# Internet of Things in Marine Environment Monitoring: A Review
## 6 Conclusions  
During the past couple of decades, marine environment monitoring has attracted wide attention. Governments and research organizations have heavily invested in the research and development of new technologies in this area. Advanced information and communication technologies have been applied to the development of various marine environment monitoring technologies and systems. Internet of Things has played an important role in this area. This paper presents an updated review of the related technologies and systems on the application of the Internet of Things in marine environment monitoring.  
A comprehensive review of about 40 related projects revealed that most systems and applications developed thus far are for ocean sensing and monitoring and water quality monitoring. Some specific efforts have been made for fish farm monitoring, coral reef monitoring, wave and current monitoring. Several projects focused on specific technologies or devices like buoys, energy saving and harvesting devices, routing protocols, data transmitting mechanisms, and data analysis techniques.  
It can also be noted that testing places are very much different among these projects. About half of the developed systems have been tested or deployed in real marine or river environments; a number of them were experimented in lab settings or indoor environments; a few others were tested in outdoor pools or small ponds and lakes; and several of them were only tested through simulations.  
While most systems use GPRS and/or ZigBee for wireless communication, a few systems used underwater acoustic communication.  
Emerging offshore and deep-sea fish farming provides more opportunities and also challenges, not only for marine environment monitoring but also for operation controls and marine environment protection, which is a new area of research.  
The energy management issue is mainly considered from two aspects: Reducing energy consumption and using alternative renewable energy sources. Optimizing network topologies and developing advanced routing protocols are the ways to reduce energy consumption. Even though many researchers discussed different options for energy harvesting including solar, wind, waves and ocean currents as alternative renewable energy sources, only solar energy has been used in about a third of the developed systems.  
The results of Big Data analytics can be used not only for feedback to marine environment management agencies and control centers for quick decision making and real time manual interventions but also for autonomous vessels and remotely deployed devices to take real time actions in order to protect the marine environment from some disasters (e.g., oil spills and bad weather). It is a growing area of research and development.  
This review also identified several research challenges and opportunities, including energy management, standardization of system platforms and technologies, and marine environment protection measures.  
All the co-authors have contributed to the conceptualization of the paper and the review of the cited references. As the first author, [PERSON] prepared the first draft based on his previously published survey paper. [PERSON] searched and collected the most recent references and provided a first review of these references. [PERSON] contributed to the review of new IoT and wireless communication technologies. [PERSON] defined the paper structure, re-organized the content, and edited the whole paper.  
This work was supported in part by the Science Foundation for Enhancing School with Innovation of Guangdong Ocean University (Grant Nos. GDOU2015050207).  
No conflict of interests exits in the submission of this manuscript, and the manuscript has been approved by all the co-authors for publication. We would also like to declare that the work described in this paper is original and it has not been published previously, and not under consideration for publication elsewhere, in whole or in part.