Draft:UC Davis Tahoe Environmental Research Center

The UC Davis Tahoe Environmental Research Center (TERC), a Special Research Program of the Office of Research at the University of California, Davis, is in the Tahoe Basin and on the main campus of UC Davis.

UC Davis TERC has three facilities at Lake Tahoe. The Tahoe Center for Environmental Sciences in Incline Village, Nevada, and the Eriksson Education Center and Field Station in Tahoe City, California . TERC was founded in 2004 with Dr. Geoffrey Schladow as the founding director. Previously, most UC Davis research at Lake Tahoe was conducted through the Tahoe Research Group, led by Dr. Charles Goldman.

History of University of California Research at Lake Tahoe

The first scientific measurements at Lake Tahoe were taken in 1868 by physicist John LeConte, the first acting president of the University of California. LeConte published his Lake Tahoe Physical Studies I and II in 1883 and was the first to take clarity measurements using a Secchi disk in Lake Tahoe, which has been used to measure lake clarity for the last 60 years. Limnologist Dr. Charles R. Goldman began taking measurements at Lake Tahoe in 1959. He founded the Tahoe Research Group in 1968. Thus began a regular, year-round program of measuring lake clarity and nutrient concentrations and identifying and cataloging phytoplankton and zooplankton species. In 2004, UC Davis created TERC as a campus-wide center with Dr. Geoffrey Schladow as the founding director. Since that time, TERC has broadened the research beyond just an ecological program to an integrated, interdisciplinary aquatic ecology, physical limnology, atmospheric science, forest ecology, and watershed hydrology program. An education program linked to ongoing research has also been created.

Facilities

Tahoe Center for Environmental Sciences

The Tahoe Center for Environmental Sciences is a Leadership in Energy and Environmental Design (LEED) Platinum-certified building in Incline Village. It was the first building in Nevada to receive this certification from the U.S. Green Building Council. The building was designed and constructed in partnership between UC Davis and Sierra Nevada College and was completed in 2006. The building uses 60% less energy than a traditional building of the same size and function. For more information on the standards and levels of LEED-certified buildings, see https://www.usgbc.org/leed The building houses TERC's laboratories, administrative offices, and TERC's Tahoe Science Education Center.

Ericksson Education Center and Field Station

TERC's Tahoe City Field Station was once home to a state fish hatchery. The hatchery was operational from 1921 to the mid-1950s. In 1975, the California Dept. of Fish and Wildlife transferred the hatchery to UC Davis. In 2007, TERC completed a historical renovation of the building. The Field Station now houses TERC's field research instruments and small boats, a chemistry lab, a lath house, and a small interactive educational exhibit space.

UC Davis Campus

On the UC Davis campus, TERC has administrative offices in the Watershed Sciences Center, as well as offices and labs in Ghausi Hall and Wickson Hall.

Research

TERC's interdisciplinary research is conducted at Lake Tahoe, and other locations in the US like Clear Lake, CA. small lakes throughout the Sierra Nevada, and globally. TERC's global research is summarized here: https://storymaps.arcgis.com/stories/ee0049d959794b9d997231531538d7f9

Lake Tahoe

Much of the research at Lake Tahoe is summarized each year in the Tahoe: State of the Lake Report.

Lake clarity- Lake Tahoe is known for its outstanding clarity. TERC researchers measure the Secchi depth every 10 days throughout the year. Clarity is an excellent metric of lake water quality and environmental health. The lake's optical properties are also measured using instruments such as transmissometers, optical backscatter sensors, and underwater radiometers. The status of the lake's clarity is summarized annually in a separate clarity report.

Climate change - continuous measurements of Lake Tahoe's changing temperature enable scientists to track climate change's impact. As well as the overall warming of the lake, an intensification of the thermal stratification and a lengthening of the stratified season has been observed.

Physical limnology - refers to the physical mixing processes that take place in lakes. At Lake Tahoe, because of its large size, the Earth's rotation contributes to the motions observed in the lakes. Using moorings in the deepest parts of the lake, nearshore water quality stations in the shallows, and weekly profiles from top to bottom, models of the complex motions have been developed.

Autonomous vehicles - TERC has a long history of engaging with autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) since the early 2000s. They have been used for inspection work, mapping invasive species, characterizing substrate, measuring internal waves, etc. In 2018, TERC also started using buoyancy-driven autonomous vehicles (aka gliders) and has conducted work in Lake Tahoe nearly every year since measuring particle size distributions, temperature gradients, and dissolved oxygen in the lake. While many of the applications are targeted at answering scientific questions in Tahoe, the lake is also used as a natural laboratory to test new applications.

Routine lake monitoring - TERC has been undertaking the year-round monitoring of water quality at Tahoe monthly since 1968. Although the program has changed over the decades due to funding it has always included the nutrient analysis of water at 13 depths from top to bottom at two locations, algal sampling (for both speciation and enumeration), clarity measurements, primary productivity measurements, and temperature measurements.

Nearshore monitoring - Since the 1970s, the nearshore regions have been monitored for attached algae or periphyton growth. The monitoring took place at fixed regions around the lake. The results indicated that the growth had not changed over time, but it was believed that the spatial extent had changed. TERC now utilizes monthly helicopter and drone flights to better track spatial extent to assess periphyton growth. Starting in 2021, TERC also monitored for metaphyton, unattached filamentous algae in the nearshore. These are believed to be increasing due to the presence of invasive Asian clams (corbicula fluminea).

Stream monitoring - in partnership with the US Geological Survey, TERC samples the water quality in Tahoe streams. Currently 6 streams are monitored, down from 10 in the 1990s. A total of 63 streams flow into Lake Tahoe. The nutrient and fine particle analyses of all six streams are done by TERC's laboratory.

Other topics of monitoring and reasearch

Atmospheric Deposition

Food web changes

Invasive Species

Impacts of Wildfire

Microplastics

Lake modeling

Predictive tools

Forest & Conservation Biology – The TERC Forestry lab is actively involved in studying the physiological, phenological, and biochemical mechanisms involved in how forest trees respond and adapt to biotic (i.e., pathogens, insects) and abiotic (e.g., drought, fire) pressures. The lab is also involved in climate-resilient reforestation strategies while building equity in the forestry workforce.

Clear Lake

General - TERC is engaged in a multi-year research study to understand the dominant processes that are negatively impacting the rehabilitation of Clear Lake water quality and ecosystem health. With funding provided by the California State Assembly, researchers are collecting a wide variety of data to form the basis of a long-term monitoring strategy to measure status and trends in the future. A set of numerical models, calibrated and validated with these data, will be developed to inform local and State decision-making.

Long-term monitoring - TERC has developed a monitoring network since spring 2019 in Clear Lake that includes the high-resolution data acquisition for (1) stream properties at three locations (Middle, Scott, and Kelsey Creeks), (2) meteorological data at seven locations around the perimeter of the lake, and (3) lake temperature and dissolved oxygen at multiple depths and locations across the lake (six permanent water quality stations). In addition, we measure particle size in the water during each of the routine monitoring events as part of our ongoing research on the impact of wildfire smoke on lakes. We also measure nutrient concentrations throughout the water column and across all three lake basins during seven to eight sampling events per year. The water samples were analyzed for dissolved and particulate forms of nitrogen, phosphorus, and carbon; chlorophyll; and particle size distribution. Samples were also collected for phytoplankton identification and quantification and zooplankton identification.

Eutrophication - Excessive nutrient concentrations, principally phosphorus (P) is one of the primary problems of Clear Lake. Phosphorus is derived from both external sources (i.e., runoff from agricultural and urban areas conveyed into the lake via streamflows and urban flows) and internal sources (i.e., recycling of legacy phosphorus pools released from lake sediments). Internal loading of phosphorus can be caused by anoxic conditions in the sediment, benthic bioturbation, and mechanical resuspension. We have quantified external and internal phosphorus loads to Clear Lake. Internal phosphorus loading was calculated using two different methods. Anoxic and oxic sediment P release rates were quantified by laboratory chamber experiments while the spatial and temporal extent of anoxia was measured by moored hypolimnion dissolved oxygen sensors throughout Clear Lake. Modeled internal loads released via diffusion from anoxic sediments closely agreed with the observed increase in water column P in the lake's two deeper arms (Oaks and Lower). However, in the large and shallow Upper Arm, theoretical estimates significantly unpredicted the observed increase of P. The discrepancy between observed and theoretical internal P load estimates in the Upper Arm is a current research focus.

Remote sensing & Harmful Algal Blooms- We measure cyanobacteria blooms in Clear Lake using a variety of remote sensing methods. Satellite-based remote sensing of cyanobacteria blooms is emerging as a useful tool for researchers and water managers because of the high spatial coverage and the frequent data availability. However, a limitation of currently available multispectral cyanobacteria algorithms is that they detect the presence and abundance of cyanobacteria but do not tell you whether a bloom contains cyanobacteria species that produce cyanotoxins. With the upcoming launches of satellites with hyperspectral sensors, higher spectral resolution data will be readily available. These rich datasets will allow for new algorithms to be developed based on detailed spectral differences between targets. During the summer and fall of 2022, we collected hyperspectral data and phytoplankton samples coincident with DESIS image collections to refine remote sensing tools for algal species at Clear Lake.

Lake modeling - The field and laboratory measurements are essential to build, calibrate, and validate a three-dimensional (3-D) numerical lake model. The processes the model simulates are organized into two groups: those that characterize how the water moves (i.e. hydrodynamic) and those that modify nutrients and algae in the lake (i.e. water quality). We completed the calibration and validation of the hydrodynamic model. We are concurrently developing a water quality or biogeochemical model to simulate the evolution of different constituents, such as dissolved oxygen, nitrogen species, phosphorus species, phytoplankton, and suspended solids. This model will include cyanobacteria as one of the phytoplankton groups.

Education

Tahoe Science Center The Tahoe Science Center (TSC), located on the first floor of the Tahoe Center for Environmental Sciences, is an interactive, environmental education museum. It provides school tours for youth from the greater Lake Tahoe area, as well as catering to the general public. Over 15,000 visitors typically come through the TSC. The goal of the center is to link environmental education with the research currently being undertaken. This is done through a combination of hands-on activities, audiovisual explorations, 3-D movies, displays showing real time data from around the Tahoe Basin and immersive Augmented Reality displays.

Virtual research boat A two-thirds scale-model of the UC Davis Research Vessel John LeConte that explores collecting field data.

Virtual laboratory A "laboratory" that describes what happens to water samples in a laboratory. 3D visualization theater

3D movies take viewers around the Lake Tahoe watershed and explore the formation of the basin Shaping watersheds interactive sandbox

Explores how water moves through a watershed through interactive sand building and "water" technology. The sandbox was created by LakeViz3D and funded by the National Science Foundation in partnership with UC Davis KeckCAVES UC Davis Tahoe Environmental Research Center, Lawrence Hall of Science, ECHO Lake Aquarium and Science Center, and Audience Viewpoints Consulting.

Tahoe's plastic problem

An area with hands-on activities and microscopes to understand the microplastic problem in Lake Tahoe. Lake Tahoe in depth Interactive touch screens that map out the Tahoe Basin and show graphic visualizations of real-time Lake Tahoe data. Categories available on the touchscreens include images, activities in the basin, historic to present weather data, citizen science data collections, rivers and creeks visualization, and real-time lake condition data. Eriksson Education Center and Demonstration Garden The Eriksson Education Center at the Tahoe City Field Station is focused on native and non-native fish, and the history of the Tahoe City Field Station. A three-acre demonstration garden surrounds the Tahoe City Field Station. Gall