Bright blue: Advanced technologies for marine environmental monitoring and offshore energy

Major programs such as the Ocean Observatories Initiative (OOI) seek to increase societal understanding of subsurface marine environments. This interest has arisen because of environmental concerns related to degradation of marine habitats, climate change, as well as the globally increasing demand for marine natural resources, particularly food and energy. These pressures now affect marine systems at scales that require active management of marine environments. Nevertheless, our ability to monitor and perform even relatively simple operations in subsurface environments remains limited and costly because of technological limitations. This paper provides an overview of advanced platform, power generation, communications, and sensing technologies that are intended to enable high-resolution environmental monitoring, real-time field surveillance, subsea infrastructure operation and maintenance, and unattended robotic intervention for event response. Among these technologies are new modes of subsea communication that can provide long-range and high-bandwidth data transfer for geographically dispersed instrumentation with real-time data communications on the seafloor. The WHOI Optical Modem has demonstrated high-bandwidth (>10Mb/s) wireless data transfer across ranges exceeding 100 meters. The LoRELi (Long Range Extension Link) operates on less than 0.2 Watts and is capable of medium-bandwidth (>100kb/s) data transfer across hundreds of kilometers without repeater nodes. The Nereus hybrid remotely operated vehicle (HROV) is a next generation robotic platform utilizing advanced materials and technologies that enable operation at extreme depths (to 11km) and at lateral standoff distances of several kilometers. These vehicle characteristics enable long-range reconnaissance and light intervention without dynamic ship positioning or large traction winches for the vehicle tether. TETHYS (TETHered Yearlong Spectrometer) is an in-situ mass spectrometer that has demonstrated operation on a variety of platforms, including tethered observatory nodes, towed ship cables, remotely operated vehicles, autonomous underwater vehicles, and human occupied submersibles. The TETHYS instrument can autonomously identify and accurately quantify dissolved gases and volatile chemicals at trace levels (to less than 1 part-per-billion) in depths throughout most of the earth's oceans and across temporal scales ranging from seconds to months. TETHYS has enabled new methods of dissolved gas analysis for scientific and ecological investigations as well as environmental cleanup operations in the aftermath of chemical spills. The Flip Wing benthic turbine is a hydrokinetic power generation system designed for operation on deep (~1km) subsurface buoys enabling low power recharge (1-10Watts) from low velocity (3-20cm/s) benthic currents. This turbine provides a mechanism for long-term operation of subsurface sensor nodes, or periodic recharge of high-power devices such as AUVs without need for a shore power cable or large (>10kWHr) battery pack. Individually, each of these technologies provides significant advancement within its respective area of sensing, robotics, communications, and endurance. Used in combination for observation and inspection, such as for deep offshore petroleum production or ecological monitoring located at substantial distances offshore, these technologies can provide large gains in efficiency while also reducing operation costs. The technologies presented here are particularly valuable for emerging uses, including security/defense applications, subsurface infrastructure completion for energy production, and offshore carbon capture and storage (CCS) because these operations require continuous real-time surveillance and long-term unattended operation. We present scenarios illustrating how these advanced technologies can be implemented, then compare these approaches with conventional methods and evaluate their potential advantages.