Influence of the Amazon River plume on distributions of free‐living and symbiotic cyanobacteria in the western tropical north Atlantic Ocean

  title={Influence of the Amazon River plume on distributions of free‐living and symbiotic cyanobacteria in the western tropical north Atlantic Ocean},
  author={Rachel A Foster and Ajit Subramaniam and Cody Mahaffey and Edward J. Carpenter and Douglas G. Capone and Jonathan P. Zehr},
  journal={Limnology and Oceanography},
The vertical and horizontal distributions of seven diazotrophic populations in the western tropical north Atlantic (WTNA) Ocean were examined using a nifH DNA quantitative polymerase chain reaction (QPCR) approach. The nifH phylotype abundances were highest near the surface and decreased with depth, with the exception of the cyanobacterial symbiont Calothrix, which was not detected at any station. Richelia associated with the diatoms Rhizosolenia clevei and Hemiaulus hauckii were distributed… 

Abundance and distribution of major groups of diazotrophic cyanobacteria and their potential contribution to N₂ fixation in the tropical Atlantic Ocean.

Overall, highest diazotroph abundances were observed at the surface and declined with depth, except for some subsurface peaks in Trichodesmium,UCYN-B and UCYN-A, which suggested that Trichodemium had the largest input to N₂ fixation.

Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic

This study represents the first evidence of consumption of DDAs, Trichodesmium, and unicellular cyanobacteria by calanoid copepods in an area of the WTNA known for high carbon export.

Amazon River influence on nitrogen fixation and export production in the western tropical North Atlantic

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Cyanobacterial Diazotroph Distributions in the Western South Atlantic

Inputs of new nitrogen by cyanobacterial diazotrophs are critical to ocean ecosystem structure and function. Relative to other ocean regions, there is a lack of data on the distribution of these

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The gene abundance and gene expression of six diazotroph populations from the Eastern Equatorial Atlantic in June 2007 were examined using nifH gene quantitative polymerase chain reaction (q PCR)

Latitudinal constraints on the abundance and activity of the cyanobacterium UCYN‐A and other marine diazotrophs in the North Pacific

The number of marine environments known to harbor dinitrogen (N2)‐fixing (diazotrophic) microorganisms is increasing, prompting a reassessment of the biogeography of marine diazotrophs and N2

Abundances and Distributions of the Dominant nifH Phylotypes in the Northern Atlantic Ocean

Environmental DNA samples from four cruises to the North Atlantic Ocean were analyzed for the presence and amount of seven nifH phylotypes using real-time quantitative PCR and TaqMan probes and the cyanobacterial phylotypes dominated in abundance and were the most widely distributed.

Seasonal Shifts in Diazotrophs Players: Patterns Observed Over a Two-Year Time Series in the New Caledonian Lagoon (Western Tropical South Pacific Ocean)

This dataset suggests that seasonality is less pronounced than previously thought, and that relatively high N2 fixation rates are maintained in the New Caledonian lagoon all year long, despite seasonal changes in the diazotroph community composition.

Basin scale variability of active diazotrophs and nitrogen fixation in the North Pacific, from the tropics to the subarctic Bering Sea

This study provides evidence for nitrogen fixation in the Bering Sea and suggests a clear contrast in the composition of diazotrophs between the tropical/subtropical gyre and the separate waters in the cold northern regions of the North Pacific.

Dominance of unicellular cyanobacteria in the diazotrophic community in the Atlantic Ocean

Phylogenetic analysis of representative samples revealed that most of the sequences belong to diazotrophic unicellular cyanobacteria Group A (UCYN-A or Candidatus Atelocyanobacterium thalassa), which suggests that the activity of this group of organisms may not be strongly controlled by the availability of fixed N.



Widespread occurrence of the Hemiaulus-cyanobacterial symbiosis in the southwest north Atlantic Ocean

Epifluorescent examination of Jive Hemiaulus spp. during September 1991 and JanuaryFebruary 1992 in the Bahama Islands, southwest North Atlantic Ocean, and Caribbean Sea indicated that 91-100% of the

Nitrogen fixation by Trichodesmium spp.: An important source of new nitrogen to the tropical and subtropical North Atlantic Ocean

Results from 154 stations on six research cruises in the North Atlantic Ocean show depth-integrated N2 fixation by Trichodesmium spp.

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The data suggest a community shift from filamentous cyanob bacteria in surface waters to unicellular cyanobacteria and/or heterotrophic bacteria in deeper waters.

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The distribution of chromophoric-dissolved-organic-matter (CDOM) was investigatedin the western tropical North Atlantic Ocean (WTNA) during the low and high flowperiods of the Amazon River. A strong

High rates of N2 fixation by unicellular diazotrophs in the oligotrophic Pacific Ocean

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The temporal separation of nifH expression by the various phylotypes suggests that open ocean diazotrophic cyanobacteria have unique in situ physiological responses to daily fluctuations of light in the upper ocean.

The dispersal of the Amazon's water

The Amazon is the largest river system in the world, contributing about 6 × 1012 m3 of fresh water to the tropical Atlantic each year1,2. This is about 16% of the annual discharge into the world's

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Measurements of abundance, plus a review of earlier observations, indicate that the diazotrophic cyanobacterium Trichodesmium is the most important primary producer in the tropical North Atlantic Ocean and introduces the largest fraction of new nitrogen to the euphotic zone.

Vertical distributions of nitrogen-fixing phylotypes at Stn ALOHA in the oligotrophic North Pacific Ocean

Differences in the depth distributions of N 2 -fixing plankton at Stn ALOHA are revealed, and it is suggested that unicellular diazotrophs comprise a significant component of plankton biomass in this oligotrophic marine ecosystem.

N2 Fixation by Unicellular Bacterioplankton from the Atlantic and Pacific Oceans: Phylogeny and In Situ Rates

Unicellular cyanobacteria from the tropical North Atlantic and subtropical North Pacific share a common ancestry (16S rDNA) and that potential unicellular N2 fixers have diverged (nifH), and rates of fixation by bacterioplankton can be almost as high as those by the colonial N2-fixing marine cyanob bacteria Trichodesmium spp.