Sequoia Application Note SEQ-001-V1 Beam attenuation (c, [m-1]) is a critical inherent optical property (IOP) for oceanographers studying underwater visibility and suspended particles in the water column. Measuring beam attenuation in-situ requires transmissometers or attenuation meters, which employ...
PyOPIA (Python Ocean Particle Image Analysis) was introduced in 2023. It is an open-source Python library for combing through large amounts of particle image data collected by camera instruments such as LISST-Holo / LISST-Holo2, SilCam, UVP-6 and others. Using a standardized and user-customizable pipeline,...
You can integrate Sequoia’s LISST-Deep or LISST-200X onto a Sea-Bird CTD using the 6-pin auxiliary connector on the LISST connector endcap and a 2-m cable. This will power the instrument via the CTD and output two analog signals, one for mean particle size and one for total concentration for immediate...
There are several ocean science community-developed and supported software resources available for LISST and Hyper users interested in logging and/or processing data in other ways than supported by Sequoia’s standard software: PyOPIA PyOPIA is a Python-based ocean particle image analysis toolbox....
The Boycott effect refers to the substantial enhancement of particle sedimentation rates in settling columns that are inclined relative to gravity, compared to an otherwise identical vertical settling column. It was first observed experimentally by A. E. Boycott (1920) during studies of blood sedimentation,...
Measurements with Sequoia Scientific’s Hyper-a and Sea-Bird Scientific’s ac-s collected in East Sound, WA on May 20, 2024, during a period of strong Noctiluca scintillans bioluminescence The comparison is not strictly one-to-one, as the two instruments sampled slightly different water volumes. The...
Harmful algae. The phrasing itself almost seems it would be an oxymoron, like harmful carrots or something similar. But it is real: Given the right circumstances (light, nutrients), all algae can bloom and some of these can become Harmful Algae Blooms (HABs) if the algae can make toxins. It is most commonly...
A melting pot Researchers in oceanography come to the field from all sides: physicists, biologists, geologists, geographers, hydrologists, mathematicians and many more. As a result, there can be a confounding number of terms for the same thing. An example of this is how we name the various components...
Measuring trace contaminants in water is a challenging task. By definition, trace contaminants appear in very low concentrations. Accurate measurements require collection and filtration of large volumes of water with suspended particles (sediment) in order to collect enough material for analysis. The...
In the Beginning… In the 1960’s oceanographers started suggesting that sinking particles were a main source of food and nutrient delivery to deep-sea organisms. Researchers soon conceived and deployed sediment traps to investigate further (Wiebe et al., 1976). They quickly realized that the sediment...