Algal bioassessment
Algae are excellent storytellers of their environment. Their fast metabolisms make them sensitive and rapid responders to environmental change. Algal bioassessment is the use of algal community composition to better understand the biological condition, or health, of an ecosystem. In California, we use algal bioassessment to better understand the condition of streams, rivers, lakes and estuaries.
Microbial diversity and carbon cycling in coastal wetlands
Wetland ecosystems may serve as either a source or a sink for atmospheric carbon and greenhouse gases. This delicate carbon balance is influenced by the activity of below-ground microbial communities that return carbon dioxide and methane to the atmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may help to reverse land subsidence and possibly increase carbon storage in soils. However, the effects of wetland restoration on microbial communities, which mediate soil metabolic activity and carbon cycling, are poorly studied. In an effort to better understand the underlying factors which shape the balance of carbon flux in wetland soils, we study the microbial communities in a suite of restored and historic wetlands in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we profile the diversity and metabolic potential of the wetland soil microbial communities along biogeochemical and wetland age gradients. Additionally, we are interested in microbial communities in former industrial salt ponds and their response to wetland restoration.
Microbial response to wetland restoration
Haptophyte algae and their molecular fossils
Haptophyte algae are not only critical players in the global carbon cycle, as big-time marine photosynthesizers and calcium carbonate shell-makers, but they are also critical players in our ability to decipher past climate change. Haptophyte algae synthesize a unique molecule, the alkenone, that is preserved for thousands of years in the sediments underlying waters where these algae have lived. We use this alkenone molecule to reconstruct the temperature of the ancient haptophytes' water, a tool we call a "paleothermometer". My research focuses on better understanding the enigmatic triggers of lake-dwelling, or lacustrine, haptophyte algae blooms in an effort to better understand the molecular fossils they leave behind. This research involved in situ observations of haptophyte bloom events in Lake BrayaSo, in Southwestern Greenland and Lake George, North Dakota, as well as high-throughput DNA sequencing and the culturing of novel species of haptophytes.