Byrne Lab Research

ecolo

Research

The focus of our research is the reconstruction of past environmental and ecological change. While most recent studies have included the analysis of sediment cores for fossil pollen, we have not limited our research to such methods.

Current and recent lab members are working on:

utilizing stable and radio-isotopes found in the cellulose of tree rings to reconstruct paleohydrology and tritium contamination.
utilizing stable isotopes found in bio and lithogenic carbonate to reconstruct lake water balance.
reconstruction of the timing and magnitude of contamination to depositional basins by heavy metals such as mercury and lead.
constraining earthquake events on fault traces using non-native pollen types in sediments as isochronological markers.
understanding the response of coastal areas to subsidence associated with groundwater pumping.
surveying and re-surveying vegetation in order to better understand the response of ecological systems to environmental change.
utilizing historic air photos to map shoreline changes.
surveying bathymetry in coastal lagoons to reconstruct sediment volume change.
the analysis of sediments for geochemistry in order to reconstruct sediment sources.

Quaternary Paleoclimate Reconstructions for Central Mexico
Dr. Byrne and his students have undertaken numerous studies of Mexican and Central American paleoecology over the past decades. Some of the questions and themes addressed by this research include the following:

How can we infer plant distribution patterns in the tropics and sub-tropics during the Pleistocene and Holocene using fossil pollen records?
What effect did the Pleistocene-Holocene transition have on vegetation in central Mexico?
What can be said of climate changes at that time based on the available physical evidence? How do these findings match with available climate models?
How were human settlements and agriculture impacted by climate variability throughout the Holocene?
How has variability in solar output impacted precipitation, vegetation and overall climate in Mexico and Central America?

Recent sedimentation rates in Bolinas Lagoon

Bolinas Lagoon is a 1,000 acre coastal lagoon located about 20 miles north of San Francisco directly on the San Andreas fault. Bolinas Lagoon has been the focus of an ongoing debate for at least half a century. Some have argued that destructive land use practices during the period of Mexican and American settlement increased the rate of sediment accumulation to the extent that without direct intervention in the form of dredging the lagoon will become a freshwater marsh or meadow within the next 50 years. In 1997, the U.S. Army Corps of Engineers concluded that dredging or otherwise diverting sediment from entering lagoon was in the national interest. Others have claimed that recent sedimentation rates have not been high enough to threaten the lagoon with extinction and that dredging is not needed. As is often the case with protracted debates, the amount of reliable evidence relative to the issue has been limited.

Currently, Marin County Open Space is conducting a rigorous scientific review regarding sediment accumulation in the lagoon, in order to determine the necessity of dredging. As part of this process, Professor Roger Byrne was contacted in order to estimate historic and recent prehistoric sedimentation rates within the lagoon. With one exception, all active lab members were involved in some aspect of the project. This study found that impacts from logging to Bolinas Lagoon were largely restricted to the northern end of the North Basin and the Pine Gulch Creek Delta. For the rest of the North Basin, post-1850 deposition rates were more modest. Another important finding is that sedimentation rates during the 20th Century were largely impacted by the 1906 earthquake. Finally, this study found that even if 20th century deposition rates were to continue throughout the next 50 years, sediment accumulation would not be large enough to convert Bolinas Lagoon to a marsh.

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lab phone (510) 643-1834
fax (510) 642-3370

107 McCone Hall
Geography Department
University of California, Berkeley
Berkeley, CA 94720