Cyanobacteria from marine oxygen-deficient zones encode both form I and form II Rubiscos.

Cyanobacteria are highly abundant in the marine photic zone and primary drivers of the conversion of inorganic carbon into biomass. To date, all studied cyanobacterial lineages encode carbon fixation machinery relying upon form I Rubiscos within a CO-concentrating carboxysome. Here, we report that the uncultivated anoxic marine zone (AMZ) IB lineage of from pelagic oxygen-deficient zones (ODZs) harbors both form I and form II Rubiscos, the latter of which are typically noncarboxysomal and possess biochemical properties tuned toward low-oxygen environments.

Two Metatranscriptomic Profiles through Low-Dissolved-Oxygen Waters (DO, 0 to 33 µM) in the Eastern Tropical North Pacific Ocean.

We present 16 seawater metatranscriptomes collected from a marine oxygen-deficient zone (ODZ) in the eastern tropical North Pacific (ETNP). This data set will be useful for identifying shifts in microbial community structure and function through oxic/anoxic transition zones, where overlapping aerobic and anaerobic microbial processes impact marine biogeochemical cycling.

Cyanophage host-derived genes reflect contrasting selective pressures with depth in the oxic and anoxic water column of the Eastern Tropical North Pacific.

Cyanophages encode host-derived genes that may increase their fitness. We examined the relative abundance of 18 host-derived cyanophages genes in metagenomes and viromes along depth profiles from the Eastern Tropical North Pacific Oxygen Deficient Zone (ETNP ODZ) where Prochlorococcus dominates a secondary chlorophyll maximum within the ODZ. Cyanophages at the oxic primary chlorophyll maximum encoded genes related to light and phosphate stress (psbA, psbD and pstS in T4-like and psbA in T7-like), but the proportion of cyanophage with these genes decreased with depth.

Cyanobacteria and cyanophage contributions to carbon and nitrogen cycling in an oligotrophic oxygen-deficient zone.

Up to half of marine N losses occur in oxygen-deficient zones (ODZs). Organic matter flux from productive surface waters is considered a primary control on N production. Here we investigate the offshore Eastern Tropical North Pacific (ETNP) where a secondary chlorophyll a maximum resides within the ODZ.

Complete arsenic-based respiratory cycle in the marine microbial communities of pelagic oxygen-deficient zones.

Microbial capacity to metabolize arsenic is ancient, arising in response to its pervasive presence in the environment, which was largely in the form of As(III) in the early anoxic ocean. Many biological arsenic transformations are aimed at mitigating toxicity; however, some microorganisms can respire compounds of this redox-sensitive element to reap energetic gains. In several modern anoxic marine systems concentrations of As(V) are higher relative to As(III) than what would be expected from the thermodynamic equilibrium, but the mechanism for this discrepancy has remained unknown.