Offshore Industry News

Sequoia Delivers NASA-Funded Prototype LISST Instrument for Research Vessels

Ushering in 2019 with an R&D milestone, Sequoia Scientific, Inc. has completed a NASA-sponsored Phase II Small Business Innovation Research (SBIR) project spearheaded by Principle Investigator Dr. Wayne Slade.

Sequoia’s Dr. Slade caught the interest of NASA program managers with his proposal for an instrument designed for continuous and automated measurement of suspended particle size distribution (PSD) in flow-through systems. PSD is a key environmental parameter with diverse biogeochemical applicability, and estimation of particle size is a goal of next generation ocean color remote sensors. However, presently, PSD variability in the ocean is not well understood due to the challenges of routine measurement, thus minimal ground truth data exists for ocean color validation efforts.

Dr. Slade aims to bridge the known data gap with his design of the new LISST-Horizon instrument. Initially known as the Flow through Extended Range Particle Sizer (FERPS), the LISST-Horizon is designed for installation in ship-based flow-through systems, allowing for collection of PSD data over large space and time scales. The LISST-Horizon uses laser scattering to estimate PSD across a wide range of particle sizes from submicron to hundreds of microns, covering pico- to mesoplankton size scales. This week a prototype LISST-Horizon instrument has been delivered to NASA for testing.

The LISST-Horizon is a self-contained instrument for bench-top deployment in a research vessel laboratory. Plumbed to continuous underway uncontaminated seawater, it continuously measures PSD and particle concentration, as well as inherent optical properties (IOPs) beam attenuation (c) and volume scattering function (VSF, β) at 520 nm. From these IOPs, scattering (b), backscattering (bb), backscattering ratio (bb/b), and by difference, absorption (a = c – b), can be derived. LISST-Horizon is configured and controlled via a touch-panel graphical user interface, data and logs are accessed via a network connection, and the instrument’s raw data files are processed and viewed on a PC using included software.

LISST-Horizon has wide applicability in the field of ocean optics, ocean biology, and biogeochemistry; and currently no purpose-built systems exist for underway measurement of PSD on research vessels. Methods currently used in oceanographic settings are time-consuming, expensive and non-automated. The LISST-Horizon will therefore be an attractive option for particle size measurement and advancing the state of the art in ocean color and biogeochemistry.

For more information about the LISST-Horizon prototype, contact Sequoia’s sales & marketing manager Jim Decker: jim.decker [at]

Story by Sequoia Scientific

Sequoia designs and manufactures the LISST series of laser, holographic and acoustic instruments and sensors - used worldwide since 1995 for marine, freshwater, environmental, energy and industrial applications. For more information, click here.

Our Partners

Frontiers in Marine Science

ECO Magazine is a marine science trade publication committed to bringing scientists and professionals the latest ground-breaking research, industry news, and job opportunities from around the world.


8502 SW Kansas Ave
Stuart, FL 34997

Newsletter Signup

The ECO Newsletter is a weekly email featuring the Top 10 stories of the past seven days, providing readers with a convenient way to stay abreast on the latest ocean science and industry news.