SGER- Impact of the Angora Fire on Colloidal Black Carbon in Lake Tahoe and Fallen Leaf Lake

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ABSTRACTThe primary goal of the proposal is to collect and quantify black carbon colloids(BC) in water samples from Lake Tahoe and Fallen Leaf Lake in the wake of the LakeTahoe basin Angora fire. The sampling program will collect near-shore, mid-lake andoutlet river samples from Fallen Leaf Lake and Lake Tahoe. In addition to samplingconducted by the project, we will leverage pre-existing sampling programs such as theUC-Davis Mid-Lake Tahoe Profile (MLTP), which collects depth profiles from the lakeevery 30 days. A proposal will be submitted in December to the NSF HydrologicSciences to interpret the data resulting from the SGER.Scientific meritLittle is known regarding black carbon colloids, produced by incompletecombustion, in aquatic systems. However these nano-particles are now believed to bean important component of the global carbon cycle, the hydrologic cycle, globalwarming, accelerated snow pack and glacier melt, fresh water and marine chemistry andsediment geochemistry. Recent studies of BC in seawater and marine sedimentssuggest that BC may have a very long residence time in the ocean and fresh waterbodies. These particles may also determine the partitioning of many toxic organiccompounds in aquatic ecosystems. To our knowledge there have been no studies of BCcolloids in a lake system following a major fire in its basin.Objectives. Collect and analyze BC in water samples from Lake Tahoe and Fallen Leaf Lakeover a two year period after the Angora Fire.Broader impactsThe project represents a rare opportunity to study the impact of a fire on BCcolloids and determine how these colloids impact the aquatic environment. The results ofthe project may have wide ranging impacts on the global Earth Science Community aswell as the Lake Tahoe community. For example, if the study can establish theresidence time of BC in the lake, we will be able to determine the impact of BC on thelakes optical properties and chemistry over time. The results from the study may then beapplied to other lakes and rivers. The data will be used by Federal and Statepolicymakers and local planners to evaluate and implement environmental policy in theLake Tahoe area. The project will communicate the results to the Lake Tahoestakeholders and scientific community through journal publications and public meetings.