual climate changes or increase of crown-of-thorns starfish resulting from the global warming. Coral can thus be an index of ocean environment. It is widely known that some kinds of corals have an inherent characteristic of fluorescence due to 'coral fluorescent protein (CFP).' The authors are developing an oceangoing solar-powered underwater glider, named 'Tonai60'. The operational depth of the Tonai60 glider is 60m, for ocean environmental monitoring in twilight ocean zone. The Tonai60 glider is equipped with an ocean-environment monitoring data logger 'RINKO-Profiler' of JFE Advantech Co., Ltd. and an underwater passive acoustic data logger 'A-tag' of Marine Micro Technology Corp. for monitoring marine mammals. Measuring items of RINKO-Profiler are depth, temperature, conductivity, salinity, dissolved oxygen, chlorophyll and turbidity. The glider is also equipped with a coral monitoring system at the forefront of its fuselage. This system consists of a network camera and 3-axis digital compass. Coral can be detected from an image binarised with a certain threshold. This paper deals with a coral monitoring system using ultraviolet LEDs and image analyses.

A Reliable Architecture for IoT-based Aquatic Monitoring System of Coral Reef and Algae

“…In the last decades, several methods have been developed to monitor or inspect aquatic life like coral reefs and algae, this includes using Autonomous Underwater Vehicles (AUV) [2,22], remote sensing system [1,23] and underwater sensors network [24]. A coral monitoring system particularly for the use of autonomous underwater vehicles (AUVs) has been developed [2] by using the ultraviolet LEDs and image analyses. In their system, the LabVIEW is developed using Google Maps and from the testing, consistent data and communication in the ocean condition has been successfully achieved.…”

“…This huge population needs to maintain a congenial environment so that the algae and coral reefs can grow healthily. Factors such as pollution due to vast development and climate change have harmed the environment such as water pollution [2]. Algae are the majority of coral reef communities [3].…”

“…Coral reefs are sensitive to climate change, and coral bleaching occurs as sea temperatures increase [2,4,5]. To note, the corals exposed to changes in salinity show higher survival than those exposed to changes in temperature and in freshwater that produces normal salinities much higher than the world average [6,7].…”

Current status and prospects of marine renewable energy applied in ocean robots

“…Solar‐powered ocean robots: A, solar‐powered autonomous underwater vehicle (SAUV) II; B, solar‐powered autonomous surface vehicle (SASV); C, solar‐powered unmanned surface vehicle (USV); D, solar‐powered underwater glider (UG) [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…In order to study the relationship between solar power supply system and laboratory environment, an experimental platform, SORA, has been established, with 3.48‐kg weight, 0.7‐m length, 0.73 m wide, and 0.205‐m height, to demonstrate the possibility of solar energy application in the UG . Subsequently, this team has developed a solar‐powered UG, Tonai60, to be applied to monitor shallow coral reefs, as shown in Figure D, with 92‐kg weight, 1.65‐m length, 1.03 m wide, height of 0.528 m. Tonai60 can dive to 60 m and was equipped with a network camera, a digital compass, and an environmental data logger, which can record the water depth, temperature, salinity, chlorophyll, turbidity, and other environmental data . Because of their unique driving principle and motion mode, the solar‐powered UG has to adjust their attitude to the level state on the water surface to achieve charging the batteries.…”