Real-Time Harmful
Algal Bloom Detection
Continuous lake monitoring backed by Woods Hole Oceanographic Institution science — early detection and decision-grade insight, with transparent confidence.
Join Our 2026 Freshwater Harmful Algal Bloom Pilot
After a successful 2025 pilot season across four kettle ponds on Cape Cod, we’re expanding our freshwater harmful algal bloom program nationwide in 2026. Pilot partners receive real-time bloom detection, alerts, and scientifically grounded insight into likely bloom drivers to support lake health, safety decisions, and long-term management.
Across pilot lakes, we study recurring bloom patterns to better understand what tends to drive blooms under different lake conditions. As a pilot program, we analyze multiple lakes together to improve confidence in these insights over time.
Program Overview
24/7 Continuous Lake Monitoring
Each lake receives a solar-powered multi-depth buoy streaming real-time cyanobacteria activity, dissolved oxygen, temperature, conductivity, light/PAR, and wave/stratification dynamics along with integrated meteorological data.
Real-Time Alerts & Dashboard
Optional text/email alerts notify partners as bloom conditions evolve. An intuitive online dashboard tracks bloom status, seasonal trends, and key environmental drivers—providing timely visibility into lake conditions and supporting informed management and public-safety decisions.
Season-End Driver Memo (with Confidence Levels)
At the end of the season, partners receive a clear, plain-language summary of what appears to be driving bloom activity in their lake, how confident we are in those insights, and what additional information would help increase certainty. The goal is to help narrow management decisions — not to overstate conclusions. For lakes where decisions hinge on distinguishing between plausible drivers, we may recommend optional targeted diagnostics (e.g., customer-collected sampling sent to a lab and/or watershed/GIS screening).
How we build confidence
Continuous sensing & HAB event detection
Optional targeted diagnostics (water sampling with lab analysis and GIS watershed analysis data)
Scientist review & transparent confidence levels
Case Studies & Partners
Real deployments. Actionable insights aquatic systems.
2025 Freshwater Harmful Algal Bloom Pilot. Cape Cod, MA | 4 Lakes
In 2025, Subtidal deployed continuous monitoring systems across four freshwater lakes to detect harmful algal blooms (HABs) and assess causal mechanisms and overall lake health. Our pilot successfully detected cyanobacterial activity and tracked key water quality, stratification, and environmental drivers influencing bloom dynamics. By integrating real-time lake data with local climate and weather conditions, we helped partners better understand bloom mechanisms, timing, and risk.
This pilot forms the foundation of Subtidal’s expanded 2026 Freshwater HAB Program for lake associations and municipalities.
Waquoit Bay Algal Mats
Waquoit Bay is experiencing widespread algal mat coverage, and local stakeholders are mobilizing to identify and remediate root causes. We’re partnering with WBNERR to pinpoint bloom drivers and inform practical remediation strategies.
Read the Cape News article to learn more »
GreenWave Kelp Marine Carbon Removal Measurement, Long Island Sound
As part of a two-year R&D deployment in conjunction with GreenWave and Schmidt Marine Technology Partners, we completed 5-week pilot this spring analyzing the total carbon removal potential of GreenWave’s kelp farms and contributors to fertile, productive kelp farms.
Partners
Subtidal partners with lake associations, municipalities, and research organizations to deliver real-time freshwater harmful algal bloom monitoring and actionable lake and marine ecosystem insights.
These deployments inform the design of Subtidal’s 2026 Freshwater Harmful Algal Bloom Pilot, expanding real-time monitoring to more lakes and communities.
Proven Marine & Coastal Deployments
Our monitoring systems are field-tested in some of the toughest marine environments, and this proven platform underpins our freshwater lake and harmful algal bloom (HAB) deployments.
Rugged, Field-Tested Systems: 18+ months of continuous operation through gale-force winds and complete ice cover.
Comprehensive Environmental Monitoring: Measurement of waves, currents, wind speed and direction, humidity, temperature, and water chemistry — with sensing configurations adapted for both marine and freshwater environments.
Carbon Removal & Growth Metrics for Kelp Farms: Partnering with GreenWave in Long Island Sound to measure carbon sequestration potential and track drivers of healthy kelp growth, including nutrient flux, light, and temperature. This work was initially supported by the National Science Foundation (NSF) and the Department of Energy (DOE), with continued support from Schmidt Marine Technology Partners.
Waquoit Bay Deployment (WBNERR / NOAA): Partnering to identify drivers of marine algal mats, inform local remediation strategies, and validate Subtidal’s monitoring technology against NOAA gold-standard observing stations.
Meet Our Team
At Subtidal, we’re united by our passion for the oceans, regeneration, and data-driven innovation. A proud spinout from the world-renowned Woods Hole Oceanographic Institution, we leverage 20 years of deep expertise from our Co-Founder & Chief Scientific Officer, Dr. Matt H. Long, who pioneered advanced marine carbon and ecosystem monitoring solutions.
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CO-FOUNDER & CEO
Casey has spent the last 15 years building startups with a social good. She was formerly COO @ Greener Grazing, where her team was working to eliminate methane in cows through ocean-based Asparagopsis seaweed farming, and was previously Head of Product @ Spire, the first wearable to track mental and physical health via respiratory monitoring. She was named Most Influential Foreigner in China in 2010 for founding China’s first person-to-person microfinance platform, Wokai.
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CO-FOUNDER & CHIEF SCIENTIFIC OFFICER
Matt has spent the last 15 years figuring out how to solve hard carbon flux measurement problems in our oceans. Hailing from Woods Hole Oceanographic Institution (WHOI), Matt is a world leader in biogeochemistry, ocean engineering, and fluid dynamics to combine existing technologies to create transformational ocean technologies.