Siderophores in marine coastal waters and their relevance for iron uptake by phytoplankton: experiments with the diatom Phaeodactylum tricornutum

Soria-Dengg, S.; Reissbrodt, Rolf; Horstmann, Ulrich

doi:10.3354/meps220073

Cited by 42 publications

(32 citation statements)

References 41 publications

(43 reference statements)

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“…Bacteria produce and excrete siderophores, which scavenge iron. Diatoms are not known to produce siderophores, but genome sequence analyses identified the presence of a gene orthologue of a bacterial ferrichrome binding protein that suggests the possibility of iron (III)-siderophore utilization by P. tricornutum [56,57]. Furthermore, it was shown that P. tricornutum was able to uptake siderophores ferrioxamines B and E [58].…”

Section: Network Of Putative Interactions Between Phaeodactylum Tricomentioning

confidence: 99%

Dynamics of the Bacterial Community Associated with Phaeodactylum tricornutum Cultures

et al. 2017

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Abstract:The pennate diatom Phaeodactylum tricornutum is a model organism able to synthesize industrially-relevant molecules. Commercial-scale cultivation currently requires large monocultures, prone to bio-contamination. However, little is known about the identity of the invading organisms. To reduce the complexity of natural systems, we systematically investigated the microbiome of non-axenic P. tricornutum cultures from a culture collection in reproducible experiments. The results revealed a dynamic bacterial community that developed differently in "complete" and "minimal" media conditions. In complete media, we observed an accelerated "culture crash", indicating a more stable culture in minimal media. The identification of only four bacterial families as major players within the microbiome suggests specific roles depending on environmental conditions. From our results we propose a network of putative interactions between P. tricornutum and these main bacterial factions. We demonstrate that, even with rather sparse data, a mathematical model can be reconstructed that qualitatively reproduces the observed population dynamics, thus indicating that our hypotheses regarding the molecular interactions are in agreement with experimental data. Whereas the model in its current state is only qualitative, we argue that it serves as a starting point to develop quantitative and predictive mathematical models, which may guide experimental efforts to synthetically construct and monitor stable communities required for robust upscaling strategies.

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Section: Network Of Putative Interactions Between Phaeodactylum Tricomentioning

confidence: 99%

Dynamics of the Bacterial Community Associated with Phaeodactylum tricornutum Cultures

et al. 2017

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“…Iron limitation of bacterial productivity is the subject of debate (Pakulski et al, 1996;Kirchman et al, 2000), however it is known that in order to aid iron acquisition, some heterotrophic bacteria produce siderophores, which are high affinity iron(III) binding ligands (Neilands, 1995). Several marine siderophores have been characterised (Trick et al, 1983;Haygood et al, 1993;Reid et al, 1993;Martinez et al, 2000;Martinez et al, 2001;Martinez et al, 2003), and their production is ubiquitous in marine bacterial isolates (Trick, 1989;Trick and Kerry, 1992;Haygood et al, 1993;Soria-Dengg and Reissbrodt, 2001). However the presence of siderophores in seawater has not been directly confirmed, although siderophore type chelating groups have been detected in extracts isolated from seawater (Macrellis et al, 2001) and siderophores are known to have similar binding strengths to natural ligands detected in seawater (Rue and Bruland, 1995;Lewis et al, 1995;van den Berg, 1997;Gledhill et al, 1998;Witter et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Production of siderophore type chelates by mixed bacterioplankton populations in nutrient enriched seawater incubations

Gledhill

2004

Marine Chemistry

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Siderophore type chelates were isolated from nutrient enriched seawater collected from coastal and near shore environments and detected using a novel high performance liquid chromatography -electrospray ionisationmass spectrometric technique. Seawater was enriched with added glucose, ammonia and phosphate, and incubated for four days. Seven different siderophore type compounds were detected in the extracted supernatants and tentatively identified based on mass numbers and spectra. The compounds comprised two groups, the ferrioxamines and the amphibactins. They were produced at typical coastal iron concentrations (total dissolved iron = 2.9 ± 1.4 2 nM and 2.2 ± 0.1 nM) both in the presence and absence of the iron chelating ligand ethylene diamine-N,N′-diacetic acid.

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“…A nighttime decrease in nitrate uptake was more pronounced than the decrease in ammonium uptake (15-16% and 30-36% of the daylight rates, respectively). Iron uptake may also be highly light dependent: the diatom Phaeodactylum tricornutum had higher iron uptake rates during the light period (Soria-Dengg et al 2001).…”

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confidence: 99%

Phytoplankton nutrient competition under dynamic light regimes

Litchman

Klausmeier

Bossard

2004

Limnology & Oceanography

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Many physiological processes in phytoplankton, including nutrient uptake, vary on a number of temporal scales. Experiments show that the daily cycle in irradiance affects nutrient uptake rates. We used a Droop-based model of resource competition to investigate how diel variability in nutrient uptake influences phytoplankton competition and community structure. The analytical approximation we derive shows that if nutrient uptake is light dependent, the minimum nutrient requirements and, hence, nutrient competitive abilities depend on light regime in a species-specific way. Consequently, daily variations in irradiance may slow rates of competitive exclusion or reverse the identity of the superior competitor but not allow stable coexistence. Irradiance-induced fluctuations in the maximum nutrient uptake rate of the superior competitor can lead to fluctuations in ambient nutrient concentration and an increase in the average nutrient concentration compared to constant light conditions. This can enhance nutrient use by inferior competitors. These results may be applicable to bacteria-phytoplankton nutrient competition as well. Depending on the costs and benefits of maintaining nutrient uptake in the dark, different strategies of nutrient use are optimal under different light regimes. Our results suggest that by mediating limiting nutrient use, fluctuations in irradiance may alter the structure of phytoplankton communities.In aquatic systems, physical forcing and biotic responses are tightly coupled (Steele and Henderson 1994). Major ecological interactions such as competition and predation are affected by environmental fluctuations. Light is an important environmental factor and an essential resource for phytoplankton that fluctuates on multiple temporal scales. Previously we have demonstrated that daily and seasonal light fluctuations significantly affect phytoplankton competition for light (Litchman and Klausmeier 2001). However, in many aquatic systems phytoplankton compete not for light but for nutrients. A substantial body of literature indicates that nutrient uptake rates depend on many environmental factors including light. It is, therefore, likely that light fluctuations can mediate nutrient competition among phytoplankton. Here we explore how variation in the uptake rates of the limiting nutrient modifies resource competition in phytoplankton.Numerous experimental studies have shown that uptake of many essential nutrients by phytoplankton depends on irradiance. Frequently, the uptake rates are lower in the dark. Riegman et al. (2000) showed that nitrogen (N) uptake of Emiliania huxleyi in the dark was 30% of the uptake rate in the light. Phosphorus (P) uptake in the dark was also lower than in the light, and the greatest difference between the uptake rates was for the lowest growth rate.The maximum nutrient uptake rate (V max ) usually exhibits a much stronger light dependence than the half-saturation

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Siderophores in marine coastal waters and their relevance for iron uptake by phytoplankton: experiments with the diatom Phaeodactylum tricornutum

Cited by 42 publications

References 41 publications

Dynamics of the Bacterial Community Associated with Phaeodactylum tricornutum Cultures

Dynamics of the Bacterial Community Associated with Phaeodactylum tricornutum Cultures

Production of siderophore type chelates by mixed bacterioplankton populations in nutrient enriched seawater incubations

Phytoplankton nutrient competition under dynamic light regimes

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