Spatial variability of phytoplankton in a shallow tidal freshwater system reveals complex controls on abundance and community structure.

Estuaries worldwide are undergoing changes to patterns of aquatic productivity because of human activities that alter flow, impact sediment delivery and thus the light field, and contribute nutrients and contaminants like pesticides and metals. These changes can influence phytoplankton communities, which in turn can alter estuarine food webs. We used multiple approaches-including high-resolution water quality mapping, synoptic sampling, productivity and nitrogen uptake rates, Lagrangian parcel tracking, enclosure experiments and bottle incubations-over a short time period to take a "spatial snapshot" of conditions in the northern region of the San Francisco Estuary (California, USA) to examine how environmental drivers like light availability, nutrients, water residence time, and contaminants affect phytoplankton abundance and community attributes like size distribution, taxonomic structure, and nutrient uptake rates.

Elevated ammonium concentrations from wastewater discharge depress primary productivity in the Sacramento River and the Northern San Francisco Estuary.

Primary production in the Northern San Francisco Estuary (SFE) has been declining despite heavy loading of anthropogenic nutrients. The inorganic nitrogen (N) loading comes primarily from municipal wastewater treatment plant (WTP) discharge as ammonium (NH(4)). This study investigated the consequences for river and estuarine phytoplankton of the daily discharge of 15 metric tons NH(4)-N into the Sacramento River that feeds the SFE.

Characterization of cyanobacterial glnA gene diversity and gene expression in marine environments.

PCR primers were designed and used to amplify glnA, the gene that encodes glutamine synthetase, from pure cultures of cyanobacteria and four samples from different marine environments. The glnA phylogeny was similar to that of the 16S rRNA gene, indicating that glnA gene sequences can be used to identify cyanobacteria expressing the glnA gene. Diverse unicellular cyanobacteria glnA genes were recovered from the North Pacific Subtropical Gyre, Monterey Bay, Chesapeake Bay and waters off the New Jersey coast.

The genome of the diatom Thalassiosira pseudonana: ecology, evolution, and metabolism.

Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for approximately 20% of global carbon fixation. We report the 34 million-base pair draft nuclear genome of the marine diatom Thalassiosira pseudonana and its 129 thousand-base pair plastid and 44 thousand-base pair mitochondrial genomes.