| 1. |
- Temmink, R. J. M., et al.
(author)
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Mimicry of emergent traits amplifies coastal restoration success
- 2020
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Journal article (peer-reviewed)abstract
- Restoration is becoming a vital tool to counteract coastal ecosystem degradation. Modifying transplant designs of habitat-forming organisms from dispersed to clumped can amplify coastal restoration yields as it generates self-facilitation from emergent traits, i.e. traits not expressed by individuals or small clones, but that emerge in clumped individuals or large clones. Here, we advance restoration science by mimicking key emergent traits that locally suppress physical stress using biodegradable establishment structures. Experiments across (sub)tropical and temperate seagrass and salt marsh systems demonstrate greatly enhanced yields when individuals are transplanted within structures mimicking emergent traits that suppress waves or sediment mobility. Specifically, belowground mimics of dense root mats most facilitate seagrasses via sediment stabilization, while mimics of aboveground plant structures most facilitate marsh grasses by reducing stem movement. Mimicking key emergent traits may allow upscaling of restoration in many ecosystems that depend on self-facilitation for persistence, by constraining biological material requirements and implementation costs.
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| 2. |
- van der Heide, T., et al.
(author)
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Coastal restoration success via emergent trait-mimicry is context dependent
- 2021
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In: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 264
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Journal article (peer-reviewed)abstract
- Coastal ecosystems provide vital ecosystem functions and services, but have been rapidly degrading due to human impacts. Restoration is increasingly considered key to reversing these losses, but is often unsuccessful. Recent work on seagrasses and salt marsh cordgrasses highlights that restoration yields can be greatly enhanced by temporarily mimicking key emergent traits. These traits are not expressed by individual seedlings or small clones, but emerge in clumped individuals or large clones to locally suppress environmental stress, causing establishment thresholds where such density-dependent self-facilitation is important for persistence. It remains unclear, however, to what extent the efficacy of restoration via emergent trait-based mimicry depends on the intensity of stressors. We test this in a restoration experiment with the temperate seagrass Zostera marina at four sites (Finland, Sweden, UK, USA) with contrasting hydrodynamic regimes, where we simulated dense roots mats or vegetation canopies with biodegradable structural mimics. Results show that by mimicking sediment-stabilizing root mats, seagrass transplant survival, growth and expansion was strongly enhanced in hydrodynamically exposed environments. However, these positive effects decreased and turned negative under benign conditions, while mimics insufficiently mitigated physical stress in extremely exposed environments, illustrating upper and lower limits of the application. Furthermore, we found that aboveground structures, designed to mimic stiff rather than flexible vegetation canopies, underperformed compared to belowground mimics. Our findings emphasize the importance of understanding the conditions at the restoration site, species-specific growth requirements, and self-facilitating traits that organisms may express when applying emergent trait-mimicry as a tool to improve restoration success. © 2021 The Authors
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| 3. |
- Brodu, Annalisa, et al.
(author)
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Exciton Fine Structure and Lattice Dynamics in InP/ZnSe Core/Shell Quantum Dots
- 2018
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In: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 5:8, s. 3353-3362
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Journal article (peer-reviewed)abstract
- Nanocrystalline InP quantum dots (QDs) hold promise for heavy-metal-free optoelectronic applications due to their bright and size tunable emission in the visible range. Photochemical stability and high photoluminescence (PL) quantum yield are obtained by a diversity of epitaxial shells around the InP core. To understand and optimize the emission line shapes, the exciton fine structure of InP core/shell QD systems needs be investigated. Here, we study the exciton fine structure of InP/ZnSe core/shell QDs with core diameters ranging from 2.9 to 3.6 nm (PL peak from 2.3 to 1.95 eV at 4 K). PL decay measurements as a function of temperature in the 10 mK to 300 K range show that the lowest exciton fine structure state is a dark state, from which radiative recombination is assisted by coupling to confined acoustic phonons with energies ranging from 4 to 7 meV, depending on the core diameter. Circularly polarized fluorescence line-narrowing (FLN) spectroscopy at 4 K under high magnetic fields (up to 30 T) demonstrates that radiative recombination from the dark F = +/- 2 state involves acoustic and optical phonons, from both the InP core and the ZnSe shell. Our data indicate that the highest intensity FLN peak is an acoustic phonon replica rather than a zero-phonon line, implying that the energy separation observed between the F = +/- 1 state and the highest intensity peak in the FLN spectra (6 to 16 meV, depending on the InP core size) is larger than the splitting between the dark and bright fine structure exciton states.
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| 4. |
- Lakhwani, Girish, et al.
(author)
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Intensive Chiroptical Properties of Chiral Polyfluorenes Associated with Fibril Formation
- 2009
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In: Journal of Physical Chemistry B. - : American Chemical Society. - 1520-6106 .- 1520-5207. ; 113:43, s. 14047-14051
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Journal article (peer-reviewed)abstract
- Thin films of chiral poly {9,9-bis[(3S)-3,7-dimethyloctyl]-2,7-fluorene} (1) were studied using circular dichroism (CD) spectroscopy. Films spin coated from chloroform solution, show CD with a degree of polarization g(abs) (= +4 x 10(-4) at 400 nm) that is independent of film thickness (50-290 nm). This implies that gabs is an intensive property of the material and related to the chiral organization of the molecules on a length scale less than 50 nm. Atomic force microscopy (AFM) on the films reveals fibrils. Addition of nonsolvent methanol to a solution of 1 in chloroform leads to fibril formation in solution and results in CD similar in band shape to that of the pristine spin coated films from chloroform solution and a g(abs) comparable in magnitude. Thus the chiral molecular arrangement leading to circular dichroism is part of the internal structure of these fibrils.
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