September 2019
Name: Benjamin Grassian
Department: Graduate School of Oceanography
School: University of Rhode Island
Project: Evaluation of a novel profiling echosounder for detailed observation of midwater environments
Research Advisor: Dr. Chris Roman
Ben Grassian is a PhD student in oceanography at the University of Rhode Island’s Graduate School of Oceanography. In graduate school he is working to derive detailed observation of plankton and nekton assemblages using optical and acoustic sensor platforms. Ben received a bachelor’s in Biology and Marine Science from the University of Miami and Rosenstiel School of Marine of Atmospheric Science (RSMAS). While at RSMAS, Ben worked with a towed plankton imaging system, ISIIS (in situ ichthyoplankton imaging system) to determine the species-specific distributions of gelatinous zooplankton communities in the upper water column and helped to provide the first evidence of ontogenetic migration in a ctenophore species. He was also part of a coral reef ecology lab at RSMAS examining the complex dynamics of coral reef bioerosion in the eastern tropical Pacific. After finishing these projects, Ben joined Dr. Chris Roman’s marine robotics lab for his graduate research to continue pursuing the technology-enabled study of fine to submesoscale ecosystem dynamics within the water column. Since joining the Roman lab, he has developed software to perform autonomous data mining of stereo image water column profiles to construct 3-D biological datasets coupled to environmental sensors and shipboard echosounder surveys. He is using these tools to describe micronekton thin layers in oxygen minimum zones. Going forward, funding from the Link Foundation will allow Ben to develop the acoustic sampling capabilities of the Wire Flyer, a new vehicle that is able to perform repeat profiling with three or more times the horizontal resolution of other towed undulating systems. By designing sensor fusion methods to assimilate in three dimensions the unique side-looking acoustic backscatter information from a dual frequency echosounder integrated into the vehicle, and determining the acoustic data quality as a function of the vehicle trajectories and transceiver configurations, Ben will be able to develop the Wire Flyer as a novel tool for assessing the distributions and diel patterns of midwater organisms as they relate to fine scale water column features. Biological processes in midwater habitats are critical drivers of ocean biogeochemical cycling, oxygen availability, fish population dynamics, and ecological interactions over a wide range of scales. Traditional sampling platforms are often unable to resolve marine biota at scales comparable to the variability in their physical environment. The biological and matching environmental data collected by this new system will be of novel resolutions desirable for elucidating the manners and drivers of organismal distributions in the undersampled and vast midwater realm.
Name: Alexandre Immas
Department: Mechanical Engineering
School: University of California, Berkeley
Project: High-Bandwidth Underwater Wireless Communication using a swarm of Autonomous Underwater Vehicles
Research Advisor: Associate Professor Reza Alam
Alexandre Immas is a PhD Candidate in Mechanical Engineering at UC Berkeley within the Ocean Engineering group. He was previously senior team leader at Nenuphar Wind, a start-up developing a new offshore wind turbine for deep water. He holds a Master of Science in Mechanical Engineering from UC Berkeley and a Master of Science and Bachelor of Science in Mechanical Engineering and Physics from Ecole Polytechnique. His PhD dissertation will contribute to the development of a new method for underwater wireless communication with high bandwidth. A swarm of Autonomous Underwater Vehicles (AUVs) is used to relay an optical signal between two or more points at any distance. Each vehicle is equipped with multiple attitude stabilization systems to reach the required pointing and tracking accuracy for optical communication. The swarm of AUVs can be used to create an underwater communication link between a mother ship and Remotely Operated Vehicle(s) or it can be used as a monitoring system. With the support of the Link Foundation, Alexandre’s research goal is to develop and test a control strategy for the swarm of AUVs to maximize the communication link autonomy while ensuring its robustness. This highly nonlinear problem can be solved using convex optimization, model predictive control and deep learning. The outcome of Alexandre’s project will be an important milestone towards reliable underwater wireless data communication with high-bandwidth, which constitutes one of the most important outstanding problems in ocean exploration. Lack of underwater wireless communication has left our oceans mostly unexplored. In fact, it is known that only 5% of the world's oceans have been explored so far. We know about stars billions of light-years far away a lot more than what we know about the depth of the oceans. The unsuccessful search for MH370 aircraft that has been ongoing for more than four years shows a glimpse of how limited our today's capabilities are. Once this technology is developed, it would be a matter of days, if not hours, to locate anything lying on the seabed.
Name: Saksham Gakhar
Department: Civil and Environmental Engineering Department
School: Stanford University
Project: Bathymetric Inversion from Free-Surface Signatures Using Drone-deployable Infrared Optical Profilometry (DIROP)
Research Advisor: Prof. Jeffrey Koseff and Prof. Nicholas Ouellette
Saksham Gakhar is a PhD student in the Environmental Fluid Mechanics and Hydrology program at Stanford University. He obtained his Master’s degree in the same program in April 2019. Before joining Stanford, he graduated from Indian Institute of Technology (IIT) Bombay, India in 2017 with Bachelor of Technology (Honors) in Mechanical Engineering and Minor in Computer Science and Engineering. Saksham’s research focuses on small-scale remote sensing of bathymetry from free-surface signatures in the littoral environment where the hydrodynamic flow is turbulent and shallow. Saksham is developing field-deployable remote sensing techniques that leverage advanced optical metrology to map the free-surface deformation of both optically transparent and opaque flows on heretofore unresolved spatiotemporal scales. One such technique that he is working on is Drone-deployable Infrared Optical Profilometry (DIROP). DIROP has several advantages over techniques such as satellite imagery or LiDAR: first, it requires no addition of tracers to the flow. Second, DIROP will not require the ability to see through the water column making it deployable for both turbid and transparent flows. Third, completely non-intrusive, DIROP will not require the placement of any instrumentation in the water column. Finally, DIROP will have sufficient dynamic range and will be capable of measuring the free-surface deformation field with high precision for relatively small (~meter scale or less) sized features that satellite imagery simply cannot resolve. With the help of the techniques he develops and the investigation of the physical link between a bedform and its surface manifestation in shallow flows, Saksham’s work will ultimately enable the inference of bedforms using only free-surface imagery. This will help with the mapping of bathymetric features and bedforms such as submerged vegetation canopies, dunes, coral reefs, and other benthic communities. This mapping is then crucial for naval applications, modeling, tidal simulations and coastal restoration efforts.
Name: Ben Hurwitz
Department: Ocean Science and Engineering, School of Earth and Atmospheric Sciences
School: Georgia Institute of Technology
Project: CTD-on-a-Chip: Enabling Polar In-Situ Ice-Ocean Data Collection
Research Advisor: Dr. Britney Schmidt
Ben Hurwitz is a PhD candidate in the Ocean Science and Engineering program under the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. He has previous degrees in mathematical science from Colby College in 2011, and in electrical engineering from the University of Maryland at College Park in 2017, where he was involved with sensor development and nanofabrication, including development of digital microfluidic nanoelectrode arrays, and design and fabrication of nano-scale integrated circuits. At Georgia Tech, Ben has been working as a member of the electrical engineering team for the NASA-funded PSTAR program “Ross Ice Shelf and Europa Underwater Probe” (RISE-UP), an interdisciplinary team of engineers and scientists developing an autonomous under-ice vehicle called Icefin to explore beneath the Antarctic ice shelves. This effort is collecting important oceanographic data both for polar and climate sciences while studying the under-ice environment as an astrobiological analogue to Europa and other icy planetary bodies. The Link Fellowship will fund work on a microscale CTD that will enable lower-power instrumentation for oceanographic measurements at a smaller size and weight while maintaining the high accuracy and resolution of currently deployed devices. These smaller scale instruments will encourage use on a wider variety of platforms, such as smaller vehicles and floats, while taking advantage of the economies of scale inherent in modern day nanoscale fabrication to significantly lower costs, leading to lower barriers to entry for both academics and citizen scientists. This type of research will also inform future miniaturization of oceanographic instrumentation towards similar goals, enhancing our data collection of the Earth system for future ocean and climate modeling. Further into the future, missions to ocean worlds, such as Europa or Titan, will require oceanographic instruments to meet their scientific goals, but these must fit into the low-weight, -size, and -power requirements that spacecraft operate with. Miniaturization of sensors and devices will therefore be critical to the long term success of oceanographic data collection both here on Earth and on other planetary bodies in our solar system.
If you would like to find out more about our Link Foundation Ocean Engineering and Instrumentation Fellows and projects that have been funded in the field of Ocean Engineering and Instrumentation by the Link Foundation, please visit the Link Ocean Engineering and Instrumentation webpage at http://www.linkoe.org/.