LISST Particle Analysis & Zooplankton Monitoring
High-resolution particle size distribution and zooplankton monitoring using ROV-deployed LISST sensors — quantifying fine particles, turbidity sources, and plankton communities throughout the water column to 500 meters depth
Call (775) 230-1116 Request ProposalThe Fine Particle & Plankton Data Gap
Water clarity degradation, turbidity sources, and plankton dynamics often involve particles too small for traditional sampling methods and organisms distributed across depths conventional equipment can’t access. Without in-situ particle analysis and depth-stratified plankton data, management decisions lack the resolution needed to identify causes and evaluate solutions.
⚠️ What Traditional Methods Miss
Discrete Water Samples: Bottle samples provide a single point in space and time. Particle aggregation and disaggregation during sample retrieval alter size distributions. By the time samples reach the lab, they don’t represent in-situ conditions.
Surface-Only Measurements: Plankton distributions are rarely uniform. Deep chlorophyll maxima, zooplankton vertical migration, and stratified particle layers occur at depths that surface sampling misses entirely.
Insufficient Resolution: Traditional transmissometers provide bulk turbidity but can’t distinguish between clay-sized inorganic particles, algal cells, and zooplankton — yet management needs to know which particle type is causing water quality degradation.
🔬 LISST Technology: In-Situ Particle Sizing
LISST (Laser In-Situ Scattering and Transmissometry) instruments use laser diffraction to measure particle size distribution in real-time underwater — providing data impossible to obtain through traditional sampling.
How LISST Works
A collimated laser beam passes through the water. Particles scatter light at angles inversely proportional to their size. A detector array measures the scattered light pattern, and algorithms compute particle size distribution across 32 logarithmically-spaced size classes from 1.25–500 micrometers.
- Non-invasive: Measures particles undisturbed in natural state
- Real-time: Data every 1-2 seconds during profiling
- High resolution: 32 size classes across full range
- Volume concentration: µL/L for each size class
- Total volume: Integrated across all size classes
- Optical transmission: Beam attenuation coefficient
What LISST Reveals
- Particle size distribution: Clay vs silt vs fine sand fractions
- Turbidity sources: Distinguish inorganic particles from algae
- Flocculation dynamics: Particle aggregation and settling
- Zooplankton communities: Size classes 200-500µm indicate zooplankton
- Deep particle layers: Identify depth of maximum particle concentration
- Temporal dynamics: Track particle size changes over time
- Vertical structure: Map particle stratification throughout water column
💡 ROV Deployment Advantage
Most LISST deployments use free-falling profilers or fixed mooring installations. Our ROV-mounted LISST provides precise positioning control, extended deployment duration, and the ability to target specific features (thermoclines, deep chlorophyll layers, particle plumes) identified in real-time during the mission. The ROV can hold station at any depth for extended LISST measurements or execute controlled horizontal transects to map spatial variability.
LISST & Plankton Monitoring Services
📊 Vertical Particle Profiling
High-resolution LISST profiles from surface to 500 meters depth, providing particle size distribution at 0.1-meter vertical intervals throughout the entire water column.
- Continuous profiling at controlled descent rates
- Particle size distribution at every depth increment
- Total particle volume concentration
- Optical transmission (beam attenuation)
- Identification of particle maximum layers
- Co-located CTD data (temperature, salinity, depth)
🗺️ Horizontal Particle Mapping
ROV-executed horizontal transects at fixed depths to map spatial variability in particle size distribution across survey areas — identifying sources, plumes, and transport pathways.
- GPS-tracked horizontal transects
- Constant-depth autonomous navigation
- Particle concentration mapping
- Plume detection and characterization
- Source identification (rivers, resuspension, blooms)
- Transport pathway documentation
🦐 Zooplankton Community Analysis
LISST data in the 200–500µm size range provides proxy estimates of zooplankton abundance and vertical distribution, complemented by traditional net tows for species identification.
- Zooplankton size class abundance (LISST)
- Vertical migration pattern documentation
- Deep-water community profiling
- Diel vertical migration tracking
- Coordinated net tow sample collection
- Species identification and enumeration (lab analysis)
🪨 Fine Sediment Transport Studies
Document fine particle (<63µm) introduction, transport, and fate using LISST time-series and spatial surveys — critical for understanding turbidity sources and sediment delivery to lakes and reservoirs.
- Pre/post-event particle size analysis
- Flocculation and aggregation quantification
- Settling velocity estimation
- Residence time calculations
- Watershed input characterization
- BMP effectiveness monitoring
Research & Management Applications
💎 Water Clarity Studies
Quantify particle size distribution throughout the water column to determine which particle types (clay, silt, algae, zooplankton) contribute most to light attenuation and clarity loss.
🌊 Turbidity Source Identification
Distinguish between inorganic sediment, phytoplankton, and zooplankton contributions to turbidity using particle size signatures and vertical distribution patterns.
🔄 Nutrient Cycling
Document zooplankton vertical migration and grazing impacts on phytoplankton populations — key drivers of nutrient cycling and water quality in stratified systems.
📈 Restoration Effectiveness
Track changes in particle size distribution and plankton communities before and after management actions — providing quantitative measures of restoration success.
🏗️ BMP Evaluation
Measure fine particle reduction following implementation of erosion control or watershed BMPs using LISST to detect changes in <63µm fraction delivery.
🧪 Model Calibration
LISST-derived particle size distributions and settling velocities provide critical parameters for calibrating water quality models and sediment transport simulations.
Why Agencies Choose Our LISST Services
🤖 ROV-Mounted Advantage
Unlike free-falling profilers or fixed moorings, our ROV provides precise positioning control, extended deployment duration, and the ability to target specific features identified in real-time. We can hold station at exact depths for extended measurements or execute controlled transects.
📊 High-Quality Data
We follow established LISST protocols for calibration, deployment, and data processing. QA/QC procedures include background correction, beam attenuation verification, and inversion algorithm validation to ensure defensible results.
🏔️ Deep-Water Capability
500-meter ROV depth rating provides access to deep lakes, reservoirs, and offshore environments where particle dynamics and plankton communities remain unstudied due to depth limitations of conventional sampling.
🔬 Integrated Approach
LISST data is most powerful when combined with other sensors. We integrate CTD, fluorometry, transmissometry, and traditional plankton net tows to provide comprehensive characterization of particle and plankton dynamics.
What You Receive
📦 Standard LISST Project Deliverables
- Raw LISST Data Files: Native instrument format with all metadata
- Processed Particle Size Distributions: Volume concentration by size class
- Vertical Profile Plots: Depth vs particle concentration, size classes, transmission
- Size Distribution Spectra: Surface, mid-depth, and bottom characterization
- Horizontal Maps: Spatial distribution of particle parameters (GIS-compatible)
- Statistical Summary: Mean, median, mode particle sizes by depth or zone
- Technical Report: Methods, QA/QC, results, interpretation, recommendations
- Coordinated Plankton Data: Net tow results, microscopy, species identification
Ready for High-Resolution Particle Analysis?
ROV-deployed LISST provides data that conventional sampling methods can’t match. Let’s discuss your monitoring objectives.
(775) 230-1116Call or email Scott at DiveRobotix
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