Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic
Diazotrophic cyanobacteria, those capable of fixing di-nitrogen (N2), are considered one of the major sources of new nitrogen (N) in the oligotrophic tropical ocean, but direct incorporation of diazotrophic N into food webs has not been fully examined. In the Amazon River-influenced western tropical...
Published in: | PLoS ONE |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Frontiers Media S.A.
2017
|
Subjects: | |
Online Access: | https://doi.org/10.3389/fmicb.2017.01436 https://doaj.org/article/273b6e1e92974c599d20550aef9f66dc |
id |
ftdoajarticles:oai:doaj.org/article:273b6e1e92974c599d20550aef9f66dc |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:273b6e1e92974c599d20550aef9f66dc 2023-05-15T17:30:07+02:00 Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic Brandon J. Conroy Deborah K. Steinberg Bongkuen Song Andrew Kalmbach Edward J. Carpenter Rachel A. Foster 2017-08-01T00:00:00Z https://doi.org/10.3389/fmicb.2017.01436 https://doaj.org/article/273b6e1e92974c599d20550aef9f66dc EN eng Frontiers Media S.A. http://journal.frontiersin.org/article/10.3389/fmicb.2017.01436/full https://doaj.org/toc/1664-302X 1664-302X doi:10.3389/fmicb.2017.01436 https://doaj.org/article/273b6e1e92974c599d20550aef9f66dc Frontiers in Microbiology, Vol 8 (2017) mesozooplankton cyanobacteria diazotroph grazing Amazon River plume North Atlantic Ocean Microbiology QR1-502 article 2017 ftdoajarticles https://doi.org/10.3389/fmicb.2017.01436 2022-12-31T09:47:57Z Diazotrophic cyanobacteria, those capable of fixing di-nitrogen (N2), are considered one of the major sources of new nitrogen (N) in the oligotrophic tropical ocean, but direct incorporation of diazotrophic N into food webs has not been fully examined. In the Amazon River-influenced western tropical North Atlantic (WTNA), diatom diazotroph associations (DDAs) and the filamentous colonial diazotrophs Trichodesmium have seasonally high abundances. We sampled epipelagic mesozooplankton in the Amazon River plume and WTNA in May–June 2010 to investigate direct grazing by mesozooplankton on two DDA populations: Richelia associated with Rhizosolenia diatoms (het-1) and Hemiaulus diatoms (het-2), and on Trichodesmium using highly specific qPCR assays targeting nitrogenase genes (nifH). Both DDAs and Trichodesmium occurred in zooplankton gut contents, with higher detection of het-2 predominantly in calanoid copepods (2.33–16.76 nifH copies organism-1). Abundance of Trichodesmium was low (2.21–4.03 nifH copies organism-1), but they were consistently detected at high salinity stations (>35) in calanoid copepods. This suggests direct grazing on DDAs, Trichodesmium filaments and colonies, or consumption as part of sinking aggregates, is common. In parallel with the qPCR approach, a next generation sequencing analysis of 16S rRNA genes identified that cyanobacterial assemblage associated with zooplankton guts was dominated by the non-diazotrophic unicellular phylotypes Synechococcus (56%) and Prochlorococcus (26%). However, in two separate calanoid copepod samples, two unicellular diazotrophs Candidatus Atelocyanobacterium thalassa (UCYN-A) and Crocosphaera watsonii (UCYN-B) were present, respectively, as a small component of cyanobacterial assemblages (<2%). 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. These diazotroph populations are quantitatively important in the global N budget, ... Article in Journal/Newspaper North Atlantic Copepods Directory of Open Access Journals: DOAJ Articles PLoS ONE 8 6 e64166 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
mesozooplankton cyanobacteria diazotroph grazing Amazon River plume North Atlantic Ocean Microbiology QR1-502 |
spellingShingle |
mesozooplankton cyanobacteria diazotroph grazing Amazon River plume North Atlantic Ocean Microbiology QR1-502 Brandon J. Conroy Deborah K. Steinberg Bongkuen Song Andrew Kalmbach Edward J. Carpenter Rachel A. Foster Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic |
topic_facet |
mesozooplankton cyanobacteria diazotroph grazing Amazon River plume North Atlantic Ocean Microbiology QR1-502 |
description |
Diazotrophic cyanobacteria, those capable of fixing di-nitrogen (N2), are considered one of the major sources of new nitrogen (N) in the oligotrophic tropical ocean, but direct incorporation of diazotrophic N into food webs has not been fully examined. In the Amazon River-influenced western tropical North Atlantic (WTNA), diatom diazotroph associations (DDAs) and the filamentous colonial diazotrophs Trichodesmium have seasonally high abundances. We sampled epipelagic mesozooplankton in the Amazon River plume and WTNA in May–June 2010 to investigate direct grazing by mesozooplankton on two DDA populations: Richelia associated with Rhizosolenia diatoms (het-1) and Hemiaulus diatoms (het-2), and on Trichodesmium using highly specific qPCR assays targeting nitrogenase genes (nifH). Both DDAs and Trichodesmium occurred in zooplankton gut contents, with higher detection of het-2 predominantly in calanoid copepods (2.33–16.76 nifH copies organism-1). Abundance of Trichodesmium was low (2.21–4.03 nifH copies organism-1), but they were consistently detected at high salinity stations (>35) in calanoid copepods. This suggests direct grazing on DDAs, Trichodesmium filaments and colonies, or consumption as part of sinking aggregates, is common. In parallel with the qPCR approach, a next generation sequencing analysis of 16S rRNA genes identified that cyanobacterial assemblage associated with zooplankton guts was dominated by the non-diazotrophic unicellular phylotypes Synechococcus (56%) and Prochlorococcus (26%). However, in two separate calanoid copepod samples, two unicellular diazotrophs Candidatus Atelocyanobacterium thalassa (UCYN-A) and Crocosphaera watsonii (UCYN-B) were present, respectively, as a small component of cyanobacterial assemblages (<2%). 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. These diazotroph populations are quantitatively important in the global N budget, ... |
format |
Article in Journal/Newspaper |
author |
Brandon J. Conroy Deborah K. Steinberg Bongkuen Song Andrew Kalmbach Edward J. Carpenter Rachel A. Foster |
author_facet |
Brandon J. Conroy Deborah K. Steinberg Bongkuen Song Andrew Kalmbach Edward J. Carpenter Rachel A. Foster |
author_sort |
Brandon J. Conroy |
title |
Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic |
title_short |
Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic |
title_full |
Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic |
title_fullStr |
Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic |
title_full_unstemmed |
Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic |
title_sort |
mesozooplankton graze on cyanobacteria in the amazon river plume and western tropical north atlantic |
publisher |
Frontiers Media S.A. |
publishDate |
2017 |
url |
https://doi.org/10.3389/fmicb.2017.01436 https://doaj.org/article/273b6e1e92974c599d20550aef9f66dc |
genre |
North Atlantic Copepods |
genre_facet |
North Atlantic Copepods |
op_source |
Frontiers in Microbiology, Vol 8 (2017) |
op_relation |
http://journal.frontiersin.org/article/10.3389/fmicb.2017.01436/full https://doaj.org/toc/1664-302X 1664-302X doi:10.3389/fmicb.2017.01436 https://doaj.org/article/273b6e1e92974c599d20550aef9f66dc |
op_doi |
https://doi.org/10.3389/fmicb.2017.01436 |
container_title |
PLoS ONE |
container_volume |
8 |
container_issue |
6 |
container_start_page |
e64166 |
_version_ |
1766125920753549312 |