Microsensor measurements of oxygen concentration profiles, and computer-simulated concentration profiles of oxygen, ammonium and nitrate oxygen in Trichodesmium colonies

Trichodesmium is an important dinitrogen (N~2~)-fixing cyanobacterium in marine ecosystems. Recent nucleic acid analyses indicate that Trichodesmium colonies with their diverse epibionts support various nitrogen (N) transformations beyond N~2~-fixation. However, rates of these transformations and concentration gradients of N-compounds in Trichodesmium colonies remain largely unresolved. We combined isotope-tracer incubations, micro-profiling, and numeric modelling to explore carbon fixation, N-cycling processes, as well as oxygen, ammonium and nitrate concentration gradients in individual field-sampled Trichodesmium colonies. Colonies were net-autotrophic, with carbon and N~2~-fixation occurring mostly at day-time. Ten percent of the fixed N was released as ammonium after 12-hour incubations. Nitrification was not detectable but nitrate consumption was high when nitrate was added. The consumed nitrate was partly reduced to ammonium, while denitrification was insignificant. Thus, the potential N-transformation network was characterized by fixed N gain and recycling processes rather than denitrification. Oxygen concentrations within colonies were 60–200% air-saturation. Moreover, our modelling predicted steep concentration gradients, with up to 6-fold higher ammonium concentrations, and nitrate depletion in the colony centre compared to the ambient seawater. These gradients created a chemically heterogeneous microenvironment, presumably facilitating diverse microbial metabolisms in millimetre-sized Trichodesmium colonies.

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Cite this as

Klawonn, Isabell, Eichner, Meri, Wilson, Samuel T, Moradi, Nasrollah, Thamdrup, Bo, Kümmel, Steffen, Gehre, Matthias, Khalili, Arzhang, Grossart, Hans-Peter, Karl, Dave, Ploug, Helle (2019). Dataset: Microsensor measurements of oxygen concentration profiles, and computer-simulated concentration profiles of oxygen, ammonium and nitrate oxygen in Trichodesmium colonies. https://doi.org/10.1594/PANGAEA.907637

DOI retrieved: 2019

Additional Info

Field Value
Imported on November 29, 2024
Last update November 30, 2024
License CC-BY-4.0
Source https://doi.org/10.1594/PANGAEA.907637
Author Klawonn, Isabell
Given Name Isabell
Family Name Klawonn
More Authors
Eichner, Meri
Wilson, Samuel T
Moradi, Nasrollah
Thamdrup, Bo
Kümmel, Steffen
Gehre, Matthias
Khalili, Arzhang
Grossart, Hans-Peter
Karl, Dave
Ploug, Helle
Source Creation 2019
Publication Year 2019
Resource Type text/tab-separated-values - filename: Klawonn-etal_2019
Subject Areas
Name: Biosphere

Name: Ecology

Related Identifiers
Title: Distinct nitrogen cycling and steep chemical gradients in Trichodesmium colonies
Identifier: https://doi.org/10.1038/s41396-019-0514-9
Type: DOI
Relation: IsSupplementTo
Year: 2020
Source: The ISME Journal
Authors: Klawonn Isabell , Eichner Meri J , Wilson Samuel T , Moradi Nasrollah , Thamdrup Bo , Kümmel Steffen , Gehre Matthias , Khalili Arzhang , Grossart Hans-Peter , Karl David Michael , Ploug Helle .