Access comprehensive scientific data spanning decades of Great Lakes research. Our database contains over 2.4 million data points from all five lakes — physical measurements, chemical analysis, biological surveys, and historical records that power scientific discovery and environmental protection.
Each lake tells its own story through data. Our profiles capture the unique characteristics that define Superior, Huron, Michigan, Erie, and Ontario — from thermal stratification patterns to nutrient cycling dynamics. Want to understand why Lake Erie experiences algal blooms while Superior remains pristine? The answers lie in our detailed lake-specific datasets.
The largest and deepest lake. Maximum depth: 406.3 meters. Average temperature: 4.2°C. Contains 10% of the world's fresh surface water — nearly 12,100 cubic kilometers.
Second largest by surface area. Famous for Georgian Bay's 30,000 islands. Average depth: 59 meters. Home to the world's largest freshwater sand dunes along its eastern shore.
The only Great Lake entirely within U.S. borders. Surface area: 58,016 square kilometers. Known for dramatic temperature variations — surface waters reach 24°C in summer.
The shallowest and warmest lake (average depth: 19 meters). Most productive for commercial fishing. Experiences significant seasonal ice cover — up to 85% in severe winters.
Smallest by surface area but second deepest (maximum: 244 meters). Rarely freezes completely due to its depth. Contains 1,640 cubic kilometers of water.
Temperature, depth, currents, ice coverage — the physical properties that shape each lake's behavior. Our sensors record water temperature at 47 different depths across all lakes. Why does this matter? Because a 2°C temperature shift can trigger massive ecosystem changes.
Lake Superior takes six months to warm up each spring — its massive volume creates thermal inertia that influences regional weather patterns. Meanwhile, shallow Lake Erie can warm 8°C in just three weeks during May.
Detailed lake bottom mapping reveals underwater canyons, ridges, and basins that influence water circulation. Lake Huron's Alpena-Amberley Ridge creates a natural barrier that affects nutrient distribution throughout the entire lake system.
Every drop tells a story. pH levels, dissolved oxygen, phosphorus concentrations, trace metals — we track 89 different chemical parameters. Our automated buoys collect samples every 15 minutes, creating an unprecedented record of water chemistry changes.
Phosphorus concentrations range from 3.2 μg/L in Lake Superior to 18.7 μg/L in Lake Erie. These seemingly small differences determine whether a lake stays clear or experiences harmful algal blooms.
Great Lakes maintain a pH between 7.8 and 8.2 — slightly alkaline. But climate change and atmospheric deposition are slowly lowering these values at a rate of 0.02 units per decade.
Oxygen levels vary dramatically with depth and season. Surface waters reach 14-16 mg/L in winter, while deep Erie waters can drop below 2 mg/L during summer stratification.
Legacy pollutants like PCBs persist in sediments decades after their ban. Current levels: 0.3-2.1 ng/L across the lakes. We also monitor emerging contaminants — pharmaceuticals, microplastics, and per- and polyfluoroalkyl substances (PFAS) that weren't even known when monitoring began.
Life in the Great Lakes — from microscopic phytoplankton to 200-pound lake trout. Our biological monitoring captures population dynamics, species diversity, and food web relationships. Did you know that zebra mussels can filter the entire volume of western Lake Erie in just four days?
Complete species counts for each lake: 79 fish species, 1,247 invertebrate species, and over 2,800 algae and plant species. But these numbers change constantly as invasive species arrive and native populations shift.
186 non-native species now call the Great Lakes home. Round gobies reached densities of 340 individuals per square meter in some areas — completely reshaping bottom-dwelling communities.
Lake trout populations are slowly recovering after near-extinction. Current biomass: 2.3 million pounds across all lakes, up from just 84,000 pounds in the 1960s.
Context matters. Our archives stretch back to 1918 — nearly a century of observations that reveal long-term trends invisible in short-term studies. Ice coverage in the 1970s averaged 38% across all lakes; today it's just 22%. These records document environmental change in unprecedented detail.
Surface water temperatures have increased 2.3°C since 1973 — faster than air temperatures. Winter ice duration has shortened by 24 days. These changes affect everything from fish spawning success to harmful algal bloom timing.
Detailed measurements since 1918 show cycles of high and low water. The 2013 record lows in Huron-Michigan (175.57 meters) were followed by record highs in 2020 (177.02 meters).
Wave height measurements document increasing storm intensity. Storms with waves over 6 meters now occur 31% more frequently than in the 1980s.
Annual precipitation has increased 9% since 1950, but seasonal distribution has changed dramatically — wetter springs, drier summers, more intense fall storms.
The data tells a story of recovery. Phosphorus levels in Lake Erie peaked at 28.6 μg/L in 1975, then dropped to 11.2 μg/L by 1995 following pollution controls. Recent increases (back to 18.7 μg/L) highlight the ongoing challenges of agricultural runoff management.
Why does Lake Superior support lake trout while Lake Erie struggles with algae? Comparative analysis reveals the connections between physical, chemical, and biological factors. Our data visualization tools make these complex relationships accessible to researchers, policymakers, and curious citizens.
Each lake responds differently to the same environmental pressures. Climate change affects all five lakes, but the impacts vary dramatically — Superior warms slowly but loses ice rapidly, while Erie experiences more frequent harmful algal blooms.
Phosphorus loading rates demonstrate these differences: Superior receives 0.08 kg/hectare annually, while Erie receives 1.34 kg/hectare — a 17-fold difference that explains their contrasting water quality.
Interactive dashboards allow users to explore relationships between variables. Want to see how zebra mussel populations correlate with water clarity changes? Or how winter ice coverage affects spring phytoplankton blooms? The tools are at your fingertips.
Machine learning algorithms identify patterns humans might miss. Our models predict harmful algal bloom likelihood with 87% accuracy up to two weeks in advance — critical information for drinking water managers and beach safety officials.
Ready to explore decades of Great Lakes data? Our database serves researchers, educators, policymakers, and anyone curious about these incredible freshwater seas. Free access to core datasets, with premium tools for advanced analysis.
Explore Database Research Partnerships"The Great Lakes Database has been essential for our research on climate change impacts. The long-term temperature records helped us identify trends that shorter studies would miss entirely."
— Dr. Sarah Chen, University of Minnesota Duluth