Diatom Derived Polyunsaturated Aldehydes Do Not Structure the Planktonic Microbial Community in a Mesocosm Study

Paul, Carsten; Reunamo, Anna; Lindehoff, Elin; Bergkvist, Johanna; Mausz, Michaela A.; Larsson, Henrik; Richter, Hannes; Wängberg, Sten-Åke; Leskinen, Piia; Båmstedt, Ulf; Pohnert, Georg

doi:10.3390/md10040775

Cited by 28 publications

(25 citation statements)

References 44 publications

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“…In contrast to our 100 μM results, recent work by Paul et al (42) concluded that PUAs do not impact the structure of freeliving bacterial communities. However, these investigators examined the effects of individual PUAs at nanomolar concentrations, and it is possible that nanomolar concentrations simply do not affect community structure, whereas micromolar concentrations do.…”

Section: Discussioncontrasting

confidence: 56%

Dose-dependent regulation of microbial activity on sinking particles by polyunsaturated aldehydes: Implications for the carbon cycle

Edwards

Bidle

Mooy

2015

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

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Diatoms and other phytoplankton play a crucial role in the global carbon cycle, fixing CO 2 into organic carbon, which may then be exported to depth via sinking particles. The molecular diversity of this organic carbon is vast and many highly bioactive molecules have been identified. Polyunsaturated aldehydes (PUAs) are bioactive on various levels of the marine food web, and yet the potential for these molecules to affect the fate of organic carbon produced by diatoms remains an open question. In this study, the effects of PUAs on the natural microbial assemblages associated with sinking particles were investigated. Sinking particles were collected from 150 m in the water column and exposed to varying concentrations of PUAs in dark incubations over 24 h. PUA doses ranging from 1 to 10 μM stimulated respiration, organic matter hydrolysis, and cell growth by bacteria associated with sinking particles. PUA dosages near 100 μM appeared to be toxic, resulting in decreased bacterial cell abundance and metabolism, as well as pronounced shifts in bacterial community composition. Sinking particles were hot spots for PUA production that contained concentrations within the stimulatory micromolar range in contrast to previously reported picomolar concentrations of these compounds in bulk seawater. This suggests PUAs produced in situ stimulate the remineralization of phytoplankton-derived sinking organic matter, decreasing carbon export efficiency, and shoaling the average depths of nutrient regeneration. Our results are consistent with a "bioactivity hypothesis" for explaining variations in carbon export efficiency in the oceans. polyunsaturated aldehydes | sinking particles | particle-associated bacteria | marine carbon cycle | bioactivity hypothesis

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Section: Discussioncontrasting

confidence: 56%

Dose-dependent regulation of microbial activity on sinking particles by polyunsaturated aldehydes: Implications for the carbon cycle

Edwards

Bidle

Mooy

2015

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

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“…In contrast to our 100 µM results, recent work by Paul et al concluded that PUAs do not impact the structure of free living bacterial communities (Paul and al, 2012). However, these investigators examined the effects of individual PUAs at nanomolar concentrations, and it is possible that nanomolar concentrations simply do not affect community structure, while micromolar concentrations do.…”

contrasting

confidence: 53%

The biogeochemistry of lipid derived infochemical signals in the ocean

Edwards¹

2016

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“…Our H1 is hence rejected. Similarly, in a natural system, no significant changes in Chl were observed in PUA vs. control treatments (Paul et al 2012). Depending on the amount of PUA produced and released in the water, cells can develop resistance to successive exposure or undergo cell lysis (Vidoudez and Pohnert 2008).…”

Section: Microplankton Responsementioning

confidence: 97%

Diatom‐produced allelochemicals trigger trophic cascades in the planktonic food web

Franzè

Pierson

Stoecker

et al. 2017

Limnology & Oceanography

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Diatoms produce a series of cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA) in response to cell injury or stress. However, little information exists on the PUA effects on the pelagic food web. A set of experiments was conducted in the Chesapeake Bay and the coastal Atlantic waters using dissolved PUA (2E,4E-octadienal and 2E,4E-heptadienal), natural assemblages of phytoplankton and microzooplankton, and the copepod Acartia tonsa. The results demonstrate that PUA primarily acts as deterrent for microzooplankton herbivory on diatoms, while enhancing herbivory on picophytoplankton. This switch should favor PUA-producing diatoms by simultaneously reducing direct grazing losses and competition. Additionally, PUA stimulated copepod predation on microzooplankton, particularly on ciliates. Combined, these effects have the potential to disrupt growth-grazing equilibrium in the pelagic food web and create an opportunity for bloom development.

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Diatom Derived Polyunsaturated Aldehydes Do Not Structure the Planktonic Microbial Community in a Mesocosm Study

Cited by 28 publications

References 44 publications

Dose-dependent regulation of microbial activity on sinking particles by polyunsaturated aldehydes: Implications for the carbon cycle

Dose-dependent regulation of microbial activity on sinking particles by polyunsaturated aldehydes: Implications for the carbon cycle

The biogeochemistry of lipid derived infochemical signals in the ocean

Diatom‐produced allelochemicals trigger trophic cascades in the planktonic food web

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