Oligotrophic bacteria are adapted to low nutrient concentrations. As most of the ocean is oligotrophic (low in nutrients), oligotrophic bacteria thrive in the ocean and make up the majority of planktonic cells. Because of this, oligotrophs are crucial to oceanic nutrient cycles. However, marine oligotrophic bacteria are dwarfed by their...
Historically, the difficulty of obtaining pure cultures of abundant marine
microbial plankton has an obstacle to reconstructing the underlying
mechanisms of biogeochemistry in the ocean. While a number of dominant
marine species from the ocean surface have been cultured, the dominant
microbial plankton of the dark ocean proved far more...
SAR11 Alphaproteobacteria are the most abundant aerobic chemoheterotrophs in ocean surface waters. Previous studies have indicated SAR11 cells play an important role in marine carbon cycling and consume up to half of some common dissolved organic compounds, such as amino acids. During sequencing of the first SAR11 genome, genes for...
Members of the SAR11 clade of heterotrophic α-proteobacteria are ubiquitous and abundant in the world's oceans where they are thought to play a pivotal role in the global carbon cycle. The first SAR11 bacterium cultivated in vitro, 'Candidatus Pelagibacter ubique' HTCC1062 (Ca. P. ubique), was isolated by dilution into sterile...
The phylogenetic diversity of two continental shelf picoplankton
communities was examined by analyzing SSU (16S) ribosomal RNA (rRNA)
genes amplified from environmental DNA with bacterial-specific primers and
the polymerase chain reaction (PCR). Picoplankton populations collected from
the pycnocline (10 m) over the eastern continental shelf of the United States
near...
Research on natural environments, over the last decade, is replete with microbial diversity studies that used culture-independent approaches. The cloning and sequencing of the 16S rRNA genes has been the driving force in the expansion of awareness about the great diversity of previously undiscovered microorganisms. Well-known uncultured groups of microorganisms...
Continental shelves located along eastern boundary currents occupy relatively small volumes of the world’s oceans, yet are responsible for a large proportion of global primary production. The Oregon coast is among these ecosystems. Recent analyses of dissolved oxygen at shallow depths in the water column has suggested increasing episodes of...
Microorganisms play key roles in ocean biogeochemistry. However, several
predominant groups of uncultured bacterioplankton thought to contribute to
important biogeochemical processes in the oceans are known primarily from gene
cloning studies. Although these studies have greatly expanded our view of
microbial diversity in the oceans, they are not quantitative and...
Batch cultures of Candidatus Pelagibacter ubique were grown under iron-, organosulfur-, and nitrogen-limiting conditions to understand how this ubiquitous marine bacterium responds to and interacts with environments where growth is limited by the availability of these nutrients. Global gene expression was monitored using microarrays and quantitative mass spectrometry to observe...
A series of experiments was performed to determine the feasibility of genomic
DNA-based methods for ecological and physiological studies of dominant bacteria from
complex natural systems. Two approaches, bacterial chromosomal painting (BCP) and
environmental genomics (EG), were evaluated for the potential to identify and enumerate
specific bacterial groups in situ...
To identify factors limiting 'Candidatus Pelagibacter ubique' maximum cell density and growth rate in pure culture on seawater, the genome sequence of 'Cand. P. ubique' was analyzed, culturing experiments with organic and inorganic nutrient additions were made, and radiotracer uptake experiments were performed. The genome was sequenced, custom data mining...
The lack of availability of a single, complete paper on the
analysis of a digital data acquisition system for in situ oceanographic
measurements brought about the present work. In order to compile
an accurate technical paper on such a complex system, it was necessary
to design, construct, and calibrate a...
Proteins are the metabolic machines of the cell and as such, the study of proteins could illuminate the dominant biological activities that are occurring within cells and reveal how an organism interacts with its environment. Here, we used proteomic techniques to study the abundant marine bacterium SAR11 both as an...
Oceanic crust covers nearly 70% of the Earth's surface, of which, the upper,
sediment layer is estimated to harbor substantial microbial biomass. Marine crust;
however, extends several kilometers beyond this surficial layer, and includes the
basalt and gabbro layers. In particular, the basalt layer has high permeabilities which
allows for...