May 22-24: Daniel Wangpraseurt attends the European Algae Biomass Association Workshop in Brussels.   Thanks to the organizers for two great workshops about potential of algae based foods in Europe!

May 22-24: Daniel Wangpraseurt attends the European Algae Biomass Association Workshop in Brussels.

Thanks to the organizers for two great workshops about potential of algae based foods in Europe!

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FINALLY OUT!    NEW PAPER IN JOURNAL OF THE ROYAL SOCIETY INTERFACE     Link

FINALLY OUT!

NEW PAPER IN JOURNAL OF THE ROYAL SOCIETY INTERFACE

Link

 
January 29    Daniel Wangpraseurt featured in Plantae.    Read it    here

January 29

Daniel Wangpraseurt featured in Plantae.

Read it here

 
NEW PAPER IN PLANT PHYSIOLOGY    JANUARY 28, 2019:    !BEWARE PAM USERS! !BEWARE PAM USERS! !BEWARE PAM USERS! !BEWARE PAM USERS!    ABSTRACT:  Pulse-amplitude–modulated (PAM) fluorimetry is widely used in photobiological studies of corals, as it rapidly provides numerous photosynthetic parameters to assess coral ecophysiology. Coral optics studies have revealed the presence of light gradients in corals, which are strongly affected by light scattering in coral tissue and skeleton. We investigated whether coral optics affects variable chlorophyll (Chl) fluorescence measurements and derived photosynthetic parameters by developing planar hydrogel slabs with immobilized microalgae and with bulk optical properties similar to those of different types of corals. Our results show that PAM-based measurements of photosynthetic parameters differed substantially between hydrogels with different degrees of light scattering but identical microalgal density, yielding deviations in apparent maximal electron transport rates by a factor of 2. Furthermore, system settings such as the measuring light intensity affected  F 0,  Fm , and  Fv / Fm  in hydrogels with identical light absorption but different degrees of light scattering. Likewise, differences in microalgal density affected variable Chl fluorescence parameters, where higher algal densities led to greater  Fv / Fm  values and relative electron transport rates. These results have important implications for the use of variable Chl fluorimetry in ecophysiological studies of coral stress and photosynthesis, as well as other optically dense systems such as plant tissue and biofilms.

NEW PAPER IN PLANT PHYSIOLOGY

JANUARY 28, 2019:

!BEWARE PAM USERS! !BEWARE PAM USERS! !BEWARE PAM USERS! !BEWARE PAM USERS!

ABSTRACT: Pulse-amplitude–modulated (PAM) fluorimetry is widely used in photobiological studies of corals, as it rapidly provides numerous photosynthetic parameters to assess coral ecophysiology. Coral optics studies have revealed the presence of light gradients in corals, which are strongly affected by light scattering in coral tissue and skeleton. We investigated whether coral optics affects variable chlorophyll (Chl) fluorescence measurements and derived photosynthetic parameters by developing planar hydrogel slabs with immobilized microalgae and with bulk optical properties similar to those of different types of corals. Our results show that PAM-based measurements of photosynthetic parameters differed substantially between hydrogels with different degrees of light scattering but identical microalgal density, yielding deviations in apparent maximal electron transport rates by a factor of 2. Furthermore, system settings such as the measuring light intensity affected F0, Fm, and Fv/Fm in hydrogels with identical light absorption but different degrees of light scattering. Likewise, differences in microalgal density affected variable Chl fluorescence parameters, where higher algal densities led to greater Fv/Fm values and relative electron transport rates. These results have important implications for the use of variable Chl fluorimetry in ecophysiological studies of coral stress and photosynthesis, as well as other optically dense systems such as plant tissue and biofilms.

 
NEW PAPER IN FRONTIERS IN MARINE SCIENCE    7 JANUARY 2019    ABSTRACT:  Crustose coralline algae (CCA) are key organisms in coral reef ecosystems, where they contribute to reef building and substrate stabilization. While ocean acidification due to increasing CO2 can affect the biology, physiology and ecology of fully developed CCA, the impacts of elevated CO2 on the early life stages of CCA are much less explored. We assessed the photosynthetic activity and growth of 10-day-old recruits of the reef-building crustose coralline alga  Porolithon  cf.  onkodes  exposed to ambient and enhanced CO2 seawater concentration causing a downward shift in pH of ∼0.3 units. Growth of the CCA was estimated using measurements of crust thickness and marginal expansion, while photosynthetic activity was studied with O2 microsensors. We found that elevated seawater CO2enhanced gross photosynthesis and respiration, but significantly reduced vertical and marginal growth of the early life stages of  P.  cf.  onkodes . Elevated CO2 stimulated photosynthesis, particularly at high irradiance, likely due to increased availability of CO2, but this increase did not translate into increased algal growth as expected, suggesting a decoupling of these two processes under ocean acidification scenarios. This study confirms the sensitivity of early stages of CCA to elevated CO2 and identifies complexities in the physiological processes underlying the decreased growth and abundance in these important coral reef builders upon ocean acidification

NEW PAPER IN FRONTIERS IN MARINE SCIENCE

7 JANUARY 2019

ABSTRACT: Crustose coralline algae (CCA) are key organisms in coral reef ecosystems, where they contribute to reef building and substrate stabilization. While ocean acidification due to increasing CO2 can affect the biology, physiology and ecology of fully developed CCA, the impacts of elevated CO2 on the early life stages of CCA are much less explored. We assessed the photosynthetic activity and growth of 10-day-old recruits of the reef-building crustose coralline alga Porolithon cf. onkodes exposed to ambient and enhanced CO2 seawater concentration causing a downward shift in pH of ∼0.3 units. Growth of the CCA was estimated using measurements of crust thickness and marginal expansion, while photosynthetic activity was studied with O2 microsensors. We found that elevated seawater CO2enhanced gross photosynthesis and respiration, but significantly reduced vertical and marginal growth of the early life stages of P. cf. onkodes. Elevated CO2 stimulated photosynthesis, particularly at high irradiance, likely due to increased availability of CO2, but this increase did not translate into increased algal growth as expected, suggesting a decoupling of these two processes under ocean acidification scenarios. This study confirms the sensitivity of early stages of CCA to elevated CO2 and identifies complexities in the physiological processes underlying the decreased growth and abundance in these important coral reef builders upon ocean acidification

 
NEW PAPER IN FEMS MICROBIOLOGY ECOLOGY:    31 OCT 2018    ABSTRACT   Microbial mats and stromatolites are widespread in Hamelin Pool, Shark Bay, however the phototrophic capacity of these systems is unknown. This study has determined the optical properties and light-harvesting potential of these mats with light microsensors. These characteristics were linked via a combination of 16S rDNA sequencing, pigment analyses and hyperspectral imaging. Local scalar irradiance was elevated over the incident downwelling irradiance by 1.5-fold, suggesting light trapping and strong scattering by the mats. Visible light (400–700 nm) penetrated to a depth of 2 mm, whereas near-infrared light (700–800 nm) penetrated to at least 6 mm. Chlorophyll  a  and bacteriochlorophyll  a  (Bchl  a ) were found to be the dominant photosynthetic pigments present, with BChl  a  peaking at the subsurface (2–4 mm). Detailed 16S rDNA analyses revealed the presence of putative Chl  f -containing  Halomicronema  sp. and photosynthetic members primarily decreased from the mat surface down to a depth of 6 mm. Data indicated high abundances of some pigments and phototrophic organisms in deeper layers of the mats (6–16 mm). It is proposed that the photosynthetic bacteria present in this system undergo unique adaptations to lower light conditions below the mat surface, and that phototrophic metabolisms are major contributors to ecosystem function.  AUTHORS:  Amy Fisher,  Daniel Wangpraseurt , Anthony Larkum, Michael Johnson, Michael Kuhl, Min Chen, HOn Lun Wong, Brendan Burns

NEW PAPER IN FEMS MICROBIOLOGY ECOLOGY:

31 OCT 2018

ABSTRACT

Microbial mats and stromatolites are widespread in Hamelin Pool, Shark Bay, however the phototrophic capacity of these systems is unknown. This study has determined the optical properties and light-harvesting potential of these mats with light microsensors. These characteristics were linked via a combination of 16S rDNA sequencing, pigment analyses and hyperspectral imaging. Local scalar irradiance was elevated over the incident downwelling irradiance by 1.5-fold, suggesting light trapping and strong scattering by the mats. Visible light (400–700 nm) penetrated to a depth of 2 mm, whereas near-infrared light (700–800 nm) penetrated to at least 6 mm. Chlorophyll a and bacteriochlorophyll a (Bchl a) were found to be the dominant photosynthetic pigments present, with BChl a peaking at the subsurface (2–4 mm). Detailed 16S rDNA analyses revealed the presence of putative Chl f-containing Halomicronema sp. and photosynthetic members primarily decreased from the mat surface down to a depth of 6 mm. Data indicated high abundances of some pigments and phototrophic organisms in deeper layers of the mats (6–16 mm). It is proposed that the photosynthetic bacteria present in this system undergo unique adaptations to lower light conditions below the mat surface, and that phototrophic metabolisms are major contributors to ecosystem function.

AUTHORS:

Amy Fisher, Daniel Wangpraseurt, Anthony Larkum, Michael Johnson, Michael Kuhl, Min Chen, HOn Lun Wong, Brendan Burns

NEW PAPER IN SCIENCE ADVANCES    26 SEP 2018

NEW PAPER IN SCIENCE ADVANCES

26 SEP 2018

 
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New preprint

july 26 2018

New preprint now available on biorxiv.org “Microscale light management and inherent optical properties of intact corals studied with optical coherence tomography” Coral reefs are highly productive photosynthetic systems and coral optics studies suggest that such high efficiency is due to optimised light scattering by coral tissue and skeleton. Here, we characterise the inherent optical properties, i.e., the scattering coefficient, μs, and the anisotropy of scattering, g, of 8 intact coral species using optical coherence tomography (OCT). Specifically, we describe light scattering by coral skeletons, coenoarc tissues, polyp tentacles and areas covered by fluorescent pigments (FP). Our results reveal that light scattering between coral species ranges from μs = 3 mm-1 (Stylophora pistillata) to μs = 25 mm-1 (Echinopora lamelosa). For Platygyra pini, μs was 10-fold higher for tissue vs skeleton, while in other corals (e.g., Hydnophora pilosa) no difference was found between tissue and skeletal scattering. Tissue scattering was 3-fold enhanced in coenosarc tissues (μs = 24.6 mm-1) vs polyp tentacles (μs = 8.3 mm-1) in Turbinaria reniformis. FP scattering was almost isotropic when FP were organized in granule chromatophores (g=0.34) but was forward directed when FP were distributed diffusely in the tissue (g=0.96). Our study provides detailed measurements of coral scattering and establishes a rapid approach for characterising optical properties of photosynthetic soft tissues via OCT in vivo.

Authors: Daniel WangpraseurtSteven L Jacques, Niclas Lyndby, Jacob B Holm, Christine Ferrier Pages, Michael Kuhl

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August 28: New manuscript submitted:

Title: “Elevated CO2 leads to enhanced photosynthesis but decreased growth in early life stages of reef building coralline algae”

Alexandra Ordoñez,Daniel Wangpraseurt, Niclas Lyndby, Michael Kühl, and Guillermo Diaz-Pulido.

 

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July 28: New manuscript submitted:

Title: “Correlation of bio-optical properties with photosynthetic pigment and microorganism distribution in stromatolites from Hamelin Pool, Australia”
Authors: Fisher, Amy; Wangpraseurt, Daniel; Larkum, Anthony; Johnson, Michael; Kühl, Michael; Wong, Hon; Chen, Min; Burns, Brendan

New pre-print July 26

New pre-print July 26

July, 2018: New preprint on Bio-optical properties and radiative energy budgets in fed and starved scleractinian corals (Pocillopora damicornis) during thermal bleaching in collaboration with researchers from the micro-ecology group at the University of Copenhagen and the coral group at the Centre of Scientifique de Monaco. The study uses optical coherence tomography to characterize the optical properties of intact corals.

Public news coverage: The preprint is featured in OCT news.

Details:

Bio-optical properties and radiative energy budgets in fed and starved scleractinian corals (Pocillopora damicornis) during thermal bleaching

Daniel Wangpraseurt, Steven L Jacques, Niclas Lyndby, Jacob B Holm, Christine Ferrier Pages, Michael Kuhl

NEW PUBLICATION MAY 14

NEW PUBLICATION MAY 14

MAY 14, 2018: Frommlett, Wangpraseurt and co-authors publish in Frontiers in Microbiology on mechanisms underlying ‘Symbiolite’ formation. Symbiolites are aragonitic microbialites that incorporate Symbiodinium as endolithic cells. The first report of Symbiodinium (i.e. symbiotic microalgae) calcification outside of the coral host was an unexpected discovery (see PNAS paper). The new study now suggests that this calcification process is tightly controlled by the physico-chemical microenviroment and the structure of the developing biofilm. The research uses Ca2+ microsensors to study single cell calcification. The study sheds new fundamental research in microalgal calcification which has also applications for the construction of hybrid living calcifying photosynthetic structures.

Details: Frommlet JC*, Wangpraseurt D*, Sousa ML, Guimarães B, da Silva MM, Kühl M, Serôdio J. Symbiodinium-induced formation of microbialites: Mechanistic insights from in vitro experiments and the prospect of its occurrence in nature. Frontiers in Microbiology. 2018;9. *shared first author


NEW PUBLICATION APRIL 19

NEW PUBLICATION APRIL 19

April 19, 2018: New paper published in New Phytologist on “Structure-based optics of centric diatom frustules: modulation of the in vivo light field for efficient diatom photosynthesis” by Goessling J, Su Y, Cartaxana PI, Maibohm C, Rickelt LF< Trampe ECL, Walby SL, Wangpraseurt D, Wu X, Ellegaard M, Kuhl M. The paper demonstrates that the optical properties of the frustule valves in water affect light harvesting and photosynthesis in live cells of centric diatoms (Coscinodiscus granii). Microscale cellular mapping of photosynthesis around localized spot illumination demonstrated optical coupling of chloroplasts to the valve wall. Photonic structures of the three-layered C. granii valve facilitated light redistribution and efficient photosynthesis in cell regions distant from the directly illuminated area. The different porous structure of the two sides of the valve exhibited photon trapping and forward scattering of blue light enhancing photosynthetic active radiation inside the cell. The publication highlights the importance of diatom frustule morphology for diatom photosynthesis.

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APRIL 1 2018

Noah Martin (UC Berkeley) and Tatum Bernat (UCLA) join the biomicfuel team. Noah and Tatum will be working on the development of Bio-inspired algal-bacterial hydrogels for space efficeint microalgal growth.

 

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Cambridge University, April 13, 2018

Cambridge University, April 13, 2018

aPRIL 11-14, 2018 living light conference, cambridge, uk

APRIL 13, 2018: Daniel Wangpraseurt gives a talk on ‘3D bioprinted photosynthetic matter inspired by corals’. The talk is co-authored by an international research group from the University of Cambridge, the University of California San Diego and the University of Copenagen. The abstract booklet can be found here.

Living light 2018 is organised by the Vignolini lab. Living light is a biennial interdisciplinary conference focusing on light-matter interaction in living organisms. Following the 2016's success at the Scripps Research Institute, the next conference will take place in Cambridge, United Kingdom from the 11th to 14th of April 2018. We invite everyone with an interest in light in living organisms to participate. The conference topics covers (without being limited to):

  • Biological photonic structures

  • Optics of natural materials

  • Development and evolution of structural colouration in nature

  • Bio-photoluminescence

  • Ecology and biochemistry of structural colour in nature

The conference report written by Olimpia Onelli et al. (2018) is published in Biomimetics.

 

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NEW PUBLICATION: FEBRUARY 19, 2018

NEW PUBLICATION: FEBRUARY 19, 2018

FEBRUARY 19: Researcheres from the University of Copenhagen, Ringhospitalet Copnhagen and Cambridge University develop an alginate bead model that mimics chronic bacterial infections. The study is published NPJ Biofilms and Microbiomes. The developed model system is suitable for testing antiomicrobial susceptibility and tolerance of bacterial strains causing chronic infections. The study also developed new approaches that combine Optical coherence tomography imaging, confocal imaging and microsensor technology to characterise the non-invasive rapid development of bacterial aggregates and biofilms. Such model systems are now optimized for efficient algal-bacterial co-culture.

Publication details:

Sønderholm M, Koren K, Wangpraseurt D, Jensen PØ, Kolpen M, Kragh KN, Bjarnsholt T, Kühl M. Tools for studying growth patterns and chemical dynamics of aggregated Pseudomonas aeruginosa exposed to different electron acceptors in an alginate bead model. NPJ biofilms and microbiomes. 2018 Feb 19;4(1):3.

Public news coverage:

Video by Prof Thomas Bjarsnholt (University of Copenhhagen):

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January 18, 2018 gordon research conference, ventura, usa

JANUARY 18, 2018: Daniel Wangpraseurt presenting his work on coral-inspired photosynthetic matter at the Gordon Research Conference for Multifunctional Materials and Structures in Venutra, California. The conference focusses on addressing the scientific issues underpinning advancements in: the translation of model biological functions to synthetic systems, signaling (e.g. chemical, electrical, mechanical), self-learning, chemical transport and transformation for control of mechanical properties, the role of interfaces and design/fabrication approaches for creating multi-scale hierarchical material systems with multifunctional performance. The conference program and furher can be found here.