Introduction and Overview

Kirchman, David L.

doi:10.1002/9780470281840.ch1

Cited by 64 publications

(78 citation statements)

References 56 publications

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“…A fraction of this organic material is released into the 30 surrounding environment as dissolved organic matter (DOM), where it supports microbial 31 growth or is respired to carbon dioxide (del Giorgio and Cole, 1998; Kirchman, 2008). The rates 32 of utilization or remineralization of individual compounds are determined by their structure, 33 concentration, and the metabolic properties of ambient microorganisms (Azam and Worden, 34 2004).…”

Section: Introduction 28mentioning

confidence: 99%

Dissolved organic matter produced by Thalassiosira pseudonana

2015

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13Phytoplankton are significant producers of dissolved organic matter (DOM) in marine 14 ecosystems but the identity and dynamics of this DOM remain poorly constrained. Knowledge 15 on the identity and dynamics of DOM are crucial for understanding the molecular-level reactions 16 at the base of the global carbon cycle. Here we apply emerging analytical and computational 17 tools from metabolomics to investigate the composition of DOM produced by the centric diatom 18 Thalassiosira pseudonana. We assessed both intracellular metabolites within T. pseudonana (the 19 endo-metabolome) and extracellular metabolites released by T. pseudonana (the exo-20 metabolome). The intracellular metabolites had a more variable composition than the 21 extracellular metabolites. We putatively identified novel compounds not previously associated 22 with T. pseudonana as well as compounds that have previously been identified within T. 23 pseudonana's metabolic capacity (e.g. dimethylsulfoniopropionate and degradation products of 24 chitin). The resulting information will provide the basis for future experiments to assess the 25 impact of T. pseudonana on the composition of dissolved organic matter in marine 26 environments. 27 3

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Section: Introduction 28mentioning

confidence: 99%

Dissolved organic matter produced by Thalassiosira pseudonana

2015

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“…Their impact on marine food webs increases with increasing oligotrophy (Kirchman, 2008), with heterotrophic bacterial biomass equaling or even exceeding that of phytoplankton (Furhman et al, 1989;Cho & Azam, 1990;Gasol et al, 1997;Duarte et al, 2000). Heterotrophic bacteria and phytoplankton communities interact in very complex ways (Azam & Malfatti, 2007), but both the biomass and production of heterotrophic bacteria usually covary with those of phytoplankton (Bird & Kalff, 1984;Cole et al, 1988;Simon et al, 1992;.…”

Section: Introductionmentioning

confidence: 99%

Heterotrophic bacterial responses to the winter–spring phytoplankton bloom in open waters of the NW Mediterranean

Gomes

Gasol

Estrada

et al. 2015

Deep Sea Research Part I: Oceanographic Research Papers

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. were temporally opposite in the study periods, with maxima in March and September, respectively. Different relationships were found between physiological structure and bottom-up variables, with HNA bacteria apparently more responsive to phytoplankton only during the bloom, coinciding with larger average cell sizes of LNA bacteria.Moderate phytoplankton-bacterioplankton coupling of biomass and activity was only observed in the bloom and post-bloom phases, while relationships between both compartments were not significant under stratification. With all data pooled, bacteria were only weakly bottom-up controlled. Our analyses show that the biomass and 3 production of planktonic algae and bacteria followed opposite paths in the transition from bloom to oligotrophic conditions.

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“…There is no parsimonious resolution to this apparent dichotomy. Current work on prokaryote genomics highlights the enormous metabolic diversity that can exist within aqueous habitats (14), requiring us to consider numerous different forms of cell membrane, and to explore the ways in which both their organic and inorganic products as well as their metabolic pathways may yet be discovered in the geological record (Fig. S3).…”

Section: The Gunflint Chert: New Analytical Techniquesmentioning

confidence: 99%

Changing the picture of Earth's earliest fossils (3.5–1.9 Ga) with new approaches and new discoveries

Brasier

Antcliffe

Saunders

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

146

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New analytical approaches and discoveries are demanding fresh thinking about the early fossil record. The 1.88-Ga Gunflint chert provides an important benchmark for the analysis of early fossil preservation. High-resolution analysis of Gunflintia shows that microtaphonomy can help to resolve long-standing paleobiological questions. Novel 3D nanoscale reconstructions of the most ancient complex fossil Eosphaera reveal features hitherto unmatched in any crown-group microbe. While Eosphaera may preserve a symbiotic consortium, a stronger conclusion is that multicellular morphospace was differently occupied in the Paleoproterozoic. The 3.46-Ga Apex chert provides a test bed for claims of biogenicity of cell-like structures. Mapping plus focused ion beam milling combined with transmission electron microscopy data demonstrate that microfossil-like taxa, including species of Archaeoscillatoriopsis and Primaevifilum, are pseudofossils formed from vermiform phyllosilicate grains during hydrothermal alteration events. The 3.43-Ga Strelley Pool Formation shows that plausible early fossil candidates are turning up in unexpected environmental settings. Our data reveal how cellular clusters of unexpectedly large coccoids and tubular sheath-like envelopes were trapped between sand grains and entombed within coatings of dripstone beach-rock silica cement. These fossils come from Earth’s earliest known intertidal to supratidal shoreline deposit, accumulated under aerated but oxygen poor conditions.

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Introduction and Overview

Cited by 64 publications

References 56 publications

Dissolved organic matter produced by Thalassiosira pseudonana

Dissolved organic matter produced by Thalassiosira pseudonana

Heterotrophic bacterial responses to the winter–spring phytoplankton bloom in open waters of the NW Mediterranean

Changing the picture of Earth's earliest fossils (3.5–1.9 Ga) with new approaches and new discoveries

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