Close up view of periphyton on rocks along the shore of Lake Tahoe.
Lake Tahoe Nearshore Periphyton Study Completed
Periphyton, a type of algae, is growing on bottom sediment and rocks along nearshore areas of Lake Tahoe. Periphyton is seen as a nuisance and negatively impacts the recreational value of the lake. Periphyton biomass (PB) data collected along the nearshore of Lake Tahoe exhibit increasing trends over the last decade. However, the mechanisms that have caused these changes are not well understood.
We worked with the University of Nevada-Reno, in cooperation with the Lahontan Regional Control Board, to investigate the cause and effect relationships between periphyton biomass and chemical and physical characteristics of the lake and shallow groundwater surrounding Ward Creek, near Tahoe City, California.
Our research provided important information on what are considered the most influential variables controlling the growth of periphyton including
- Is Ward Creek an important source of nutrients to periphyton assemblages at distal locations along the Lake Tahoe shoreline?
- What chemical and physical variables are important to periphyton growth?
- Specifically, are there correlations among these variables to patterns in productivity, nutrient limitation, and taxonomic composition?
Five monitoring transects were installed to help to distinguish whether nutrients are coming from Ward Creek, other on-shore locations, groundwater, or from lake upwelling to the Pineland Periphyton Monitoring Site (PPMS). Ultimately, our results may assist in providing the context for managing water quality in the Tahoe basin.
Monitoring Strategy
We sampled five transects on the west shore of Lake Tahoe, north of Ward Creek.
- Temperature, electrical conductance, dissolved oxygen and chlorophyll-a were measured at 20 locations (4 locations per transect) using hand-held sensors shown in yellow on map.
- Sediment and lake water quality samples were obtained from approximate locations (green triangles on map).
- Temperature probes were installed at two locations per transect (three at PPMS) shown in red on map.
- Lake stage and head was monitored by a sensor, temperature rod (TROD), and pressure transducer inside a piezometer driven into lake bed sediments.
- Turbidity was measured at 1 location in transect 4. Four light loggers were installed in transect 4 and 1 light logger was installed at transects 1 and 3.
- Temperature was monitored with iButtons in the Lake column and with the TROD for lake bed sediments at 6 depths.
- Groundwater influence was measured by a 1-inch diameter PVC piezometer installed at the PPMS to a depth of 1 m.
Pineland Periphyton Monitoring Site
Automated (hourly) measurements of temperature, electrical conductance, and dissolved oxygen were collected. Samples of nitrogen and phosphorus were collected in the lake water columns and shallow pore water at 3 points (green triangles).
Water-Quality, Physical, and Nutrient Data
We sampled transects at a high frequency over a 10-month period on the west shore of Lake Tahoe, north of Ward Creek. All data and sample analysis results underwent quality assurance/quality control evaluation according to USGS protocols. Data has been uploaded into the USGS National Water Information System (NWIS). Results from Ward Creek surface water samples has been compared to concurrent Lake Tahoe Interagency Monitoring Program (LTMP) samples for inter-laboratory comparison.
Data Collected
- Temperature
- Solar Radiation
- Dissolved Oxygen
- Specific Conductance
- Turbidity
- Chlorophyll-a
- Nitrogen
- Phosphorus
Additional Data
- Tracked periphyton assemblage dynamics by estimating standing stocks of biomass.
- Identified shifts in taxonomic structure.
- Quantified rates of net primary productivity.
- Assessed potential nutrient limitation.
A trend analysis provided information about how measured parameters varied at seasonal and sub-seasonal time scales. Multivariate statistics (e.g., regression analysis, principal components analysis) were used to determine which physical and chemical conditions are most correlated to periphyton metabolic rates and biomass.
Correlation and Trend Analysis
We graphed time series of all measured parameters in order to evaluate qualitative patterns and statistical moments. Multivariate analysis included analysis of variance and principal component analysis. When necessary, structural equation modeling was used to explore direct and indirect relations between possible explanatory variables and seasonal changes in periphyton biomass and periphyton metabolic rates. These analyses are intended to reveal correlation between the seasonal and sub-seasonal variability in physical and chemical properties of lake and pore-water as explanatory variables for the variability and growth of periphyton.
Structural equation modeling and/or mechanistic algal hydrodynamic modeling were used to explore direct and indirect relations between possible explanatory variables and seasonal changes in periphyton biomass and periphyton metabolic rates.
Timeline of Periphyton Growth
Quantifying watershed controls on fine sediment particles and nutrient loading to Lake Tahoe using data mining and machine learning
Nutrient Source Identification in Groundwater and Periphyton Along the Nearshore of Lake Tahoe
Lake Tahoe Water Quality Shorezone Monitoring
Lake Tahoe Tributary Monitoring
Below are multimedia items associated with this project.
Close up view of periphyton on rocks along the shore of Lake Tahoe.
View of periphyton from the shoreline of Lake Tahoe.
View of periphyton from the shoreline of Lake Tahoe.
Underwater view of periphyton on rocks and the Lake Tahoe shoreline.
Underwater view of periphyton on rocks and the Lake Tahoe shoreline.
Cyanobacteria on rocks along the Lake Tahoe shoreline.
Cyanobacteria on rocks along the Lake Tahoe shoreline.
Underwater view of periphyton on rocks and a data-collection sonde along the nearshore, Lake Tahoe. Data was being collected as part of the Lake Tahoe Nearshore Periphyton Study.
Underwater view of periphyton on rocks and a data-collection sonde along the nearshore, Lake Tahoe. Data was being collected as part of the Lake Tahoe Nearshore Periphyton Study.
Data collection sonde in the swash zone at Lake Tahoe. Data was being collected for the Lake Tahoe Nearshore Periphyton study.
Data collection sonde in the swash zone at Lake Tahoe. Data was being collected for the Lake Tahoe Nearshore Periphyton study.
Lake Tahoe Hydro Mapper
The Hydro Mapper is an interactive map viewer which allows users to see real-time information on stream flow discharge, stage, nutrient, turbidity, sediment loads, and storage data.
- Overview
Periphyton, a type of algae, is growing on bottom sediment and rocks along nearshore areas of Lake Tahoe. Periphyton is seen as a nuisance and negatively impacts the recreational value of the lake. Periphyton biomass (PB) data collected along the nearshore of Lake Tahoe exhibit increasing trends over the last decade. However, the mechanisms that have caused these changes are not well understood.
We worked with the University of Nevada-Reno, in cooperation with the Lahontan Regional Control Board, to investigate the cause and effect relationships between periphyton biomass and chemical and physical characteristics of the lake and shallow groundwater surrounding Ward Creek, near Tahoe City, California.
Our research provided important information on what are considered the most influential variables controlling the growth of periphyton including
- Is Ward Creek an important source of nutrients to periphyton assemblages at distal locations along the Lake Tahoe shoreline?
- What chemical and physical variables are important to periphyton growth?
- Specifically, are there correlations among these variables to patterns in productivity, nutrient limitation, and taxonomic composition?
Five monitoring transects were installed to help to distinguish whether nutrients are coming from Ward Creek, other on-shore locations, groundwater, or from lake upwelling to the Pineland Periphyton Monitoring Site (PPMS). Ultimately, our results may assist in providing the context for managing water quality in the Tahoe basin.
Monitoring Strategy
We sampled five transects on the west shore of Lake Tahoe, north of Ward Creek.
- Temperature, electrical conductance, dissolved oxygen and chlorophyll-a were measured at 20 locations (4 locations per transect) using hand-held sensors shown in yellow on map.
- Sediment and lake water quality samples were obtained from approximate locations (green triangles on map).
- Temperature probes were installed at two locations per transect (three at PPMS) shown in red on map.
- Lake stage and head was monitored by a sensor, temperature rod (TROD), and pressure transducer inside a piezometer driven into lake bed sediments.
- Turbidity was measured at 1 location in transect 4. Four light loggers were installed in transect 4 and 1 light logger was installed at transects 1 and 3.
- Temperature was monitored with iButtons in the Lake column and with the TROD for lake bed sediments at 6 depths.
- Groundwater influence was measured by a 1-inch diameter PVC piezometer installed at the PPMS to a depth of 1 m.
Pineland Periphyton Monitoring Site
Automated (hourly) measurements of temperature, electrical conductance, and dissolved oxygen were collected. Samples of nitrogen and phosphorus were collected in the lake water columns and shallow pore water at 3 points (green triangles).
Water-Quality, Physical, and Nutrient Data
We sampled transects at a high frequency over a 10-month period on the west shore of Lake Tahoe, north of Ward Creek. All data and sample analysis results underwent quality assurance/quality control evaluation according to USGS protocols. Data has been uploaded into the USGS National Water Information System (NWIS). Results from Ward Creek surface water samples has been compared to concurrent Lake Tahoe Interagency Monitoring Program (LTMP) samples for inter-laboratory comparison.
Data Collected
- Temperature
- Solar Radiation
- Dissolved Oxygen
- Specific Conductance
- Turbidity
- Chlorophyll-a
- Nitrogen
- Phosphorus
Additional Data
- Tracked periphyton assemblage dynamics by estimating standing stocks of biomass.
- Identified shifts in taxonomic structure.
- Quantified rates of net primary productivity.
- Assessed potential nutrient limitation.
A trend analysis provided information about how measured parameters varied at seasonal and sub-seasonal time scales. Multivariate statistics (e.g., regression analysis, principal components analysis) were used to determine which physical and chemical conditions are most correlated to periphyton metabolic rates and biomass.
Correlation and Trend Analysis
We graphed time series of all measured parameters in order to evaluate qualitative patterns and statistical moments. Multivariate analysis included analysis of variance and principal component analysis. When necessary, structural equation modeling was used to explore direct and indirect relations between possible explanatory variables and seasonal changes in periphyton biomass and periphyton metabolic rates. These analyses are intended to reveal correlation between the seasonal and sub-seasonal variability in physical and chemical properties of lake and pore-water as explanatory variables for the variability and growth of periphyton.
Structural equation modeling and/or mechanistic algal hydrodynamic modeling were used to explore direct and indirect relations between possible explanatory variables and seasonal changes in periphyton biomass and periphyton metabolic rates.
Timeline of Periphyton Growth
Sources/Usage: Public Domain. View Media Details - Science
Quantifying watershed controls on fine sediment particles and nutrient loading to Lake Tahoe using data mining and machine learning
Since the late 1980’s, the USGS has collected discharge, sediment, and water quality data at seven major drainages under the Lake Tahoe Interagency Monitoring Program (LTIMP). Recently, continuous, real-time measurements of turbidity were added to the LTIMP. These data can be combined with in situ, model simulations, and remotely-sensed datasets available from the USGS, National Aeronautics and...Nutrient Source Identification in Groundwater and Periphyton Along the Nearshore of Lake Tahoe
High concentrations of phosphorus (P) and nitrogen (N) are responsible for excessive, or nuisance algal blooms in many ecosystems world-wide, and climate change is predicted to exacerbate the problem1,2. Excessive nutrients supplied to the nearshore zone of Lake Tahoe may have significant consequences to ecological communities, water clarity, and water quality. The nearshore zone represents the...Lake Tahoe Water Quality Shorezone Monitoring
USGS Nevada Water Science Center (NVWSC) is sampling for Volatile Organic Compounds (VOCs) in 2019 in order to confirm previous data collection efforts at Lake Tahoe. The Tahoe Regional Planning Agency (TRPA) requested sampling in targeted locations and at times when petroleum constituents are most likely to be detected in the lake.Lake Tahoe Tributary Monitoring
The Lake Tahoe Interagency Monitoring Program (LTIMP) is an essential part of integrated science in the Lake Tahoe Basin and has provided long-term, consistent, reliable, and accessible tributary monitoring data for decades. - Multimedia
Below are multimedia items associated with this project.
Close up view of periphyton on rocks along the shore of Lake TahoeClose up view of periphyton on rocks along the shore of Lake TahoeClose up view of periphyton on rocks along the shore of Lake Tahoe.
Close up view of periphyton on rocks along the shore of Lake Tahoe.
View of periphyton from the shoreline of Lake TahoeView of periphyton from the shoreline of Lake TahoeView of periphyton from the shoreline of Lake Tahoe.
View of periphyton from the shoreline of Lake Tahoe.
Underwater view of periphyton on rocks and the Lake Tahoe shorelineUnderwater view of periphyton on rocks and the Lake Tahoe shorelineUnderwater view of periphyton on rocks and the Lake Tahoe shoreline.
Underwater view of periphyton on rocks and the Lake Tahoe shoreline.
Cyanobacteria on rocks along the Lake Tahoe shorelineCyanobacteria on rocks along the Lake Tahoe shorelineCyanobacteria on rocks along the Lake Tahoe shoreline.
Cyanobacteria on rocks along the Lake Tahoe shoreline.
Underwater view of periphyton on rocks Lake TahoeUnderwater view of periphyton on rocks and a data-collection sonde along the nearshore, Lake Tahoe. Data was being collected as part of the Lake Tahoe Nearshore Periphyton Study.
Underwater view of periphyton on rocks and a data-collection sonde along the nearshore, Lake Tahoe. Data was being collected as part of the Lake Tahoe Nearshore Periphyton Study.
Data collection sonde in the swash zone at Lake TahoeData collection sonde in the swash zone at Lake TahoeData collection sonde in the swash zone at Lake Tahoe. Data was being collected for the Lake Tahoe Nearshore Periphyton study.
Data collection sonde in the swash zone at Lake Tahoe. Data was being collected for the Lake Tahoe Nearshore Periphyton study.
- Web Tools
Lake Tahoe Hydro Mapper
The Hydro Mapper is an interactive map viewer which allows users to see real-time information on stream flow discharge, stage, nutrient, turbidity, sediment loads, and storage data.