Transitions in community genomic features and biogeochemical processes were examined in surface and subsurface chlorophyll maximum (SCM) microbial communities across a trophic gradient from mesotrophic waters near San Diego, California to the oligotrophic Pacific. Transect end points contrasted in thermocline depth, rates of nitrogen and CO2 uptake, new production and SCM light intensity. Relative to …
The biodiversity of phytoplankton is a core measurement of the state and activity of marine ecosystems. In the context of historical approaches, we review recent major advances in the technologies that have enabled deeper characterization of the biodiversity of phytoplankton. In particular, high-throughput sequencing of single loci/genes, genomes, and communities (metagenomics) has revealed exceptional phylogenetic …
Fungi contribute substantially to biogeochemical cycles of terrestrial and marine habitats by decomposing matter and recycling nutrients. Yet, the diversity of their planktonic forms in the open ocean is poorly described. In this study, culture-independent and molecular approaches were applied to investigate fungal diversity and abundance derived from samples collected from a broad swath of …
In an article to appear in PLoS ONE, the PICO team describes the natural variability of ocean acidity (pH) at an estuarine site near the Duke Marine Lab. The team found that the natural level of variability over the course of a year exceeds the long term predictions for acidification of the global ocean. These …
In an article appearing in today’s issue of EOS, Zackary Johnson and Dave Johnston discuss how smartphones are changing the way geoscience is taught. Smartphones and other personal electronic devices are now allowing students and the public to measure ocean color, record species encountered, visualize environmental acoustics, document the distance between landforms, and more, all …
Prochlorococcus, the smallest but most abundant marine primary producer, plays an important role in carbon cycling of the global ocean. As a phototroph, Prochlorococcus is thought to be confined to the euphotic zone, with commonly observed maximum depths of ∼150–200 m. But here we show, using flow cytometry and cellular ribosomal content, for the first …
In the open ocean genetically diverse clades of the unicellular cyanobacteria Prochlorococcus are biogeographically structured along environmental gradients, yet little is known about their in situ activity. To address this gap, here we use the numerically dominant Prochlorococcus clade eHL-II (eMIT9312) as a model organism to develop and apply a method to examine their in …
Marine phytoplankton have conserved elemental stoichiometry, but there can be significant deviations from this Redfield ratio. Moreover, phytoplankton allocate reduced carbon to different biochemical pools based on nutritional status and light availability, adding complexity to this relationship. This allocation influences physiology, ecology and biogeochemistry. Here we present results on the physiological and biochemical properties of …
Marine microbial communities are complex and dynamic and their ecology impacts biogeochemical cycles in pelagic ecosystems. Yet little is known about the relative activity of different microbial populations within genetically diverse communities. Here we use rRNA as a proxy for activity to quantify the relative specific activity (rRNA/rDNA) of eubacterial populations and to identify locations …
The industrial-scale production of biofuels from cultivated microalgae has gained considerable interest in the last several decades. While the climate benefits of microalgae cultivation that result from the capture of atmospheric CO2 are known, the counteracting effect from the potential emission of other greenhouse gases has not been well quantified. Here, we report the results …